Search

Recent research suggests that long-interval intracortical inhibition (LICI) is followed by a transitory period of late cortical disinhibition (LCD) that can even lead to a net increase in cortical excitability. The relationship between LICI/LCD and voluntary drive remains poorly understood. Our study aims at investigating the influence of index abduction on LICI and LCD in an actively engaged muscle and a neighboring muscle, while varying the intensity of the conditioning stimulus (CS). Motor-evoked potentials (MEPs) were recorded from the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles in 13 subjects. Paired-pulses were delivered with 10 different interstimulus intervals (ranging from 60 to 290 ms). Whatever the condition (relaxed or active FDI), the test stimulus was set to evoke an MEP of 1 mV. The time course of conditioned MEP amplitude was compared for relaxed and active conditions when the CS intensity was set to (i) 130% of the rest motor threshold (RMT) or (ii) to evoke the same size of MEP under both conditions. LICI lasted longer (i.e. disinhibition occurred later) at rest than during abduction when evoked either by similar or matched conditioning stimuli. No post-LICI facilitation was observed at rest – even when the CS intensity was set to 160% RMT. In contrast, long-interval intracortical facilitation (LICF) was observed in the quiescent ADM when FDI was active. LICF may then be associated with voluntary activity albeit with lack of topographic specificity. [ABSTRACT FROM AUTHOR]

Objective To compare the diagnostic accuracy of standard (st) and long-term video (lt) EEG in elderly patients with suspected non-convulsive seizures. Methods Over a 12-month period, we prospectively included all elderly (over-65) hospitalized patients having undergone lt-EEG for suspected non-convulsive seizures ( n = 43). st-EEG was defined as the first 20 min of each lt-EEG. We recorded the patients’ clinical and imaging characteristics and final diagnosis and assessed the respective diagnostic values of st-EEG and lt-EEG. Results Epileptiform discharges were detected on standard EEG in only 7% of patients and in 28% of patients on Lt-EEG ( p = 0.004). Non-convulsive seizures were recorded in 1 case vs. 4, respectively. Nine of 40 negative standard EEG showed later epileptiform activities. The median time to occurrence of the first epileptiform activities was 46.5 min (interquartile range: 36.5–239.75 min). Epileptiform activity occurred during sleep only in 33% patients with a negative st-EEG. Dementia was associated with a positive lt-EEG ( p :0.047). Conclusion Lt-EEG was clearly superior to standard EEG for detecting epileptiform activity in elderly when suspecting non convulsive seizures. Significance St-EEG has a low diagnostic yield in elderly patients with suspected non-convulsive seizures and so lt-EEG is preferable in this situation. [ABSTRACT FROM AUTHOR]

Rapid eye movement (REM) sleep is known to be essential for memory. Hence, REM sleep deprivation impairs memory processes. The frequently prescribed selective serotonin reuptake inhibitors (SSRIs) are known to cause REM sleep deprivation and to impair cognitive performance in humans and rodents. We suggested that impaired memory processes by citalopram in C57/BL6 mice could be explained by the acute inhibition of REM sleep. We hypothesized that those acute citalopram 5 and 10 mg/kg injections induced REM sleep deprivation, altered cognitive performance in passive avoidance, impaired spatial memory compared to controls. Three experiments have been realized: (1) mice received successively physiological saline, injection of citalopram 5 and 10 mg/kg and were recorded by polysomnographic recording after each injection. (2) Cognitive performance was evaluated in the passive avoidance with two groups of mice. One group received citalopram before training and one, after training. (3) Spatial learning was evaluated with another group of animals in the Y-maze test. At 5 and 10 mg/kg, citalopram delayed REM sleep onset and decreased REM sleep amounts (vs. controls). The same doses were administrated in the passive avoidance test and have significantly shortened latency to enter the dark compartment. In the Y-maze, citalopram-treated mice showed a decreased percentage of time spent in the novel arm in contrast to the two other arms compared with controls. We showed that citalopram impaired cognitive performance in behavioral tasks. Those impairments could be linked to REM sleep deprivation induced by citalopram although causal relationship needs to be investigated in further studies. [ABSTRACT FROM AUTHOR]

Background: Seizures occur in 10% of stroke patients, but their predictors have not been clearly identified. Pre-existing dementia is present in 12-16% of stroke patients and, at the community level, patients with dementia have increased risk of seizures. However, the question of whether pre-existing dementia is associated with a higher risk of seizures after stroke has never been studied. Aim: To evaluate whether pre-existing dementia is associated with an increased risk of seizures after stroke. Methods: The study was conducted on 202 consecutive stroke patients recruited to the Lille stroke/ dementia study (97 men; median age, 75 years; range, 42-100). Pre-stroke cognitive functions were evaluated using the Informant Questionnaire on Cognitive Decline in the Elderly, with a cutoff value of 104 for the diagnosis of dementia. Seizures were defined as early seizures when occurring within seven days of stroke onset, and as late seizures when occurring more than seven days after stroke. Results: OF 202 patients, 33 (16.3%) met the criteria for pre-existing dementia, and 11(5.4%) developed early seizures. During 289 person-years of follow up, 14 patients developed late seizures, resulting in an incidence rate of 4.8 new cases/100 person-years. Pre-existing dementia was not associated with the occurrence of early seizures, but was independently associated with the occurrence of late seizures (adjusted odds ratio, 4.66; 95% confidence interval, i .34 to 16.21). Conclusion: Stroke patients with pre-existing dementia have an increased risk of late seizures. Any factor increasing the risk of seizures (drugs, metabolic changes) should be avoided in these patients. [ABSTRACT FROM AUTHOR]

In the early stages of Parkinson’s disease (PD), impaired motor preparation has been related to a delay of mu rhythm movement-related desynchronisation, suggesting hypoactivation of the contralateral, primary sensorimotor (PSM) cortex. Following movement, a decrease in the amplitude of beta rhythm movement-related synchronisation was observed over the same region. This decrease—not seen in control subjects—was thus thought to be related to an impairment in cortical deactivation. By monitoring movement-related (de)synchronisation, we aimed (i) to extend to advanced PD the observations made in less-advanced situations and (ii) to test the effect of acute L-Dopa on these abnormalities. The United Parkinson’s Disease Rating Scale (UPDRS) III score decreased by about 60% following acute L-Dopa administration, and we observed the following concurrent changes: a marked increase in mu desynchronisation pre-movement latency (thus reduced delay) during movement preparation over contralateral, central regions; an increase in mu desynchronisation during movement execution over bilateral central regions; a decrease in mu desynchronisation latency over bilateral frontocentral regions, and a significant increase in beta synchronisation over contralateral, central regions after movement. Changes of mu and beta rhythm parameters seemed to be inversely correlated with bradykinesia. Mu rhythm desynchronisation latency and beta synchronisation amplitude further decreased in advanced PD compared to earlier stages of the disease, suggesting greater impairment of cortical activation/deactivation as the disease progresses. L-Dopa partially restored the abnormal mu and beta rhythm cortical (de)synchronisation patterns over the PSM cortex. [Copyright &y& Elsevier]

Two kinds of methods are available in order to assess the functional relationships between different cerebral structures from the analysis of EEG signals: linear and non-linear methods. In this paper, we describe didactically the methodological bases of signal processing. After recalling the significance of the fundamental parameters of a sine wave: frequency, amplitude and phase, we show, from a first example about an epileptic seizure propagation, how a linear variation between phase and frequency can be interpreted as a small time difference between two EEG channels. This linear method hypothesises that these two signals are respectively the input and the output of a linear system. Then, we point out the limits of this method and we introduce non-linear methods. Among the latter, a recent approach introduces a realistic model of EEG which try to relate signal measured quantities to relations between underlying structures which produce them. [ABSTRACT FROM AUTHOR]

Background: Subclinical vascular or degenerative lesions occur in the brain before the clinical expression of dementia. Those lesions in a brain that just experienced a stroke may have lower thresholds for early epileptic seizures. Therefore, epileptic seizures may be a marker of subclinical brain lesions, which may lead to dementia.Objective: To test the hypothesis that patients with stroke who have epileptic seizures without dementia have an increased risk of new-onset dementia.Methods: 169 consecutive patients with stroke without pre-existing dementia recruited in the Lille Stroke/Dementia Study were investigated (90 men; 150 ischaemic strokes; median age 73 years). Pre-stroke cognitive functions were evaluated with the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), with a cut-off of 104 for the diagnosis of dementia. The patients were followed up over a 3-year period. Dementia was diagnosed with International Classification of Diseases, 10th revision criteria in survivors who underwent neurological visits, and with the IQCODE score in those who could not. The relationship between epileptic seizures and new-onset dementia was studied within 3 years, using life-table methods.Results: 9 patients (5.3%; 95% CI 2.9 to 8.7%) had early seizures. Epileptic seizures were independent predictors of new-onset dementia within 3 years after stroke (HR 3.81; 95% CI 1.13 to 12.82), with increasing age (HR 1.04; 95% CI 1.01 to 1.08), IQCODE scores at admission (HR 1.08; 95% CI 1.02 to 1.13) and diabetes mellitus (HR 3.52; 95% CI 1.46 to 8.47).Conclusion: Patients with stroke who have epileptic seizures may be at increased risk of dementia. Whether cognitive follow-up should be systematically performed in those patients remains to be validated. [ABSTRACT FROM AUTHOR]

Introduction: Prepulse inhibition (PPI) is considered to mirror an organism's ability to filter out irrelevant sensory or cognitive information. The disruption of PPI has never been studied in individuals suffering from dementia with Lewy bodies (DLB). As attention deficits largely contribute to cognitive impairment in DLB, an investigation with a PPI paradigm is useful for differential diagnosis of DLB versus Alzheimer's disease (AD) and Parkinson's disease dementia (PDD).Objective and Methods: PPI of the N1/P2 component of auditory evoked potentials was used to investigate the early stages of attention selectivity in 10 DLB, 10 AD, and 10 PDD patients, as well as in 10 healthy controls. The PPI paradigm consisted of the presentation of sound pulses (40 ms, 115 dB) preceded by a prepulse (40 ms, 80 dB). Sound stimuli were presented in a total of 80 trials in a pseudo-random order. Results: Non-parametric analyses of variance revealed a significant group effect on the 120 ms lead interval. Retrospective analyses revealed that PPI was significantly reduced in DLB compared to healthy controls and AD. In the PDD group, the disturbance was of intermediate intensity. Conclusion: The present study revealed a severe disturbance of PPI in DLB patients. The DLB patients displayed a specific disruption profile in terms of magnitude as well as time course. [ABSTRACT FROM AUTHOR]

Abstract Self-conscious emotions (SCEs) with a negative valence (such as shame and guilt) or a positive valence (such as pride) are moral emotions that emerge from self-reflection and self-evaluation processes in social contexts. In some neurologic and psychiatric disorders, experiences of SCEs are dysregulated. The objectives of the present study were to (i) evaluate whether patients with temporal lobe epilepsy (TLE) experience SCEs in the same way as nonclinical (control) participants and (ii) probe the relationships between experiences of SCEs on the one hand and the psychological symptoms frequently diagnosed in patients with TLE (anxiety and depression), the patients' clinical characteristics, and their functional outcomes in everyday life on the other. Sixty-one patients with TLE and 61 matched controls completed a self-questionnaire (the Positive and Negative Affect Schedule (PANAS)) that enabled us to evaluate the extent to which they experienced shame, guilt, and pride. Demographic data, cognitive data, the severity of anxiety symptoms, and the severity of depressive symptoms were recorded for all participants. In patients with TLE, data of clinical characteristics and quality of life were also evaluated. Relative to controls, patients with TLE were more likely to experience negative-valence SCEs to a higher extent and positive SCEs to a lesser extent. The patients who experienced negative-valence SCEs to a higher extent (rather than to a lesser extent) had a higher frequency of seizures, more severe anxiety and depressive symptoms, and a greater prevalence of anxiety and depressive disorders. Furthermore, patients who experienced positive-valence SCEs to a lesser extent (rather than to a higher extent) displayed a higher level of anxiety. Lastly, differences in experiences of SCEs by patients with TLE were associated with a lower quality of life. In conclusion, experiences of SCEs can be dysregulated in patients with TLE. This dysregulation is linked to the patients' clinical and psychological symptoms and quality of life. In this context, SCEs might be a target of interest in the management of epilepsy. Highlights • Shame, guilt, and pride are referred to as self-conscious emotions (SCEs). • Experiences of SCEs were dysregulated in patients with temporal lobe epilepsy. • Higher extent of negative SCEs was associated with a higher frequency of seizures. • These patients had a greater prevalence of anxiety and depressive disorders. • This dysregulation of SCEs had a functional impact on the patients' quality of life. [ABSTRACT FROM AUTHOR]

Restless legs syndrome (RLS) is characterized by the association of an urge to move, and vesperal or nocturnal sensory symptoms; it is frequently associated with periodic limb movements. Evidence from imaging and electrophysiological studies suggests that RLS is linked to changes in sensorimotor integration. Nevertheless, the underlying mechanisms have not been characterized, and the cortical origin has yet to be confirmed. The objective of the present study was to establish whether or not sensorimotor integration in RLS patients is impaired in the evening. The time-dependent modulation of motor cortex excitability following peripheral electric nerve stimulation was studied in 14 idiopathic RLS patients, and 14 paired healthy controls. Different inter-stimulus intervals were used to measure short-latency and long-latency afferent inhibition (SAI and LAI) and afferent-induced facilitation (AIF). Motor evoked potentials were recorded from the first dorsal interosseous muscle in two experimental sessions (one in the morning and one in the evening). With the exception of LAI (which was present in the morning but absent in the evening in both healthy controls and RLS patients), no circadian variations were observed in sensorimotor integration. Although SAI was present in patients with RLS, AIF was disrupted (relative to controls) - suggesting the presence of an indirect sensorimotor integration disorder affecting the long corticocortical pathways in patients with RLS. The lack of circadian modulation in sensorimotor integration suggests that clinical circadian variations have other causes. [ABSTRACT FROM AUTHOR]

Highlights: [•] The cingulate cortex and the central precuneus are involved in the N200 generation. [•] Target-N200 has sources in the anterior cingulate cortex and anterior precuneus. [•] The anterior cingulate cortex is critical for conflict monitoring. [•] The anterior cingulate cortex interacts with other median and frontoparietal areas. [ABSTRACT FROM AUTHOR]

Highlights: [•] Step initiation necessitates the release of anticipatory postural adjustments. [•] They are released twice more frequently in the case of focused attention. [•] Attentional load modulates step initiation. [Copyright &y& Elsevier]

Abstract: Step initiation is associated with anticipatory postural adjustments (APAs) that vary according to the speed of the first step. When step initiation is elicited by a “go” signal (i.e. in a reaction time task), the presentation of an unpredictable, intense, acoustic startling stimulus (engaging a subcortical mechanism) simultaneously with or just before the imperative “go” signal is able to trigger early-phase APAs. The aim of the present study was to better understand the mechanisms underlying APAs during step initiation. We hypothesized that the early release of APAs by low-intensity, non-startling stimuli delivered long before an imperative “go” signal indicates the involvement of several different mechanisms in triggering APAs (and not just acoustic reflexes triggering brainstem structures). Fifteen healthy subjects were asked to respond to an imperative visual “go” signal by initiating a step with their right leg. A brief, binaural 40, 80 or 115dB auditory stimulus was given 1.4s before the “go” signal. Participants were instructed not to respond to the auditory stimulus. The centre of pressure trajectory and the electromyographic activity of the orbicularis oculi, sternocleidomastoid and tibialis anterior muscles were recorded. All three intensities of the auditory stimulus were able to evoke low-amplitude, short APAs without subsequent step execution. The louder the stimulus, the more frequent the elicitation. Depending on the intensity of the stimulus, APAs prior to step initiation can be triggered without the evocation of a startle response or an acoustic blink. Greater reaction times for these APAs were observed for non-startling stimuli. This observation suggested the involvement of pathways that did not involve the brainstem as a “prime mover”. [Copyright &y& Elsevier]

Abstract: Objective: We sought to characterize cortical activity related to motor control in patients presenting with isolated cortical tremor, in order to determine whether or not myoclonus-related impairments are a source of event-related desynchronization/synchronization (ERD/ERS) disruption. Methods: Nine patients presenting with isolated cortical tremor were compared with controls. Mu and beta ERD/ERS were computed over the scalp and brain surfaces using 128-channel electroencephalographic (EEG) recording during voluntary and passive finger extensions. We recorded somatosensory-evoked potentials following median nerve stimulation and performed myoclonic jerk-locked back-averaging of EEG activity. Results: Back-averaging revealed a cortical premyoclonic spike in all patients. Five of the nine patients had exaggerated SEPs. The amplitude of mu ERD was greater in patients. Beta ERD/ERS did not differ from that seen in controls. Localizations of mu and beta ERD/ERS did not differ from controls and were identified in pre- and post-central sensorimotor cortical areas. Conclusions: The present results suggest a hyperexcitability of the cortico-subcortical loops responsible for movement preparation and execution. Post-movement inhibition related to cortical processing of afferent input is unaffected in isolated cortical myoclonus. Significance: Intracortical abnormalities can differ in patients suffering from cortical myoclonus, according to whether or not the individuals have associated epileptic symptoms. [Copyright &y& Elsevier]

Abstract: Objective: Although it is well known that postural adjustment (PA) is impaired in advanced Parkinson’s disease (PD), the potentially compensatory effects of bilateral subthalamic nucleus deep brain stimulation (STN DBS) in this respect are less clear. Methods: While standing on a force platform and in the absence of antiparkinsonian medication, 10 patients performed voluntary, unilateral arm movements before surgery (the ‘off stim’ condition) and then afterwards (the ‘on stim’ condition). The patients’ PAs were monitored by vertical torque (Tz) and compared with those recorded in control subjects. Results: Patients with STN DBS and control subjects showed similar values for PA amplitude, duration and latency. Conclusions: STN stimulation may induce better postural control during the movement preparation and execution phases. Our results argue in favour of a positive effect of STN DBS on PA. Significance: The PA amplitude (provided by Tz) may be a strong marker reflecting the clinical improvement seen in stimulated PD patients. [Copyright &y& Elsevier]

Abstract: Background: Restless legs syndrome (RLS) is characterized by closely interrelated motor and sensory disorders. Two types of involuntary movement can be observed: periodic leg movements during wakefulness (PLMW) and periodic leg movements during sleep (PLMS). Basal ganglia dysfunction in primary RLS has often been suggested. However, clinical observations raise the hypothesis of sensorimotor cortical involvement in RLS symptoms. Here, we explored cortical function via movement-related beta and mu rhythm reactivity. Methods: Twelve patients with idiopathic, primary RLS were investigated and compared with 10 healthy subjects. In the patient group, we analyzed event-related beta and mu (de)synchronization (ERD/S) for PLMS and PLMW during a suggested immobilization test (SIT). An ERD/S analysis was also performed in patients and controls during self-paced right ankle dorsal flexion at 8:30PM (i.e., the symptomatic period for patients) and 8:30AM (the asymptomatic period). Results: Before PLMS, there was no ERD. Intense ERS was recorded after PLMS. As with voluntary movement, cortical ERD was always observed before PLMW. After PLMW, ERS had a diffuse scalp distribution. Furthermore, the ERS and ERD amplitudes and durations for voluntary movement were greater during the symptomatic period than during the asymptomatic period and in comparison with healthy controls, who presented an evening decrease in these parameters. Patients and controls had similar ERD and ERS patterns in the morning. Conclusion: On the basis of a rhythm reactivity study, we conclude that the symptoms of RLS are related to cortical sensorimotor dysfunction. [Copyright &y& Elsevier]

Summary: Study aims: The sensory symptoms that are reported in restless legs syndrome (RLS) suggest involvement of the peripheral nervous system (PNS) in general and of the small-fibre system in particular. We aimed to study the status of the small-fibre system in primary RLS. Patients and methods: We investigated 10 patients with idiopathic RLS (mean time since disease onset: 11.4±12 years, mean International Restless Legs Syndrome Study Group [IRLSSG] score: 23.4±8). Five had a family history. All had normal results for laboratory tests, neurological examination, and a sural/deep-peroneal nerve conduction study. Lower-limb thulium YAG laser-evoked potentials (LEP) and skin sympathetic reflexes (SSR) were performed. The results were compared with data from 10 healthy subjects. Results: The nociceptive thresholds were 293±62mJ for patients and 333±77mJ for controls. For patients, the vertex N2 and P2 latencies were 208±25ms and 366±51ms, respectively (controls: N2=235±41ms; P2=373±44ms). The N2-P2 amplitude was 19±6μV for patients and 18±7μV for controls. SSR were normal in all patients. No significant differences between patients and healthy subjects were observed. Conclusion: We failed to demonstrate any significant involvement of small fibres and spinothalamic tracts in idiopathic RLS. Even though sufferers of this specific form of RLS report sensory symptoms, pathogenesis appears to be dissociated from a PNS alteration. [Copyright &y& Elsevier]

Sensory inputs from cutaneous and limb receptors are known to influence motor cortex network excitability. Although most recent studies have focused on the inhibitory influences of afferent inputs on arm motor responses evoked by transcranial magnetic stimulation (TMS), facilitatory effects are rarely considered. In the present work, we sought to establish how proprioceptive sensory inputs modulate the excitability of the primary motor cortex region controlling certain hand and wrist muscles. Suprathreshold TMS pulses were preceded either by median nerve stimulation (MNS) or index finger stimulation with interstimulus intervals (ISIs) ranging from 20 to 200 ms (with particular focus on 40–80 ms). Motor-evoked potentials recorded in the abductor pollicis brevis (APB), first dorsalis interosseus and extensor carpi radialis muscles were strongly facilitated (by up to 150%) by MNS with ISIs of around 60 ms, whereas digit stimulation had only a weak effect. When MNS was delivered at the interval that evoked the optimal facilitatory effect, the H-reflex amplitude remained unchanged and APB motor responses evoked with transcranial electric stimulation were not increased as compared with TMS. Afferent-induced facilitation and short-latency intracortical inhibition (SICI) and intracortical facilitation (ICF) mechanisms are likely to interact in cortical circuits, as suggested by the strong facilitation observed when MNS was delivered concurrently with ICF and the reduction of SICI following MNS. We conclude that afferent-induced facilitation is a mechanism which probably involves muscle spindle afferents and should be considered when studying sensorimotor integration mechanisms in healthy and disease situations. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Beta rhythm movement-related synchronization (beta synchronization) reflects motor cortex deactivation and sensory afference processing. In Parkinson’s disease (PD), decreased beta synchronization after active movement reflects abnormal motor cortex idling and may be involved in the pathophysiology of akinesia. The objectives of the present study were to (i) compare event-related synchronization after active and passive movement and electrical nerve stimulation in PD patients and healthy, age-matched volunteers and (ii) evaluate the effect of levodopa. Methods: Using a 128-electrode EEG system, we studied beta synchronization after active and passive index finger movement and electrical median nerve stimulation in 13 patients and 12 control subjects. Patients were recorded before and after 150% of their usual morning dose of levodopa. Results: The peak beta synchronization magnitude in the contralateral primary sensorimotor (PSM) cortex was significantly lower in PD patients after active movement, passive movement and electrical median nerve stimulation, compared with controls. Levodopa partially reversed the drop in beta synchronization after active movement but not after passive movement or electrical median nerve stimulation. Discussion: If one considers that beta synchronization reflects sensory processing, our results suggest that integration of somaesthetic afferences in the PSM cortex is abnormal in PD during active and passive movement execution and after simple electrical median nerve stimulation. Significance: Better understanding of the mechanisms involved in the deficient beta synchronization observed here could prompt the development of new therapeutic approaches aimed at strengthening defective processes. The lack of full beta synchronization restoration by levodopa might be related to the involvement of non-dopaminergic pathways. [Copyright &y& Elsevier]

Objective: To study anticipatory postural adjustments (APAs) in Parkinsons disease (PD) via a biomechanical analysis, including vertical torque )Tz). Methods: Ten patients with PD (in the off-drug' condition) and 10 age matched controls were included. While standing on a force platform, the subject performed a right shoulder flexion in order to grasp a handle in front of him/her, under three conditions (all at maximal velocity): movement triggered by a sound signal and loaded/non-loaded, self-paced movement. The anteroposterior coordinates of the centre of pressure (COP) and Tz were calculated. Results: A group effect was observed for Tz and COP in patients with PD (compared with controls): the maximal velocity peak appeared later and the amplitude of the COP backward displacement and the area of the positive phase of Tz were lower, whereas the duration of the positive phase of Tz was greater. Interaction analysis showed that the area of Tz was especially affected in the triggered condition and the loaded, self-paced condition. The onset of the COP backward displacement was delayed in the triggered condition. Conclusion: Our biomechanical analysis revealed that patients with PD do indeed perform APAs prior to unilateral arm movement, although there were some abnormalities. The reduced APA magnitude appears to correspond to a strategy for not endangering postural balance. [ABSTRACT FROM AUTHOR]

Abstract: Objective: We studied the time course and location of post-movement beta synchronization (PMBS) in patients presenting with sensory deafferentation, in order to assess the hypothetical relationship between the PMBS and the cortical processing of movement-related somatosensory afferent inputs. Methods: We used the event-related synchronization (ERS) method. EEG activity was recorded (via a 128-electrode system) during brisk, unilateral right and left index finger extension by 10 patients presenting with neuropathic pain related to sensory deafferentation. Intra- and post-movement changes in beta source power were calculated relative to pre-movement baseline activity. We compared the PMBS results for the painful and non-painful body sides. Furthermore, PMBS patterns in patients were compared with those in nine healthy volunteers. Results: PMBS pattern related to the painful side had a spatial distribution, with an ipsilateral preponderance, significantly more restricted than PMBS pattern on the non-painful side and in the control group. There were no significant differences between patient PMBS patterns on the non-painful side and those in the control group. Conclusions: Sensory deafferentation disrupts normal PMBS patterns. Significance: This work provides additional arguments to the hypothesis supporting that the PMBS is influenced by movement-related somatosensory input processing. [Copyright &y& Elsevier]

The objective of this study was to characterize the effects of various parameters (notably the frequency and intensity) of repetitive transcranial magnetic stimulation (rTMS) applied over the primary motor (M1) and premotor (PMC) cortices on the excitability of the first dorsalis interosseus (FDI) corticospinal pathway. To this end, we applied a comprehensive input–output analysis after fitting the experimental results to a sigmoidal function. Twenty-six healthy subjects participated in the experiments. Repetitive TMS was applied either over M1 or PMC at 1 Hz (LF) for 30 min (1,800 pulses) or at 20 Hz (HF) for 20 min (1,600 pulses). In the HF condition, the TMS intensity was set to 90% (HF90) of the FDI’s resting motor threshold (RMT). In the LF condition, the TMS intensity was set to either 90% (LF90) or 115% (LF115) of the RMT. The FDI input/output (I/O) curve was measured on both sides of the body before rTMS (the Pre session) and then during two Post sessions. For each subject, the I/O curves (i.e., the integral of the FDI motor-evoked potential (MEP) vs. stimulus intensity) were fitted using a Boltzmann sigmoidal function. The graph’s maximum slope, S 50 and plateau value were then compared between Pre and Post sessions. LF115 over M1 increased the slope of the FDI I/O curve but did not change the S 50 and plateau value. This also suggested an increase in the RMT. HF90 led to a more complex effect, with an increase in the slope and a decrease in the S 50 and plateau value. We did not see a cross effect on the homologous FDI corticospinal pathway, and only PMC LF90 had an effect on ipsilateral corticospinal excitability. Our results suggest that rTMS may exert a more complex influence on cortical network excitability than is usually reported (i.e. simple inhibitory or facilitatory effects). Analysis of the fitted stimulus response curve indicates a dichotomous influence of both low- and high-frequency rTMS on M1 cortical excitability; this may reflect intermingled effects on excitatory and inhibitory cortical networks. [ABSTRACT FROM AUTHOR]

Summary: Introduction: Locomotion disorders are important in Huntington''s disease (HD). Although the rates of evolution of motor, functional or cognitive aspects of HD have been studied, the evolution of locomotion disorders in early stages of the disease remains unknown. Objectives: To determine the rate of evolution of the HD-associated gait and gait initiation disorders and their correlates. Patients and methods: Eighteen HD patients were recorded with a minimum interevaluation interval of one year. Akinesia was studied by evaluating the anticipatory postural adjustment (APA) phase preceding the first step. We also evaluated gait speed, stride time and stride length. Results: We observed an alteration in the APA phase, whose evolution was correlated with that of akinesia. We also observed a decrease in gait speed, which was due both to an increase in stride time and a decrease in stride length. Stride-to-stride variability did not worsen between both evaluations. Conclusions: A worsening in both gait initiation and gait performance was observed in HD. Initial weak functional capacity and more severe motor impairment seem to be associated with a faster progression of locomotion parameters in these mildly impaired HD patients. [Copyright &y& Elsevier]

Abstract: Introduction: Sleep disorders are common in extrapyramidal diseases, but have rarely been demonstrated in corticobasal degeneration (CBD). Methods: Here, we describe sleep and vigilance in five consecutive patients with CBD. Results: All five patients had insomnia, four displayed periodic limb movements during sleep (PLMS) and/or restless leg syndrome (RLS), and two had sleep respiratory disorders. None had REM sleep behaviour disorders or excessive daytime sleepiness. Conclusions: Polysomnography is useful for diagnosing treatable sleep disorders in CBD. [Copyright &y& Elsevier]

Abstract: Objective: To examine the effects of a 30min, 1Hz subthreshold rTMS in a case of cortical tremor which is caused by hyperexcitability of sensorimotor cortex. Methods: Stimulation was applied over primary and, in a second time, over premotor cortex (M1 and PMC, respectively). Tremor was monitored by accelerometers placed on the index fingers of hands outstretched, before and several times after rTMS. Each rTMS session consisted of 1800 pulses delivered at 1Hz with an intensity of 90% of resting motor threshold. Results: PMC but not M1 stimulation led to a decrease of the postural tremor (90% decrease of acceleration total spectral power). This functional benefit was associated to normalization of electrophysiologic parameters (short-interval intracortical inhibition and cortical silent period duration). Moreover, when stimulating PMC during two daily sessions, improvement of the tremor was longer than one day stimulation and this benefit was associated with functional improvement. Conclusions: This study shows that 1Hz rTMS over premotor cortex can improve cortical tremor. Significance: These results raise the interest of the motor cortical stimulation as a possible therapeutic target for treatment of action tremor. [Copyright &y& Elsevier]

Summary: Purpose: This study used TMS mapping to investigate the motor representation of the abductor pollicis brevis (APB) muscles in a group of patients with focal epilepsy originating in central or pre-central region. Methods: Eight epileptic patients and eight control subjects participated in the study. The coil was moved in 1.5-cm steps along a grid drawn on the subject''s skull over the motor cortex of both hemispheres. At each site, six APB motor responses (evoked by TMS at 1.2 times the resting motor threshold) were recorded and averaged. The peak-to-peak amplitude was measured and plotted against the mediolateral and anteroposterior coil positions. The area of each APB muscle representation was measured and the position of the optimal point was calculated. Results: The resting motor threshold was increased bilaterally in epileptic patients. The maps were distorted in most patients (but not in control subjects), as evidenced by an off-centre optimal point. Interhemispheric differences in APB map areas were greater in patients than in control subjects. However, whether these increases in map area were on the epileptic side or on healthy side depended on the given subject. Conclusions: The changes in APB representation observed in epileptic patients demonstrate that reorganization occurs within the motor cortex. The heterogeneity of the present results is probably related to different locations of the epileptogenic and/or lesional areas and to a variety of compensatory phenomena that may occur, notably with respect to the disease duration. [Copyright &y& Elsevier]

Abstract: Background: Akinesia in basal ganglia disorders is essentially defined by delayed movement initiation; the reaction time increases and it becomes difficult (or even impossible) for the subject to initiate movement. A biomechanical study of gait initiation would help evaluate the role of akinesia in early stage Huntington''s disease (HD) patients. Methods: We recorded kinematic, spatiotemporal and angular parameters (using video motion analysis, a force platform and an optoelectronic system) for the first two steps taken by 15 HD patients and 15 gender- and age-matched controls. In order to evaluate the influence of an external cue on gait initiation parameters, we studied two movement paradigms: self-triggered initiation and initiation triggered (cued) by a “beep” sound. We analyzed kinematic, spatiotemporal (the speed, length and duration of the two first steps) and angular parameters (range of joint angles) as well as kinetic data (the trajectory of the centre of pressure (COP); the speed and trajectory of the centre of mass (COM)). Results: HD patients presented akinesia in both externally triggered and self-triggered conditions. Patients had more difficulties with self-triggered gait than with triggered gait. In HD, anticipatory postural adjustments (APAs) were more impaired in self-triggered gait initiation than in cued initiation. Indeed, an alteration in the kinetic parameters revealed a reduction in first step speed in both conditions. Hypokinesia (as assessed by a reduction in the range of angle joints) played an important role in this reduction. Conclusion: Akinesia is a major feature of impaired gait initiation in HD. The deficiencies in self-triggered initiation in HD seen here fit with a hypothesis whereby deficient internal cueing can be replaced by an external trigger. [Copyright &y& Elsevier]

Abstract: Objective: Abnormal low- and high-frequency oscillatory activities have been linked to abnormal movement control in Parkinson’s disease. We aimed to study how low- and high-frequency oscillatory activities are modulated by movement in the contralateral and ipsilateral subcorticocortical loops. Methods: We studied mu, beta and gamma rhythm event-related desynchronisation (ERD) and synchronisation (ERS) recorded from electrode contacts in the subthalamic nucleus (STN) areas and over the primary sensorimotor (PSM) cortex. Results: Mu and beta ERD/ERS patterns were very similar when comparing PSM cortex and STN areas and very different when comparing contralateral and ipsilateral structures. Beta rhythm ERS was more predominant over contralateral structures than over ipsilateral ones. Gamma rhythm ERS was only recorded from the contralateral STN area (particularly following administration of L-Dopa). For all patients, the best bipolar derivations – as defined by the earliest mu and beta ERD and the strongest beta and gamma ERS – always included the STN electrode contacts that produced the best clinical results. Conclusions: Movement-related activity is involved in the movement preparation in the contralateral subthalamo-cortical loop and in the movement execution in the bilateral subthalamo-cortical loops. Significance: Contralateral beta rhythm ERD seemed to be related to bradykinesia of the limb performing the movement. [Copyright &y& Elsevier]

Abstract: Objective: In this study we aimed to investigate if there are age-related differences in cortical oscillatory activity induced by self-paced muscular pure relaxation in comparison with muscle contraction as reference movement. Methods: Event-related (de)synchronization (ERD/ERS) have been recorded related to voluntary muscle contraction and relaxation in 10 young and 10 elderly right-handed healthy subjects. The muscle relaxation task consisted in a voluntary relaxation of maintained wrist extension without any overt, associated muscle contraction. The muscle contraction task corresponded to a self-initiated brief wrist extension. Results: In elderly subjects compared to young ones, mu and beta ERD preceding muscular relaxation was more widespread, beginning significantly earlier over contralateral frontocentral and parietocentral regions (p <0.05) as well as over ipsilateral regions (p <0.05). The beta synchronization was significantly attenuated (p <0.05). Conclusions: These results suggest an alteration of inhibitory motor systems and an altered post-movement somesthetic inputs processing with normal aging. These alterations were accompanied by compensatory mechanisms. Significance: These age-related alterations during different phases of muscle relaxation could participate to explain global sensorimotor slowing observed with normal aging. [Copyright &y& Elsevier]

Abstract: Background and purpose: To assess the prevalence of vigilance disorders in Parkinson''s disease patients, relate the observed phenomena to potential causes and confirm these troubles with polysomnographic analysis. Patients and methods: A questionnaire was used to gather information on demographic data, previous and current treatments, disease characteristics, sleep and vigilance troubles. Somnolence was measured using the Epworth Sleepiness Scale (ESS). Nocturnal polysomnography (PSG) and multiple sleep latency tests (MSLT) were performed for a sample of parkinsonian patients. Results: Two hundred twenty-two parkinsonian patients completed the questionnaire, and 36 patients had objective analyses. Of the patients, 43.2% had an ESS score >10, and 28.4% reported somnolence in the hour after taking dopaminergic drugs, whereas 6.8% reported unintended sleep episodes. In view of questionnaire data, these vigilance disorders may be partly explained not only by the impact of nocturnal sleep disorders (e.g. sleep apnea syndromes) but also by dopaminergic therapy (especially with dopaminergic agonists). With PSG and MSLT results, we have shown a significant correlation between mean sleep latency and ESS score. Patients with unintended sleep episodes have severe sleepiness in MSLT compared with others patients. Conclusions: Vigilance disorders are frequently observed in Parkinson''s disease. We recommend informing patients of the risk of occurrence of such conditions, notably for patients with unintended sleep episodes and with sleepiness in the hour after taking dopaminergic drugs. [Copyright &y& Elsevier]

Background Bilateral pallidal lesions induce a range of cognitive and motor disorders, principally a parkinsonian syndrome in which severe disturbances of gait and gait initiation are frequently reported. However, the precise clinical features of these disorders (and the role of the pallidum therein) remain to be established. Objectives The goal of this study was to characterise gait and gait initiation disorders within the context of a parkinsonian syndrome in patients with acquired, bilateral, pallidal lesions (PAL patients), to compare these disorders to those seen in Parkinson's disease (PD), and to assess the corresponding physiopathological implications. Patients and methods By using a video motion analysis system (VICON), we studied gait kinematic parameters in two patients presenting with bilateral, pallidal lesions. Kinematic and kinetic parameters were also determined during gait initiation. The two patients were compared with a group of 17 PD patients and to 20 healthy controls. Results In both PAL and PD patients, kinematic parameters (gait and gait initiation) and kinetic parameters (gait initiation) were similarly impaired, evidenced by akinesia (difficulty in initiating gait characterized by impairment of anticipatory postural adjustments). Hypokinesia and bradykinesia (respectively reduced stride length and reduced speed during gait) were also noted. Conclusion The gait and gait initiation disorders seen in cases of bilateral pallidal lesions (namely akinesia, hypokinesia and bradykinesia) are similar to those observed in PD. Subject to confirmation in more extensive studies, we hypothesize that bipallidal patients may present higher level gait disorders,with potential mediation by cognitive impairment. [ABSTRACT FROM AUTHOR]

Abstract: Dystonia is characterized by sustained muscle contraction, which frequently causes repetitive, twisting movements or abnormal posture. The precise pathophysiological mechanisms of dystonia are still unknown. Several studies did demonstrate that, although motor cortex hyperexcitability appears to be responsible for abnormal co-contraction and overflow to adjacent muscles, plasticity mechanisms and integrative sensorimotor processing are also likely to be involved in this condition. Current dystonia treatments are based on oral medication, injection of botulinum toxin and, in a low proportion of cases, bi-pallidal deep brain stimulation. However, treatment outcome is generally disappointing. A few researchers have reported the application of repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex or the premotor cortex, with the goal of decreasing motor cortex hyperexcitability. This article reviews all studies using this technique in dystonia and discusses rTMS therapeutic impact and its possible mechanisms of action in this indication. Currently, the premotor cortex seems to be the best target for rTMS in dystonia. Rather than merely reducing the hyperexcitability of the primary motor cortex, this technique''s clinical benefit seems to result from modifications in plasticity and restoration of sensorimotor integration. The corollary technique for chronic rTMS is electrical cortical stimulation. Even though this new therapeutic tool may have therapeutic promise, more studies are required to confirm it. In particular, we need to broaden our knowledge of rTMS impact on the various forms of dystonia and to optimize target localization. [Copyright &y& Elsevier]

Abstract: Objective. – Preparation of upper-limb movements differs between self-paced and triggered conditions. This study analyzed the anticipatory postural adjustments (APAs) of gait initiation in normal subjects in 2 conditions: self-generated and triggered by a “beep” sound. Methods. – We recorded kinematic, spatiotemporal parameters of the first two steps by means of video motion analysis (6 infrared cameras), and kinetic parameters (using a force platform and the optoelectronic system) in 20 normal subjects. Two conditions: 1) self-generated initiation; and 2) initiation triggered by a “beep” sound were studied to evaluate the APA phase, by recording kinetic data (duration of the APAs, trajectory of the center of pressure, speed and trajectory of the center of mass). Kinematic data (first and second step speed, length and duration) were also recorded. Results. – First step speed and length were increased in self-paced gait initiation compared to triggered gait initiation in controls. We found no difference between the 2 conditions in terms of second step kinematic data. It was caused by a significant difference between the 2 conditions for the temporal characteristics of anticipatory postural adjustments (APAs) in the initiation of the first step, which was longer when normal subjects performed self-generated gait initiation. The trajectory of center of pressure and center of mass remained the same in the 2 conditions. Conclusion. – APAs of gait initiation process are delayed under self-paced condition, although they do not differ qualitatively between reaction time and self-paced condition. Neuphysiological support of self-generated movement could explain these differences. [Copyright &y& Elsevier]

Gait analysis studies involve continuous curves of data measured over a gait cycle. Curve analysis and interpretation require adequate statistical methods. Three principal problems may be encountered in clinical practice: (i) the reliability of gait curves for a given patient, (ii) classifying a new subject as belonging to a given population or not and (iii) comparison of two populations (independent or paired). This paper presents three statistical tools for solving these problems: (i) intra-class correlation coefficients, (ii) confidence bands for a population (iii) a combination of analysis of variance and confidence bands for the difference between the means and shows how they can be used in clinical practice. [Copyright &y& Elsevier]

The aim of this study was to determine how cerebral aging influences the pattern of cortical oscillatory activity when a targeting movement with visual control is planned. Changes in cortical oscillatory activity were assessed by recording the event-related (de)synchronization (ERD/S) of μ and β rhythms. Young and elderly subjects performed a distal movement, a proximal movement and a visuo-guided targeting movement. Our results demonstrated an increase in μ ERD over ipsilateral regions and showed the spatial extent of μ ERD over parietocentral and parietal regions during motor planning in elderly subjects compared to young ones. After the movement, the beta ERS was significantly modified (a decrease in slope and amplitude) in elderly subjects. The most pronounced age-related changes in ERD/S pattern were observed for the targeting movement. Our results suggest that motor planning is less efficient in elderly subjects. This deficit might result from impaired parietal integrative function and/or changes in inputs from subcortical structures. Subsequently, the changes observed in the post-movement phase might reflect a decrease in (reafferent) sensory inputs and hence impaired their input processing. [Copyright &y& Elsevier]

Objective:. Sleep disturbances are frequently observed in Parkinson’s disease (PD). Bilateral chronic subthalamic nucleus (STN) stimulation is an alternative treatment for advanced PD. Improvements in motor disturbances after STN stimulation are well documented and seem to be associated with better sleep quality, even though the objective effect on sleep structure remains unclear. We have therefore studied the sleep/wakefulness cycle before and after surgical treatment in 10 consecutive parkinsonian patients. Methods:. Subjective sleep quality and sleep recordings were evaluated one month before and three months after initiation of STN stimulation. After surgery, the recordings were performed under two conditions: with stimulation (the “on” condition) and—if patients had given their consent—in the absence of stimulation (the “off” condition). Results:. With STN stimulation, subjective and objective sleep qualities were improved. Total sleep time, sleep efficiency and the durations of deep slow wave sleep and paradoxical sleep increased significantly. When stimulation was absent, sleep disturbances were similar to those observed before surgery. Conclusion:. Chronic STN stimulation is associated with a sleep improvement, which can be explained in part by the concomitant decrease in motor disturbances but also by the reduction in dosages of antiparkinsonian medication. However, we can not exclude a direct effect of STN stimulation on sleep regulatory centres. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate changes in spatio-temporal, event-related (de)synchronization (ERD/ERS) patterns recorded with respect to the more akinetic versus the less akinetic side during performance of a visuo-guided targeting movement when compared to an index finger extension.Methods: Twelve de novo parkinsonian patients were recorded. ERD/ERS in mu and beta frequency bands was computed from 21 source derivations.Results: When the index finger extension was performed with the less akinetic limb, mu ERD focused over contralateral central region appeared 2 s before movement. With the targeting movement, additional pre-movement mu ERD was observed over the parietal region, as well as earlier ipsilateral mu ERD. When the same movements were performed with the more akinetic limb, we observed delayed mu ERD over contralateral regions, earlier ipsilateral mu ERD and a lack of contralateral parietal mu ERD before the targeting movement. Following index finger extension for the less akinetic limb, a focused contralateral central beta ERS was recorded, increasing and spreading after the targeting movement. In contrast, for the more akinetic limb, beta ERS was dramatically attenuated and remained unchanged after the targeting movement.Conclusions: These results confirm the fact that motor programming is delayed, and provide some insight into what may well be impaired sensorimotor integration in Parkinson''s disease. [Copyright &y& Elsevier]

In Parkinson's disease, poor motor performance (resulting primarily from abnormal cortical activation during movement preparation and execution) may also be due to impaired sensorimotor integration and defective cortical activity termination of the ongoing movement, thus delaying preparation of the following one. Reduced movement-related synchronization of the beta rhythm in Parkinson's disease compared to controls has been put forward as evidence for impaired postmovement cortical deactivation. We assessed the effects of subthalamic deep brain stimulation and l-dopa on beta rhythm synchronization over the premotor and primary sensorimotor cortex. Ten advanced patients performed self-paced wrist flexion in four conditions according to the presence or not of stimulation and l-dopa. Compared to without treatment, the motor score improved by ≈ 60%; the beta synchronization was present over the contralateral frontocentral region and increased significantly over the contralateral central region under stimulation and under l-dopa, with a maximal effect when both treatments were associated. Our advanced patients displayed very focused and attenuated beta rhythm synchronization which, under stimulation, increased over the contralateral premotor and primary sensorimotor cortex. Stimulation and l-dopa both partly restored postmovement cortical deactivation in advanced Parkinson's disease, although the respective mechanisms probably differ. They may improve bradykinesia and cortical deactivation by reestablishing movement-related somatosensory processing at the end of the movement through the basal ganglia into the cortex. [ABSTRACT FROM AUTHOR]

Training modalities, health and self-medication behaviors of athletes with high training level are not well-known. Our goal was to study these specifications during an ultramarathon race of 65 km with 3500 meters of positive altitude difference ("6000D") and determine factors associated with better performance. We conducted a transversal and descriptive survey by questionnaire. Three hundred questionnaires were distributed (random sampling) and explained by the principal investigator during the 2 days before the 2016 edition of La 6000D. One hundred and ninety two men and 20 women replied (mean age: 40.8 ± 10.3 years and BMI: 22.6 ± 2.1 kg/m2). Runners averaged 7 ± 6.1 years of practice. They trained specifically 12.1 ± 10.4 weeks, traveled 64.5 ± 30 km per week in 7.6 ± 5.1 hours, with an average altitude difference of 1205 ± 1172 meters. Half of the runners used food supplements before the race. Seventy-two runners (34%) had taken or planned to take drugs in the race: half of them were NSAIDs and 65.6% were not at risk of using NSAIDs. Main factors statistically associated with an improved performance were weekly training volume in the 2 months preceding the race, BMI, best marathon time, body fat percentage, weekly altitude gain, age, affiliation at a club, use of gels during the race, weekly kilometric volume, sex, use of spirulina and years of practice. We evidence some factors that seem to be associated with an improved performance: low age, low BMI, high years of practice, high weekly hours and club membership. Contrary to popular belief among runners, performance seems not or only slightly improved by intake or medication before, during or after the race (sports cake, multi-vitamin complex, BCAA, paracetamol, NSAID, beta-2-mimetics, etc.). Some of these relationships may exist and may not be clearly perceived by athletes. However, such results can help practitioners communicate with more confidence about the risks of certain supplements and NSAIDs compared to a non-significant performance advantage. [ABSTRACT FROM AUTHOR]

Objective Freezing of gait in Parkinson’s disease seems to result from different factors including attention disorders. Our objective was to explore cortical integration of attentional stimulus during motor preparation. Methods Three groups were recruited: older people ( n = 6) and parkinsonian patients with ( n = 7) or without ( n = 7) freezing of gait. Attention was modulated during postural preparation of the step by an auditory oddball discrimination task consisting in discriminating a target sound among a series of standard ones. The primary endpoint was quantification of EEG oscillations following the attentional stimulus. Results An increase of power in low frequencies (delta and theta bands) occurred during the 500 msec following the target stimulus, followed by a decrease in mild frequencies (alpha and beta bands). For freezers patients, early event-related synchronization after the attention stimulus was preserved, whereas EEG oscillations in alpha and beta band were impaired, with a specific impairment to generate an event-related desynchronization after the perception of an attentional stimulus. Conclusions Early attentional discrimination was efficient in freezers patients. At the opposite, further mechanisms reflecting post-discrimination processing were deficient in those patients. Key message Cortical modulations during the attention – motor preparation coupling are different in parkinsonian patients with freezing of gait. [ABSTRACT FROM AUTHOR]

Chez les patients atteints d’une épilepsie du lobe temporal (ELT), la dépression constitue la comorbidité psychiatrique la plus fréquente (Gaitatzis et al., 2004). Celle-ci peut être associée à l’apathie, mais l’apathie peut exister en tant que syndrome, indépendamment de la présence d’un trouble dépressif (Kirsch-Darrow et al., 2006). L’apathie n’ayant jamais été évaluée chez les patients avec une ELT, l’objectif de cette étude était donc de mesurer la prévalence de l’apathie dans cette population, et ses liens potentiels avec la dépression. Méthodes Cinquante patients ELT et 50 contrôles sains appariés selon leurs caractéristiques démographiques ont été inclus. Pour l’ensemble des participants, la sévérité de la symptomatologie dépressive et apathique était évaluée à l’aide de l’inventaire de dépression de Beck et de l’échelle d’apathie Lilloise (Sockeel et al., 2006). Résultats Chez les patients ELT comparativement aux contrôles, la sévérité de la symptomatologie dépressive et apathique était significativement plus importante. Parmi les patients ELT, 18 (soit 36 %) présentaient une apathie modérée à sévère (i.e. un score > –17), et 14 (soit 28 %) présentaient une dépression modérée à sévère (i.e. un score > 19). Les niveaux de sévérité de la symptomatologie apathique et dépressive étaient positivement associés. L’apathie coexistait avec la dépression chez 8 patients ELT (soit 16 %), et 6 patients ELT (soit 12 %) présentaient une dépression sans apathie. Cependant, 10 patients ELT (soit 20 %) présentant une apathie, ne présentaient pas de dépression. Conclusion Cette étude donne des indications sur la prévalence de l’apathie dans le cadre d’une épilepsie du lobe temporal. Cette apathie peut être associée à une dépression. Néanmoins, elle est plus fréquemment relevée indépendamment de toute symptomatologie dépressive associée. D’autres études sont nécessaires afin de mieux caractériser les liens entre, apathie, dépression et épilepsie. [ABSTRACT FROM AUTHOR]

Introduction Le freezing de la marche dans la maladie de Parkinson résulterait de troubles attentionnels, notamment lors d’intégration des stimuli externes. L’objectif de cette étude était d’explorer l’intégration corticale de stimuli attentionnels durant la préparation motrice (initiation du pas). Nous faisions l’hypothèse que l’intégration corticale serait différente chez les patients avec freezing de la marche. Matériel et méthodes Trois groupes ont été constitués : patients avec freezing ( n = 12), sans freezing ( n = 13) et témoins âgés ( n = 13). L’attention était modulée au moyen d’un paradigme oddball auditif, survenant 1,4 seconde avant le signal d’initiation du pas. Le critère principal était la modulation des oscillations EEG, de la présentation du stimulus attentionnel jusqu’au signal de départ. Résultats Durant les 500 msec suivant le stimulus cible, il y avait une augmentation de puissance dans les basses fréquences (delta et thêta), suivie d’une diminution de puissance dans les moyennes (alpha et bêta). Il existait un effet groupe avec, pour les patients avec freezing , la préservation d’une synchronisation liée à l’événement après le stimulus mais l’absence de désynchronisation après la perception du stimulus attentionnel. Discussion–conclusion La discrimination du stimulus attentionnel était efficace chez les patients avec freezing . Cependant, les mécanismes plus tardifs de traitement post-perceptifs étaient altérés (absence de diminution de puissance alpha bêta). Ceci renforce l’idée d’une dissociation entre la discrimination correcte des stimuli externes mais d’un échec de l’allocation attentionnelle correcte envers ces stimuli. Les mécanismes intégratifs nécessaires au couplage perception-action sont altérés chez ces patients. [ABSTRACT FROM AUTHOR]