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Background . Alzheimer's cognitive-behavioral syndrome is the result of impaired connectivity between nerve cells, due to misfolded proteins, which accumulate and disrupt specific brain networks. Electroencephalography, because of its excellent temporal resolution, is an optimal approach for assessing the communication between functionally related brain regions. O bjective . To detect and compare EEG resting-state networks (RSNs) in patients with amnesic mild cognitive impairment (aMCI), and healthy elderly (HE). Methods . We recruited 125 aMCI patients and 70 healthy elderly subjects. One hundred and twenty seconds of artifact-free EEG data were selected and compared between patients with aMCI and HE. We applied standard low-resolution brain electromagnetic tomography (sLORETA)-independent component analysis (ICA) to assess resting-state networks. Each network consisted of a set of images, one for each frequency (delta, theta, alpha1/2, beta1/2). Results . The functional ICA analysis revealed 17 networks common to groups. The statistical procedure demonstrated that aMCI used some networks differently than HE. The most relevant findings were as follows. Amnesic-MCI had: i) increased delta/beta activity in the superior frontal gyrus and decreased alpha1 activity in the paracentral lobule (ie, default mode network); ii) greater delta/theta/alpha/beta in the superior frontal gyrus (i.e, attention network); iii) lower alpha in the left superior parietal lobe, as well as a lower delta/theta and beta, respectively in post-central, and in superior frontal gyrus(ie, attention network). Conclusions . Our study confirms sLORETA-ICA method is effective in detecting functional resting-state networks, as well as between-groups connectivity differences. The findings provide support to the Alzheimer's network disconnection hypothesis.

Recent studies demonstrated that beta oscillations are elicited during cognitive processes. To investigate their potential as electrophysiological markers of amnestic mild cognitive impairment (aMCI), we recorded beta EEG activity during resting and during an omitted tone task in patients and healthy elderly. Thirty participants were enrolled (15 patients, 15 healthy controls). In particular, we investigated event-related spectral perturbation and intertrial coherence indices. Analyses showed that ( a) healthy elderly presented greater beta power at rest than patients with aMCI patients; ( b) during the task, healthy elderly were more accurate than aMCI patients and presented greater beta power than aMCI patients; ( c) both groups showed qualitatively similar spectral perturbation responses during the task, but different spatiotemporal response patterns; and ( d) aMCI patients presented greater beta phase locking than healthy elderly during the task. Results indicate that beta activity in healthy elderly differs from that of patients with aMCI. Furthermore, the analysis of task-related EEG activity extends evidences obtained during resting and suggests that during the prodromal phase of Alzheimer's disease there is a reduced efficiency in information exchange by large-scale neural networks. The study for the first time shows the potential of task-related beta responses as early markers of aMCI impairments.

There are several evidences indicating that an impairment in attention-executive functions is present in prodromal Alzheimer's disease and predict future global cognitive decline. In particular, the issue of temporal orienting of attention in patients with mild cognitive impairment (MCI) due to Alzheimer's disease has been overlooked. The present research aimed to explore whether subtle deficits of cortical activation are present in these patients early in the course of the disease. We studied the upper-alpha event-related synchronization/desynchronization phenomenon during a paradigm of temporal orientation of attention. MCI patients (n = 27) and healthy elderly controls (n = 15) performed a task in which periodically omitted tones had to be predicted and their virtual onset time had to be marked by pressing a button. Single-trial responses were measured, respectively, before and after the motor response. Then, upper-alpha responses were compared to upper-alpha power during eyes-closed resting state. The time course of the task was characterized by two different behavioral conditions: (1) a pre-event epoch, in which the subject awaited the virtual onset of the omitted tone, (2) a post-event epoch (after button pressing), in which the subject was in a post-motor response condition. The principal findings are: (1) during the waiting epoch, only healthy elderly had an upper-alpha ERD at the level of both temporal and posterior brain regions; (2) during the post-motor epoch, the aMCI patients had a weaker upper-alpha ERS on prefrontal regions; (3) only healthy elderly showed a laterality effect: (a) during the waiting epoch, the upper-alpha ERD was greater at the level of the right posterior-temporal lead; during the post-motor epoch, the upper alpha ERS was greater on the left prefrontal lead. The relevance of these findings is that the weaker upper-alpha response observed in aMCI patients is evident even if the accuracy of the behavioral performance (i.e., button pressing) is still spared. This abnormal upper-alpha response might represent an early biomarker of the attention-executive network impairment in MCI due to Alzheimer's disease.

We examined the hypothesis that the attention/executive deficits in mild cognitive impairment (MCI) due to Alzheimer's disease is associated to an abnormal cortical activation, revealed by the method of event-related synchronization/desynchronization (ERS/ERD) in the theta band during a paradigm of temporal orienting of attention. MCI patients (n = 25) and healthy elderly (HE) matched controls (n = 15) performed a task in which periodically omitted tones had to be predicted and their virtual onset time had to be marked by pressing a button. Single-trial theta responses were measured, respectively, before and after the motor response. Then, theta responses were compared to theta power during eyes closed resting state (ERD/ERS method).The temporal course of the task was characterized by two different behavioural conditions: (1) a pre-event epoch, in which the subject awaited the virtual onset of the omitted tone, (2) a post-event (after button pressing) epoch, in which the subject was in a post-motor response condition. The most important findings are summarized as follows: (1) in both groups, the pre-event epoch was characterized by theta ERS on temporal electrodes, but HE had a greater theta ERS compared to that of MCI group; (2) in both groups, during the post-motor condition, there was a theta ERS on prefrontal regions, and, also in this case, HE showed a greater theta enhancement compared to that of MCI patients; (3) HE showed evidence of lateralization: during the waiting epoch, theta ERS was dominant on the right posterior temporal lead (T6), whilst, during the post-motor epoch, theta ERS was greater on the left, as well as the midline prefrontal leads. Compared to the traditional neuropsychological measures for the episodic memory, these theta ERS indicators were less accurate in differentiating MCI patients from healthy elderly. The clinical relevance of these findings is that the weaker theta reactivity in MCI would indicate an early impairment in the temporal orienting of attention in the early stage of the clinical course of this neurodegenerative disease.

Guillain-Barré syndrome is a post infectious, immune-mediated disease with cranial nerve involvement observed in 45-75% of patients. Bilateral facial nerve palsy is rather uncommon and occurs in 0.3% to 2% of all facial palsies. We describe a rare case of a 29-year-old man with bilateral facial palsy caused by a Guillain-Barré syndrome with an unusual onset and progression of neurological symptoms. Neuroradiological findings in our patient are described and compared with data from literature on bilateral facial palsies to make differential diagnosis easier for neuroradiologists.

There is evidence that theta responses reflect cognitive performance: good performances are associated with a decrease in tonic theta power as well as an increase in phasic theta power. In the present study, both tonic and phasic theta activity were analysed in 22 patients with mild Alzheimer's disease (AD), and 16 healthy elderly controls. Single-trial theta power responses were evaluated by an active auditory oddball paradigm along an early poststimulus window (0-250 ms) and a late time window (250-500 ms), and then compared to prestimulus theta power during both target tone and standard tone processing. The main findings were: (1) in AD patients, there was an increased prestimulus theta power, as well as no significant poststimulus theta power increase upon both target and non-target stimulus processing; (2) in healthy aged controls, only during target tone processing, an enhancement of both early and late theta responses relative to the prestimulus baseline was found. Moreover, healthy controls had a frontal dominance of theta power. The results might indicate that, during target processing, theta response is not functionally sensitive in AD and cannot be involved in processing demands as efficiently as in healthy controls. From a psychophysiological point of view, this might suggest an impairment of attentional allocation resources. The psychological implications might be related to selective attention/working-memory impairment from the early stage of the disease. Our data confirm that both tonic and phasic theta are relevant indicators of cognitive performance: the lack of a phasic theta and an increase in tonic theta are congruous findings in cognitive decline. Another factor worth noting is that in AD patients theta response is not dominant at the frontal site (as observed in healthy controls), indicating a weaker frontal lobe network reactivity during stimulus processing.

The present study assessed auditory event-related potentials in patients with Alzheimer's disease (AD). Delta responses of 21 mild probable AD subjects according to NINCDS-ADRDA criteria, and 16 healthy elderly controls were evaluated by an active oddball paradigm. Averaged and single sweep potentials were analyzed during target tone processing. As far as time domain averaged event-related potentials (ERPs) are concerned, no significant group differences were observed for N100 and P200 components (both latency and amplitude); also, N200 and P300 amplitude did not differ between groups, whilst N200 and P300 latency were significantly prolonged in AD patients. Concerning delta frequency component of the averaged ERPs, no significant differences between groups were obtained for delta response amplitude as well as delta response topography (Fz, Cz, Pz). Analysis of delta responses was performed for single sweep maximal peak-to-peak amplitude. Significant between groups differences were revealed at the level of single sweep amplitude at the 3 midline sites (Fz, Cz, Pz), during target tone processing. In particular, the difference between healthy controls and AD subjects was at the level of stimulus-related delta amplitude changes: in all locations a significant enhancement of the delta response is recorded in healthy subjects (especially at the frontal location), whilst this delta reactivity was not detectable in AD patients. From a clinical point of view, the lack of delta reactivity might relate to a decision-making function impairment since mild Alzheimer's disease.

Background: Few studies exist on ERPs and patients with subcortical vascular cognitive impairment (SVCI). This latter is a quite homogeneous subtype of vascular dementia whose cognitive profile is quite different from that of Alzheimer disease (AD)., Aims: The present study aims at comparing the ERPs profile both in patients with SVCI and in patients with AD., Subjects and Methods: ERPs and psychometric tests were collected from 39 healthy elderly controls, 51 patients with SVCI and 43 patients with AD. Subjects mentally count high pitched target tones that were randomly intermixed with low pitched frequent tones. We measured ERPs latencies (N1, P2, N2 and P3), and interpeak latencies (N1-P3, N1-P2, N1-N2)., Results: Grand averaged potentials in SVCI showed a significant increase of P3 latency. AD patients showed a prolongation of N1, P2, N2, P3 latencies. As far as interpeak latencies are concerned, SVCI patients showed a significant prolongation of N1-P3, AD patients had a significant increase of N1-N2, and N1-P3 intervals. When all patients were considered as a single group, correlation of neuropsychological tests scores showed a significant negative relationship between P300 latency and, respectively, Mini Mental Status Examination, auditive and visual span forward. In both groups, ERPs latency sensitivity, was low, whilst specificity values were quite high., Conclusions: Our finding suggest that these two dementing diseases have different electrophysiologic features that may be related to their specific underlying pathogenetic mechanism; in particular, we hypothesise that, differently from AD, P300 latency prolongation characterizes the early stage of SVCI. So, this ERPs approach could be helpful to detect early alterations of the attentional/working-memory functions in patients with subcortical ischaemic vascular disease.

This survey covered 60 post-menopausal women with osteoporosis. The patients were divided into three equal groups, and each group was treated with one of the three so-called anti-resorptive drugs, namely alendronate (10 mg/day) risedronate (5 mg/day) and raloxifene (60 mg/day) for 12 months. The Elisa technique was used to measure circulating IL-18 and MMP-9. Lumbar bone mineral density (BMD) levels were determined by using dexa mineralometry (Lunar DPX) at baseline and after 12 months of treatment. The results showed comparable responses of the patients treated with alendronate or risedronate, being a significant increase in BMD, an increase in circulating IL-18, and only slight modifications in circulating MMP-9 levels. After 12 months of treatment with raloxifene, there were minimal, non-significant increases in BMD, slight modifications in IL-18 levels, and a significant reduction in circulating MMP-9 levels. The conclusions can be drawn that all three drugs, albeit through different mechanisms, can be considered valid treatments for post-menopausal osteoporosis. Although measurements of circulating IL-8 and MMP-9 levels allowed us to differentiate the effects of the three drugs used, as of today, they have no real role in the diagnosis and/or follow-up of osteoporosis.