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Growth of abdominal aortic aneurysms (AAAs) is often described as erratic and discontinuous. This study aimed at describing growth patterns of AAAs with respect to maximal aneurysm diameter (Dmax) and aneurysm volume, and to characterize changes in the intraluminal thrombus (ILT) and biomechanical indices as AAAs grow. 384 computed tomography angiographies (CTAs) from 100 patients (mean age 70.0, standard deviation, SD = 8.5 years, 22 women), who had undergone at least three CTAs, were included. The mean follow-up was 5.2 (SD = 2.5) years. Growth of Dmax was 2.64 mm/year (SD = 1.18), volume 13.73 cm3/year (SD = 10.24) and PWS 7.3 kPa/year (SD = 4.95). For Dmax and volume, individual patients exhibited linear growth in 87% and 77% of cases. In the tertile of patients with the slowest Dmax-growth (< 2.1 mm/year), only 67% belonged to the slowest tertile for volume-growth, and 52% and 55% to the lowest tertile of PWS- and PWRI-increase, respectively. The ILT-ratio (ILT-volume/aneurysm volume) increased with time (2.6%/year, p < 0.001), but when adjusted for volume, the ILT-ratio was inversely associated with biomechanical stress. In contrast to the notion that AAAs grow in an erratic fashion most AAAs displayed continuous and linear growth. Considering only change in Dmax, however, fails to capture the biomechanical risk progression, and parameters such as volume and the ILT-ratio need to be considered. [ABSTRACT FROM AUTHOR]

It remains difficult to predict when which patients with abdominal aortic aneurysm (AAA) will require surgery. The aim was to study the accuracy of geometric and biomechanical analysis of small AAAs to predict reaching the threshold for surgery, diameter growth rate and rupture or symptomatic aneurysm. 189 patients with AAAs of diameters 40–50 mm were included, 161 had undergone two CTAs. Geometric and biomechanical variables were used in prediction modelling. Classifications were evaluated with area under receiver operating characteristic curve (AUC) and regressions with correlation between observed and predicted growth rates. Compared with the baseline clinical diameter, geometric-biomechanical analysis improved prediction of reaching surgical threshold within four years (AUC 0.80 vs 0.85, p = 0.031) and prediction of diameter growth rate (r = 0.17 vs r = 0.38, p = 0.0031), mainly due to the addition of semiautomatic diameter measurements. There was a trend towards increased precision of volume growth rate prediction (r = 0.37 vs r = 0.45, p = 0.081). Lumen diameter and biomechanical indices were the only variables that could predict future rupture or symptomatic AAA (AUCs 0.65–0.67). Enhanced precision of diameter measurements improves the prediction of reaching the surgical threshold and diameter growth rate, while lumen diameter and biomechanical analysis predicts rupture or symptomatic AAA. [ABSTRACT FROM AUTHOR]

To aid development and evaluation of new treatments, we need a clear understanding of the deficits PSP produces and their progression. Progressive Supranuclear Palsy (PSP) is a rapidly progressive neurodegenerative tauopathy1 without any disease-modifying treatment. At baseline, only 52% of PSP participants were strategy adherent, versus 96% of PD and 100% of HC participants ( I P i < 0.001 for PSP vs. [Extracted from the article]

Background: Information on the predictive determinants of abdominal aortic aneurysm rupture from CT angiography are scarce. The aim of this study was to investigate biomechanical parameters in abdominal aortic aneurysms and their association with risk of subsequent rupture. Methods: In this retrospective study, the digital radiological archive was searched for 363 patients with ruptured abdominal aortic aneurysms. All patients who underwent at least one CT angiography examination before aneurysm rupture were included. CT angiography results were analysed to determine maximum aneurysm diameter, aneurysm volume, and biomechanical parameters (peak wall stress and peak wall rupture index). In the primary survival analysis, patients with abdominal aortic aneurysms less than 70 mm were considered. Sensitivity analyses including control patients and abdominal aortic aneurysms of all sizes were performed. Results: A total of 67 patients who underwent 109 CT angiography examinations before aneurysm rupture were identified. The majority were men (47, 70%) and the median age at the time of CTA examination was 77 (71–83) years. The median maximum aneurysm diameter was 56 (interquartile range 46–65) mm and the median time to rupture was 2.13 (interquartile range 0.64–4.72) years. In univariable analysis, maximum aneurysm diameter, aneurysm volume, peak wall stress, and peak wall rupture index were all associated with risk of rupture. Women had an increased HR for rupture when adjusted for maximum aneurysm diameter or aneurysm volume (HR 2.16, 95% c.i. 1.23 to 3.78 (P = 0.007) and HR 1.92, 95% c.i. 1.06 to 3.50 (P = 0.033) respectively). In multivariable analysis, the peak wall rupture index was associated with risk of rupture. The HR for peak wall rupture index was 1.05 (95% c.i. 1.03 to 1.08) per % (P < 0.001) when adjusted for maximum aneurysm diameter and 1.05 (95% c.i. 1.02 to 1.08) per % (P < 0.001) when adjusted for aneurysm volume. Conclusion: Biomechanical factors appear to be important in the prediction of abdominal aortic aneurysm rupture. Women are at increased risk of rupture when adjustments are made for maximum aneurysm diameter alone. [ABSTRACT FROM AUTHOR]

Investigates the functional importance of ipsilateral motor areas in recovered hand movements after a stroke. Correlation of the degree of motor impairment with the relative slowing of movements with ipsilateral primary motor or dorsal premotor cortex stimulation; Analysis of brain activity in the subjects as they performed the movements.

Objective: To report on the control group of a trial primarily designed to investigate exercise for improving mobility in people with Parkinson’s disease (pwP). The control group undertook a handwriting intervention to control for attention and time spent practising a specific activity. Design: Secondary analysis of a two-arm parallel phase II randomized controlled trial with blind assessment. Setting: Community. Participants: PwP able to walk ⩾100 m and with no contraindication to exercise were recruited from the Thames Valley, UK, and randomized (1:1) to exercise or handwriting, via a concealed computer-generated list. Intervention: Handwriting was undertaken at home and exercise in community facilities; both were delivered through workbooks with monthly support visits and involved practice for 1 hour, twice weekly, over a period of six months. Main measures: Handwriting was assessed, at baseline, 3, 6 and 12 months, using a pangram giving writing speed, amplitude (area) and progressive reduction in amplitude (ratio). The Movement Disorder Society (MDS)–Unified Parkinson’s Disease Rating Scale (UPDRS) item 2.7 measured self-reported handwriting deficits. Results: In all, 105 pwP were recruited (analysed: n = 51 handwriting, n = 54 exercise). A total of 40 pwP adhered to the handwriting programme, most completing ⩾1 session/week. Moderate effects were found for amplitude (total area: d = 0.32; 95% confidence interval (CI): −0.11 to 0.7; P = 0.13) in favour of handwriting over a period of12 months; effects for writing speed and ratio parameters were small ≤0.11. Self-reported handwriting difficulties also favoured handwriting (UPDRS 2.7: odds ratio (OR) = 0.55; 95% CI: 0.34 to 0.91; P = 0.02). No adverse effects were reported. Conclusion: PwP generally adhere to self-directed home handwriting which may provide benefit with minimal risk. Encouraging effects were found in writing amplitude and, moreover, perceived ability. [ABSTRACT FROM AUTHOR]

Apathy is a debilitating and under-recognized condition that has a significant impact in many neurodegenerative disorders. In Parkinson's disease, it is now known to contribute to worse outcomes and a reduced quality of life for patients and carers, adding to health costs and extending disease burden. However, despite its clinical importance, there remains limited understanding of mechanisms underlying apathy. Here we investigated if insensitivity to reward might be a contributory factor and examined how this relates to severity of clinical symptoms. To do this we created novel ocular measures that indexed motivation level using pupillary and saccadic response to monetary incentives, allowing reward sensitivity to be evaluated objectively. This approach was tested in 40 patients with Parkinson's disease, 31 elderly age-matched control participants and 20 young healthy volunteers. Thirty patients were examined ON and OFF their dopaminergic medication in two counterbalanced sessions, so that the effect of dopamine on reward sensitivity could be assessed. Pupillary dilation to increasing levels of monetary reward on offer provided quantifiable metrics of motivation in healthy subjects as well as patients. Moreover, pupillary reward sensitivity declined with age. In Parkinson's disease, reduced pupillary modulation by incentives was predictive of apathy severity, and independent of motor impairment and autonomic dysfunction as assessed using overnight heart rate variability measures. Reward sensitivity was further modulated by dopaminergic state, with blunted sensitivity when patients were OFF dopaminergic drugs, both in pupillary response and saccadic peak velocity response to reward. These findings suggest that reward insensitivity may be a contributory mechanism to apathy and provide potential new clinical measures for improved diagnosis and monitoring of apathy. [ABSTRACT FROM AUTHOR]

Abstract: The basal ganglia may play an important role in the control of motor scaling or effort. Recently local field potential (LFP) recordings from patients with deep brain stimulation electrodes in the basal ganglia have suggested that local increases in the synchronisation of neurons in the gamma frequency band may correlate with force or effort. Whether this feature uniquely codes for effort and whether such a coding mechanism holds true over a range of efforts is unclear. Here we investigated the relationship between frequency-specific oscillatory activities in the subthalamic nucleus (STN) and manual grips made with different efforts. The latter were self-rated using the 10 level Borg scale ranging from 0 (no effort) to 10 (maximal effort). STN LFP activities were recorded in patients with Parkinson's Disease (PD) who had undergone functional surgery. Patients were studied while motor performance was improved by dopaminergic medication. In line with previous studies we observed power increase in the theta/alpha band (4–12Hz), power suppression in the beta band (13–30Hz) and power increase in the gamma band (55–90Hz) and high frequency band (101–375Hz) during voluntary grips. Beta suppression deepened, and then reached a floor level as effort increased. Conversely, gamma and high frequency power increases were enhanced during grips made with greater effort. Multiple regression models incorporating the four different spectral changes confirmed that the modulation of power in the beta band was the only independent predictor of effort during grips made with efforts rated <5. In contrast, increases in gamma band activity were the only independent predictor of effort during grips made with efforts ≥5. Accordingly, the difference between power changes in the gamma and beta bands correlated with effort across all effort levels. These findings suggest complementary roles for changes in beta and gamma band activities in the STN in motor effort coding. The latter function is thought to be impaired in untreated PD where task-related reactivity in these two bands is deficient. [Copyright &y& Elsevier]

Abstract: Local field potential recordings made from the basal ganglia of patients undergoing deep brain stimulation have suggested that frequency specific activity is involved in determining the rate of force development and the peak force at the outset of a movement. However, the extent to which the basal ganglia might be involved in motor performance later on in a sustained contraction is less clear. We therefore recorded from the subthalamic nucleus region (STNr) in patients with Parkinson''s disease (PD) as they made maximal voluntary grips. Relative to age-matched controls they had more rapid force decrement when contraction was meant to be sustained and prolonged release reaction time and slower rate of force offset when they were supposed to release the grip. These impairments were independent from medication status. Increased STNr power over 5–12Hz (in the theta/alpha band) independently predicted better performance—reduced force decrement, shortened release reaction time and faster rate of force offset. In contrast, lower mean levels and progressive reduction of STNr power over 55–375Hz (high gamma/high frequency) over the period when contraction was meant to be sustained were both strongly associated with greater force decrement over time. Higher power over 13–23Hz (low beta) was associated with more rapid force decrement during the period when grip should have been sustained, and with a paradoxical shortening of the release reaction time. These observations suggest that STNr activities at 5–12Hz and 55–375Hz are necessary for optimal grip performance and that deficiencies of such activities lead to motor impairments. In contrast, increased levels of 13–25Hz activity both promote force decrement and shorten the release reaction time, consistent with a role in antagonising (and terminating) voluntary movement. Frequency specific oscillatory activities in the STNr impact on motor performance from the beginning to the end of a voluntary grip. [Copyright &y& Elsevier]

The neural substrates that enable individuals to achieve their fastest and strongest motor responses have long been enigmatic. Importantly, characterization of such activities may inform novel therapeutic strategies for patients with hypokinetic disorders, such as Parkinson’s disease. Here, we ask whether the basal ganglia may play an important role, not only in the attainment of maximal motor responses under standard conditions but also in the setting of the performance enhancements known to be engendered by delivery of intense stimuli. To this end, we recorded local field potentials from deep brain stimulation electrodes implanted bilaterally in the subthalamic nuclei of 10 patients with Parkinson’s disease, as they executed their fastest and strongest handgrips in response to a visual cue, which was accompanied by a brief 96-dB auditory tone on random trials. We identified a striking correlation between both theta/alpha (5–12 Hz) and high-gamma/high-frequency (55–375 Hz) subthalamic nucleus activity and force measures, which explained close to 70% of interindividual variance in maximal motor responses to the visual cue alone, when patients were ON their usual dopaminergic medication. Loud auditory stimuli were found to enhance reaction time and peak rate of development of force still further, independent of whether patients were ON or OFF l-DOPA, and were associated with increases in subthalamic nucleus power over a broad gamma range. However, the contribution of this broad gamma activity to the performance enhancements observed was only modest (&leq;13%). The results implicate frequency-specific subthalamic nucleus activities as substantial factors in optimizing an individual’s peak motor responses at maximal effort of will, but much less so in the performance increments engendered by intense auditory stimuli. [ABSTRACT FROM AUTHOR]

The article discusses the case of a 19-year-old woman with severe Epstein-Barr virus (EBV) encephalitis and raised intracranial pressure requiring decompressive craniectomy is described. She was treated with corticosteroids and acyclovir, was critically unwell for 3 weeks, requiring artificial ventilation but eventually made a good recovery. This case proves that EBV can be a causative agent of encephalitis and can be relieved by craniectomy and corticosteroids in selected cases.

The pedunculopontine nucleus, a component of the reticular formation, is topographically organized in animal models and implicated in locomotor control. In Parkinson's disease, pedunculopontine nucleus stimulation is an emerging treatment for gait freezing. Local field potentials recorded from pedunculopontine nucleus electrodes in such patients have demonstrated oscillations in the alpha and beta frequency bands, reactive to self-paced movement. Whether these oscillations are topographically organized or relevant to locomotion is unknown. Here, we recorded local field potentials from the pedunculopontine nucleus in parkinsonian patients during rest and unconstrained walking. Relative gait speed was assessed with trunk accelerometry. Peaks of alpha power were present at rest and during gait, when they correlated with gait speed. Gait freezing was associated with attenuation of alpha activity. Beta peaks were less consistently observed across rest and gait, and did not correlate with gait speed. Alpha power was maximal in the caudal pedunculopontine nucleus region and beta power was maximal rostrally. These results indicate a topographic distribution of neuronal activity in the pedunculopontine nucleus region and concur with animal data suggesting that the caudal subregion has particular relevance to gait. Alpha synchronization, proposed to suppress ‘task irrelevant’ distraction, has previously been demonstrated to correlate with performance of cognitive tasks. Here, we demonstrate a correlation between alpha oscillations and improved gait performance. The results raise the possibility that stimulation of caudal and rostral pedunculopontine nucleus regions may differ in their clinical effects. [ABSTRACT FROM PUBLISHER]

Gait freezing and postural instability are disabling features of Parkinsonian disorders, treatable with pedunculopontine nucleus stimulation. Both features are considered deficits of proximal and axial musculature, innervated predominantly by reticulospinal pathways and tend to manifest when gait and posture require adjustment. Adjustments to gait and posture are amenable to pre-preparation and rapid triggered release. Experimentally, such accelerated release can be elicited by loud auditory stimuli—a phenomenon known as ‘StartReact’. We observed StartReact in healthy and Parkinsonian controls. However, StartReact was absent in Parkinsonian patients with severe gait freezing and postural instability. Pedunculopontine nucleus stimulation restored StartReact proximally and proximal reaction times to loud stimuli correlated with gait and postural disturbance. These findings suggest a relative block to triggered, pre-prepared movement in gait freezing and postural instability, relieved by pedunculopontine nucleus stimulation. [ABSTRACT FROM AUTHOR]