Subspecialty preferences among Neurologists of the future.

INTRODUCTION: In the era of neurological subspecialization, most neurologists will have a field of specialist interest. The aim of this cross-sectional multi-national study was to identify the key areas of interest among trainees or junior specialists, assess the potential influence of an interest in research, and consider the results in light of population needs. METHODS: A total of 300 residents and junior neurologists who received a bursary to attend the European Academy of Neurology conference were invited to participate in this study. Demographic and work-related characteristics, as well as main subspecialty of choice were examined via an anonymous electronic questionnaire. Participants holding a higher degree (PhD/MD) or working in research posts were considered research oriented. RESULTS: In total, 191 Neurologists in training or junior specialists responded (response rate 63.7%). Full data were available for 187 participants (59.4% females). The study sample had a mean age of 30.5±3.4 years (range 25 - 45). The most popular subspecialty was movement disorders (18.2%), followed by multiple sclerosis (11.2%) and epilepsy (10.2%). This did not differ significantly between the participants who were or were not research-oriented. CONCLUSIONS: There is a potential mismatch between the interests of trainees, and the future needs of the populations they serve, which it is important to identify for workforce planning

Dopaminergic Modulation of Sensory Attenuation in Parkinson's Disease: Is There an Underlying Modulation of Beta Power?

Background and Aims: Pathological high amplitude of beta oscillations is thought as the underlying mechanism of motor symptoms in Parkinson's disease (PD), in particular with regard to bradykinesia. In addition, abnormality in a neurophysiological phenomenon labeled sensory attenuation has been found in patients with PD. The current study explored the hypothesis that the abnormal sensory attenuation has a causal link with the typical abnormality in beta oscillations in PD. Methods: The study tested sixteen right-handed patients with a diagnosis of PD and 22 healthy participants, which were matched by age and gender. Somatosensory evoked potentials were elicited through electrical stimulation of the median nerve at the wrist. Electrical activity was recorded at the scalp using a 128 channels EEG. Somatosensory evoked potentials were recorded in 2 conditions: at rest and at the onset of a voluntary movement, which was a self-paced abduction movement of the right thumb. Results: Healthy participants showed a reduction of the N20-P25 amplitude at the onset of the right thumb abduction compared to the rest condition (P < 0.05). When patients were OFF medication, they showed mild reduction of the N20-P25 component at movement onset (P < 0.05). On the contrary, they did show greater attenuation of the N20-P25 component at the onset of movement compared to the rest condition when ON medication (P < 0.05). There was no significant evidence of a link between the degree of sensory attenuation and the change in beta oscillations in our cohort of patients. Conclusion: These results confirmed a significant link between dopaminergic modulation and sensory attenuation. However, the sensory attenuation and beta oscillations were found as two independent phenomena

High-frequency peripheral vibration decreases completion time on a number of motor tasks.

A recent theoretical account of motor control proposes that modulation of afferent information plays a role in affecting how readily we can move. Increasing the estimate of uncertainty surrounding the afferent input is a necessary step in being able to move. It has been proposed that an inability to modulate the gain of this sensory information underlies the cardinal symptoms of Parkinson's disease (PD). We aimed to test this theory by modulating the uncertainty of the proprioceptive signal using high-frequency peripheral vibration, to determine the subsequent effect on motor performance. We investigated if this peripheral stimulus might modulate oscillatory activity over the sensorimotor cortex in order to understand the mechanism by which peripheral vibration can change motor performance. We found that 80 Hz peripheral vibration applied to the right wrist of a total of 54 healthy human participants reproducibly improved performance across four separate randomised experiments on a number of motor control tasks (nine-hole peg task, box and block test, reaction time task and finger tapping). Improved performance on all motor tasks (except the amplitude of finger tapping) was also seen for a sample of 18PD patients ON medication. EEG data investigating the effect of vibration on oscillatory activity revealed a significant decrease in beta power (15-30 Hz) over the contralateral sensorimotor cortex at the onset and offset of 80 Hz vibration. This finding is consistent with a novel theoretical account of motor initiation, namely that modulating uncertainty of the proprioceptive afferent signal improves motor performance potentially by gating the incoming sensory signal and allowing for top-down proprioceptive predictions

Objective, computerized video-based rating of blepharospasm severity

OBJECTIVE: To compare clinical rating scales of blepharospasm severity with involuntary eye closures measured automatically from patient videos with contemporary facial expression software. METHODS: We evaluated video recordings of a standardized clinical examination from 50 patients with blepharospasm in the Dystonia Coalition's Natural History and Biorepository study. Eye closures were measured on a frame-by-frame basis with software known as the Computer Expression Recognition Toolbox (CERT). The proportion of eye closure time was compared with 3 commonly used clinical rating scales: the Burke-Fahn-Marsden Dystonia Rating Scale, Global Dystonia Rating Scale, and Jankovic Rating Scale. RESULTS: CERT was reliably able to find the face, and its eye closure measure was correlated with all of the clinical severity ratings (Spearman ρ = 0.56, 0.52, and 0.56 for the Burke-Fahn-Marsden Dystonia Rating Scale, Global Dystonia Rating Scale, and Jankovic Rating Scale, respectively, all p < 0.0001). CONCLUSIONS: The results demonstrate that CERT has convergent validity with conventional clinical rating scales and can be used with video recordings to measure blepharospasm symptom severity automatically and objectively. Unlike EMG and kinematics, CERT requires only conventional video recordings and can therefore be more easily adopted for use in the clinic

Tremor and dysmetria in multiple sclerosis: a neurophysiological study

Objective: The mechanisms contributing to the pathogenesis of tremor and/or dysmetria in multiple sclerosis (MS) are poorly understood. Abnormal oscillations within the olivo-cerebello-thalamo-cortical networks are believed to play an important part in tremor aetiology, but could also contribute to intention dysmetria due to disruptions in motor timing. Conversely, delayed central motor conduction times are a common feature of ataxias, but could also contribute to the expression of dysmetria in MS. This study examined the roles of central conduction delays in the manifestation of tremor and/or dysmetria in MS. Methods: Twenty-three individuals with MS participated: 8 with no movement disorder, 6 with tremor, 4 with pure dysmetria and 5 with both tremor and dysmetria. Median nerve somatosensory evoked potentials (SEPs), transcranial magnetic stimulation (TMS) over the motor cortex and cervical spine, stretch reflexes were used assess sensory and motor conduction times. Results: Central, but not peripheral, sensory conductions time were significantly delayed in participants with dysmetria, regardless of the presence of tremor. Similarly, the TMS evoked muscles responses and the long-latency component of stretch reflexes were significantly delayed in those with dysmetria, but not pure tremor. Conclusion: Dysmetria in MS is associated with delays in central conduction of sensory or motor pathways, or both, likely leading to disruption of muscle activation timing and terminal oscillations that contribute to dysmetria. Significance: The presence of dysmetria in MS is associated with decreased conduction velocities in central sensory and/or motor pathways likely reflects greater demyelination of these axons compared to those with no movement disorder or pure tremor

Peripheral trauma and risk of dystonia: What are the evidences and potential co-risk factors from a population insurance database?

BACKGROUND: Dystonia is a neurological syndrome typically resulting in abnormal postures. OBJECTIVES: We tested the role of physical injury as potential risk factor for development of dystonia using The National Health Insurance Research Database of Taiwan. METHODS: We identified 65704 people who were coded in the database as having had peripheral traumatic injuries (ICD-9-CM 807-848 and 860-959) in the year 2000. Patients with traumatic brain or spine injuries were excluded from analysis. We matched them using purposive sampling with 65704 people in the database who had not suffered peripheral trauma. We looked then at the incidence of dystonia occurring at least 1 year from the date of the peripheral trauma until 2011. Psychiatric symptoms (depression and anxiety) and sleeps difficulties have been investigated as potential covariates. RESULTS: We found 189 patients with dystonia (0.28%) in the trauma group, and 52 patients with dystonia (0.08%) in the non-trauma group. Trauma was independently associated with dystonia (adjusted HR = 3.12, 95% CI = 2.30-4.24). The incidence density of dystonia in the trauma group was 2.27 per 10000 person-years, while it was 0.71 per 10000 person-years in the non-trauma group Beyond the peripheral trauma, other variables associated to the incidence of dystonia included female sex, aged 40 years and above, depression and sleep disorders. CONCLUSION: These data from a large population dataset support traumatic injury as a risk factor for the development of dystonia