Bright light therapy with a head-mounted device for anxiety, depression, sleepiness and fatigue in patients with Parkinson's disease.

The beneficial effects of bright light therapy (BLT) on the disabling non-motor symptoms of Parkinson's disease (PD) remain uncertain. The objective of this study was to investigate if daily BLT, with a head-mounted device (Luminette®), has a beneficial effect on depression, anxiety, daytime sleepiness and fatigue in patients with PD. In this double-blind, placebo-controlled study, 16 patients with PD were randomized to receive either 1 month of BLT or 1 month of placebo therapy, separated by a 2-week washout period, in a crossover fashion. Patients completed questionnaires for the Hospital Anxiety and Depression Scale (HADS), the Epworth Sleepiness Scale (ESS) and the Fatigue Impact Scale (FIS) before and after each treatment period. The primary outcome measures were changed from baseline in scores between treatment groups. No significant changes were observed in the HADS anxiety scores and FIS scores after BLT and after placebo. The ESS scores decreased non-significantly only after BLT. A post hoc analysis of patients who had baseline ESS scores > 11 revealed a significantly greater decrease in ESS scores after BLT than after placebo. Future studies investigating the effect of BLT on sleepiness could focus specifically on patients with high ESS scores.

Increased functional connectivity one week after motor learning and tDCS in stroke patients.

Recent studies using resting-state functional magnetic resonance imaging (rs-fMRI) demonstrated that changes in functional connectivity (FC) after stroke correlate with recovery. The aim of this study was to explore whether combining motor learning to dual transcranial direct current stimulation (dual-tDCS, applied over both primary motor cortices (M1)) modulated FC in stroke patients. Twenty-two chronic hemiparetic stroke patients participated in a baseline rs-fMRI session. One week later, dual-tDCS/sham was applied during motor skill learning (intervention session); one week later, the retention session started with the acquisition of a run of rs-fMRI imaging. The intervention+retention sessions were performed once with dual-tDCS and once with sham in a randomized, cross-over, placebo-controlled, double-blind design. A whole-brain independent component analysis based analysis of variance (ANOVA) demonstrated no changes between baseline and sham sessions in the somatomotor network, whereas a FC increase was observed one week after dual-tDCS compared to baseline (qFDR <0.05, t63=4.15). A seed-based analysis confirmed specific stimulation-driven changes within a network of motor and premotor regions in both hemispheres. At baseline and one week after sham, the strongest FC was observed between the M1 and dorsal premotor cortex (PMd) of the undamaged hemisphere. In contrast, one week after dual-tDCS, the strongest FC was found between the M1 and PMd of the damaged hemisphere. Thus, a single session of dual-tDCS combined with motor skill learning increases FC in the somatomotor network of chronic stroke patients for one week.

Neural substrates underlying motor skill learning in chronic hemiparetic stroke patients.

Motor skill learning is critical in post-stroke motor recovery, but little is known about its underlying neural substrates. Recently, using a new visuomotor skill learning paradigm involving a speed/accuracy trade-off in healthy individuals we identified three subpopulations based on their behavioral trajectories: fitters (in whom improvement in speed or accuracy coincided with deterioration in the other parameter), shifters (in whom speed and/or accuracy improved without degradation of the other parameter), and non-learners. We aimed to identify the neural substrates underlying the first stages of motor skill learning in chronic hemiparetic stroke patients and to determine whether specific neural substrates were recruited in shifters versus fitters. During functional magnetic resonance imaging (fMRI), 23 patients learned the visuomotor skill with their paretic upper limb. In the whole-group analysis, correlation between activation and motor skill learning was restricted to the dorsal prefrontal cortex of the damaged hemisphere (DLPFCdamh: r = -0.82) and the dorsal premotor cortex (PMddamh: r = 0.70); the correlations was much lesser (-0.16 < r > 0.25) in the other regions of interest. In a subgroup analysis, significant activation was restricted to bilateral posterior parietal cortices of the fitters and did not correlate with motor skill learning. Conversely, in shifters significant activation occurred in the primary sensorimotor cortexdamh and supplementary motor areadamh and in bilateral PMd where activation changes correlated significantly with motor skill learning (r = 0.91). Finally, resting-state activity acquired before learning showed a higher functional connectivity in the salience network of shifters compared with fitters (qFDR < 0.05). These data suggest a neuroplastic compensatory reorganization of brain activity underlying the first stages of motor skill learning with the paretic upper limb in chronic hemiparetic stroke patients, with a key role of bilateral PMd.

Neural substrates underlying stimulation-enhanced motor skill learning after stroke.

Motor skill learning is one of the key components of motor function recovery after stroke, especially recovery driven by neurorehabilitation. Transcranial direct current stimulation can enhance neurorehabilitation and motor skill learning in stroke patients. However, the neural mechanisms underlying the retention of stimulation-enhanced motor skill learning involving a paretic upper limb have not been resolved. These neural substrates were explored by means of functional magnetic resonance imaging. Nineteen chronic hemiparetic stroke patients participated in a double-blind, cross-over randomized, sham-controlled experiment with two series. Each series consisted of two sessions: (i) an intervention session during which dual transcranial direct current stimulation or sham was applied during motor skill learning with the paretic upper limb; and (ii) an imaging session 1 week later, during which the patients performed the learned motor skill. The motor skill learning task, called the 'circuit game', involves a speed/accuracy trade-off and consists of moving a pointer controlled by a computer mouse along a complex circuit as quickly and accurately as possible. Relative to the sham series, dual transcranial direct current stimulation applied bilaterally over the primary motor cortex during motor skill learning with the paretic upper limb resulted in (i) enhanced online motor skill learning; (ii) enhanced 1-week retention; and (iii) superior transfer of performance improvement to an untrained task. The 1-week retention's enhancement driven by the intervention was associated with a trend towards normalization of the brain activation pattern during performance of the learned motor skill relative to the sham series. A similar trend towards normalization relative to sham was observed during performance of a simple, untrained task without a speed/accuracy constraint, despite a lack of behavioural difference between the dual transcranial direct current stimulation and sham series. Finally, dual transcranial direct current stimulation applied during the first session enhanced continued learning with the paretic limb 1 week later, relative to the sham series. This lasting behavioural enhancement was associated with more efficient recruitment of the motor skill learning network, that is, focused activation on the motor-premotor areas in the damaged hemisphere, especially on the dorsal premotor cortex. Dual transcranial direct current stimulation applied during motor skill learning with a paretic upper limb resulted in prolonged shaping of brain activation, which supported behavioural enhancements in stroke patients.

Disappearance of essential tremor after stroke.

Improvement of a patient's essential tremor (ET) after a stroke has rarely been reported. In such patients, cerebral imaging could help to identify structures involved in the maintenance of ET and improves the knowledge of its physiopathology. This article reports the disappearance of ET, after a stroke in 4 patients and reviews similar previously published cases. These cases suggest that the interruption of cerebellar loops during a stroke could be responsible for the disappearance of ET.

Impaired osmoregulation in anorexia nervosa: a case-control study.

BACKGROUND: Anorexia nervosa (AN) has been associated with abnormal osmoregulation and impaired urinary concentrating capacity. Conflicting results suggest that the disorder may be related to hypothalamic dysfunction and/or a primary renal defect. The role of antidepressants, which are increasingly prescribed in AN patients, has not been evaluated. METHODS: We analysed renal function as well as electrolyte disturbances and osmoregulation parameters at baseline and following a water deprivation test in 12 well-defined AN patients (all females, 10 taking antidepressants) vs 12 age-matched controls and 11 young female patients taking antidepressants. RESULTS: In comparison with matched controls, patients with AN were characterized by a significant alteration of osmoregulation both at baseline [lower plasma sodium and osmolality, abnormally high levels of antidiuretic hormone (ADH) and tendency towards more concentrated urine] and after water deprivation (impaired ADH reaction and lower urinary concentrating ability). The AN patients had no electrolyte abnormalities. The two patients with the shortest duration of AN showed a normal urinary concentrating ability. Patients taking antidepressants showed similar but less marked changes than AN patients, including a lower urinary concentrating ability. CONCLUSIONS: These results show that AN patients are characterized by abnormal osmoregulation at baseline and a lack of reactivity of ADH with a significant urinary concentrating defect after water deprivation. The origin of these defects in AN patients is probably multifactorial, but the duration of the disease and the prescription of antidepressants could play a role.