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.

No abstract

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.

We report a case of Takotsubo syndrome after epilepsy, and review the literature. We identified 59 cases of Takotsubo syndrome after focal or generalised epilepsy. As in Takotsubo syndrome in general, the patients were mostly female (84%), with a mean age of 63 years, and the evolution was generally favourable. There was one death and one stroke, and 4 cases were of relapsing Takotsubo after a new seizure. Takotsubo syndrome may induce cardiac arrhythmias. A near-SUDEP (sudden unexplained death in epilepsy) was reported in one patient. Animal models of SUDEP have shown similar cardiac lesions to those seen in Takotsubo syndrome, and strengthen the hypothesis of a link between these conditions. Takotsubo syndrome after epilepsy may be relatively common; we suggest measurement of serum troponin levels in high-risk patients and cardiac follow-up.

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.