Myasthenia gravis seven years after removal of an invasive thymoma.

This report describes a 59-year-old male who developed myasthenia gravis 92 months following excision of an invasive thymoma, in the absence of tumour recurrence. This report highlights the importance of prolonged clinical surveillance in post-thymectomy patients.

Changes in axonal excitability and burst pattern behaviour in synkinesis.

Synkinesis after severe facial nerve paralysis has been related to the processes of aberrant reinnervation and increased excitability of the facial nucleus. We present the electrophysiological features of synkinesis in a 32-year-old woman who developed grouped 'myokymic-like' discharges with eye blinking in the absence of spontaneous muscle activity. With eye blinks, the interspike intervals of discharges in the orbicularis oris varied between 25-150Hz, overlapping with rates of myokymia and neuromyotonia.

Sway patterns in orthostatic tremor: impairment of postural control mechanisms.

Sway parameters in orthostatic tremor (OT) patients were compared with age-matched controls. The effects of vision (eyes open or closed), stance width (feet apart or together), and external support (with or without) on sway and 14-18 Hz energy were measured. Sway in OT patients decreased in the presence of each of the stabilizing factors but the extent of benefit obtained by OT patients was significantly less than controls for support for the sagittal plane (22% vs.

Sway patterns in a case of orthostatic tremor responsive to alcohol.

We describe changes in the extent of sway in a man with orthostatic tremor (OT) who reported increased stability after alcohol. He was tested at baseline and again after 40 g (0.5 g/kg) of alcohol.

Evidence for reflex and perceptual vestibular contributions to postural control.

Vestibular signals are known to have an important role in stance under specific conditions. Potentially these effects could be modulated by vestibular reflexes or by voluntary responses to perceived vestibular signals. Our preliminary aim was to confirm that vestibulospinal reflexes change in parallel with sway under different postural conditions, and then to determine whether any relationship was present between these reflexes and body sway within fixed postural conditions.

Anodal vestibular stimulation does not suppress vestibular reflexes in human subjects.

Anodal current applied to the vestibular apparatus has previously been found to inhibit discharge from irregular vestibular afferents in squirrel monkeys. We wished to investigate whether anodal currents applied over the mastoid processes of human subjects would significantly reduce ongoing vestibular activity and thereby the size of galvanic-evoked vestibulospinal reflexes, measured by soleus electromyogram. Nine subjects were tested, of whom six subjects (five females, one male) provided data for the final analysis.

Galvanic and acoustic vestibular stimulation activate different populations of vestibular afferents.

Objective: To deduce whether similar or distinct populations of vestibular afferents are activated by acoustic and galvanic vestibular stimulation by comparing the effectiveness of 'matched' stimuli in eliciting vestibulospinal reflexes.

Methods: Twelve subjects (5 men, 7 women) underwent individual 'matching' of 2 ms tone burst and galvanic stimuli, using vestibulocollic reflexes so that corrected reflex amplitudes to tone burst and galvanic stimuli were within 10% of each other. These same intensities were then administered using 20 ms durations to determine whether they were equally effective in evoking vestibulospinal responses.