Vestibulogenic ‘pseudoseizures’

s analysed scores for eight patients tested identically following amytal (30-40 mg) injected directly into a posterior cerebral artery (PCA), to the inactivate hippocampus without causing aphasia. Mean scores (maximum = 8) by dominance/pathology were: for ISA normal D = 6.4 ND = 4.2, pathological D = 35 ND = 21; for PCA, normal D = 7.5 ND = 7.7, pathological D = 5.0 ND = 2.0. On ISA normal D vs. ND differ significantly (P < 0.05). The difference disappears on PCA. So, it is not due to primarily mnestic factors, and should be allowed for in assessing ND normality on ISA. The aim of the study was to identify possible disturbances of sensorimotor gating and of habituation of the eye-blink response in patients with non-epileptic seizures (NESS). Prepulse inhibition (PPI), as an operational measure of sensorimotor gating and habituation was studied in 21 patients with NESS and 22 healthy controls. Six NESS patients were taking anti-epileptic drugs (AEDs) at the time of testing. The PPI was significantly impaired in the NESS group compared with the controls (P < 0.05), with deficits being greater in unmedicated patients (P = 0.01). There was a trend for medicated NESS patients to show higher PPI than unmedicated patients, but this was not significant (P = 0.08). Habituation was intact in both medicated and unmedicated NESS patients. It is proposed that deficits of information processing related to sensorimotor gating in patients with NESS may be associated with abnormalities within the limbic system-basal ganglia circuitry which have been shown to be the substrate of 'gating' assessed by PPI. This study suggests that such impairment may be improved by AEDs. It was also found that anxiety had a role in the deterioration of PPI in the NESS group. Eight cases are presented. All the patients experienced bouts of altered consciousness, five had the diagnosis of epilepsy. Features, which had suggested the diagnosis of epilepsy included blackouts , trance-like behaviour or unresponsiveness, gaze fixation, urinary incontinence and disordered behaviour during the bouts. After comprehensive neurological and vestibular testing the diagnosis was revised. A history of vertigo, defined as the illusion ofmovement, preceding or following the ictus, the frequency of the attacks with little cognitive dysfunction but with a greater impact on handicap, the lack of response to anticonvulsants and, in some cases a normal electroencephalogram (EEG) or one with non-specific features raised doubts about the diagnosis. …