Abstracts

Objective: To identify polysomnographic differences among patients with non-syndromic hypothalamic hamartomas and seizures and patients with hypothalamic hamartomas associated with Pallister-Hall Syndrome (PHS).
The hypothalamus plays a key role in the regulation of sleep. Preliminary evidence suggests that sleep architecture, especially during rapid eye movement (REM) sleep, is altered in patients with non-syndromic hypothalamic hamartomas. The mechanism by which this occurs is not clear. To better understand this process, we collected preliminary data on two groups of patients with hypothalamic hamartomas. Group one patients have non-syndromic (sporadic) hypothalamic hamartomas and group two patients have hypothalamic hamartomas associated with Pallister-Hall Syndrome (PHS), an autosomal dominant disease, associated with hypothalamic hamartomas, central polydactyly, pituitary dysplasia/hypopituitarism, bifid epiglottis, and visceral anomalies.
METHODS: Eight patients each underwent two nights of polysomnography (PSG). Ten nights of PSG data was available for the six patients with nonsyndromic hypothalamic hamartomas and four nights of PSG data was available for the two patients who had hypothalamic hamartomas associated with PHS. PSG data was analyzed for: latency to sleep onset, REM latency, percentage of time spent in each sleep stage, sleep efficiency, and presence of epileptiform discharges during the recording.
RESULTS: No significant differences were seen between the two groups with regard to sleep efficiency, latency to sleep onset, and percentage of time spent in non-REM sleep. However, a significant increase in REM latency and decrease in the percentage of time spent in REM sleep was seen in the non-syndromic group (mean 5.3%) when compared with the PHS group (mean 20.2%), who had normal REM latencies and REM durations. In the non-syndromic group, the characteristic bursts of rapid eye movement were more subtle and REM sleep was less sustained than in the PHS group. All six patients with non-syndromic hypothalamic hamartomas had a history of seizures and all had spike-wave discharges during PSG. There was a nonstatistically significant trend towards increased seizure frequency with decreased time spent in REM sleep. Neither of the PHS patients had a history of seizures and no spike-wave discharges were seen during PSG.
CONCLUSIONS: Sleep structure in the group with hypothalamic hamartoma associated with PHS was relatively preserved. However, the quality and quantity of REM sleep in the group of patients with non-syndromic hypothalamic hamartomas was disrupted. The correlation of seizure frequency with amount of time spent in REM sleep requires further investigation. The presence of a hypothalamic hamartoma may not by itself account for disruption of REM sleep in individuals with non-syndromic hypothalamic hamartomas.
[Supported by: NINDS Intramural Program]