[Neurophysiological study in Alpers syndrome]

Infantil progressive polydystrophy was described by Alpers in a child with psychomotor retardation, crises which were resistant to treatment and diffuse loss of cortical neurons.

The aim of this study was to review the neurophysiological aspects of Alpers syndrome and their clinical correlation.

We present three children with subacute encephalopathy, progressive psychomotor retardation, myoclonic epilepsy which was resistant to treatment and crises of apnea, who had degeneration of the cerebral grey matter. Serial EEG, polysomnographs, auditory evoked potentials of the brain stem and visual evoked potentials were done.

The electroencephalogram findings showed the presence of complex bursts of acute waves, small many-pointed or slow waves of great amplitude which were irregular and arrhythmical, lasting one to five seconds, separated by periods of inactivity on the tracing which lasted from three to ten seconds. The EEG was distinctive, changing over the course of the illness, and with increasing numbers and duration of the bursts of suppression of cerebral bioelectric activity. Polysomnography showed cerebral bioelectric activity which was markedly unstructured and with little difference between the tracings when asleep and when awake, together with a large number of apneas of obstructive and mixed types. The PEAT showed reduced amplitude and altered morphology in all the waves, and even absence of some of them. The visual evoked potentials were asymmetrical and with delay in the latency of the P100 wave.

Although definite diagnosis of progressive neurone degeneration requires post mortem examination of the brain, clinico-pathological studies, including electrophysiological, radiological and biochemical studies are sufficiently characteristic to suggest the diagnosis during life.