Spinocerebellar degeneration and slow saccades in three generations of a kinship: clinical and electrophysiologic findings.

Four members of a family with spinocerebellar degeneration and slow saccadic eye movements are described. Detailed electrophysiological studies revealed abnormalities of neurological pathways not apparent clinically. The patients had slow saccades as measured electrophysiologically, as well as absence of rapid eye movements (REM) despite REM stages of sleep. These studies suggest that although saccadic eye movement and REM are mediated through the pontine paramedian reticular formation, other characteristics of REM sleep are not necessarily mediated through the same neurons.