Tremor with cerebellar and cortical atrophy is associated with a CAG repeat expansion. Two individuals studied had nondisabling neurologic signs neonatally, including nystagmus and lower extremity dystonia. Brain images of affected individuals revealed cerebral and cerebellar atrophy. SCA-12 is a slowly progressive, autosomal dominant, neurodegenerative disorder that differs from other SCA in that it typically presents with action tremor in patients in their mid 30s and usually includes hyperreflexia and subtle parkinsonian signs. Cerebellar dysfunction, including gait ataxia, is relatively nondisabling, and cognitive or psychiatric disorders may occur.
Neuroradiologic studies reveal atrophy of the cerebellum and cerebral cortex.
The measurement of fusional vergence ranges is an important clinical test in the assessment of binocular vision status. Published reliability data on fusional vergence ranges are very limited. Eight subjects underwent four testing sessions, at which repeated measurements of fusional vergence ranges were taken. Near ranges were tested at the first session only Distance ranges were tested at all four sessions. Intra-examiner standard deviations were averaged.