Spinocerebellar Ataxia Type 6 Concurrent with Normal-Pressure Hydrocephalus: A Case Report
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Updated: Nov 6, 2026

Neuronavigation and Laparoscopy Guided Ventriculoperitoneal Shunt Insertion for the Treatment of Hydrocephalus
Published on: October 14, 2022
Rei Yazaki1, Yuka Hosaka1, Yutaka Oji2
1Department of Neurology, Juntendo University Faculty of Medicine, Tokyo, Japan.
Abstract:
Gait disturbance in hereditary cerebellar ataxia may obscure coexisting, potentially treatable disorders. We describe a patient with genetically confirmed spinocerebellar ataxia type 6 (SCA6) and coexisting idiopathic normal-pressure hydrocephalus (iNPH) whose gait disturbance partially improved after cerebrospinal fluid drainage and shunting. A 73-year-old Japanese man with progressive gait disturbance over 2 years exhibited gaze-evoked nystagmus, dysarthria, bilateral limb ataxia, and a broad-based shuffling gait. The patient also reported urinary urgency. Brain magnetic resonance imaging revealed disproportionately enlarged subarachnoid-space hydrocephalus and cerebellar atrophy. Genetic testing identified a heterozygous CAG repeat expansion in CACNA1A (22/13 repeats), consistent with SCA6. After a cerebrospinal fluid tap test, the mean 3-m Timed Up-and-Go time decreased from 52 to 37 s by day 7. Following lumboperitoneal shunting, the International Cooperative Ataxia Rating Scale posture and gait subscore improved from 21 to 15, whereas the limb coordination subscore worsened from 15 to 20. Postural sway area decreased from 9.37 to 5.77 cm2. Gait improvement was maintained at 6 months, while cerebellar signs persisted. The differential response to shunting suggests a hydrocephalic contribution to gait and postural impairment alongside persistent SCA6-related cerebellar dysfunction. Coexisting iNPH should be considered in patients with hereditary ataxia when suggestive clinical and imaging features are present, as identifying a shunt-responsive component may provide meaningful symptomatic benefit.
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