Objective: To retrospectively report prVEPs in SPG11 ARHSP-TCC.
Background: ARHSPTCC is characterized by a thin corpus callosum, progressive spastic paraparesis, cognitive decline,and axonal neuropathy by SPG11 mutations. Additionally, seizures, cerebellar ataxia, speech and swallowing problems, extrapyramidal signs, and skeletal deformities may occur. Neuroradiological findings include thinning of the anterior corpus callosum (TCC), periventricular white matter changes, and cortical atrophy. Electromyography and nerve conduction studies may reveal axonal neuropathy or anterior horn involvement. However, optic nerve involvement and prVEPs have not been well described.
Design/methods: Routine prVEPs were performed in 11 subjects with genetically confirmed (Athena Diagnostic USA) SPG11 ARHSPTCC. Independent stimulation of each eye with a full-field checkerboard pattern reverse stimulation technique was performed. Repetitive waveforms were averaged and the P-100 was recorded.
Results: Eleven subjects aged 20 to 37 years were studied, 5 were female. Nine were from consanguineous parents. Nine had a family history and 3 pairs were siblings. Nine had TCC, 8 had diffuse brain atrophy and 1 had cerebellum and brainstem atrophy. Additionally, 9 had bilaterally abnormal prVEPs. The mean P100 latency of the left eye was 129.45 ms±19.47, and a mean amplitude of 7 μV±2.33, while the right had a mean P100 of 127.72 ms±12.69, and mean amplitude of 6.74 μV±2.84.
Conclusions: Abnormal prVEPs occurred in 81.82% of our subjects with significantly prolonged P100 bilateral responses. This indicates that the visual pathway is affected in patients with SPG11 ARHSPTCC. However, no specific mutation was predominant. prVEPs should be considered in the routine evaluation for spastic paraparesis.
Keywords: Hereditary spastic paraparesis; Optic nerve disease; SPG11; Thin corpus callosum.
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