Pattern reversal visual evoked potentials (prVEPs) in autosomal recessive hereditary spastic paraplegia with thin corpus callosum (ARHSPTCC) patients with SPG 11 mutations in Saudi Arabia (P2.206)

Objective: To retrospectively report prVEPs in patients with SPG11 ARHSP-TCC.

Background: ARHSPTCC is a type of complicated hereditary spastic paraparesis y caused by SPG11 mutations. ARHSPTCC is characterized by thin corpus callosum, progressive spastic paraparesis, cognitive decline, and axonal neuropathy. Also seizures, cerebellar ataxia, speech and swallowing problems, extra pyramidal signs and skeletal deformities may occur. The neuroradiological findings include thinning of the anterior corpus callosum (TCC), periventricular white matter changes and cortical atrophy. Electromyography and nerve conduction studies may reveal an axonal neuropathy or anterior horn involvement. However, optic nerve involvement and prVEPs have not been well described.

Design/Methods: Routine prVEPs were performed in 8 patients with genetically confirmed (Athena Diagnostic USA) SPG11 ARHSPTCC. Independent stimulation of each eye with full field checkerboard pattern reverse stimulation technique was performed at a frequency of 1.5 Hz, checker size 12 × 16, sweep time 30ms/D and sensitivity 5 uV/D using a montage of Oz-Fz. Repetitive waveforms were obtained using averaging and the P-100 was recorded.

Results: Eight subjects, aged 17 to 37 years were studied, 4 of which were female. Five subjects were from consanguineous parents. Five had a positive family history and 2 were siblings. All subjects had thin corpus callosum on brain MRI. Additionally, 5 subjects had diffuse brain atrophy, one with cerebellum and brainstem atrophy. Six subjects had bilaterally abnormal prVEPs. The mean absolute P100 latencies of the left eye was 124ms, S.D. +/−10.9 ms and a mean amplitude 6.06 μV, SD +/− 2.2 μV. The right eye had mean P100 of 128.8ms, SD 14.8ms and a mean amplitude 5.77 μV, SD +/−2.8 μV.

Conclusions: Abnormal prVEPs occur in 75% of our subjects with significantly prolonged P100 bilateral responses. The visual pathways are affected in patients with SPG11 ARHSPTCC however no specific mutation is predominant. prVEPs should be included in the routine evaluation spastic pareparesis

Disclosure: Dr. Al-Faidi has nothing to disclose. Dr. Ali has nothing to disclose. Dr. Al Said has nothing to disclose. Dr. Karim has nothing to disclose. Dr. Khan has nothing to disclose. Dr. Bohlega has nothing to disclose. Dr. Cupler has received personal compensation for activities with Sanofi as a member of their speaker bureau.