Sympathetic skin response, cutaneous silent period and nociceptive flexion reflex in Fabry disease

Background & Objective: Fabry disease is one of the well-known causes of the small fiber neuropathy. This study aims to explore small and large nerve fiber functions in patients with Fabry disease without using any extra equipment in a standard neurophysiology laboratory. Methods: Patients with Fabry disease at our tertiary center were invited to the electrophysiology laboratory. Routine nerve conduction studies (NCS), sympathetic skin response (SSR), cutaneous silent period (CSP) and nociceptive flexion reflex (NFR) tests were performed. The same protocol was applied to matched healthy subjects. Results: Nineteen patients and 19 healthy controls were included. Carpal tunnel syndrome was diagnosed in 3 patients (15.9%). Palmar and plantar SSRs could not be obtained in 4 and 9 patients, respectively. Abnormal CSP responses in the upper and lower extremities were recorded in 2 and 7 patients, respectively. The NFR response was abnormal in 8 patients. In total, at least one of the SSR, CSP or NFR was abnormal in 73.7% of patients.Conclusions: The study showed that combining SSR, CSP and NFR tests along with NCS could help to determine any abnormality in small and large fiber functions in most patients. The overall sensitivity of all tests was approximately 70% compared with the clinical diagnosis of small fiber neuropathy. This study is unique in that it explored a combination of NCS, SSR, CSP and NFR tests in Fabry disease.