FM latency, FM ratio, F-wave latency versus F-wave index in the diagnosis of diabetic neuropathy

Abstract

Abstract Background Diabetes is one of the most common causes for peripheral neuropathy which warrants early diagnosis and treatment. The conventional nerve conduction studies appear to be normal if few of the nerve roots are escaping the lesion. In view of identifying a better clinical testing method, a late response index comprising most of the parameter of F wave was constructed and compared with the diagnosing ability of other parameters. Methods This hospital-based cross-sectional study was conducted among male diabetics aged 30 to 50 years in a tertiary care hospital. Maintaining an ambient temperature of 28 °C and following a supramaximal stimulation of the median nerve of both upper limbs, using a digitalized nerve conduction/electromyography/EP machine, the F-wave tracing was obtained. Results The F-wave index detected a greater number of subjects with diabetic peripheral neuropathy when compared to F-wave mean latency, F M latency and F–M ratio. Conclusion F-wave index can be used as a surrogate electrophysiological study to detect peripheral neuropathy at an early stage and aids in better prognosis.

Keywords

• F wave
• F index
• Median nerve
• F–M ratio
• FM latency