Brain dysfunction explored by long latency reflex: a study of adrenomyeloneuropathy

Objectives - We can assess brain function by measuring the cortical relay time (CRT) of long latency reflex (LLR) of hand muscle. We would study if measurement of CRT of LLR can explore the brain involvement of adrenomyeloneuropathy (AMN). Methods - Two AMN patients were included in the study. Both of them had spastic gait and mild sensory deficits but normal mental function. The LLRs were provoked at the first dorsal interosseous muscle by electrical stimulation of the middle finger. We measured the latency of LLR and its CRT. Results - Delayed LLR and prolonged CRT were noted in AMN patients, even though the magnetic resonance imaging of brain did not show any significant abnormalities. Conclusions - Measuring CRT of LLR reveals brain involvement of AMN patients, and it is an adjunct in the assessment of brain function though without specific anatomic diagnosis.