Auditory middle latency-evoked potentials during sleep apnea.

Auditory middle-latency evoked potentials (AMEP) were recorded in 10 subjects with predominantly central sleep apnea. AMEP were recorded during: waking; non-rapid eye movement (non-REM) sleep between apneic episodes; first half of apneas; and second half of apneas. Latencies of vertex positive peaks Po and Pa were determined, and the effect of the apnea phase on these latencies was evaluated. The latencies measured did not reveal chronic or acute functional abnormality of central auditory structures, which may result from or cause apneic episodes during non-REM sleep. The normalcy and stability of AMEP during apneic sleep may indicate effective compensatory mechanisms in central auditory structures. Alternatively, the lack of changes may result from the variability of AMEP, which may obscure small functional changes.