Brainstem auditory evoked response recorded using maximum length sequencesin term neonates

Brainstem auditory evoked response (BAER) was studied in term neonates usin g maximum length sequences (MLS), which allows presentation of acoustic sti muli at much higher rate than possible with conventional averaging techniqu e. The response waveforms, especially for waves III and V, were well define d at the click rates of 91-455/s. Wave latencies and interpeak intervals at various click rates were all significantly longer and wave V amplitude was smaller in the neonates than in the adults. As click rate was increased, w ave latencies increased and amplitudes progressively reduced. The slopes of wave latency-rate functions were progressively steeper for the later waves . The sio pes of both III-V and I-V interval-rate functions were significan tly steeper in the neonates than in the adults, indicating greater rate-dep endent changes in the central components of the neonatal MLS BAER. These ra te-dependent changes in the neonatal MLS BAER are generally similar to thos e in neonatal conventional BAER, although there are some differences. The r esults indicate that the neonatal brainstem can process rapid acoustic stim ulation up to 455/s, although this ability remains immature.