Maximum length sequences -- a fast method for measuring brain-stem-evoked responses.

A technique is described which allows faster evaluation of brain-stem-evoked responses (BER) than the conventional method. It is based on a pseudorandom arrangement of the click stimuli in "maximum length sequences' (MLS). In this way, the responses to each click stimulation can overlap with the responses to other clicks. A simple deconvolution of the averaged response to MLS leads to a click response pattern which is in good agreement with the responses obtained by conventional BER audiometry (BERA). Thus, the procedure for the assessment of BER can be accelerated by a factor of about 6. Repetition rates up to 856 Hz were tested. Even for high repetition rates, the main features of the BER are preserved, although the latency of wave V increases by as much as 1.3 ms.