On the rate of maturation of sensory evoked potentials.

The maturational changes in auditory, somatosensory, and visual evoked potential latencies are re-analyzed using a simple developmental model. It is assumed that latency changes between birth and adulthood can be described by a sum of decaying exponential functions. Curve fitting procedures resulted for all 3 stimulus modalities in 3 exponential functions. The rates of decay, interpreted as representing specific maturation rates, can be described with time constants of about 4 weeks, about 40 weeks, and about 4 years. For the short time constant process the growth spurt in myelination as well as that in increasing synaptic density can be held responsible. Evidence is provided that the medium time constant process parallels a slower myelination stage. Using the above described model, the maturational changes in evoked potentials for the 3 stimulus modalities, both for short and long latency evoked potentials, can be unified.