Task complexity effect on vocal reaction time in aged speakers

The aged population is at risk for impaired speech communication due to the increased likelihood of deterioration of central nervous system (CNS) proc esses that underlie cognition, language, and/or speech motor control, Vocal reaction time (RT) may provide a means of quantifying the efficiency of CN S processes that underlie speech production. The present study used a simpl e RT paradigm to investigate effects of the complexity of the required task on vocal RT in normal young and aged speakers. Task complexity was represe nted by two levels: a single word and a short sentence. Only the aged subje cts showed a significant task complexity effect on vocal RT. Furthermore, t he between-group RT difference increased as a function of task complexity. Specific causes for the increase in vocal RT for the aged subjects an prese ntly unknown, but likely reside in altered respiratory biomechanics and red uced efficiency of CNS motor processing.