Influence of age on auditory startle responses in humans

The auditory startle reaction is considered a brainstem reflex in response to an unexpected loud stimulus. We investigated the influence of age on aud itory startle responses (ASRs) in 54 adult healthy subjects separated in th ree age groups (below 30; 30 to 50; above 50 years). ASRs were elicited by auditory stimuli randomly presented through tubal insert phones. Reflex ele ctromyographic activity was simultaneously recorded from eight facial, neck , and extremity muscles. ASR probability was lower in extremity muscles of younger versus older subjects, but did not differ among age groups in facia l and neck muscles. Median ASR latencies were significantly shorter in all muscles of younger versus older subjects. Our data provide evidence of a si gnificant influence of age on ASRs. The observed differences are likely due to age-specific variations of central processing in the brainstem centers involved in ASR generation. (C) 2001 Elsevier Science Ireland Ltd. All righ ts reserved.