Temporal jitter disrupts speech intelligibility: Simulations of auditory aging

Declines in auditory temporal processing have been observed in aging adults and may partially account for their difficulty in understanding spoken language. To mimic age‐related loss of synchrony, sentences were temporally jittered. Intact and jittered SPIN sentences were presented in background babble, and sentence–final word recognition was measured in young listeners with normal hearing. If x(t) is the input signal, the internal representation of the signal, y(t), is assumed to be a time‐delayed version of the input with the time delay, d, varying over time as y(t)=x[t−d(t)]. The first factor contributing to the jitter is the range of delays that might occur over time, modeled as the rms value of a band‐limited noise. The second factor is the rate at which delays change, modeled as the bandpass of a band‐limited noise. Word recognition was unchanged when the second factor dominated the jitter (rms=0.05 ms, BW=500 Hz), reduced slightly (10%) when the first factor dominated (rms=0.25 ms, BW=100 Hz), and ...