Temporal and spectral factors affecting speech perception were analyzed for the hearing impaired through three experiments. Results suggested the following. 1) The hearing impaired needed a longer vowel and a longer inter-stimuli interval to succeed in cue extraction and integration than the normal hearing subjects. 2) For normal hearing subjects, the vowel intelligibility was affected significantly by spectral distortion. 3) For the hearing impaired, the higher the speech rate was, the lower the word intelligibility was. For the inner-ear hearing impaired, word intelligibility was higher than monosyllable intelligibility at normal speech rate, but not at fast rate. This indicates that the inner-ear hearing impaired have high ability to extract and integrate temporally distributed cues which are richer in words than monosyllables, but this ability does not function at faster speech rate. For the retrocochlear hearing-impaired, cue extraction and integration seemed difficult even at normal speech rate. These results suggest that hearing impairments constrain temporal processing capabilities in several ways.