The effects of age and hearing loss on interaural phase difference discrimination

Abstract

The discrimination of interaural phase differences (IPDs) requires accurate binaural temporal processing and has been used as a measure of sensitivity to temporal envelope and temporal fine structure (TFS). Previous studies found that TFS-IPD discrimination declined with age and with sensorineural hearing loss (SNHL), but age and SNHL have often been confounded. The aim of this study was to determine the independent contributions of age and SNHL to TFS and envelope IPD discrimination by using a sample of adults with a wide range of ages and SNHL. A two-interval, two-alternative forced-choice procedure was used to measure IPD discrimination thresholds for 20-Hz amplitude-modulated tones with carrier frequencies of 250 or 500 Hz when the IPD was in either the stimulus envelope or TFS. There were positive correlations between absolute thresholds and TFS-IPD thresholds, but not envelope-IPD thresholds, when age was accounted for. This supports the idea that SNHL affects TFS processing independently to age. Age was positively correlated with envelope-IPD thresholds at both carrier frequencies and TFS-IPD thresholds at 500 Hz, when absolute thresholds were accounted for. These results suggest that age negatively affects the binaural processing of envelope and TFS at some frequencies independently of SNHL.

Effects of Age and Hearing Loss on the Processing of Auditory Temporal Fine Structure

“…3.3, suggested that hearing loss adversely affected the discrimination of ITD carried in ENV p , King et al (2014) found that thresholds for detecting IPDs in ENV p were not significantly correlated with absolute thresholds. Also, Léger et al (2015) reported that thresholds for detecting IPDs in ENV p were similar for subjects with normal and impaired hearing (both groups had a wide range of ages).…”

“…The study of King et al (2014), described above, is relevant here. Recall that they tested 46 subjects with a wide range of ages (18-83 years) and degrees of hearing loss.…”

“…King et al (2014) measured the ability to discriminate IPD using amplitude-modulated sinusoids. The IPDs were imposed either on the carrier, TFS p , or the modulator, ENV p .…”

Age-Related Changes in Processing Simultaneous Amplitude Modulated Sounds Assessed Using Envelope Following Responses

“…Perceptual difficulties observed with age in processing competing sound stimuli may depend on a variety of factors, including the fidelity of the auditory information entering the system at the level of the auditory nerve (AN), processing of this information by brainstem, midbrain, and forebrain nuclei in the central auditory pathway, integration of binaural spatial and temporal information, as well as the effects of non-auditory cognitive mechanisms such as attention (Grimault et al 2001;Alain and McDonald 2007;Bidet-Caulet et al 2007;Ruggles et al 2012;Johnsrude et al 2013;Sergeyenko et al 2013;Bharadwaj et al 2014;King et al 2014). Understanding the changes that occur in processing sound in the auditory periphery will help separate out the deficits inherited from earlier stages from those generated in the later stages of the auditory pathway.…”

Congenital amusics use a secondary pitch mechanism to identify lexical tones

“…All tones had a frequency of 500 Hz, amplitude modulated (AM) at 20 Hz to a depth of 100%. In one condition IPDs were created in the TFS of the AM tone, in a second condition IPDs were created in the envelope (King et al, 2014;Lacher-Fougère and Demany, 2005). At the beginning of each block ΔΦ was set to 180°.…”