Effects of Age and Hearing Loss on Gap Detection and the Precedence Effect

Abstract

Deficits in temporal resolution and/or the precedence effect may underlie part of the speech understanding difficulties experienced by older listeners in degraded acoustic environments. In a previous investigation, R. Roberts and J. Lister (2004) identified a positive correlation between measures of temporal resolution and the precedence effect, specifically across-channel gap detection (as measured dichotically) and fusion. Across-channel gap detection may also be measured using frequency-disparate markers. Thus, the present investigation was designed to determine if the relation is specific to dichotic gap detection or may generalize to all types of across-channel gap detection. Gap-detection thresholds (GDTs) for fixed-frequency and frequency-disparate markers and lag-burst thresholds (LBTs) were measured for 3 groups of listeners: young with normal hearing sensitivity (YNH), older with normal hearing sensitivity (ONH), and older with sensorineural hearing loss (OIH). Also included were conditions of diotic and dichotic GDT. Largest GDTs were measured for the frequency-disparate markers, whereas largest LBTs were measured for the fixed-frequency markers. ONH and OIH listeners exhibited larger frequency-disparate and dichotic GDTs than YNH listeners. Listener age and hearing loss appeared to influence temporal resolution for frequency-disparate and dichotic stimuli, which is potentially important for the resolution of timing cues in speech. Age and hearing loss did not significantly influence fusion as measured by LBTs. Within each participant group, most GDTs and LBTs were positively, but not significantly, correlated. For all participants combined, across-channel GDTs and LBTs were positively and significantly correlated. This suggests that the 2 tasks may rely on a common across-channel temporal mechanism.

Cortical Evoked Response to Gaps in Noise: Within-Channel and Across-Channel Conditions

“…Most interesting in light of the present results are the behavioral findings for older adults. This group often has poorer within-and across-channel gap detections than young adults; yet, age-group differences are much larger for acrosschannel than within-channel conditions (e.g., Lister & Roberts, 2005;Lister, et al, 2002).As within-and across-channel performance was not correlated in the present study (r = 0.22, p = 0.50) or others (Phillips & Smith, 2004), it is likely that different mechanisms are involved in the two tasks. The present study represents a first step in the investigation of the physiological underpinnings of across-channel gap detection.…”

“…The shortest gap that a listener can detect (relative to the standard) is called a gap detection threshold (GDT). Psychophysical GDTs are influenced by a number of stimulus factors, including marker bandwidth (Eddins, Hall, & Grose, 1992;Snell, Ison, & Frisina, 1994), marker duration (He, Horwitz, Dubno, & Mills, 1999), monotic, diotic, or dichotic presentation modes (Gordon-Salant & Fitzgibbons, 1999;He, et al, 1999;Lister & Roberts, 2005), and the spectral similarity of the markers before and after the gap (Lister, Besing & Koehnke, 2002;Oxenham, 2000).…”

“…The shortest gap that a listener can detect (relative to the standard) is called a gap detection threshold (GDT). Psychophysical GDTs are influenced by a number of stimulus factors, including marker bandwidth (Eddins, Hall, & Grose, 1992;Snell, Ison, & Frisina, 1994), marker duration (He, Horwitz, Dubno, & Mills, 1999), monotic, diotic, or dichotic presentation modes (Gordon-Salant & Fitzgibbons, 1999;He, et al, 1999;Lister & Roberts, 2005), and the spectral similarity of the markers before and after the gap (Lister, Besing & Koehnke, 2002;Oxenham, 2000).Behavioral studies have shown that, when the stimuli that mark the silent gap are noise bands of similar frequency, known as within-channel gap detection, the task is relatively easy and GDTs are small (Lister & Roberts, 2005;Lister, et al, 2002). When the noise bands that mark the gap are of different frequencies, known as across-channel gap detection, the task is more difficult and GDTs are larger (Lister & Roberts, 2005;Lister, et al, 2002).…”

Perception of Across-Frequency Asynchrony by Listeners with Cochlear Hearing Loss

“…However, the HI listeners in this study were on average older than the NH listeners in the study by Wojtczak et al (2012) used as a control group. A large number of studies have reported clear effects of age on gap detection and gap-duration discrimination for both within-channel and across-channel markers (Fitzgibbons and Gordon-Salant 1994;Schneider et al 1994;He et al 1999;Lister et al 2000Lister et al , 2002Lister and Roberts 2005). Since the NH and HI listeners compared in this study were not age-matched, some of the observed differences between their data may reflect poorer coding of temporal information or a reduced ability to integrate temporal information across frequency due to the age of the HI listeners.…”

“…However, deficits due to cochlear hearing loss have been shown in tasks involving comparisons of temporal information across frequency, although not consistently. Across-channel gap detection and gap-duration discrimination measured with frequency-disparate markers preceding and following silent gaps have been shown to be unaffected by hearing loss (Lister et al 2002;Lister and Roberts 2005). Similarly, the ability to detect a difference in temporal envelope patterns in the presence of an interfering modulation in the remote frequency region is comparable for the NH and HI listeners (Grose and Hall, 1996).…”