Section Editor(s): Musiek, Frank E.
Jennifer Paulovicks is a PhD student in the Department of Communication Disorders, University of Connecticut. Readers may contact her at email@example.com. Frank E. Musiek, PhD, the Editor of Pathways. may be contacted with suggestions for future topics or questions at firstname.lastname@example.org.
The Gaps-In-Noise (GIN) test measures temporal resolution, which is the ability to follow rapid changes in the envelope of an auditory stimulus over time.1 The GIN test was derived from traditional gap-detection procedures as a clinically feasible means of measuring temporal resolution abilities in patients with possible central auditory deficits.2 Recent reports on the GIN test have shown it to have considerable diagnostic consistency in populations with central auditory disorders.
The GIN is composed of a series of computer-generated, uniformly distributed, broadband noise segments of 6 seconds in duration. Each 6-second segment of noise contains from zero to three silent gaps, which vary in duration from as little as 2 msec to as long as 20 msec. The GIN is presented monaurally and the patients are instructed to push a response button as soon as they perceive a gap.
It takes about 17 minutes to administer and score the test. Approximate gap-detection threshold (A.th.) and the overall percent correct are the two measures used to determine performance on the GIN test. The A.th. is the gap duration at which the patient was able to perceive the gap correctly at least four of the six times it was presented. The second measure is the percent of correctly identified gaps for each list. Normal results are an A.th. of 6 msec or shorter and an overall percent correct score of 54% or better. Sensitivity and specificity measures were determined based on these normative values.
Musiek and colleagues showed that the GIN test is sensitive and specific to central auditory nervous system lesions.2 They found a sensitivity of 67% and a specificity of 94% when using an A.th. criterion of 6 msec or shorter. Further analysis of this paper showed poorer GIN test performance in patients with confirmed neurological lesions affecting the central auditory nervous system. Those with confirmed lesions had mean gap-detection thresholds that were approximately 3 msec longer than those of the control group of normal listeners, and their overall percent correct scores were approximately 10% lower than those of the control group. All the subjects in this study had normal pure-tone audiograms. In addition to sensitivity and specificity, they demonstrated that the GIN test has a high test-retest reliability, which is important for the clinical use of the test.
While Musiek et al. studied GIN performance in a population with more general central auditory nervous system lesions,2 Bamiou et al. studied auditory temporal processing deficits in patients with strokes involving the insula.3 They used the GIN test to assess the temporal resolution abilities of these subjects. Their study showed that all eight subjects with insular lesions had abnormal GIN performance. Three patients performed abnormally on the side contralateral to the lesion and five patients had abnormal GIN performance bilaterally. Mean A.ths were as high as 11 msec and mean percent correct scores were as low as 29% in the patients with insular lesions.
Researchers have also investigated GIN performance in patients with multiple sclerosis (MS).4 Many patients with MS have normal pure-tone audiograms, yet they report having difficulty hearing, especially in background noise,5 which is likely due to the involvement of the central auditory system. Lewis et al. found that of the 19 subjects with MS, 15 failed in a least one ear when using the approximate gap-detection threshold measurement. Mean gap-detection thresholds were approximately 8 msec for the group with MS, and approximately 5 msec for the control group of normal listeners. Percent correct scores were about 10% to 15% lower for the group with MS than in the control group. The sensitivity was 79% and the specificity was 80% when using the criteria mentioned earlier.
In summary, three recent studies have provided evidence of the usefulness of the GIN tests in diagnosing patients with central auditory disorders. These data further support the clinical use of this new procedure in special populations.
1. Viemeister N, Plack CJ: Time analysis. In Yost WA, Popper AN, Fay RR, eds., Human Psychophysics. New York: Springer-Verlag, 1993: 116–154.
2. Musiek F, Shinn J, Jirsa R, et al.: GIN (Gaps-in-Noise) test performance in subjects with confirmed central auditory nervous system involvement. Ear Hear 2005;26(6):608–618.
3. Bamiou D, Musiek F, Stow I, et al.: Auditory temporal processing deficits in patients with insular stroke. Neurology 2006;67:614–619.
4. Lewis S, Hutter M, Musiek F, et al.: Temporal resolution in patients with multiple sclerosis. Presented at the American Academy of Audiology Convention, Minneapolis, April 2006.
5. Musiek F, Gollegly K, Kibbe K, Reeves A: Electrophysiologic and behavioral auditory findings in multiple sclerosis. Am J Otol 1989;10:343–350.
© 2008 Lippincott Williams & Wilkins, Inc.