RGDT (The Random Gap Detection Test)

The Random Gap Detection Test is a modification of the Auditory Fusion Test-Revised with the following improvements. The auditory gap detection threshold of tones and white noise (clicks) is obtained by having the subject identify when signal pairs are separated in time from 0 to 40 msec. The major improvement in the signal presentation during the RGDT is that the gap interval is randomly assigned, and therefore unpredictable to the subject. The test includes stimuli at four frequencies (500, 1000, 2000, and 4000 Hz) and white noise clicks of 50 microseconds duration. A practice session is presented with tone pairs at 1000 Hz. The test takes approximately 10 minutes to administer, including instructions and practice. Interpretation is made by averaging the gap detection threshold for all tonal stimuli and comparing the results to normative data that is currently available on subjects from 5 to 12 years of age.

The RGDT-Expanded test is intended  for individuals whose gap detection threshold exceeds 40 msec.  This test begins at time intervals longer than those measured by the standard RGDT, and includes time intervals between 50 and 300 msec.  The test is administered in the same manner as the standard RGDT.

 Individuals who require this test to establish a gap detection threshold have already demonstrated abnormal temporal processing abilities.  The single purpose is to determine the time interval in which their gap detection thresholds exist.  These data can be used to measure improvement in temporal processing abilities that may occur with maturation or following remediation. 

Results of gap detection testing can help identify individuals whose language and reading disorder may be related to a fundamental disorder in temporal processing. These are disorders of auditory timing in which the individual is unable to perceive rapid changes in formant frequencies of ongoing speech. Once these problems are identifies remediation programs to enable the individual to compensate for their problem can be recommended. In addition, this particular disorder may benefit from certain programs designed to remediate these problems at the perceptual level. . .