Table 6.

Summary of auditory assessment methods

Assay/Assessment	Method	Laboratory/Reference
Auditory
Reverse digit span	With gaze aversion by listening participant and tester, digits are read in set sequence. The tested participant is asked to repeat them in reverse order. Reported as the absolute number of digits correctly recalled in reverse order.	Subset of Wechsler Adult Intelligence Scale III (Wechsler 1997)
(Measures auditory (verbal) working memory)
Normal range is 6 to 7
Competing words performance for age as a percentage of age	A voice-over CD and earphones test ability to correctly identify both of two competing-words (CW), delivered separately to the right and left ears. Using this test’s normative-for-age database, the difference between each test subject’s expected and actual performance-for-age was calculated, and this was then divided by the actual age of the test subject, and multiplied by 100.	SCAN-3 (Keith 2009)
(Intra-cerebral dichotic listening performance for processing of auditory information)
Normal ranges vary with age
Threshold speed of Auditory processing as a percentage of age	Person tested hears two clicks, randomly presented from right to left and left to right side, presented through headphones. By pressing a right or left button, a decision must be made from which side the dual-stimulus originates. If the answer is correct, the inter-stimulus interval between flashes (ISI) is shortened, otherwise it is lengthened. The auditory order threshold is the shortest ISI a person can correctly differentiate between two auditory impressions. A read-out of the threshold speed of auditory (order) processing is provided, along with a norm performance-age rating. Auditory speed of (order) processing performance as a percentage of age is calculated by subtracting the norm-for-age from the performance-age, divided by the age of the test subject, multiplied by 100.	Brain Boy Universal Professional instrument (MediTECH 2010)
(Speed of auditory processing systems relative to age)
Speed of auditory processing reduces with age. For adults in the age range of 18 and 60 years, the normal range for auditory speed of processing is 46 to 72 milliseconds.