The exam includes stimuli at four different frequencies (500, 1000, 2000, and 4000 Hz) and white noise clicks of 50 ms duration. It is a useful test because it provides an index of auditory temporal resolution. In children, an overall gap detection threshold greater than 20 ms means they have failed and may have an auditory processing disorder based on abnormal perception of sound in the time domain. Gaps in Noise Test (GIN) also measures temporal resolution by testing the patients gap detection threshold in white noise. Pitch Patterns Sequence Test (PPT) and Duration Patterns Sequence Test (DPT) measure auditory pattern identification. The PPS has s series of three tones presented at either of two pitches (high or low). Meanwhile, the DPS has a series of three tones that vary in duration rather than pitch (long or short). Patients are then asked to describe the pattern of pitches presented. Masking Level Difference (MLD) at 500 Hz measures overlapping temporal processing, binaural processing, and low-redundancy by measuring the difference in threshold of an auditory stimulus when a masking noise is presented in and out of phase. The Staggered Spondaic Word Test (SSW) is one of the oldest tests for APD developed by Jack Katz. Although it has fallen into some disuse by audiologists as it is complicated to score, it is one of the quickest and most sensitive tests to determine APD. Modality-specificity and controversies
The issue of modality-specificity has led to considerable debate among experts in this field.
Relation to true melanoses
The condition is unrelated to true melanoses, such as Peutz–Jeghers syndrome and smokers melanosis.Peutz–Jeghers syndrome causes pigmentation of the skin and mucous surfaces with melanin, and polyps in the digestive tract. Non-colonic pseudomelanoses
Pseudomelanoses of other parts of the gastrointestinal tract have also been reported, and are of unclear relevance.Patients with colostomies can have melanosis involving the stoma, which is also of no significance. References


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