We reviewed the APD test battery results of over 200 patients, age 7-15, who were referred to our clinic for an APD assessment. We were curious if the using the DDS would provide additional information from our former patients who were referred for auditory processing disorder (APD) assessment. Moncrief & Wertz (2008) did note “A significant asymmetry was defined as a difference of greater than 20% for children younger than eight years, 15% for children eight to nine years and greater than 10% for children ten years and older (p 86).” Moncrief has used the DDS to make a diagnosis of amblyaudia. Unfortunately, there is little published normative data for interaural differences and sometimes the published papers will report, “…an abnormally large asymmetry or significant ear deficit,” but sometimes fail to define the criterion. These would affect scores from both ears, and not be ear-specific. An abnormality of the DDS is auditory driven and is not related to high-order processes of cognition, such as memory and attention. Each individual ear is within normal limits however, the DDS is a 32% and would be interpreted as abnormal. However, there is an abnormal DDS of 34% DDS, greater than the predicted 15%, as evidenced in Table 2.Īn abnormal DDS may also occur when one ear performs much better than expected. For example, a 7 year old may score 60% and 98% for the left and right ears, respectively.
A left ear weakness is noted, after comparing the individual ear scores to normative data (Table 1). For example, a 7 year old may score 44% and 78% for the left and right ears, respectively.
#Dichotic listening manual
DDS values from the Dichotic Digits Test as provided in the manual and from normative data from Rosenburg (2011) AgeĪn abnormal DDS may occur when there is a unilateral weakness. These values are very similar to those from the Dichotic Digits Test and may allow audiologists to have greater confidence in interpretation of ear differences on the Dichotic Digits Test. Data for each age group are also provided in Table 2. Rosenburg (2011) reported a Mean Ear Difference Score, or DDS, in her published normative data from 200 children between the ages of referred to the Sarasota Florida School District for an audiological evaluation.
The age-predicted DDS calculated from the normative data provided by the Dichotic Digits Test are shown in Table 2. This calculation may be referred to as the right or left ear advantage or the Standard Integration Ratio (Katz, 2015). This computation may be useful in assessing unusual auditory weaknesses or asymmetries in one ear, not explained by age. The DDS is a simple calculation of the individual right ear score minus the left ear score. Age cut-off scores for the Dichotic Digits Test AgeĪnother less common way to interpret a dichotic listening test is the Dichotic Difference Score (DDS) (Musiek, 2018). Notice the increase in the performance of each ear as a function of age. These cut-off values are shown in Table 1. This normative data is provided in the Dichotic Digits Test Manual (Musiek, 1983) and reflects age cut-off scores, which is the mean age minus 2 standard deviations (SD). Interpretation of this test is most often based upon the percentage correct for each individual ear in comparison to normative data. This test assesses the ability of the auditory system to integrate information from the right and left cerebral hemispheres. The listener is instructed to repeat all four numbers in any order. During this test, two numbers are presented to the right ear at the same time as two numbers are presented to the left ear. The Dichotic Digits Test (Musiek, 1983) is a widely used test in the APD test battery. Dichotic tests are sensitive to the maturation and development of the central auditory nervous system (CANS), underlying lesions of the CANS, and inter-hemispheric transfer of auditory information (Musiek, 1983 Musiek et al, 1984). Some abnormal unilateral findings or specific ear deficits or weaknesses are associated with various language- based learning disorders (Moncrief & Musiek, 2002). of Communication Disorders LSU Health Sciences Center, listening tests are one of the most frequently used behavioral tests included in the behavioral Auditory Processing disorder (APD) test battery (Emanuel et al, 2011).
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