Central auditory processes and test measures: ASHA 1996 revisited.

The theoretical issues surrounding central auditory processing disorders (CAPD) are reviewed here, especially with reference to the central auditory behavioral processes and the auditory test measures as prescribed in the ASHA (1996, American Journal of Audiology, 5(2), 41-54) statement on CAPD. A simplified nomenclature is recommended that directly relates process and test measure to facilitate the diagnostic process in CAPD. This new terminology closely follows the ASHA (1996, American Journal of Audiology, 5(2), 41-54) document, but provides some refinement based on recent research in CAPD. To support this recommendation, a confirmatory factor analysis (CFA) was applied to the findings of Domitz and Schow (2000, American Journal of Audiology), who proposed use of a battery of CAPD tests, the Multiple Auditory Processing Assessment (MAPA) for testing school children. The CFA was found to reinforce the four-factor model, which clearly emerged in the exploratory factor analysis of Domitz and Schow. The model was found to be reasonably consistent even when subtests from the SCAN were included in the analysis. Refinement and revision of ASHA (1996, American Journal of Audiology, 5(2), 41-54) is recommended to facilitate diagnosis, subclassification, and intervention for CAPD.

Professional education and assessment practices in central auditory processing.

A 17-item questionnaire probing professional preparation and current practices in central auditory assessment was mailed to 500 audiologists selected randomly from the membership directory of the American Academy of Audiology. Data from 183 respondents, representing a 37 percent response rate, were analyzed. The majority of respondents reported minimal academic and clinical preparation in assessment of the central auditory nervous system. Eighty percent of respondents had not taken any graduate course explicitly dedicated to central auditory processing. However, 80 percent had taken at least one basic science course in central audition and 83 percent reported having taken at least one graduate course that included some coverage of central auditory processing and/or the central auditory nervous system. A mean of 3 clinical clock hours accrued in this area was reported. Not surprisingly, 78 percent reported a satisfaction rating of < or =50 percent relative to the graduate education they received in this area and only 41 percent reported providing central auditory assessment. Comparisons with prior surveys show substantial change in the preferred test battery. Most notable is the pivotal role of physiologic measures, with the acoustic reflex and auditory brainstem response listed along with the SCAN as the three most frequently used assessment tests/procedures. Overall, the results suggest a need for improvement in professional preparation in evaluation of central auditory function.

Comparative study of the phonology of preschool children prenatally exposed to cocaine and multiple drugs and non-exposed children.

Cocaine and multiple drug abuse among young adults has spawned research interest in fetal exposure and the sequela of that exposure during the formative developmental years. Previous study of the language development of exposed children has not specifically addressed phonological acquisition. In the present study, the speech of 25 children prenatally exposed to cocaine and multiple drugs was analyzed and compared to that of 25 children who were not prenatally exposed to determine if differences were evident in their phonological patterns. The children ranged in age from 22 months to 51 months. The number and type of phonological processes produced, number of utterances needed to produce a 50-word sample, number of unintelligible words produced, and Home Observation for Measurement of the Environment (HOME) scores were recorded and analyzed. The use of cocaine and multiple drugs during pregnancy was associated with an increase in the use of phonological processes.

Behavioral signs of central auditory processing disorder and attention deficit hyperactivity disorder.

Central auditory processing disorder (CAPD) and attention deficit hyperactivity disorder (ADHD) present overlapping symptomatology. Attention and listening problems, maladaptive behavior, distractibility, instruction-following difficulty, and increased time required to complete tasks appear on checklists purportedly characterizing behaviors exhibited by individuals with CAPD and ADHD. The present study compared audiologists' and pediatricians' rankings of 41 behavioral symptoms associated with ADHD and CAPD. Audiologists ranked the degree to which each item pertained to individuals with CAPD and pediatricians ranked the same items as related to ADHD. Item analysis revealed that only two of the most frequently cited behaviors were judged as characteristic of both disorders (i.e., inattention and distractibility). The majority of frequently cited behaviors were not seen as common to ADHD and CAPD.

Standardized test performance of children with a history of prenatal exposure to multiple drugs/cocaine.

Twenty-four children, age 14 to 50 months, with a history of prenatal exposure to multiple drugs including cocaine, were matched by adjusted birth age and sex to 24 children with no history of drug exposure. All children had been living in stable, drug-free environments from at least the age of 11 months. Tests administered included the Sequenced Inventory of Communicative Development-Revised (SICD), the Bayley Scales of Infant Development, and the Peabody Picture Vocabulary Test-Revised (PPVT-R). Results indicated significant differences between groups and genders on the SICD when age was covaried and between groups on the Bayley. No groups or genders differed on the PPVT-R. Many (45.8%) of the children in the drug-exposed group qualified for intervention services according to Washington state criteria. Subject characteristics, other than age, did not play a significant role in the findings of group differences. It is concluded that, due to the cumulative effects of prenatal history, these children should be considered at risk for language delay.

Evidence for development of distinction of voice onset time in a child with left-hemisphere lesion.

Following surgery for partial removal of the posterior left hemisphere at 5 mo., voice onset time was assessed to 9; 11 yr. Left-hemisphere language function associated with voicing appeared subsumed by the right hemisphere.

Auditory comprehension of "yes-no" questions by adult aphasics.

Two groups of adult aphasics were administered four different types of auditory-verbal "yes-no" questions. One group received questions including egocentric, environmental, pictorial, and relationship items in a consistent order. The second group received the same questions in random order. Support was found for the existence of a hierarchy of difficulty among the types of auditory-verbal "yes-no" questions. There was no significant difference between the two groups' performance even though the consistent presentation group was slightly superior to the random order group on the auditory-verbal "yes-no" questions.

Dysarthria of motor neuron disease: longitudinal measures of segmental durations.

Motor neuron disease encompasses a group of terminal, demyelinating diseases affecting upper- and lower-motor neurons and producing muscular weakness resulting in a flaccid, spastic, or spastic-flaccid dysarthria of speech. The present study presents measurements of the temporal-acoustic characteristics of dysarthria in three subjects with Motor Neuron Disease over a two-year recording period. Changes seen over the course of the disease varied by type of motor neuron disease, though all types demonstrated some degree of neutralization of the prevocalic VOT, target vowel duration, and postvocalic closure duration. These changes are discussed with relation to physical manifestation and progression of the disease.

Dysarthria of motor neuron disease: clinician judgments of severity.

Motor Neuron Disease (MND) is a terminal, demyelinating disease affecting upper- and lower-motor neurons and producing muscular weakness resulting in a characteristic spastic-flaccid dysarthria of speech. The present study investigates the relationship between the temporal-acoustic parameters of the speech of 15 individuals with MND as they relate to the progression of the disease and clinicians' judgments of dysarthria severity. When temporal-acoustic parameters are used to predict the progression of MND, it becomes apparent that victims provide compensatory gestures to mark voicing distinctions. When the same acoustic parameters are used to predict clinician judgments of severity, it is found that clinicians tend to use the same temporal cues that mark actual disease progression. Differences between the two sets of predictions relate to the linguistic systems of both speaker and judge, and the implications of this are discussed.