This three year project will use steady-state auditory evoked potentials (SSAEPs) to study auditory temporal processing in language disordered children.
The specific aim i s to examine the responsitivity of modulation sensitive physiological mechanisms in language disordered children and to evaluate the role that dysfunction of these mechanisms may have in the emergence of their language impairment. The study groups include: 1) 40 children with developmental language disorders (DLD); 2) 40 children with normal language development; 3) 20 children with acquired language disorders. SSAEPs will be obtained in response to pulsed modulations of a continuous tone presented at a constant rate of 4 Hz. The domain of modulation (Amplitude-AM or Frequency-FM) and duration of the pulses will be varied to comprise two experimental conditions with two levels in each condition (FM - 50msec, 100msec; AM- 50msec, 100msec). Responsitivity to AM and FM will be related to clinical measures including a neurologic exam, an intelligence test, academic achievement tests, measures of receptive and expressive language ability, and measures of sensory-motor ability. The major objectives of the project are to: 1) determine whether anomalies in auditory temporal processing in DLD children are reflected in abnormal SSAEP's specifically to AM or FM or to global impairment of processing rapidly changing auditory information; 2) define the temporal specificity of observed modulation analysis deficits with respect to duration of modulation; 3) ascertain the clinical characteristics of DLD that are significantly related to difficulties with processing AM or FM; and 4) provide a better understanding of neuroanatomic considerations underlying modulation analysis deficits, by examining SSAEP's in children presenting with acquired language impairment associated with circumscribed lesions of the cerebral cortex. We will test the hypothesis that deficits in FM analysis are especially related to receptive developmental language disorders, and are associated with cortical dysfunction in posterior temporal regions. The project is intended to advance our understanding of the neural basis of developmental language disorders and the ways in which language impairment are associated with auditory temporal impairment consequent to cortical dysfunction, damage or maldevelopment. The results could aid in the development of objective neurophysiological measures to defect potential problems with language development early in life.
| Stefanatos, G A; Foley, C; Grover, W et al. (1997) Steady-state auditory evoked responses to pulsed frequency modulations in children. Electroencephalogr Clin Neurophysiol 104:31-42 |
| Stefanatos, G A; Grover, W; Geller, E (1995) Case study: corticosteroid treatment of language regression in pervasive developmental disorder. J Am Acad Child Adolesc Psychiatry 34:1107-11 |
