Learning Disabilities

Electrophysiological techniques have also been used in the study of learning disabilities to examine the neurobiological mechanisms that underlie these disabilities. The brain has ongoing electrical activity whose waveform can be measured and recorded. Large populations of neurons are measured by electrodes placed on the scalp with changes in the ongoing waveform occurring in response to a cognitive event, such as attention or stimulus discrimination.

Several decades of research have demonstrated different patterns of activation in the brains of children with learning disabilities and those of control groups. Abnormal electrical responses have been found in populations with learning disabilities when they are asked to process phonological information. Studies of components not involving conscious processing have demonstrated that adults and children with reading disabilities process auditory information differently than do normal readers. These components occur later in subjects with learning disabilities, indicating low-level auditory processing deficits. (McAnally and Stein 1996; Baldeweg et al. 1999). This physiological abnormality has also found to be correlated with phonological deficits.