Alterations in the functional anatomy of reading induced by rehabilitation of an alexic patient.

OBJECTIVE: The goal of the study was to measure regional cerebral blood flow (CBF) in a stroke patient with acquired phonologic alexia before and after therapy using the Auditory Discrimination in Depth (ADD) program.
BACKGROUND: After rehabilitation of acquired language disorders, functional imaging can detect activity in brain structures that do not mediate language during normal conditions. However, the anatomic correlates of recovery or rehabilitation from acquired reading disorders are largely undescribed.
METHODS: Cerebral SPECT scans were obtained before and after the intervention with Auditory Discrimination in Depth. The first and last activation tasks necessitated that the patient read nonwords during radionuclide uptake. Another (control) scan was acquired during performance of a nonlinguistic task shortly before the end of the ADD program.
RESULTS: Before therapy, the right hemisphere was inactive during nonword reading relative to the nonlinguistic task. After treatment, nonword reading increased cerebral blood flow in the posterior right perisylvian cortices homologous to the dominant hemisphere areas engaged by reading. Brain activity also increased in Broca's area of both hemispheres.
CONCLUSIONS: Dyslexia rehabilitation may facilitate right-hemisphere cortical networks in the reading process and increase engagement of phonologic articulatory motor representations in Broca's area.