Six right-handed patients experienced a slowly progressing aphasic disorder without the additional intellectual and behavioral disturbances of dementia. The symptoms almost universally started in the presenium. The initial difficulty was an anomic aphasia in five of the patients and pure word deafness in the sixth. Continuous and gradual deterioration occurred in the five patients who presented with an anomic aphasia. They eventually experienced additional impairment of reading, writing, and comprehension. In four patients, other areas of comportment were not involved within the 5 to 11 years of follow-up. A more generalized state of dementia may have emerged in the other two patients, but only after 7 years of progressive debilitating aphasia. Neurodiagnostic procedures were consistent with preferential involvement of the left perisylvian region. In one patient, cortical biopsy did not show any pathognomonic change; specifically, no neurofibrillary tangles, amyloid plaques, neuronal inclusions, or gliosis were seen. This condition may constitute a syndrome of relatively focal cerebral degeneration with a predilection for the left perisylvian region.