Slowly progressive dysarthria and impaired language function--a case report]

A 68-year-old right-handed woman was admitted to Tokyo Metropolitan Geriatric Hospital because of slowly progressive dysarthria and writing disability over 2-year period. On admission, severe dysarthria was observed, but no dysphagia. The dysarthria mostly resembled a type of pseudobulbar palsy, although it was associated with effortful speech production. An oro-facial apraxia was also found. She could name objects, and could understand spoken words correctly. Examination using the Western Aphasia Battery showed diminution of word fluency, impaired repetition and perseveration and writing errors. On the Wechsler Adult Intelligence Scale-R verbal IQ was 100 and performance IQ was 87. These scores did not suggest any significant degree of general intellectual deterioration. Wisconsin card sorting test disclosed mild frontal dysfunction. Magnetic resonance imaging showed cortical atrophy in the bilateral frontal and temporal lobes. Measurements of regional cerebral metabolic rate by 18F-FDG-PET demonstrated decreased uptake in the latero-dorso-inferior area of the bilateral frontal lobes, especially on the left side. The present case showed slowly progressive dysarthria and progressive aphasia without generalized dementia, and without typical aphasia. These symptoms are speculated to be related to the atrophy in the bilateral frontal and temporal lobes shown by MRI and the decreased metabolic rate in the left dominant bilateral frontal lobes on PET study. The pathologic process responsible for these lesions remains obscure.