Progressive dysarthria: definition and clinical follow-up.

Progressive dysarthria is a common sign of several degenerative disorders of the central nervous system; it may also be a distinct nosographic entity. We identified nine patients in which progressive dysarthria remained the sole neurological sign for at least 2 years after onset. At least a year after hospital admission, the following diagnoses were made: two cases of corticobasal degeneration, one of frontotemporal dementia, one of primary progressive aphasia, one of motor neuron disease (MND)-dementia, one of ALS, and one of ALS-aphasia. In the remaining two patients progressive dysarthria remained the only neurological sign at latest examination. We conclude that in most cases progressive dysarthria is the presenting sign of an established neurodegenerative disease (generally degenerative dementia or motor neuron disease), although the possibility that progressive dysarthria is a distinct entity cannot be excluded. To clarify this issue, studies (probably multicenter) on more patients with longer clinical follow-up and pathological confirmation are required.