Frontotemporal Dementia

Mesulam described a series of cases of slowly progressive language problems (aphasia) and subsequently named the syndrome primary progressive aphasia. The clinical and pathological overlap of PPA and FTD is considerable and we suggested the term Pick complex (Kertesz et al., 1994) to emphasize the relationship.

The initial presentation of PPA is often word-finding difficulty, or anomia. In this respect, PPA patients are not much different from Alzheimer's patients, except they have relatively preserved memory and nonverbal cognition. Mesulam suggested a two-year period of relatively pure aphasia as the operational definition of PPA, although this may be too restrictive and in many publications it is not adhered to. The more typical clinical picture progresses from anomia to a non-fluent type of aphasia, in which there is increasing word-finding difficulty.

Some patients present with stuttering, slow speech, and articulatory difficulty and errors in speech. These patients are less likely to be mistaken for AD, but unfortunately an unexplained isolated articulatory disturbance in a younger person is often considered to be hysterical. Loss of speech (mutism) used to be considered characteristic of PiD as well, and it tends to be the end-stage of all forms of frontotemporal dementia, even those that start with behavioral abnormalities rather than language disturbance. End-stage mutism also occurs in AD, but usually in a patient who already has a global dementia with loss of comprehension and basic functions of daily living.

Another form of PPA that is different from the more common nonfluent variety was described as semantic dementia by Snowden and others (1989). These patients progressively lost the meaning of words, but retained fluency and were able to carry out a conversation.