Primary progressive apraxia

We have investigated the clinical symptoms and pathological findings of primary progressive apraxia (PPA) in 31 cases in the literature and four of our own cases. The mean age of onset of the initial symptoms was 60.5 years, with a slight predilection for males. The time between the onset of symptoms and the medical examination was 3.1 years. The mean duration of illness was 4.2 years for the surviving cases and 6.8 years for the four deceased cases. The most frequently encountered apraxia symptom is a limb‐kinetic apraxia. It has become known that other forms of apraxia such as apraxia of speech, buccofacial apraxia and dressing apraxia, which are not established as a symptomatic condition, can manifest themselves in an isolated manner. Neurological examination often reveals extrapyramidal symptoms such as rigidity and myoclonus from the beginning of the illness. As for the higher functional problems, apraxia is often accompanied by a distrubance of calculation. With regard to the radiological findings, computed tomography and magnetic resonance imaging show characteristic atrophy with left–right inequality and diffuse disturbance in single photon emission computed tomography‐positron emission tomography study is seen on the more severely atrophic side. In autopsy and biopsy examinations, one patient was diagnosed with corticobasal degeneration, three cases were diagnosed with Alzheimer's disease and one with Pick's disease. PPA is a heterogeneous symptomatic condition. This paper confirm the existence of apraxias which were not previously recognized as concrete symptomatic conditions; furthermore, it is suggested that the cerebral system of behavioral association might be more subdivided than was formerly considered.