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Abstract:
Abstract: Liepmann defined ideational apraxia as impairment
on task that require a sequence of serial acts with objects. The
mechanism underlying performing serial acts correctly is not known.
We reported a 64 year-old right-handed man whose performances were
impaired when he had to arrange the sequential stages of complex
actions. He showed neither sensory-motor disturbances nor aphasia
and dementia. He performed on a single object use test correctly
with and without the actual manipulation of objects. On the
contrary, he failed on a multiple objects use test we made. On the
latter test the most frequent errors were those of sequence, while
errors of misuse were not shown. MRI demonstrated an infarction of
the left parieto-occipital lobe region. Furthermore, functional MRI
is used to investigate the neural basis for sequential acts of 6
normal right-handed Japanese subjects. In the MRI machines, the
subjects were asked to imagine to performing the multiple objects
test we made. The simplest multiple objects test is to light a
candle. The imaging the multiple objects task activated left
posterio-lateral parts of the middle frontal lobe, supplementary
motor areas and left posterior parietal lobe. These fMRI findings
and the case study above suggest left posterior parietal lobe
regions play an essential role in the process of sequential
acts.
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