Higher brain function associated with parietal lobe

• Published in: Higher Brain Function Research Vol. 28; no. 2; pp. 184 - 191
• Main Authors: Yokoyama, Eriko, Nakano, Akiko
• Format: Journal Article
• Language: Japanese
• Published: Japan Society for Higher Brain Function 30.06.2008
• Subjects: conduction aphasia; dressing apraxia; dressing disability; parietal lobe; unilateral spatial neglect(USN)
• ISSN: 1348-4818; 1880-6554
• DOI: 10.2496/hbfr.28.184

We reported recent neuroimaging studies on conduction aphasia, unilateral spatial neglect and dressing disability generally following parietal lobe lesions. In patients with conduction aphasia, X-ray CT and/or MRI finding revealed left parietal lesion, commonly involving left supramarginal gyrus, whereas PET and/or SPECT results exhibited more extensive hypoperfusion in left perisylvian regions and its surrounding left frontal, parietal, and temporal regions. The findings suggest that lesions involving not only left parietal but left frontal and temporal regions can induce conduction aphasia. The right hemisphere is predominantly involved in spatial attention. Patients with unilateral spatial neglect following unilateral hemisphere stroke were tested with behavioural inattention test, and were studied with SPECT to examine cerebral blood flow. The severity of left unilateral neglect correlated with hypoperfusion in the right superior temporal lobe, right precuneus, and right superior occipital gyrus. Right unilateral spatial neglect with left-hemisphere lesions has a strong relationship with hypoperfusion in extensive left hemisiphere regions and in right parietal regions. We speculate that right parietal lobe may be important for emergence of right and left unilateral spatial neglect. Dressing was disrupted by cognitive deficits subsequent to parietal lobe damage. SPECT studies disclosed that dressing disability after left-hemisphere stroke was closely associated with right medial frontal hypoperfusion. Recovery in dressing performance was related to increase of cerebral blood flow in bilateral frontal and occipital regions and in right temporal-parietal regions in patients with left-hemisphere lesions. For those with right-hemisphere lesios, increase of cerebral blood flow was seen in bilateral frontal and parietal regions and in the left occipital regions. The results suggest that both cerebral hemispheres may play a role in recovery from dressing disability.