1988 Volume 8 Issue 4 Pages 320-327
In 44 patients with aphasia due to cerebral infarction, the positron emission tomographic studies (PET) were carried out using the 15O steady-state method. According to the type and severity, aphasic patients were divided into 2 groups, respectively. There were 18 cases with motor aphasia, and 20 cases with sensory aphasia. Another 6 cases were global aphasia. Twentyeight cases were classified as the mild group, while 16 cases served as the severe group. The regions of interest (ROIs) for quantitative measurement of cerebral blood flow and oxygen consumption were outlined as 7 cortical regions on each cerebral hemisphere. The regional values were calculated by averaging the 405 pixels data at each ROI ; regional cerebral blood flow (rCBF) and regional oxygen consumption (rCMRO2). The mean value for the cerebral hemisphere was caluculated by averaging the 7 regional values ; mean CBF (mCBF) and mean CMRO2 (mCMRO2). Seven patients with an infarction in the region of the left renticulostriate arteries served as a control group.
1. Relationship between the types of the aphasia and the PET data
In the control group, rCBF and rCMRO2 at the poterior frontal region (PF) on the dominant hemisphere which covers the Broca's area, were 37.4 ± 6.4 (ml / 100 g / min) and 2.75 ± 0.35 (ml / 100 g / min), respectively. Those at the posterior temporal region (PT) on the dominant hemisphere which covers the Wernicke's area, were 36.4 ± 4.2 and 2.76 ± 0.38. In the motor aphasia group, the rCBF and rCMRO2 at the PF were 19.9 ± 9.3 and 1.26 ± 0.93, and those at the PT were 27.5 ± 6.6 and 2.19 ± 0.70. In the sensory aphasia group, rCBF and rCMRO2 at the PF were 30.7 ± 7.0 and 2.40 ± 0.69, and those of the PT were 23.7 ± 8.0 and 1.86 ± 0.66. The rCBF and rCMRO2 at the PF in the motor aphasia group, and those in the PT of the sensory aphasia group were significantly lower than those in the control group. The rCBF and rCMRO2 at the PF were significantly lower in the motor aphasia group than in the sensory aphasia groups. The present study suggests that the motor aphasia was associated with the ischemia in the left posterior frontal lobe.
2. Relationship between the severity of the aphasia and the the PET data.
In the control group, the mCBF and mCMRO2 were 37.5 ± 5.1 and 2.83 ± 0.38, respectively. The rCBF and rCMRO2 at the language area, which is obtained by averaging the values of left PF and PT, were 36.9 ± 5.2 and 2.76 ± 0.34. In the mild aphasia group, the mCBF and mCMRO2 were 29.1 ± 6.4 and 2.26 ± 0.57, The rCBF and rCMRO2 at the language area were 27.7 ± 6.3 and 2.17 ± 0.60. In the severe aphasia group, the mCBF and mCMRO2 were 21.3 ± 5.9 and 1.52 ± 0.49. The rCBF and rCMRO2 at the language area were 18.7 ± 6.5 and 1.20 ± 0.50. In the mild aphasia group, the values of rCBF and rCMRO2 at the language area as well as mCBF and mCMRO2 were significantly reduced as compared to the control group. The severe aphasia group showed the same reductions as compared to the control and mild aphasia groups. The present study suggests that measurements of cerebral blood flow and oxygen consumption are valid for the evaluation of the severity of aphasia due to cerebral infarction.
