Regional cerebral blood flow in aphasia

Area of Science:

• Neurology
• Neuroimaging
• Speech and Language Pathology

Background:

• Aphasia, a language disorder resulting from brain damage, presents challenges in precise localization of affected cortical areas.
• Traditional neuroradiological methods may not always identify functional deficits in aphasia.

Purpose of the Study:

• To investigate regional cerebral blood flow (rCBF) in patients with aphasia using the intracarotid xenon-133 method.
• To correlate rCBF patterns with different types of aphasia (motor, sensory, global) and identify affected cortical speech areas.
• To compare the efficacy of the rCBF method with classical neuroradiological techniques for lesion localization.

Main Methods:

• Studied 13 aphasic patients with left hemisphere lesions.
• Employed the intracarotid xenon-133 injection method for rCBF measurement.
• Utilized a 254-detector gamma camera system for data acquisition.
• Measured rCBF during rest and functional tests, including a speech test.

Main Results:

• Motor aphasia showed cortical dysfunction in the lower rolandic area, with Broca's area not consistently affected.
• Sensory aphasia consistently involved the superior-posterior temporal cortex.
• Global aphasia exhibited abnormalities in both regions identified in motor and sensory aphasia.
• The xenon-133 method identified functional abnormalities in cases where classical methods showed no clear lesions.

Conclusions:

• Regional cerebral blood flow mapping with xenon-133 effectively localizes cortical speech areas in aphasia.
• The method is superior to classical neuroradiology by detecting functionally inactivated but structurally intact cortex.
• rCBF abnormalities correlate with specific aphasia types, aiding in understanding language processing deficits.