Functional magnetic resonance imaging study of motor aphasia after cerebral stroke

Objective To explore the mechanism of changes of cerebral language area in patients with motor aphasia after stroke.Methods Fifteen right handed healthy volunteers were examined with 3T MRI machine.By blood oxygenation level dependent(BOLD),functional magnetic resonance imaging(fMRI) scans were done when the volunteers were executing picture naming and words association assignments.The raw image materials were processed with neurological functional image analysis software and brain activation maps of the two assignments were generated as the control group.Six stroke patients were also examined with 3T MRI machine.BOLD fMRI scans were done when the patients were executing picture naming and words association assignments after they got aphasia and after they were treated.The brain activation maps of the patients were set as the patient group.The patients were given fMRI scans respectively within a week and one month after stroke onset to study brain activation spots and strength.Results In the control group,multiple brain areas were activated.In the early phase of the patient group of stroke,six patients(100%) showed significantly lowered or no activation of the left Broca area.One month after stroke onset,three patients(50.0%) showed significant activation of the left Broca area's mirror zone while the other three(50.0%) showed significantly elevated intensity and range of activation of brain area around the left Broca area.Conclusion Wide range of brain cortexes are involved in the advanced language center.They form complex networks to fulfill language function.Patients with motor aphasia after stroke have diminished Broca area activation or even no activation in early period.When the language center is damaged,the brain areas around left Broca area and its mirror zone have an important role in language function remodeling.