Recovery of language function and brain metabolism in a patient with crossed aphasia: 2-year follow-up of brain FDG PET images

Abstract

BACKGROUND: Crossed aphasia, a language disturbance in right-handed individuals secondary to a right hemisphere lesion, is rare, occurring in only l-2% of brain-lesioned patients. The precise neurological mechanisms of crossed aphasia are still unknown, and follow-up studies in the long term of language function are sparse. AIMS: We describe a detailed follow-up evaluation of language function and resting brain glucose metabolism in a well-defined crossed aphasia patient after right middle cerebral artery (MCA) infarction. METHODS & PROCEDURES: A 49-year-old man was referred for the treatment of 3-week history of aphasia after right MCA infarction. He indicated a strong right-handed preference confirmed by the Edinburgh Handedness Questionnaire, and his family members are all right handed. There was no history of developmental delay or learning disability in childhood or previous neurological disease. Formal language evaluation was carried out in the subacute phase (3 weeks after onset) and the late phase (5 and 24 months after onset) with the Korean version of Western Aphasia Battery. He received 40-min sessions of conventional speech and language therapy by a qualified therapist of comparable experience, three times a week. The serial F-18 fluorodeoxyglucose positron emission tomography (FDG PET) scan was performed on 3 weeks and 24 months after onset, respectively. Subtraction PET imaging between baseline and follow-up evaluation was conducted with coregistration with the patient’s magnetic resonance imaging. OUTCOMES & RESULTS: In the initial evaluation, his aphasia was categorized as Broca’s aphasia [aphasia quotients (AQs) 50.4, language quotients (LQs) 49.8]. Four months after the initial evaluation, the function of spontaneous speech, repetition, naming, and reading significantly improved, with a relatively moderate progress of comprehension (AQ 83.5, LQ 78.1). At 2-year follow-up, the function of spontaneous speech, repetition, naming, reading, and writing improved, but the comprehension revealed impairment with minimal improvement (AQ 88.9, LQ 86.8). The result revealed that the 20% increased area of F-18 FDG uptake in the subtraction PET image corresponded to the right basal ganglia, the right medial temporal lobe, both occipital lobes, and the left cerebellum. CONCLUSIONS: Our case showed long-term recovery of brain glucose metabolism and language function in a patient with mirror image crossed aphasia. The restoration of perilesional brain function and diaschisis possibly contributed to the recovery of the crossed aphasia.