Cognitive intervention (CI) is a nonpharmacological approach used to compensate for cognitive impairment. It is categorized into cognitive training, cognitive stimulation and cognitive rehabilitation. Several studies showed that CI could induce cognitive enhancement and reduction of risk for future cognitive decline in patients with brain injury. We investigated effects of CI on cognitive functions and brain glucose metabolism based on serial cognitive assessments and [18F]-Fluorodexoxyglucose positron emission tomography (FDG-PET) in a patient with carbon monoxide (CO) intoxication.

A 40-year-old man presented with memory impairment and abnormal behaviors such as apathy, indifference, and perseveration 2-month after CO intoxication. Brain magnetic resonance image (MRI) demonstrated high signal changes in the bilateral basal ganglia, hippocampus and the subcortical white matter on T2 weighted images. FDG-PET also showed glucose hypometabolism in the bilateral hippocampus, basal ganglia, and the subcortical white matter. A detailed neuropsychological evaluation revealed multiple cognitive impairments in memory, language and frontal functions. He received twice a week sessions of 60-minute group-based cognitive intervention for 12 weeks. Several neuropsychological examinations and FDG-PETs were conducted at baseline and after CI.

After CI, he showed improvements in memory and frontal functions compared with baseline performances. These cognitive improvements persisted by the 7-month follow-up. The extent of glucose hypometabolism was decreased 1-month after CI, however increased 8-month after CI.

This case study suggested that CI could enhance cognitive functions and improve glucose metabolism in a patient with CO intoxication. Also, the effects of CI on cognitive functions seem to be last at least 7-month after training.