Apnea Linked to Lower Mammillary Body Volume

Change in brain structures that play a role in memory processing may affect sleep apnea patients

THURSDAY, June 19 (HealthDay News) -- Patients with obstructive sleep apnea (OSA) showed lower mammillary body volumes compared to control subjects, which may be a factor in the memory deficits known to accompany the condition, according to research published in the June 27 Neuroscience Letters.

Rajesh Kumar, of the University of California Los Angeles, and colleagues evaluated mammillary body dimensions in 43 individuals with OSA and 66 controls, using high-resolution structural MRI and manual volume tracing procedures. Memory processing involves linked structures including the hippocampus, anterior thalamus and mammillary bodies.

Mammillary body volume loss was visually apparent in the OSA group, the investigators found, and left, right and combined body volumes were significantly reduced compared to controls. The researchers noted greater volume reduction in the left-side mammillary bodies than the right.

"The mammillary body volume loss bears a resemblance to reduced volumes associated with Korsakoff's syndrome," the authors write. "Recent data suggest that thiamine deficiency may not be solely responsible for the neural injury accompanying Korsakoff's syndrome. Neural degenerative processes associated with alcohol intake, together with reduced thiamine may be necessary for the complete complement of structural injuries. In OSA subjects, we speculate that the injury may primarily result from hypoxic or inflammatory processes accompanying the intermittent apnea associated with the syndrome, with the possibility that lack of thiamine or other nutritional deficiency fails to provide adequate neural protection," they conclude.

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