Poor Sleep Associated with Reduced Gray Matter Volume

UC San Francisco researchers examined 144 Gulf War veterans who reported lower sleep quality, ultimately determining via MRI that those with poor sleep had decreased total cortical and frontal gray matter volume.

The study titled “Associations between Subjective Sleep Quality and Brain Volume in Gulf War Veterans” published in Sleep, and summarized in the Psychiatric Annals, determined that the lower brain volume was occurring independent of some patients’ comorbid psychiatric diagnoses.

“Previous imaging studies have suggested that sleep disturbances may be associated with structural brain changes in specific regions of the frontal lobe such as the medial prefrontal and orbitofrontal cortex,” stated Linda L. Chao, PhD, one of the studies authors. “The surprising thing about our finding is that it suggests poor sleep quality is associated with reduced gray matter volume throughout the entire frontal lobe and also globally in the brain.”

Chao and colleagues in the Department of Radiology and Biomedical Imaging and Psychiatry at UCSF measured sleep quality using the Pittsburgh Sleep Quality Index (PSQI), which assesses sleep efficiency, perceived sleep quality and daily disturbances.

Structural MRI data were reportedly gathered using a 1.5-T scanner; the data were used to calculate total cortical, lobar gray matter and hippocampal volumes. Researchers excluded poor imaging results, which led to 144 veterans’ data being used in the study out of an original pool of 247.

The study used a Structured Clinical Interview for DSM-5 (SCID) which found concurrent Axis I diagnoses in a majority of study participants:
• 58 participants (40%) had lifetime major depression disorder (MDD) and 18 (13%) had current MDD.
• 26 participants (18%) had current PTSD and 28 (19%) were diagnosed with PTSD earlier in life, but no longer met criteria for current PTSD.
• 4 participants (3%) had anxiety disorders other than PTSD, and 1 participant (1%) had obsessive compulsive disorder (OCD).
• 72 participants (50%) had past alcohol abuse/dependence histories, and 24 participants (17%) had past substance abuse/dependence histories.
• Other variable conditions that the study sought to isolate included 32 reported cases (18%) of Gulf War Illness and 18 cases (13%) of low-level sarin exposure.

“Frontal lobe volume may be associated with poorer sleep quality or decreased capacity for sleep to be experienced as restorative,” Chao wrote in the study. “Our results suggest that poor sleep quality, which has been linked to impaired psychosocial, physical and occupational functioning, is associated with frontal lobe atrophy independent of trauma exposure, current and lifetime PTSD symptom severity, current MDD and [Gulf War Illness] status.”

Click here to view abstract

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