Elevated body mass in National Football League players linked to cognitive impairment and decreased prefrontal cortex and temporal pole activity.

Obesity is a risk factor for neurodegenerative disease and has been shown to adversely affect cognitive function. Professional athletes who participate in sports, which expose them to repetitive concussions, may be at heightened risk for cognitive impairment. Here, we investigated the effects of body mass as measured by waist-to-height ratio (WHtR) on regional cerebral blood flow using single-photon emission computed tomography imaging in 38 healthy weight (WHtR mean 49.34 ± 2.8; age 58 ± 9.6) and 38 overweight (WHtR mean 58.7 ± 4.7; age 58 ± 13.3) retired National Football League football players. After matching for age and position, we used a two sample t-test to determine the differences in blood flow in healthy versus overweight subjects. Statistical parametric mapping revealed a higher WHtR ratio is associated with decreased blood flow in Brodmann areas 8, 9 and 10, brain regions involved in attention, reasoning and executive function (P<0.05, family-wise error) along with deficits in the temporal pole. Moreover, overweight athletes had significant decrease in attention (P = 0.01326), general cognitive proficiency (P = 0.012; Microcog: Assessment of Cognitive Functioning) and memory (P=0.005; Mild Cognitive Impairment Screen). The association between elevated WHtR percentage and decreased blood flow in the prefrontal cortex and temporal pole may be correlated with the decreased performance on tests of attention and memory. These findings suggest that a weight management program may be critical to the health of athletes who have been exposed to mild brain trauma during their careers.

Decreased cerebral blood flow in the limbic and prefrontal cortex using SPECT imaging in a cohort of completed suicides.

Suicide has a high comorbidity with impulsivity and depression, and finding imaging biomarkers indicative of patients at high risk for suicidal behavior is invaluable to the clinician. Using single-photon emission computed tomography (SPECT) imaging, we have previously reported regional cerebral blood flow (rCBF) decreases in the medial prefrontal cortex, ventral tegmental area and subgenual cingulate cortex (Brodmann area 25 (BA 25)), a region found to be hypoperfused with treatment-resistant depression. From 2007 to 2010, we have extended our analysis to include nine additional completed suicides. In all, 27 healthy, age- and gender-matched subjects from a previously acquired healthy brain study served as controls to our 21 completed suicides. All 21 suicides had been previously diagnosed with depression according to Diagnostic and Statistical Manual of Mental Disorder-IV criterion. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare the differences in technetium-99m hexamethylpropylene amine oxime brain uptake between the groups. Factor analysis of the data identified the top 10 regions of hypoperfusion in the suicidal group, including the bilateral superior frontal lobes, the right precuneus, the rolandic operculum, postcentral gyrus, left caudate and insular cortex. We also demonstrate more focal decreases in rCBF in the subgenual cingulate cortex (BA 25) in 18 subjects, supporting our previous hypothesis that hypoperfusion of BA 25 may be a risk factor for suicide in depressed patients. This work suggests that SPECT might be useful in predicting risk for suicide completion in subjects with depression or treatment-resistant depression. Further investigation of this work is necessary to better understand the predictive value of this finding.