Association between cognitive ability and functional outcomes following traumatic brain injury- using a computer-based neurocognitive battery

Associations Between Muscle Quality and Cognitive Function in Older Men: Cross-Sectional Data From the Geelong Osteoporosis Study

Sarcopenia-related declines appear to be adversely associated with cognition in the elderly. Poor muscle quality is a marker for sarcopenia, yet little research has examined the concurrence of poor muscle quality and poor cognition. The aim of this study was to investigate the association between muscle quality and cognitive function, overall and in specific domains, in older men. This study involved 342 men from the Geelong Osteoporosis Study (ages 60-96 years). Handgrip strength (HGS, kg) was measured by dynamometry (Vernier, LoggerPro3), and lean mass of arms (kg) and appendicular lean mass (ALM, kg) by dual-energy X-ray absorptiometry (Lunar). Muscle quality was expressed as HGS/(arm lean mass) (kg/kg) as well as HGS/ALM (kg/kg). Cognitive function was assessed in 4 domains: visual attention, psychomotor function, working memory and visual learning. Overall cognitive function scores were calculated. Higher scores represent poorer cognitive performance in attention, psychomotor function and working memory, but better performance for visual memory/learning and overall cognitive function. Additionally, cognitive impairment was determined by the mini-mental state exam (score ≤ 24). Linear regression analyses and logistic regression were performed. There were age-related declines observed for all measures relating to muscle and cognition. Muscle quality (HGS/arm lean mass) was associated with all cognition assessments before and after adjusting for age, except for age-adjusted working memory. Muscle quality (HGS/arm lean mass) was associated with psychomotor function (B -0.01, 95% CI -0.02, -0.005) and overall cognitive function (b + 0.07, 95% CI 0.03, 0.11) after adjusting for age and education. Greater muscle quality was also associated with the likelihood of cognitive impairment OR 0.64 (95%CI 0.46-0.88) after adjusting for age; associations with attention and visual memory/learning were attenuated after further adjustment for confounders. Similar patterns were observed when muscle quality was determined as HGS/ALM. Our data support an association between muscle quality and cognitive function. Further research is needed to examine temporal changes between the Two.

Skeletal Muscle Density and Cognitive Function: A Cross-Sectional Study in Men

We aimed to investigate cross-sectional associations between skeletal muscle density, a proxy measure for fatty infiltration into muscle, and cognition. Contributions from body fat mass, systemic inflammation and lifestyle were explored, as these factors have been identified in both muscle and cognitive deterioration. For 281 men (60-95 year) from the Geelong Osteoporosis Study, radial and tibial muscle density were measured using peripheral quantitative computed tomography. Body fat and appendicular lean mass were measured using dual-energy X-ray absorptiometry. Cognitive function was assessed for psychomotor function (DET), visual identification/attention (IDN), visual learning (OCL) and working memory (OBK) (CogState Brief Battery). Composite scores signified overall cognitive function (OCF). Higher scores represent poorer performance except for OCL and OCF. Regression analyses examined associations between muscle density and cognition; potential confounders included age, muscle cross-sectional area (CSA), body composition, lifestyle and serum markers of inflammation. Negative associations with age were evident for muscle density, all cognitive domains and OCF. Muscle density at both sites was positively associated with DET, OCL and OCF. After adjustment for age, the association persisted for DET (radius: B =  - 0.006, p = 0.02; tibia: B =  - 0.003, p = 0.04) and OCL (radius B =  + 0.004, p = 0.02; tibia: B =  + 0.005, p < 0.001). At the radius, further adjustment for serum TNF-α explained the association between muscle density (B =  - 0.002, p = 0.66) and DET. Education and physical activity contributed to the model for radial muscle density and DET. There were no contributions from muscle CSA, appendicular lean mass, body fat mass, other markers of inflammation or other potential confounders. At the tibia, the association between muscle density and DET (B =  - 0.003, p = 0.04) was independent of TNF-α. There was an age-adjusted association between muscle density and OCL at both sites (radius: B =  + 0.004, p = 0.02; tibia: B =  + 0.005, p < 0.001). None of the potential confounders contributed to the models. Muscle density was associated with cognitive function in the DET and OCL domains. However, there was little evidence that this was explained by inflammation or body fat mass. No associations were identified between muscle density and IDN or OBK.

Cogstate Brief Battery: Cognition and the feigning of cognitive impairment in chronic pain

Chronic pain (CP) is often associated with cognitive impairment. The Cogstate Brief Battery (CBB), a computerized assessment battery, has been studied in several neuropsychiatric disorders but not in CP. Since feigning of cognitive impairment is common in CP, the current study aimed to assess the CBB's utility in differentiating CP patients (n = 64) from healthy participants (n = 33), as well as to assess the effect of simulating cognitive impairment by CP patients on performance in the battery. CP outpatients were randomly assigned to one of two groups: (a) Patients performing the CBB to the best of their ability. (b) Patients simulating cognitive impairment. Independent-samples t-tests indicated that three of four CBB tasks successfully differentiated CP patients from matched healthy controls. Additionally, an analysis of covariance (ANCOVA) indicated that CP patients who simulated cognitive impairment performed more poorly in all four CBB tasks, with the detection task having the strongest discrimination capacity. This is the first study to point toward the usefulness and sensitivity of the CBB for assessment of cognition and detection of feigned cognitive impairment in CP. Further studies are required to validate these preliminary findings and assess the CBB's utility in daily clinical practice.

Muscle strength and gait speed rather than lean mass are better indicators for poor cognitive function in older men

We aimed to examine muscle strength, function and mass in relation to cognition in older men. This cross-sectional data-set included 292 men aged ≥60 yr. Handgrip strength (kg) was measured by dynamometry, gait speed by 4-metre walk (m/s) and appendicular lean mass (kg) by dual-energy x-ray absorptiometry. Cognition was assessed across four domains: psychomotor function, attention, visual learning and working memory. Composite scores for overall cognition were calculated. Bivariate analyses indicated that handgrip strength and gait speed were positively associated with cognitive function. After accounting for confounders, positive associations between individual muscle (or physical) measures and cognitive performance were sustained for handgrip strength and psychomotor function, gait speed and psychomotor function, gait speed and attention, handgrip strength and overall cognition, and gait speed and overall cognition. In multivariable models, handgrip strength and gait speed independently predicted psychomotor function and overall cognition. No associations were detected between lean mass and cognition after adjusting for confounders. Thus, low muscle strength and slower gait speed, rather than low lean mass, were associated with poor cognition in older men.