ABSTRACT
BACKGROUND: Patients with major depressive disorder (MDD) show neuropsychological impairments, including deficient executive functions and altered sensitivity to reward and punishment. METHODS: Executive functions (Wisconsin Card Sorting Test, WCST) and contingency learning based on the cumulative effect of reward and punishment (Iowa Gambling Test, IGT) were assessed in 30 medicated patients with unipolar MDD and in 20 healthy control volunteers. In the classic ABCD version of the IGT, advantageous decks are characterized by immediate small reward but even smaller future punishment. In the modified EFGH version, advantageous decks are characterized by immediate large punishment but even larger future reward. RESULTS: Patients with MDD were impaired in the WCST and in the ABCD version of the IGT but showed normal performances on the EFGH task. Depression, but not executive dysfunctions, significantly predicted performances on the EFGH task: less severe depressive symptoms were associated with better performances on the EFGH task. LIMITATIONS: The sample size was small and only few neuropsychological tests were used. Unmedicated patients were not assessed. Individual personality style, response strategies, and behavioral impulsivity were not investigated. CONCLUSIONS: Medicated patients with MDD show altered sensitivity to reward and punishment: immediate large reward enhanced related response patterns even when the strategy was disadvantageous and immediate large punishment did not prohibit related response patterns. Impairments in emotional decision-making were not a pure consequence of executive dysfunctions.
Subject(s)
Depressive Disorder, Major/physiopathology , Prefrontal Cortex/physiopathology , Punishment/psychology , Reward , Adult , Affect/physiology , Arousal/physiology , Association Learning/physiology , Decision Making/physiology , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/psychology , Discrimination Learning/physiology , Female , Gambling/psychology , Humans , Male , Middle Aged , Neuropsychological Tests/statistics & numerical data , Problem Solving/physiology , Regression Analysis , Statistics as Topic , Token EconomyABSTRACT
The pathology of the prefrontal cortex (PFC) may play an important role in the development of the symptoms of major depressive disorder. In this study, the authors used the Wisconsin Card Sorting Test (WCST) and the Iowa Gambling Test (IGT) to investigate PFC functions in depression. The WCST investigates cognitive set-shifting abilities, whereas the IGT is sensitive for the cumulative effect of reward and punishment on decision-making. Participants were 20 patients with DSM-IV major depressive disorder and 20 age-, gender-, and education-matched healthy control subjects. The depressed patients showed significant impairment in both tests, but the WCST and IGT scores did not correlate. There was no significant correlation between the test results and the severity of depressive and anxiety symptoms. Our results suggest a global impairment of the PFC in depression, which includes the dorsolateral and ventromedial regions.
Subject(s)
Depressive Disorder, Major/pathology , Depressive Disorder, Major/psychology , Neuropsychological Tests , Prefrontal Cortex/pathology , Adult , Case-Control Studies , Female , Humans , Male , Middle Aged , Severity of Illness IndexABSTRACT
OBJECTIVE: The aim was to evaluate electromyographically the validity of the sit-up section of the Army Physical Fitness Test as a way to assess abdominal endurance. METHODS: Twenty-eight Reserve Officer Training Corps students at the University of Scranton (Scranton, PA) performed the test while eight electromyography surface electrodes picked up the activity of the rectus abdominus and rectus femoris muscles. The researchers analyzed three groups of five contractions from the beginning, middle, and the end of the test. The percentage area of each group of five contractions for each channel and for each of the 28 participants was averaged. RESULTS: Two paired sample t tests were used to analyze the change in area for the left hip flexor and left abdominal muscle (t = 5.951, p < 0.001) and right hip flexor and right abdominal muscle (t = 5.025, p < 0.001). Results for both right and left sides indicate a statistically significant increase in the use of hip flexors as compared with abdominal muscles. CONCLUSION: Hip flexors can compensate for fatigued abdominal muscles, causing sit-ups to be performed unsafely, yet are still counted as correct according to Army Physical Fitness Test standards.
