Hannah L. Combs

Cognition and Depression Following Deep Brain Stimulation of the Subthalamic Nucleus and Globus Pallidus Pars Internus in Parkinson’s Disease: A Meta-Analysis

Parkinson’s disease (PD) is a common, degenerative disorder of the central nervous system. Individuals experience predominantly extrapyramidal symptoms including resting tremor, rigidity, bradykinesia, gait abnormalities, cognitive impairment, depression, and neurobehavioral concerns. Cognitive impairments associated with PD are diverse, including difficulty with attention, processing speed, executive functioning, memory recall, visuospatial functions, word-retrieval, and naming. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidus internus (GPi) is FDA approved and has been shown to be effective in reducing motor symptoms of PD. Studies have found that stimulating STN and GPi are equally effective at improving motor symptoms and dyskinesias; however, there has been discrepancy as to whether the cognitive, behavioral, and mood symptoms are affected differently between the two targets. The present study used random-effects meta-analytic models along with a novel p-curve analytic procedure to compare the potential cognitive and emotional impairments associated with STN-DBS in the current literature to those associated with GPi-DBS. Forty-one articles were reviewed with an aggregated sample size of 1622 patients. Following STN-DBS, small declines were found in psychomotor speed, memory, attention, executive functions, and overall cognition; and moderate declines were found in both semantic and phonemic fluency. However, GPi-DBS resulted in fewer neurocognitive declines than STN-DBS (small declines in attention and small-moderate declines in verbal fluency). With regards to its effect on depression symptomatology, both GPi-DBS and STN-DBS resulted in lower levels of depressive symptoms post-surgery. From a neurocognitive standpoint, both GPi-DBS and STN-DBS produce subtle cognitive declines but appears to be relatively well tolerated.

The Effects of Mild Traumatic Brain Injury, Post-Traumatic Stress Disorder, and Combined Mild Traumatic Brain Injury/Post-Traumatic Stress Disorder on Returning Veterans.

United States veterans of the Iraqi (Operation Iraqi Freedom [OIF]) and Afghanistan (Operation Enduring Freedom [OEF]) conflicts have frequently returned from deployment after sustaining mild traumatic brain injury (mTBI) and enduring stressful events resulting in post-traumatic stress disorder (PTSD). A large number of returning service members have been diagnosed with both a history of mTBI and current PTSD. Substantial literature exists on the neuropsychological factors associated with mTBI and PTSD occurring separately; far less research has explored the combined effects of PTSD and mTBI. The current study employed neuropsychological and psychological measures in a sample of 251 OIF/OEF veterans to determine whether participants with a history of mTBI and current PTSD (mTBI+PTSD) have poorer cognitive and psychological outcomes than participants with mTBI only (mTBI-o), PTSD only (PTSD-o), or veteran controls (VC), when groups are comparable on intelligence quotient, education, and age. The mTBI+PTSD group performed more poorly than VC, mTBI-o, and PTSD-o groups on several neuropsychological measures. Effect size comparisons suggest small deleterious effects for mTBI-o on measures of processing speed and visual attention and small effects for PTSD-o on measures of verbal memory, with moderate effects for mTBI+PTSD on the same variables. Additionally, the mTBI+PTSD group was significantly more psychologically distressed than the PTSD-o group, and PTSD-o group was more distressed than VC and mTBI-o groups. These findings suggest that veterans with mTBI+PTSD perform significantly lower on neuropsychological and psychiatric measures than veterans with mTBI-o or PTSD-o. The results also raise the possibility of mild but persisting cognitive changes following mTBI sustained during deployment.

Discriminating Among ADHD Alone, ADHD With a Comorbid Psychological Disorder, and Feigned ADHD in a College Sample

Since the early 2000s concern has increased that college students might feign ADHD in pursuit of academic accommodations and stimulant medication. In response, several studies have validated tests for use in differentiating feigned from genuine ADHD. Although results have generally been positive, relatively few publications have addressed the possible impact of the presence of psychological disorders comorbid with ADHD. Because ADHD is thought to have accompanying conditions at rates of 50% and higher, it is important to determine if the additional psychological disorders might compromise the accuracy of feigning detection measures. The present study extended the findings of Jasinski et al. (2011) to examine the efficacy of various measures in the context of feigned versus genuine ADHD with comorbid psychological disorders in undergraduate students. Two clinical groups (ADHD only and ADHD + comorbid psychological disorder) were contrasted with two non-clinical groups (normal controls answering honestly and normal participants feigning ADHD). Extending previous research to individuals with ADHD and either an anxiety or learning disorder, performance validity tests such as the Test of Memory Malingering (TOMM), the Letter Memory Test (LMT), and the Nonverbal Medical Symptom Validity Test (NV-MSVT) were effective in differentiating both ADHD groups from normal participants feigning ADHD. However, the Digit Memory Test (DMT) underperformed in this study, as did embedded validity indices from the Wechsler Adult Intelligence Scale-IV (WAIS-IV) and Woodcock Johnson Tests of Achievement-III (WJ-III).

Combinatorial Motor Training Results in Functional Reorganization of Remaining Motor Cortex after Controlled Cortical Impact in Rats

Cortical reorganization subsequent to post-stroke motor rehabilitative training (RT) has been extensively examined in animal models and humans. However, similar studies focused on the effects of motor training after traumatic brain injury (TBI) are lacking. We previously reported that after a moderate/severe TBI in adult male rats, functional improvements in forelimb use were accomplished only with a combination of skilled forelimb reach training and aerobic exercise, with or without nonimpaired forelimb constraint. Thus, the current study was designed to examine the relationship between functional motor cortical map reorganization after experimental TBI and the behavioral improvements resulting from this combinatorial rehabilitative regime. Adult male rats were trained to proficiency on a skilled reaching task, received a unilateral controlled cortical impact (CCI) over the forelimb area of the caudal motor cortex (CMC). Three days post-CCI, animals began RT (n = 13) or no rehabilitative training (NoRT) control procedures (n = 13). The RT group participated in daily skilled reach training, voluntary aerobic exercise, and nonimpaired forelimb constraint. This RT regimen significantly improved impaired forelimb reaching success and normalized reaching strategies, consistent with previous findings. RT also enlarged the area of motor cortical wrist representation, derived by intracortical microstimulation, compared to NoRT. These findings indicate that sufficient RT can greatly improve motor function and improve the functional integrity of remaining motor cortex after a moderate/severe CCI. When compared with findings from stroke models, these findings also suggest that more intense RT may be needed to improve motor function and remodel the injured cortex after TBI.

The happy survivor? Effects of differential mortality on life satisfaction in older age.

Older adults report higher psychological well-being than younger adults. Those highest in well-being also have the lowest risk of mortality. If those with lower well-being die earlier, it could affect the appearance of developmental change in well-being. In adults aged 50 and older (N = 4,458), we estimated effects of differential mortality on life satisfaction by imputing life satisfaction, adjusting for attrition due to death, or estimating life satisfaction using pattern-mixture modeling. There was an increase in life satisfaction with age; however, differential mortality affected the elevation of the curve. Observed life satisfaction, particularly above age 70, is affected by differential mortality. (PsycINFO Database Record

Time perspective and social preference in older and younger adults: Effects of self-regulatory fatigue.

Socioemotional selectivity theory predicts that when perceived time in life is limited, people will prefer emotionally close social partners over less emotionally rewarding partners. Regulating social choices with regard to time perspective can make the best use of time with regard to well-being. However, doing so may depend on the self-regulatory capacity of the individual. Two studies, 1 with younger adults (N = 101) and 1 with younger (N = 42) and older (N = 39) adults, experimentally tested the effects of time perspective and self-regulatory fatigue on preferences for emotionally close partners and knowledgeable partners. In both studies and across younger and older adults, when self-regulatory fatigue was low, the perception of limited time resulted in a greater preference for close social partners relative to knowledgeable social partners. However, this shift was eliminated by self-regulatory fatigue. In Study 2, when fatigued, younger adults preferred close social partners to knowledgeable partners across time perspectives; older adults preferred close and knowledgeable partners more equally across time perspectives. These findings have implications for social decision-making and satisfaction among people who experience chronic self-regulatory fatigue. They also contradict previous suggestions that only younger adults are susceptible to self-regulatory fatigue. (PsycINFO Database Record

The effects of symptom information coaching on the feigning of adult ADHD.

College students without ADHD may feign symptoms of ADHD to gain access to stimulant medications and academic accommodations. Unfortunately, research has shown that it can be difficult to discriminate malingered from genuine ADHD symptomatology, especially when evaluations are based only on self-report questionnaires. The present study investigated whether nonclinical college students given no additional information could feign ADHD as successfully as those who were coached on symptoms of the disorder. Similar to Jasinski et al. (2011) and other research on feigned ADHD, a battery of neuropsychological, performance validity, and self-report tests was administered. Undergraduates with no history of ADHD or other psychiatric disorders were randomly assigned to 1 of 2 simulator groups: a coached group that was given information about ADHD symptoms, or a noncoached group that was given no such information. Both simulator groups were asked to feign ADHD. Their performance was compared to a genuine ADHD group and a nonclinical group asked to respond honestly. Self-report, neuropsychological, and performance validity test data are discussed in the context of the effect of coaching and its implications for ADHD evaluations. Symptom coaching did not have a significant effect on feigning success. Performance validity tests were moderately effective at detecting feigned ADHD.

Irritability and aggression in persistent youth concussions

Objective To assess whether irritability and aggression are viable indicators of persistent post-concussive symptoms in adolescents. Design Group differences between those diagnosed with concussions were analysed using ANOVAs (p < 0.05). Setting Outpatient clinic. Participants 46 concussed adolescents age 12–17 with persisting concussion symptoms were assessed. Athletes were split into two groups: those endorsing irritability/aggression (AGG, n=24) and a control group of those denying irritability/aggression (CON, n=22). Those with baseline psychiatric history and/or special education were excluded. Assessment of risk factors Post-concussive symptom variable relationships were assessed. Outcome measures group differences were analysed using ANOVAs. Results Adolescents endorsing irritability/aggression reported more fatigue (p=0.002), disordered sleep (p=0.001), anxiety (p=0.028), depression (p=0.003), and mood lability (p<0.001) during clinical assessment. Adolescents reporting more irritability also had elevated scores on related psychometric scales, including the Beck Youth Inventory-II Anxiety [t(41)=−2.916, p = 0.006], Depression [t(41)=−3.551, p = 0.001], and Anger Scales [t(41)=−2.958, p=0.005]. Conclusions Results indicate that adolescents with self-reported irritability and aggression post-concussion were more likely to display more affective symptoms than those who did not endorse irritability and aggression following concussions. They were also more likely to complain of fatigue and disordered sleep. These findings suggest that change in level of irritability/aggression could potentially serve as an identifiable indicator for parents and coaches to recognise when an adolescent is not recovering well post-concussion. Competing interests None.