Bed rest and cognition: effects on executive functioning and reaction time

INTRODUCTION: Executive functions are high-order aspects of cognition heavily dependent upon the prefrontal cortex. Both prefrontal cortex activity and executive function task performance are enhanced by participation in aerobic physical activity, suggesting that a lack of such activity during the bed rest model of prolonged weightlessness might induce executive function deficits. METHODS: Twenty-four healthy males (ages 21-45 yr) undertook 60 d of head-down bed rest (-6 degrees) for the 2nd Berlin Bed Rest Study (BBR2-2). Three executive function tasks (Iowa Gambling Task, working memory, and flanker) and a reaction time task were administered before, during, and after bed rest. RESULTS: Iowa Gambling Task scores were significantly worse during bed rest (1.7 +/- 6.9) than in other sessions (24.3 +/- 7.8). Effects on working memory and flanker task performance were less obvious, requiring practice effects to be considered. Reaction time was significantly slower after bed rest (569 +/- 42 ms) than in earlier tests (529 +/- 45 ms). There was also significantly less intrasubject variability in reaction time after bed rest, consistent with more efficient executive functioning at this stage. DISCUSSION: Our results provide some evidence for a detrimental effect of bed rest on executive functioning. Whether this stems from a lack of aerobic physical activity and/or changes in the prefrontal cortex remains to be determined. Cognitive effects of bed rest could have implications for the planned human exploration of Mars, and for medical and lifestyle conditions with inadequate levels of aerobic physical activity.

Relationship between executive functioning and symptoms of attention-deficit/hyperactivity disorder and autism spectrum disorder in 6-8 year old children

This study examined relationships between executive functioning (EF) and ADHD/ASD symptoms in 339 6-8 year-old children to characterise EF profiles associated with ADHD and ADHD + ASD. ADHD status was assessed using screening surveys and diagnostic interviews. ASD symptoms were measured using the Social Communication Questionnaire, and children completed assessments of EF. We found the EF profile of children with ADHD + ASD did not differ from ADHD-alone and that lower-order cognitive skills contributed significantly to EF. Dimensionally, ASD and inattention symptoms were differentially associated with EF, whereas hyperactivity symptoms were unrelated to EF. Differences between categorical and dimensional findings suggest it is important to use both diagnostic and symptom based approaches in clinical settings when assessing these children's functional abilities.

Parents with psychosis : a pilot study examining self-report measures related to family functioning

The aims of this study were to examine the utility of various self-report instruments related to family functioning in families where a parent has a psychotic disorder, and to explore associations between these instruments and symptoms in the parent. Twenty-one parents with a psychotic disorders participated in the study. All participants were able to complete the questionnaires and the majority of parents reported levels of parental competence in the average range. Most parents (90%) perceived themselves to be effective parents, however 30% reported low levels of satisfaction with the parenting role. There were significant associations between objective measures of negative symptoms and self-report scores related to problems in ways of coping, and problems with parent-child interactions. Many individuals with psychosis were able to report areas of perceived need related to their role as parents and to the functioning of their families, however there are several limitations in the use of these instruments in this setting.

The long term effects of sports concussion on retired Australian football players: a study using Transranial Magnetic Stimulation

This study investigated corticomotor excitability and inhibition, cognitive functioning, and fine motor dexterity in retired elite and amateur Australian football (AF) players who had sustained concussions during their playing careers. Forty male AF players who played at the elite level (n=20; mean age 49.7±5.7 years) or amateur level (n=20; mean age 48.4±6.9 years), and had sustained on average 3.2 concussions 21.9 years previously, were compared with 20 healthy age-matched male controls (mean age 47.56±6.85 years). All participants completed assessments of fine dexterity, visuomotor reaction time, spatial working memory (SWM), and associative learning (AL). Transcranial magnetic stimulation (TMS) was used to measure corticospinal excitability: stimulus-response (SR) curves and motor evoked potential (MEP) 125% of active motor threshold (aMT); and intracortical inhibition: cortical silent period (cSP), short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI). Healthy participants performed better in dexterity (p=0.003), reaction (p=0.003), and movement time (p=0.037) than did both AF groups. Differences between AF groups were found in AL (p=0.027) and SWM (p=0.024). TMS measures revealed that both AF groups showed reduced cSP duration at 125% aMT (p>0.001) and differences in SR curves (p>0.001) than did healthy controls. Similarly, SICI (p=0.012) and LICI (p=0.009) were reduced in both AF groups compared with controls. Regression analyses revealed a significant contribution to differences in motor outcomes with the three measures of intracortical inhibition. The measures of inhibition differed, however, in terms of which performance measure they had a significant and unique predictive relationship with, reflecting the variety of participant concussion injuries. This study is the first to demonstrate differences in motor control and intracortical inhibition in AF players who had sustained concussions during their playing career two decades previously.

Review of the literature on the use of social media by people with traumatic brain injury (TBI)

Purpose: To review the literature relating to use of social media by people with a traumatic brain injury (TBI), specifically its use for social engagement, information exchange or rehabilitation.

Method: A systematic review with a qualitative meta-synthesis of content themes was conducted. In June 2014, 10 databases were searched for relevant, peer-reviewed research studies in English that related to both TBI and social media.

Results: Sixteen studies met the inclusion criteria, with Facebook™ and Twitter™ being the most common social media represented in the included studies. Content analysis identified three major categories of meaning in relation to social media and TBI: (1) risks and benefits; (2) barriers and facilitators; and (3) purposes of use of social media. A greater emphasis was evident regarding potential risks and apparent barriers to social media use, with little focus on facilitators of successful use by people with TBI.

Conclusions: Research to date reveals a range of benefits to the use of social media by people with TBI however there is little empirical research investigating its use. Further research focusing on ways to remove the barriers and increase facilitators for the use of social media by people with TBI is needed. Implications for Rehabilitation: Communication disabilities following traumatic brain injury (TBI) can be wide-ranging in scope and social isolation with loss of friendships after TBI is common. For many people, social media is rapidly becoming a usual part of everyday communication and its use has the potential to increase communication and social participation for people with TBI.There is emerging evidence and commentary regarding the perceived benefits and risks, barriers and facilitators and purposes of use of social media within the TBI population.Risks associated with using social media, and low accessibility of social media sites, form barriers to its use. Facilitators for social media use in people with TBI include training the person with TBI and their communication partners in ways to enjoy and use social media safely.There is minimal rigorous evaluation of social media use by people with TBI and scant information regarding social media use by people with communication disabilities after TBI. Further investigation is needed into the potential benefits of social media use on communication, social participation and social support with the aim of reducing social isolation in people with TBI.

Neuroimaging and electrophysiology efficacy in measuring acute effects and long-term sequelae following sports-related concussion

Traumatic brain injury (TBI) is a complex pathophysiological process resulting from external forces applied to the skull and affecting the brain. TBI is a significant global contributor to disability and death, particularly in children and young adults. The severity of a TBI may range from "mild" (a brief change in mental status or consciousness) to "severe" (an extended period of unconsciousness or amnesia after the injury), with mild TBI (mTBI) the most common form, diagnosed in 80-90% of cases. Sports-related concussion contributes significantly to mTBI accounting for nearly 20% of all mTBI cases. In the past decade there has been increasing growing public concern regarding the association of sports concussion; in particular further chance of recurrent injury following a concussion due to transient cognitive impairments, and long-term detrimental mental health issues and deterioration in brain function as a consequence of multiple concussions. Attention is also turning to methods to assess concussion with questions surrounding the reliability in traditional methods of concussion assessment that include symptom observation and cognitive assessment. This chapter will discuss the neuroscience of sports-related concussion, reviewing the evidence from new and rigorous methods of concussion assessment, such as neuroimaging and electrophysiology, with a focus on transcranial magnetic stimulation, following acute concussive events through tolong-term manifestations of multiple concussions.

The trajectory of cognitive functioning following first episode mania: a 12-month follow-up study

OBJECTIVES: Cognitive deficits are apparent in the early stages of bipolar disorder; however, the timing and trajectory of cognitive functioning following a first episode of mania remains unclear. The aim of this study was to assess the trajectory of cognitive functioning in people following a first episode of mania over a 12-month period, relative to healthy controls. METHOD: The cohort included 61 participants who had recently stabilised from a first treated manic episode, and 21 demographically similar healthy controls. These groups were compared on changes observed over time using an extensive cognitive battery, over a 12-month follow-up period. RESULTS: A significant group by time interaction was observed in one measure of processing speed (Trail Making Test - part A,) and immediate verbal memory (Rey Auditory Verbal Learning Test - trial 1), with an improved performance in people following a first episode of mania relative to healthy controls. On the contrary, there was a significant group by time interaction observed on another processing speed task pertaining to focussed reaction time (Go/No-Go, missed go responses), with first episode of mania participants performing significantly slower in comparison with healthy controls. Furthermore, a significant group by time interaction was observed in inhibitory effortful control (Stroop effect), in which healthy controls showed an improvement over time relative to first episode of mania participants. There were no other significant interactions of group by time related to other measures of cognition over the 12-month period. CONCLUSION: Our findings revealed cognitive change in processing speed, immediate memory and one measure of executive functioning over a 12-month period in first episode of mania participants relative to healthy controls. There was no evidence of change over time for all other cognitive domains. Further studies focussed on the at-risk period, subgroup analysis, and the effects of medication on the cognitive trajectory following first episode of mania are needed.

Assessment of cognitive function in heart failure patients

Background
Research on the cognitive capacity of heart failure patients is limited, with a paucity of benchmark information available for this population. It is highly likely that cognitive deficits affect patients' understanding of disease and treatment requirements, as well as limiting their functional capacity and ability to implement treatment plans, and undertake self-care.

Aims
The purpose of this study was to establish a comprehensive neurocognitive profile of the heart failure patient through systematic neurocognitive assessment and to determine whether an association existed between severity of heart failure and cognitive abilities.

Methods
Thirty-eight patients were recruited from the heart failure patient databases of two metropolitan hospitals in Melbourne, Australia. Participants were individually assessed using four standardised, internationally recognised neuropsychological tests that examined current and premorbid intelligence, memory and executive functioning.

Results
Although there was no significant decline from premorbid general intellectual function, other specific areas of deficit, including impaired memory and executive functioning, were identified. There were no significant correlations between heart failure severity and the neurocognitive measures used.

Conclusion
The results support the need to recognise cognitive impairment in people with heart failure and to develop an abbreviated method of assessing cognitive function that can be easily implemented in the clinical setting. Identifying cognitive deficits in this population will be useful in guiding the content and nature of treatment plans to maximise adherence and minimise worsening of heart failure symptoms.

Assessment of a six-week computer-based remediation program for social cognition in chronic schizophrenia

Background: Programs to remediate cognitive deficits have shown promising results in schizophrenia, but remediation of social cognition deficits is less well understood. Social cognitive deficits may cause more disability than the widely recognized neurocognitive deficits, suggesting that this is an area worthy of further investigation. Aim: Implement and evaluate a brief computerized cognitive remediation program designed to improve memory, attention, and facial affect recognition (FAR) in outpatients with chronic schizophrenia.

Methods: Baseline assessments of FAR and of clinical, cognitive, and psychosocial functioning were completed on 20 males with schizophrenia enrolled in an outpatient rehabilitation program at the Shanghai Mental Health Center (the intervention group) and on 20 males with schizophrenia recruited from among regular outpatients at the Center (the control group). Both groups received treatment as usual, but the intervention group also completed an average of 12.7 sessions of a computer-based remediation program for neurocognitive, social, and FAR functioning over a 6-week period. The baseline measures were repeated in both groups at the end of the 6-week trial.

Results: There were no statistically significant differences in the changes in clinical symptoms (assessed by the Positive and Negative Syndrome Scale, PANSS) or cognitive measures (assessed using the Hong Kong List Learning Test and the Letter-Number Sequencing Task) between the intervention and control groups over the 6-week trial, but there were modest improvements on the PANSS for the intervention group between baseline and after the intervention. There was a significantly greater improvement in the social functioning measure (the Personal and Social Performance scale, PSP) in the intervention group than in the control group. The pre-post change in the total facial recognition score in the intervention group was statistically significant (paired t-test=-2.60, p=0.018), and there was a statistical trend of a greater improvement in facial recognition in the intervention group than in the control group (F(1,37)=2.93; p=0.092).

Conclusions: Integration of FAR training with a short, computer-administrated cognitive remediation program may improve recognition of facial emotions by individuals with schizophrenia, and, thus, improve their social functioning. But more work on developing the FAR training modules and on testing them in larger, more diverse samples will be needed before this can be recommended as a standard part of cognitive remediation programs.

Effects of N-acetyl cysteine on cognitive function in bipolar disorder

Aims

Bipolar disorder is characterized by progressive changes in cognition with declines in executive functioning, memory and sustained attention. Current pharmacotherapies for bipolar disorder target mood symptoms but have not addressed these cognitive changes resulting in euthymic individuals who still experience cognitive deficits. N-acetyl cysteine (NAC) has been shown to have effects on antioxidant status, glutamate transmission, inflammation and neurogenesis. Adjunctive treatment with NAC improves the symptoms experienced by those with bipolar disorder, particularly depression, and it was hypothesized that cognition may also be improved following NAC treatment.
Methods

As part of a larger randomized, double-blind, placebo-controlled trial, participants in the current report were tested at baseline and 6 months to assess changes in cognitive function following either 2000 mg of NAC daily or placebo.
Results

This study failed to find changes in cognitive function following treatment with NAC compared to placebo.
Conclusions

While an important pilot study, this study had a small sample size and included a limited battery of cognitive tests. Further investigations on the effects of NAC on cognitive performance in bipolar disorder are required.

The effects of multivitamins on cognitive performance: a systematic review and meta-analysis

Complementary medicine use is becoming increasingly popular with multivitamins being the most commonly used vitamin supplement. Although adequate vitamin and nutrient concentrations are necessary for optimal health and cognitive functioning, there is no scientific consensus as to whether multivitamin use prevents cognitive decline or improves mental functioning. The aim of the present study was to determine if multivitamins can be used efficaciously to improve cognitive abilities. A systematic review of randomized controlled trials was performed. Meta-analysis was performed on those cognitive tests used across the largest number of studies. Multiple electronic databases were searched until July 2011 by two authors. Randomized, placebo-controlled trials were considered appropriate if they reported on the chronic effects (≥1 month) of oral multivitamin supplementation on any valid cognitive outcomes. Ten trials were included in review (n = 3,200). Meta-analysis indicated that multivitamins were effective in improving immediate free recall memory (SMD = 0.32; 95% CI: 0.09-0.56, p < 0.01) but not delayed free recall memory (SMD = -0.14; 95% CI: -0.43-0.14, p = 0.33) or verbal fluency (SMD = 0.06; 95% CI: -0.05-0.18, p = 0.26). There was no evidence of publication bias or heterogeneity. Other cognitive abilities sensitive to AD pathology, such as executive and visuospatial functions, were found to be under researched. In conclusion, multivitamins were found to enhance immediate free recall memory but no other cognitive domains.

Cognitive impairment in first-episode mania: a systematic review of the evidence in the acute and remission phases of the illness

There is evidence of cognitive impairment that persists in the remission phase of bipolar disorder; however, the extent of the deficits that occur from the first onset of the disorder remains unclear. This is the first systematic review on cognitive functioning in the early stages of bipolar I disorder. The aim of the study was to identify the patterns and degree of cognitive impairment that exists from first-episode mania. Three electronic databases (MEDLINE, PsycINFO and PubMed) were systematically searched for studies published from January 1980 to June 2014. Eligible studies were separated into two groups: acute and remission. The Newcastle-Ottawa quality assessment scale was utilised to measure the quality of the included studies. A total of seven studies (three acute and four remission), including 230 first-episode mania and 345 healthy control participants, were eligible for the review. The studies in the acute phase only examined aspects of executive functioning, with impairments identified in cognitive flexibility, though not in response inhibition and verbal fluency relative to healthy controls. The most consistent finding during the remission phase was a deficit in working memory, whereas in the other domains, the findings were equivocal. Non-verbal memory and verbal fluency were not impacted in remission from first-episode mania. In conclusion, deficits are present in some but not all areas of cognitive functioning during the early stages of bipolar I disorder. Further research is warranted to understand the longitudinal trajectory of change from first-episode mania.

Increased positive thought disorder with illness duration in patients with schizophrenia

It is unclear whether the severity of positive formal thought disorder, a core clinical feature of schizophrenia, is stable or worsening through the chronic course of the illness. The neurocognitive basis for positive thought disorder also remains unclear. The aim of the present paper was to examine the relationship between thought disorder as measured by the Thought Disorder Index (TDI) and duration of illness and neuropsychological indices in 79 patients with schizophrenia. TDI scores increased in proportion to illness duration. TDI scores were not associated with verbal memory or executive functioning. These results indicate an ongoing worsening of positive thought disorder through the course of illness in schizophrenia.