The efficacy of mindfulness-based cognitive therapy to improve depression symptoms and quality of life in individuals with memory difficulties and caregivers: A short report.

INTRODUCTION: Depression symptoms are common for older adults with memory difficulties and their caregivers. Mindfulness-based cognitive therapy (MBCT) reduces the risk of relapse in recurrent depression and improves depression symptoms. We explored recruitment and retention success and preliminary effect sizes of MBCT on depression and anxiety symptoms, as well as mindfulness facets, in individuals with memory difficulties and their caregivers. METHODS: A difficulty with memory group (DG) and caregiver group (CG) were randomized into either the MBCT intervention or waitlist control. After serving as controls, participants received the intervention. Mean pre-post changes by group were compared and effect sizes computed. Correlations between mindfulness facets and depression symptoms are also presented. RESULTS: Only 47% of the initial participants completed the study. The intervention did not have an effect on the outcome variables examined. However, improvements in non-judgmental scores were associated with reductions in the number of depression symptoms reported by DG participants (r = -0.90, 95% confidence interval [CI]: -0.98, -0.52) and CG participants (r = -0.76, 95% CI: -0.95, -0.19). Furthermore, improvements in awareness scores (r = -0.69, 95% CI: -0.93, -0.05) and level of burden (r = 0.87, 95% CI: 0.49, 0.97) also significantly correlated with reduced depression symptoms in the CG group. CONCLUSIONS: By determining preliminary MBCT effect sizes in individuals with memory difficulties and their caregivers, research with larger, controlled samples is now justified to determine the true effects of MBCT in these populations.

Evidence of cognitive decline in older adults after remote traumatic brain injury: an exploratory study.

Separate bodies of literature indicate that a history of a traumatic brain injury (TBI) and natural aging may result in overlapping cognitive profiles, yet little is known about their combined effect. We predicted that a remote TBI would compound normal age-related cognitive decline, particularly affecting executive function. Neuropsychological task performance was compared between a group of older adults who sustained a TBI in their distant past (N = 9) and a group of older adults with no history of head injury (N = 15). While all participants scored in the normal range on the Mini-Mental State Examination, the TBI group scored lower than the non-TBI group. Also, in line with predictions, the TBI group made more errors on measures of executive functioning compared to the non-TBI group (the Trail Making B test and the incongruent condition of the Stroop Test), but performed similarly on all tasks with little executive requirements. Findings from this exploratory study indicate that a past TBI may put older adults at a higher risk for exacerbated age-related cognitive decline compared to older adults with no history of TBI.

Long-term working memory deficits after concussion: electrophysiological evidence.

BACKGROUND: Persistent complaints of lingering memory and concentration difficulties are common following a concussion, although the brain basis of these is unknown. Some suggest abnormalities can be found on the P300 event-related potential component, recorded using electroencephalography (EEG), despite unobservable cognitive impairments. OBJECTIVE: To examine the P300 and cognitive performance following a remote concussion during an n-back task that varies in working memory load. RESEARCH DESIGN: Seventeen participants with a remote concussion and 17 controls performed a visual n-back task in which working memory demands were systematically increased by manipulating cognitive load. Participants also completed neuropsychological and self-report measures. RESULTS: The concussion group showed a decrease in P300 amplitude compared to controls that was independent of working memory load on the n-back task. While no performance differences were observed between groups, P300 amplitude was negatively correlated with response times at higher loads in both groups. CONCLUSION: High functioning young adults with a remote concussion may have inefficient recruitment of processing resources for target identification, evident by the attenuated P300. The negative correlations between response time and P300 amplitude suggest that the time necessary to accurately respond to targets increases as the efficiency of allocating processing resources decreases during highly demanding working memory tasks.

Slowing down after a mild traumatic brain injury: a strategy to improve cognitive task performance?

Long-term persistent attention and memory difficulties following a mild traumatic brain injury (TBI) often go undetected on standard neuropsychological tests, despite complaints by mild TBI individuals. We conducted a visual Repetition Detection working memory task to digits, in which we manipulated task difficulty by increasing cognitive load, to identify subtle deficits long after a mild TBI. Twenty-six undergraduate students with a self-report of one mild TBI, which occurred at least 6 months prior, and 31 non-head-injured controls took part in the study. Participants were not informed until study completion that the study's purpose was to examine cognitive changes following a mild TBI, to reduce the influence of "diagnosis threat" on performance. Neuropsychological tasks did not differentiate the groups, though mild TBI participants reported higher state anxiety levels. On our working memory task, the mild TBI group took significantly longer to accurately detect repeated targets on our task, suggesting that slowed information processing is a long-term consequence of mild TBI. Accuracy was comparable in the low-load condition and, unexpectedly, mild TBI performance surpassed that of controls in the high-load condition. Temporal analysis of target identification suggested a strategy difference between groups: mild TBI participants made a significantly greater number of accurate responses following the target's offset, and significantly fewer erroneous distracter responses prior to target onset, compared with controls. Results suggest that long after a mild TBI, high-functioning young adults invoke a strategy of delaying their identification of targets in order to maintain, and facilitate, accuracy on cognitively demanding tasks.

Effects of "diagnosis threat" on cognitive and affective functioning long after mild head injury.

Persistent cognitive complaints are common following a mild head injury (MHI), but deficits are rarely detected on neuropsychological tests. Our objective was to examine the effect of symptom expectation on self-report and cognitive performance measures in MHI individuals. Prior research suggests that when MHI participants are informed they may experience cognitive difficulties, they perform worse on neuropsychological tests compared to MHI participants who are uninformed. In this study, undergraduate students with and without a prior MHI were either informed that the study's purpose was to investigate the effects of MHI on cognitive functioning ("diagnosis threat" condition) or merely informed that their cognitive functioning was being examined, with no mention of status ("neutral" condition). "Diagnosis threat" MHIs self-reported more attention failures compared to "diagnosis threat" controls and "neutral" MHIs, and more memory failures compared to "diagnosis threat" controls. In the "neutral" condition, MHIs reported higher anxiety levels compared to controls and compared to "diagnosis threat" MHIs. Regardless of condition, MHIs performed worse on only one neuropsychological test of attention span. "Diagnosis threat" may contribute to the prevalence and persistence of cognitive complaints made by MHI individuals found in the literature, but may not have as strong of an effect on neuropsychological measures.

Rejecting familiar distracters during recognition in young adults with traumatic brain injury and in healthy older adults.

The most common cognitive complaint reported by healthy older adults and young adults with traumatic brain injury (TBI) is memory difficulties. We investigated the effects of normal aging and the long-term effects of TBI in young adults on the susceptibility to incorrectly endorse distracter information on a memory test. Prior to a study phase, participants viewed a "pre-exposure" list containing distracter words, presented once or three times, and half of the target study words. Subsequently, during the study phase, all target words were presented such that, across lists, study words were viewed either once or three times. On the recognition test, TBI and older adult participants were more likely to falsely endorse "pre-exposed" distracter words viewed three times as being from the target study list, compared to non-head-injured young controls. Normal aging and head injury in young may similarly compromise one's ability to reject highly familiar, but distracting, information during recognition. Older adult and TBI participants were also slower to complete the Trail Making task and had poorer output on a Digit Span task, suggesting these two populations share a deficit in executive function and working memory. Similar changes in frontal lobe function may underlie these shared cognitive deficits.

Motor map expansion in the pilocarpine model of temporal lobe epilepsy is dependent on seizure severity and rat strain.

Functional alterations in movement representations (motor maps) have been observed in some people with epilepsy and, under experimental control, electrically-kindled seizures in rats also result in persistently larger motor maps. To determine if a single event of status epilepticus and its latent consequences can affect motor map expression, we assessed forelimb motor maps in rats using the pilocarpine model of temporal lobe epilepsy. We examined both pilocarpine-induced seizures, and status epilepticus (SE) in two strains that differ in their propensity for epileptogenesis; Wistar and Long-Evans. Pilocarpine was administered intraperitoneally at dosages that resulted in equivalent proportions of seizures, SE, and survival in both strains. Rats from both strains were given saline injections as a control. Diazepam was administered to all rats to attenuate seizure activity and promote survival. All rats had high-resolution movement representations derived using standard intracortical microstimulation methodologies at 48 h, 1 week, or 3 weeks following treatment. Pilocarpine-induced seizures only gave rise to motor map enlargement in Wistar rats, which also showed interictal spiking, and only at 3 weeks post-treatment indicating altered motor map expression in this strain following a latent or maturational period. Pilocarpine-induced SE yielded larger motor maps at all time points in Wistar rats but only a transient (48 h) map expansion in Long-Evans rats. Our results demonstrate that seizures and SE induced by a convulsant agent alter the functional expression of motor maps that is dependent on seizure severity and a genetic (strain) predisposition to develop epileptiform events.

Motor maps, seizures, and behaviour.

Atypically organised motor maps have been described in some people with epilepsy and we have modelled this in rats. Our goal is to more fully understand the mechanisms responsible for seizure-induced functional brain reorganisation and to reverse their effects. Here we present an overview of the relationship between neocortical motor maps, seizures, and interictal behaviour. To begin we summarise the observations of atypical motor maps with epilepsy and in animal models following experimentally induced seizures. Our novel experiments have established that motor map expansion is linked to a functional alteration of motor behaviour. Evidence for some of the putative brain mechanisms responsible for motor map size is discussed. Our successes reversing seizure-induced map expansion by two different methods are also briefly reviewed. Lastly, unanswered questions for possible future experimentation are posed.