Biomedical subjects

Maureen Schmitter-Edgecombe

Publications and source records attributed to Maureen Schmitter-Edgecombe.

14 recordsLinked to original sources

PubMed2006

Improving the ecological validity of executive functioning assessment.

The current study investigated ways to improve the ecological validity of the neuropsychological assessment of executive functioning through the formal assessment of compensatory strategies and environmental cognitive demands. Results indicated that the group of executive functioning tests (i.e., Trail Making Test, Wisconsin Card Sorting Test, Stroop, and Controlled Oral Word Association Test) accounted for 18-20% of the variance in everyday executive ability as measured by the Dysexecutive Questionnaire and Brock Adaptive Functioning Questionnaire. The addition of extra-test variables significantly increased the variance in everyday executive ability accounted for. The current study adds to the literature on the ecological validity of executive functioning assessment by highlighting the importance of extra-test variables when trying to understand the complex relationship between cognitive testing and real world performance.

Activities of Daily Living↗

PubMed2006

Long-term retention of skilled visual search following severe traumatic brain injury.

We examined the long-term retention of a learned automatic cognitive process in 17 severe TBI participants and 10 controls. Participants had initially received extensive consistent-mapping (CM) training (i.e., 3600 trials) in a semantic category visual search task (Schmitter-Edgecombe & Beglinger, 2001). Following CM training, TBI and control groups demonstrated dramatic performance improvements and the development of an automatic attention response (AAR), indicating task-specific and stimulus-specific skill learning. After a 5- or 10-month retention interval, participants in this study performed a New CM task and the originally trained CM task to assess for retention of task-specific and stimulus-specific visual search skills, respectively. No significant group differences were found in the level of retention for either skill type, indicating that individuals with severe TBI were able to retain the learned skills over a long-term retention interval at a level comparable to controls. Exploratory analyses revealed that TBI participants who returned at the 5-month retention interval showed nearly complete skill retention, and greater skill retention than TBI participants who returned at the 10-month interval, suggesting that "booster" or retraining sessions may be needed when a skill is not continuously in use.

Adult↗

PubMed2006

Costs of a predictable switch between simple cognitive tasks following severe closed-head injury.

The authors used a predictable, externally cued task-switching paradigm to investigate executive control in a severe closed-head injury (CHI) population. Eighteen individuals with severe CHI and 18 controls switched between classifying whether a digit was odd or even and whether a letter was a consonant or vowel on every 4th trial. The target stimuli appeared in a circle divided into 8 equivalent parts. Presentation of the stimuli rotated clockwise. Participants performed the switching task at both a short (200 ms) and a long (1,000 ms) preparatory interval. Although the participants with CHI exhibited slower response times and greater switch costs, similar to controls, additional preparatory time reduced the switch costs, and the switch costs were limited to the 1st trial in the run. These findings indicate that participants with severe CHI were able to take advantage of time to prepare for the task switch, and the executive control processes involved in the switch costs were completed before the 1st trial of the run ended.

Adolescent↗

PubMed2005

Understanding text after severe closed-head injury: assessing inferences and memory operations with a think-aloud procedure.

A think-aloud method was used to examine the content of information available to working memory during narrative comprehension in a CHI population. Twenty severe CHI participants (>1 year post-injury) and 20 controls talked aloud after they read each sentence of story narratives. Trabasso and Magliano's (1996a) verbal protocol analysis was then used to code for the production of inferential and non-inferential clauses and the memory operations that supported inferential clause production. We found that CHI and control groups produced a comparable number of clauses, that inferences dominated narrative comprehension, and that both groups produced more explanatory inferences than predictive or associative inferences. Despite these qualitative similarities, the CHI group demonstrated poorer comprehension, generated proportionately fewer inferences, relied less on retrieval as a memory source for explanatory inferences, and produced more non-inferential clauses and associative inferences.

Adult↗

PubMed2004

Working memory and aging: a cross-sectional and longitudinal analysis using a self-ordered pointing task.

Age-related declines in working memory performance have been associated with deficits in inhibition, strategy use, processing speed, and monitoring. In the current study, cross-sectional and longitudinal methodologies were used to investigate the relative contribution of these components to age-related changes in working memory. In Experiment 1, a sample of 140 younger and 140 older adults completed an abstract design version of the Self-Ordered Pointing Task modeled after Shimamura and Jurica (1994). Experiment 1 revealed that only processing speed and monitoring explained age differences in SOPT performance. Participants in Experiment 2 were 53 older adults who returned 4 years after the initial testing and 53 young adults. A task that assessed the ability to generate and monitor an internal series of responses as compared to an externally imposed series of responses was also administered. Experiment 2 replicated the key findings from Experiment 1 and provided some further evidence for age-related internal monitoring difficulties. Furthermore, the exploratory longitudinal analysis revealed that older age and lower intellectual abilities tended to be associated with poorer performance on the SOPT at Time 2.

Adolescent↗

PubMed2004

Retrieval inhibition in directed forgetting following severe closed-head injury.

A variant of the list method directed forgetting procedure was used to examine the role of inhibition in memory performance following severe closed-head injury (CHI). Twenty-four participants with severe CHI and 24 controls studied picture and word stimuli in both forget and remember conditions. Memory testing for the to-be-forgotten and to-be-remembered items consisted of a free-recall test followed by a source-monitoring task. Despite poorer recall performance, the participants with CHI exhibited a directed forgetting effect similar to that in controls. Item recognition scores indicated that the inhibited items were not forgotten but rather were items whose accessibility had been lowered. These findings suggest that residual memory deficits in patients with severe CHI are unlikely to reflect inefficient retrieval inhibition.

Adult↗

PubMed2004

Event-based prospective memory following severe closed-head injury.

Twenty-four severe closed-head injury (CHI) participants and 24 controls completed event-based prospective memory tasks concurrently with an ongoing working memory task. The event cue was either integrated with the ongoing working memory task (focal cue) or peripheral to it. Prospective remembering was poorer for the CHI group in both the focal- and peripheral-cue conditions. The groups did not differ on the ongoing task. The peripheral cue and the integrated focal cue also did not differ in ability to trigger prospective remembering. The results suggest that, even with highly salient event cues, severe CHI participants (> 1 year postinjury) are more likely than controls to exhibit prospective memory failures. The data revealed a link between CHI participants' prospective memory failures and momentary lapses of intention.

Adult↗

PubMed2004

Memory self-awareness and memory self-monitoring following severe closed-head injury.

OBJECTIVE: To examine the accuracy of memory self-awareness and memory self-monitoring abilities in participants with severe closed-head injury (CHI). DESIGN AND METHODS: A performance-prediction paradigm was used to evaluate meta-memory abilities in 31 participants with severe CHI (>1 year post-injury) and 31 controls. To assess memory self-awareness, before completing story recall, visual reproduction and list learning memory tasks, participants predicted the amount of information they would remember for each task. Memory self-monitoring was evaluated by examining participants' ability to increase the accuracy of their predictions following experience with each memory task. RESULTS: Although participants with CHI exhibited poorer recall than controls, they were equally aware of how differing task demands influence recall. They also successfully modified their predictions following task exposure. CONCLUSIONS: Meta-memory was better preserved than actual memory performance. It may be possible to build on meta-memory skills to help patients with CHI more consistently use strategies that aid memory performance.

Adult↗

PubMed2003

The ecological validity of neuropsychological tests: a review of the literature on everyday cognitive skills.

Evaluating the ecological validity of neuropsychological tests has become an increasingly important topic over the past decade. In this paper, we provide a comprehensive review of the research on the ecological validity of neuropsychological tests, as it pertains to everyday cognitive skills. This review is presented in the context of several theoretical issues facing ecological validity research. Overall, the research suggests that many neuropsychological tests have a moderate level of ecological validity when predicting everyday cognitive functioning. The strongest relationships were noted when the outcome measure corresponded to the cognitive domain assessed by the neuropsychological tests. Several other factors that may moderate the degree of ecological validity established for neuropsychological tests are in need of further exploration. These factors include the effects of the population being tested, the approach utilized (verisimilitude vs. veridicality), the person completing the outcome measure (significant other vs. clinician), illness severity, and time from injury until evaluation. In addition, a standard measurement of outcome for each cognitive domain is greatly needed to allow for comparison across studies.

Cognition Disorders↗

PubMed2003

Self-ordered pointing performance following severe closed-head injury.

This study investigated executive aspects of working memory in a severe closed-head injured (CHI) population. Thirty-four severe CHI participants (>1 year postinjury) and 34 controls completed an abstract design version of Petrides and Milner's (1982) self-ordered pointing task. CHI participants made more errors than controls on the 16-item trial, but not the 9-item trial. Both CHI and control participants were able to make use of strategic processing to improve SOPT performance. As anticipated, errors on the SOPT were associated with another measure of working memory (i.e., Reading Span Test) for the control group. In contrast, for the CHI participants, errors on the SOPT were associated with a measure of delayed visual memory (i.e., Wechsler Memory Scale-Revised Visual Reproduction II subtest). Our findings suggest that, as a group, the primary factor resulting in poorer SOPT performance by the CHI group was a memory deficit and not the ability to utilize executive aspects of working memory.

Adult↗

PubMed2003

Content memory and temporal order memory for performed activities after severe closed-head injury.

Thirty severe closed-head injured (CHI) participants (more than 1 year postinjury) and 30 matched controls completed eight different cognitive activities. Participants' free recall and recognition of the activities provided a measure of content memory. Temporal order memory was assessed with a reconstruction task. CHI participants recalled and recognized fewer activities than did controls. However, the CHI and control groups did not differ in temporal order memory. For both groups, recognition memory was not correlated with temporal order memory. These results demonstrate intact temporal order memory for performed activities in a severe CHI population, and support the notion of separate processing of content memory and order information. Issues related to automaticity and the roles of the frontal lobes in temporal order memory are also discussed.

Adult↗

PubMed2002

Perceptually based implicit learning in severe closed-head injury patients.

This study suggests that perceptually based implicit learning may either be preserved following a severe closed-head injury (CHI) or recover within the 1st year. Nineteen severe CHI patients and 19 controls searched visual matrices and indicated the quadrant location of a target. Participants were exposed to the following covariation pattern: AAAABAAA. For Covariation A blocks, the matrices systematically co-occurred with a unique location of the target. This relationship was altered for the B block. Despite CHI participants' overall slower response times (RTs), both groups demonstrated the expected decline in RTs across the first 4 Covariation A blocks followed by an increase when the covariation changed. Both groups also exhibited retention of their learning after a 20-min delay. Explicit knowledge tests indicated that participants lacked awareness for the covariation.

Adult↗

PubMed2002

Prediction of employment status following traumatic brain injury using a behavioural measure of frontal lobe functioning.

OBJECTIVE: To examine whether a behavioural measure of frontal lobe functioning, the Brock Adaptive Functioning Questionnaire (BAFQ), could predict employment status following traumatic brain injury (TBI). DESIGN: A discriminant function analysis was conducted to determine the ability of the BAFQ, along with other factors, to predict occupational status post-injury. METHODS: Sixty-one TBI survivors completed a background information questionnaire, the BAFQ, and an employment status rating scale. RESULTS: A factor analysis of the BAFQ sub-scales revealed two factors, one related to functioning in the orbitofrontal area, and one related to dorsolateral frontal lobe functioning. These two factors, along with background information, were entered into a discriminant function analysis, revealing a 77.4% accuracy rate in predicting occupational status post-injury. CONCLUSIONS: Demographic variables were found to differentiate employed from unemployed survivors. The BAFQ appeared useful in differentiating survivors who may return to their pre-injury employment level from those who may require modified employment.

Adolescent↗

PubMedDate not supplied

Implications of basic science research for brain injury rehabilitation: a focus on intact learning mechanisms.

Within a theoretical framework for rehabilitation that distinguishes between automatic and controlled processes, this article reviews basic science research and addresses the following issues: What cognitive abilities remain relatively intact after severe traumatic brain injury, and how can we incorporate intact skills into rehabilitative techniques? The reviewed research indicates that individuals with severe traumatic brain injury (a) generally perform similar to controls on cognitive tasks (or task components) that require automatic and implicit processes as opposed to consciously controlled processes; (b) can learn through implicit learning mechanisms; and (c) can acquire and use automatic processes in complex, cognitive task performance.

Attention↗