Molly W. Keebler

Neural Mechanisms of Brain Plasticity with Complex Cognitive Training in Healthy Seniors

Complex mental activity induces improvements in cognition, brain function, and structure in animals and young adults. It is not clear to what extent the aging brain is capable of such plasticity. This study expands previous evidence of generalized cognitive gains after mental training in healthy seniors. Using 3 MRI-based measurements, that is, arterial spin labeling MRI, functional connectivity, and diffusion tensor imaging, we examined brain changes across 3 time points pre, mid, and post training (12 weeks) in a randomized sample (n = 37) who received cognitive training versus a control group. We found significant training-related brain state changes at rest; specifically, 1) increases in global and regional cerebral blood flow (CBF), particularly in the default mode network and the central executive network, 2) greater connectivity in these same networks, and 3) increased white matter integrity in the left uncinate demonstrated by an increase in fractional anisotropy. Improvements in cognition were identified along with significant CBF correlates of the cognitive gains. We propose that cognitive training enhances resting-state neural activity and connectivity, increasing the blood supply to these regions via neurovascular coupling. These convergent results provide preliminary evidence that neural plasticity can be harnessed to mitigate brain losses with cognitive training in seniors.

Higher-order reasoning training years after traumatic brain injury in adults.

Objective:To conduct a feasibility study to compare the effects of top-down Strategic Memory and Reasoning Training (SMART) versus information-based Brain Health Workshop (BHW, control) on gist-reasoning (ie, abstracting novel meaning from complex information), memory, executive functions, and daily function in adults with traumatic brain injury. Participants:Twenty-eight participants (of the 35 recruited), 16 men & 12 women, aged 20 to 65 years (M = 43, SD = 11.34) at chronic stages posttraumatic brain injury (2 years or longer) completed the training. Fourteen participants that received SMART and 14 participants that completed BHW were assessed both pre- and posttraining. Thirteen of the SMART trained and 11 from BHW participated in a 6-month testing. Design:The study was a single blinded randomized control trial. Participants in both groups received a minimum of 15 hours of training over 8 weeks. Results:The SMART group significantly improved gist-reasoning as compared to the BHW group. Benefits of the SMART extended to untrained measures of working memory and participation in functional activities. Exploratory analyses suggested potential transfer effects of SMART on memory and executive functions. The benefits of the SMART program as compared to BHW were evident at immediately posttraining and 6 months posttraining. Conclusion:This study provides preliminary evidence that short-term intensive training in top-down modulation of information benefits gist-reasoning and generalizes to measures of executive function and real life function at chronic stages of post-TBI.

Gist reasoning training in cognitively normal seniors

Cognitive impairment is a key factor that threatens functionality and quality of life in seniors. Given the projection that the population of individuals 65 years of age and older will double within the next 25 years, a critical need exists to identify and test effectiveness of protocols that target higher‐order cognitive skills such as gist reasoning to maximize cognitive capacity in later life.

Repetition in Narratives of African Americans: The Effects of Aphasia

This study considers the use of repetition in the narratives of African Americans and the way in which this ethnic use of repetition might be altered or constrained by aphasia. Two groups of African Americans-1 neurologically normal and 1 with aphasia-produced narratives of a frightening experience. Instances of repetition were analyzed qualitatively for function and form of expression. We were interested specifically in the balance of various structural and functional types of repetition among individuals with aphasia and neurologically normal individuals as well as how this might reflect ubiquity or specificity of a given range of repetition types. Results suggested maintenance of ethnic repetitions in individuals with aphasia. The influences of culture, narrative topic, and aphasia severity on narrative repetition and its functions are discussed.

Distinct Brain and Behavioral Benefits from Cognitive vs. Physical Training: A Randomized Trial in Aging Adults

Insidious declines in normal aging are well-established. Emerging evidence suggests that non-pharmacological interventions, specifically cognitive and physical training, may counter diminishing age-related cognitive and brain functions. This randomized trial compared effects of two training protocols: cognitive training (CT) vs. physical training (PT) on cognition and brain function in adults 56–75 years. Sedentary participants (N = 36) were randomized to either CT or PT group for 3 h/week over 12 weeks. They were assessed at baseline-, mid-, and post-training using neurocognitive, MRI, and physiological measures. The CT group improved on executive function whereas PT groups memory was enhanced. Uniquely deploying cerebral blood flow (CBF) and cerebral vascular reactivity (CVR) MRI, the CT cohort showed increased CBF within the prefrontal and middle/posterior cingulate cortex (PCC) without change to CVR compared to PT group. Improvements in complex abstraction were positively associated with increased resting CBF in dorsal anterior cingulate cortex (dACC). Exercisers with higher CBF in hippocampi bilaterally showed better immediate memory. The preliminary evidence indicates that increased cognitive and physical activity improves brain health in distinct ways. Reasoning training enhanced frontal networks shown to be integral to top-down cognitive control and brain resilience. Evidence of increased resting CBF without changes to CVR implicates increased neural health rather than improved vascular response. Exercise did not improve cerebrovascular response, although CBF increased in hippocampi of those with memory gains. Distinct benefits incentivize testing effectiveness of combined protocols to strengthen brain health.

On the nature of personal narratives of high quality

This investigation explores the discourse devices associated with high-quality personal narratives. The study examined normative characteristics of 11 high-quality personal narratives of a frightening experience identified (from a larger set of 72 narratives) for their effectiveness in engaging the audience. Lay ratings and an ethnographic interview with seven of the excellent storytellers further characterized the stories and validated their selection. Narratives of both African Americans and Caucasians were represented, and were similar in nature. The excellent narratives were longer, conveyed more fearful topics, and were more dramatic than average narratives. Drama was achieved through direct speech, prosodic shifts, voice changes, inclusion of multiple characters, repetition, and syntactic and semantic parallelism. Illustrative narrative excerpts are provided. This study illustrates the potential in pairing holistic and analytical approaches to narrative analysis.

Evaluating the effectiveness of reasoning training in military and civilian chronic traumatic brain injury patients: study protocol

BackgroundIndividuals who sustain traumatic brain injuries (TBIs) often continue to experience significant impairment of cognitive functions mediated by the prefrontal cortex well into chronic stages of recovery. Traditional brain training programs that focus on improving specific skills fall short of addressing integrative functions that draw upon multiple higher-order processes critical for social and vocational integration. In the current study, we compare the effects of two short-term, intensive, group-based cognitive rehabilitation programs for individuals with chronic TBI. One program emphasizes learning about brain functions and influences on cognition, while the other program adopts a top-down approach to improve abstract reasoning abilities that are largely reliant on the prefrontal cortex. These treatment programs are evaluated in civilian and military veteran TBI populations.Methods/designOne hundred individuals are being enrolled in this double-blinded clinical trial (all measures and data analyses will be conducted by blinded raters and analysts). Each individual is randomly assigned to one of two treatment conditions, with each condition run in groups of five to seven individuals. The primary anticipated outcomes are improvement in abstract reasoning and everyday life functioning, measured through behavioral tasks and questionnaires, and attention modulation, as measured by functional neuroimaging. Secondary expected outcomes include improvements in the cognitive processes of working memory, attention, and inhibitory control.DiscussionResults of this trial will determine whether cognitive rehabilitation aimed at teaching TBI-relevant information about the brain and cognition versus training in TBI-affected thinking abilities (e.g., memory, attention, and executive functioning) can improve outcomes in chronic military and civilian TBI patient populations. It should shed light on the nature of improvements and the characteristics of patients most likely to benefit. This trial will also provide information about the sustainability of treatment-related improvements 3 months post-training.Trial registrationClinicalTrials.gov Identifier: NCT01552473

Relationship between discourse and Western Aphasia Battery performance in African Americans with aphasia

Background: There is a need for discourse research with African Americans who have aphasia, highlighted by ethnic group differences in stroke prevalence, and potential ethnic group differences in dialect. Identification of ethnic dialect is critical to differentiate communication changes associated with pathology from normal communicative differences associated with ethnicity. Also, preliminary research on adults with aphasia indicates an uncertain relationship between discourse performance and standardised test performance. Aims: This study was designed to assess: (1) the relationship between performance on a standardised language measure and discourse performance, and (2) the use of ethnic dialect and discourse features, in the narrative productions of African-American adults with moderate aphasia on a variety of discourse tasks. Methods & Procedures: We investigated the discourse of 12 African Americans with scores in the moderate severity range on the Western Aphasia Battery, Aphasia Quotient (WAB-AQ). Each subject produced a fable retell, a story derived from a picture sequence, two stories derived from single pictures, and a topic-elicited personal narrative of a frightening experience. Analysis consisted of ratings of discourse quality (coherence, reference, and emplotment); a measure of discourse quantity (number of propositions); and a tally of the presence or absence of ethnic dialect and discourse features. Outcomes & Results: The correlation between WAB-AQ and discourse quality was statistically significant on the picture sequence task and one single-picture task, but not on the other discourse tasks. There was a significant relationship between WAB-AQ and overall quality ratings of coherence, reference, and emplotment. The correlation between WAB-AQ and discourse quantity was not significant for any task, and discourse quality was not significantly correlated with discourse quantity. Ethnic features appeared most often on one single-picture task and the personal narrative. No ethnic dialect features occurred on the fable retell. Conclusions : These findings suggest the need to supplement standardised assessment of aphasia with assessment of discourse performance, using less structured discourse tasks, such as a personal narrative task. Less structured discourse tasks may also be optimal for eliciting natural ethnic patterns of communication. The lack of relationship between narrative quantity and narrative quality may not generalise to individuals with aphasia that is severe or mild. This study contributes towards development of a discourse assessment tool for culturally and linguistically diverse populations that may supplement information provided by standardised testing.

Comparison of language impairment, functional communication, and discourse measures in African-American aphasic and normal adults

We compared performance on language impairment, functional communication, and discourse measures between 33 African-American aphasic patients and 30 African-American normal subjects. The aphasic group performed significantly lower than the normal group on the Western Aphasia Battery Aphasia and Cortical Quotients, Token Test, and ASHA Functional Assessment of Communication Skills for Adults. Moreover, the aphasic group performed significantly lower than the normal group in their quality of language on a discourse task that required telling a frightening experience. Significant relationships between performance on the measures were confined to those that index language impairment. Use of a normal ethnic cohort for comparison with African-American aphasic performance may control for potential ethnic bias in the measures. In addition, use of a discourse task permits observation of grammatical and stylistic features in African-American English that may not be captured or are ignored by traditional language impairment and functional communication measures.

Reasoning training in veteran and civilian traumatic brain injury with persistent mild impairment

Traumatic brain injury (TBI) is a chronic health condition. The prevalence of TBI, combined with limited advances in protocols to mitigate persistent TBI-related impairments in higher order cognition, present a significant challenge. In this randomised study (n = 60), we compared the benefits of Strategic Memory Advanced Reasoning Training (SMART, n = 31), a strategy-based programme shown to improve cognitive control, versus an active learning programme called Brain Health Workshop (BHW, n = 29) in individuals with TBI with persistent mild functional deficits. Outcomes were measured on cognitive, psychological health, functional, and imaging measures. Repeated measures analyses of immediate post-training and 3-month post-training demonstrated gains on the cognitive control domain of gist reasoning (ability to abstract big ideas/goals from complex information/tasks) in the SMART group as compared to BHW. Gains following the SMART programme were also evident on improved executive function, memory, and daily function as well as reduced symptoms associated with depression and stress. The SMART group showed an increase in bilateral precuneus cerebral blood flow (CBF). Improvements in gist reasoning in the SMART group were also associated with an increase in CBF in the left inferior frontal region, the left insula and the bilateral anterior cingulate cortex. These results add to prior findings that the SMART programme provides an efficient set of strategies that have the potential to improve cognitive control performance and associated executive functions and daily function, to enhance psychological health, and facilitate positive neural plasticity in adults with persistent mild impairment after TBI.