Jean Lengenfelder

Is speed of processing or working memory the primary information processing deficit in multiple sclerosis

Objective: To examine whether processing speed or working memory is the primary information processing deficit in persons with MS. Design: Case-control study. Setting: Hospital-based specialty clinic. Participants: 215 adults with clinically definite MS. Main Outcome Measure: Mean demographically corrected T-scores, prevalence rates of impairment and relative risk of impaired Processing Speed and Working Memory Index Scores from the WAIS–WMS III. Results: Deficits in Processing Speed were much more common than Working Memory in all comparisons. This was observed for both relapsing remitting (RRMS) and secondary progressive MS (SPMS) subjects, but accentuated in the latter group. Conclusions: Results strongly suggest that the primary information processing deficit in persons with MS is in speed of processing.

Divided attention and driving: A pilot study using virtual reality technology.

Background:Virtual reality (VR) was used to investigate the influence of divided attention (simple versus complex) on driving performance (speed control). Design:Three individuals with traumatic brain injury (TBI) and three healthy controls (HC), matched for age, education, and gender, were examined. Results:Preliminary results revealed no differences on driving speed between TBI and HC. In contrast, TBI subjects demonstrated a greater number of errors on a secondary task performed while driving. Conclusion:The findings suggest that VR may provide an innovative medium for direct evaluation of basic cognitive functions (ie, divided attention) and its impact on everyday tasks (ie, driving) not previously available through traditional neuropsychological measures.

Deciphering components of impaired working memory in multiple sclerosis.

ObjectiveTo identify working memory (WM) impairment by examining components of auditory working memory with the same sample of individuals with multiple sclerosis (MS). BackgroundAlthough individuals with MS have consistently demonstrated WM impairments, the specific components involved (i.e., central executive versus storage/maintenance) remain unclear. MethodIndividuals with MS with and without cognitive impairment and healthy controls were administered a task primarily assessing storage and rehearsal/maintenance (auditory n-back) and a task with a significant central executive component (Paced Auditory Serial Addition Task). ResultsResults indicate when the phonological loop is minimally challenged, maintenance of information is generally efficient. However, the addition of a central executive component to processing appears to be the key factor in differentiating individuals with MS with cognitive impairment from those without cognitive impairment and healthy controls. ConclusionsResults indicated that the primary WM impairment in MS is within the central executive rather than the phonological loop.

The Efficacy of the Generation Effect in Improving New Learning in Persons With Traumatic Brain Injury

Objective: To evaluate the usefulness of the generation effect in improving learning and memory abilitiesin neurologically impaired individuals. The generation effect is the observation that items self-generatedby participants are better remembered than items provided by the examiner. Although this effect hasshown to be relatively robust in healthy adults, few studies have examined the usefulness of thegeneration effect in neurological populations. Participants: 18 individuals with moderateÐsevere trau-matic brain injury (TBI) and 18 healthy adults. Main Outcome Measure: The measure was thegeneration effect protocol. Results: Results indicated recall and recognition of generated information wassigniÞcantly higher than that of provided information across testing conditions. However, healthy adultsshowed greater beneÞt from the generation effect than did individuals with TBI. As expected, recall andrecognition performance diminished over time (i.e., immediate recall, 30 min, 1 week) however, rates offorgetting did not differ between groups. Conclusion: Self-generation signiÞcantly improved verballearning and memory in individuals with TBI. The results of self-generation in improving learningsuggest that applying that technique may be beneÞcial in the cognitive rehabilitation of persons with TBI.Keywords: generation effect, traumatic brain injury, learning and memory, cognitive rehabilitation

The relative contributions of processing speed and cognitive load to working memory accuracy in multiple sclerosis

Cognitive symptoms of multiple sclerosis (MS) include processing-speed deficits and working memory impairment. The precise manner in which these deficits interact in individuals with MS remains to be explicated. We hypothesized that providing more time on a complex working memory task would result in performance benefits for individuals with MS relative to healthy controls. Fifty-three individuals with clinically definite MS and 36 matched healthy controls performed a computerized task that systematically manipulated cognitive load. The interval between stimuli presentations was manipulated to provide increasing processing time. The results confirmed that individuals with MS who have processing-speed deficits significantly improve in performance accuracy when given additional time to process the information in working memory. Implications of these findings for developing appropriate cognitive rehabilitation interventions are discussed.

Comparison of FIM™ communication ratings for English versus non-English speakers in the traumatic brain injury model systems (TBIMS) national database

Abstract Objective: To examine the effect of primary language on admission and discharge FIM™ communication ratings in a sample of individuals with moderate-to-severe traumatic brain injury (TBI). Design and methods: Secondary data analysis of rehabilitation admission and discharge FIM™ communication ratings of 2795 individuals hospitalized at a Traumatic Brain Injury Model Systems (TBIMS) centre between 2007–2012. Results: Individuals who spoke no English were rated worse on functional communication outcomes at inpatient rehabilitation discharge relative to individuals whose primary language was English. Conclusions: These findings may reflect systematic bias in FIM™ communication ratings of non-English-speaking individuals with TBI and/or TBI-induced communication difficulties in non-English-speaking individuals. Clinical and research implications are discussed.

NIRS-Based Quantitative Measurement of Autoregulatory Effects on Microvascular Hemoglobin Oxygenation: Applications to Assessment of Traumatic Brain Injury

Cerebral vascular autoregulation is the process by which the balance between oxygen demand and supply is maintained in brain tissue. We have developed a method for dividing the hemoglobin signal into six discrete categories that correspond to different states of vascular autoregulation. All six states occur continuously throughout the brain, however little is known about their interplay within specified regions of the cortex that subserve specific cognitive tasks. Here we report on a study that investigated cerebral vascular autoregulation (CVA) in three groups of adult subjects during a verbal working memory task: healthy controls, subjects with moderate-to-severe traumatic brain injuries, and multiple sclerosis patients. The CVA state analysis performed reveals statistically significant differences between all pairs of subject groups.