Altered effective connectivity during performance of an information processing speed task in multiple sclerosis.

Background: Functional magnetic resonance imaging (fMRI) studies of persons with multiple sclerosis (MS) reveal distinct patterns of activation during task performance. We were interested in determining whether distinct patterns of effective connectivity would be revealed with Granger causality analysis (GCA).

Objective: To characterize directed neural connections in persons with MS during a processing speed task between brain regions known to be activated in healthy controls.

Vulnerable Groups Living with Spinal Cord Injury.

There is considerable variation in rehabilitation outcomes within the population of spinal cord-injured individuals across racial and socioeconomic groups. This suggests that the long-term health following spinal cord injury (SCI) is determined, at least in part, by group differences in exposure to advantages and disadvantages among persons living in the community. This article conceptualizes the nature of vulnerability and how increased vulnerability leads to disparities in SCI outcomes.

Explaining differences in episodic memory performance among older African Americans and Whites: the roles of factors related to cognitive reserve and test bias.

Older African Americans tend to perform poorly in comparison with older Whites on episodic memory tests. Observed group differences may reflect some combination of biological differences, measurement bias, and other confounding factors that differ across groups. Cognitive reserve refers to the hypothesis that factors, such as years of education, cognitive activity, and socioeconomic status, promote brain resilience in the face of pathological threats to brain integrity in late life.

Are there control processes, and (if so) can they be studied?

Generally, so-called control processes are thought to be necessary when we must perform one out of several competing actions. Some examples include performance of a less well-practiced action instead of a well-practiced one (prepotency); learning a new action (novelty); and rapidly switching from one action to another (task-switching). While it certainly is difficult to perform the desired action in these circumstances, it is less clear that a separate set of processes (e.

L-amphetamine improves memory in MS patients with objective memory impairment.

Background: Memory impairment is prevalent in multiple sclerosis (MS), but no drugs are approved to treat these memory problems.

Objective: The objective of the study was to examine the effect of l-amphetamine versus placebo on auditory/verbal memory and visual/spatial memory in MS patients with and without baseline memory impairment.

Methods: We conducted a re-analysis of a previously published clinical trial in which MS patients were randomly assigned to treatment (30 mg l-amphetamine, N = 99) or placebo (N = 37) in a four-week, double-blind, parallel-group, dose titration trial.

Preservation of the first rocker is related to increases in gait speed in individuals with hemiplegia and AFO.

Background: Changes in impulse during the first rocker (braking force) and third rocker (propulsion force) may affect changes in gait speed after orthotic intervention. The purpose of this investigation was to objectively measure changes in impulse during double support and correlate those findings to changes in gait speed with and without ankle foot orthosis in individuals with hemiplegia.

Methods: Fifteen adults with stroke-related hemiplegia walked with and without ankle foot orthosis while foot pressure data was collected bilaterally.

Weight transfer analysis in adults with hemiplegia using ankle foot orthosis.

Background: Identifying and understanding the changes in transfer of momentum that are directly affected by orthotic intervention are significant factors related to the improvement of mobility in individuals with hemiplegia.

Objectives: The purpose of this investigation was to use a novel analysis technique to objectively measure weight transfer during double support (DS) in healthy individuals and individuals with hemiplegia secondary to stroke with and without an ankle foot orthosis.

Study Design: Prospective, Repeated measures, case-controlled trial.

Do communities matter after rehabilitation? The effect of socioeconomic and urban stratification on well-being after spinal cord injury.

Objective: To assess the influence of community-level socioeconomic status (SES) and urban composition on well-being after spinal cord injury (SCI) rehabilitation.

Design: Retrospective analysis of cross-sectional survey data.

Setting: Two participating centers in the SCI Model Systems (SCIMS) program.

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.

Evaluation of a dynamic ankle foot orthosis in hemiplegic gait: A case report.

This investigation utilized a single case design to evaluate the effects of a dynamic AFO on ambulation in post stroke hemiplegia. A single patient with stroke related hemiplegia using a dynamic AFO underwent gait analysis while walking on level ground. Outcome measures included temporal-spatial gait parameters and bilateral kinematic joint angles at the ankle, knee, and hip with and without AFO.

Premorbid cognitive leisure independently contributes to cognitive reserve in multiple sclerosis.

Objective: Consistent with the cognitive reserve hypothesis, higher education and vocabulary help persons with Alzheimer disease (AD) and multiple sclerosis (MS) better withstand neuropathology before developing cognitive impairment. Also, premorbid cognitive leisure (e.g.

Retrieval practice: a simple strategy for improving memory after traumatic brain injury.

Memory impairment is common following traumatic brain injury (TBI), but interventions to improve memory in persons with TBI have been ineffective. Retrieval practice is a robust memory strategy among healthy undergraduates, whereby practice retrieving information shortly after it is presented leads to better delayed recall than simple restudy. In a verbal paired associate paradigm, we investigated the effect of retrieval practice relative to massed and spaced restudy on delayed recall in 14 persons with chronic memory impairment following a TBI and 14 age-matched healthy controls.

Assessment of depression in multiple sclerosis: development of a "trunk and branch" model.

The objective of the present investigation was to improve the detection of depression in multiple sclerosis (MS). It has been hypothesized that the overlap of MS symptomatology and neurovegetative depression symptoms may lead to an over-diagnosis of depression in MS. Discerning what is depression and what is more attributable to the disease renders a complicated picture when assessing depression in medically ill people.

An interactive tool for visualization of spike train synchronization.

A number of studies have examined the synchronization of central and peripheral spike trains by applying signal analysis techniques in the time and frequency domains. These analyses can reveal the presence of one or more common neural inputs that produce synchronization. However, synchronization measurements can fluctuate significantly due to the inherent variability of neural discharges and a finite data record length.

Intellectual enrichment lessens the effect of brain atrophy on learning and memory in multiple sclerosis.

Objective: Learning and memory impairments are prevalent among persons with multiple sclerosis (MS); however, such deficits are only weakly associated with MS disease severity (brain atrophy). The cognitive reserve hypothesis states that greater lifetime intellectual enrichment lessens the negative impact of brain disease on cognition, thereby helping to explain the incomplete relationship between brain disease and cognitive status in neurologic populations. The literature on cognitive reserve has focused mainly on Alzheimer disease.

Retrieval practice improves memory in multiple sclerosis: clinical application of the testing effect.

The testing effect is a robust cognitive phenomenon by which memory retrieval on a test improves subsequent recall more than restudying. Also known as retrieval practice, the testing effect has been studied almost exclusively in healthy undergraduates. The current study investigated whether retrieval practice during testing leads to better delayed recall than restudy among persons with multiple sclerosis (MS), a neurologic disease associated with memory dysfunction.

Actual reality: a new approach to functional assessment in persons with multiple sclerosis.

Objective: To examine the use of an innovative approach for assessing everyday life activities of people with multiple sclerosis (MS): Actual Reality. Actual Reality is a performance-based assessment approach that involves the use of the internet to perform real, everyday life activities.

Design: A between-subjects design.

Training grip control with a Fitts' paradigm: a pilot study in chronic stroke.

Study Design: A clinical measurement study.

Purpose: To test the applicability of Fitts' paradigm to grasping tasks in individuals with chronic stroke.

Introduction: Fitts' Law relates the time of target achievement to task difficulty in repetitive motor tasks.

Evaluation of wheelchair tire rolling resistance using dynamometer-based coast-down tests.

The objective of this study was to compare the rolling resistance of four common manual wheelchair tires (two pneumatic and two airless solid) and the solid tires used on a commercially available force- and moment-sensing wheel. Coast-down tests were performed with a wheelchair positioned on a two-drum dynamometer. Within each of three load conditions, tire type had a significant effect on rolling resistance (p < 0.

Extending religion-health research to secular minorities: issues and concerns.

Claims about religion's beneficial effects on physical and psychological health have received substantial attention in popular media, but empirical support for these claims is mixed. Many of these claims are tenuous because they fail to address basic methodological issues relating to construct validity, sampling methods or analytical problems. A more conceptual problem has to do with the near universal lack of atheist control samples.

Objective assessment of functional ambulation in adults with hemiplegia using ankle foot orthotics after stroke.

Objective: To objectively evaluate the effect of ankle foot orthotics (AFOs) on functional ambulation in individuals with hemiplegia secondary to stroke using quantifiable outcome measures.

Design: With-without repeated measures design.

Setting: Rehabilitation research center.

Cognitive reserve moderates the negative effect of brain atrophy on cognitive efficiency in multiple sclerosis.

According to the cognitive reserve hypothesis, neuropsychological expression of brain disease is attenuated among persons with higher education or premorbid intelligence. The current research examined cognitive reserve in multiple sclerosis (MS) by investigating whether the negative effect of brain atrophy on information processing (IP) efficiency is moderated by premorbid intelligence. Thirty-eight persons with clinically definite MS completed a vocabulary-based estimate of premorbid intelligence (Wechsler Vocabulary) and a composite measure of IP efficiency (Symbol Digit Modalities Test and Paced Auditory Serial Addition Task).

Using co-variations in the Hb signal to detect visual activation: a near infrared spectroscopic imaging study.

The premise of this report is that functional Near Infrared Spectroscopy (fNIRS) imaging data contain valuable physiological information that can be extracted by using analysis techniques that simultaneously consider the components of the measured hemodynamic response [i.e., levels of oxygenated, deoxygenated and total hemoglobin (oxyHb, deoxyHb and totalHb, respectively)].

Functional neuroimaging of fatigue.

Clearly, the use of functional neuroimaging for the study of fatigue is in its infancy. Relatively few studies focusing on fatigue using functional neuroimaging techniques have been published, and the few that exist focus primarily on persons with MS and CFS. The vast majority of these studies have examined self-reported fatigue, an approach that benefits from ease of administration but suffers from significant difficulties in interpretation.