Biomedical subjects

Erin M Snook

Publications and source records attributed to Erin M Snook.

9 recordsLinked to original sources

PubMed2006

Cardiorespiratory fitness: A predictor of cortical plasticity in multiple sclerosis.

Deficits in cognitive abilities are commonly observed among individuals with multiple sclerosis (MS). Recent neuroimaging studies have provided evidence for the existence of cortical plasticity in MS, with cognitively impaired participants recruiting additional brain areas to perform challenging tasks. The existence of altered cerebral activations in MS provides hope for the utilization of neural resources to reduce cognitive deficits that challenge everyday living in MS by employing alternative interventions such as cognitive and fitness training. In this study, we examined whether higher physical fitness levels enhance cognitive and neural plasticity in MS patients. The present study is the first to investigate the impact of cardiorespiratory fitness on cerebrovascular functioning of MS patients. 24 participants with relapsing-remitting MS were recruited for the study. All participants went through a fitness assessment and were scanned in a 3 T MRI system during the Paced Visual Serial Addition Test (PVSAT). Higher fitness levels were associated with faster behavioral performance and greater recruitment of right IFG/MFG, a region of the cerebral cortex recruited by MS patients during performance of PVSAT to purportedly compensate for the cognitive deterioration attributable to MS. In contrast, lower levels of fitness were associated with enhanced ACC activity, suggestive of the presence of greater interference and the potential for error in lower fit MS participants. These results are promising, suggesting the need for further investigation of the utility of aerobic fitness training as a possible method to support the development of additional cortical resources in an attempt to counter the cognitive decline resulting from MS.

Adult↗

PubMed2006

Validity of physical activity measures in ambulatory individuals with multiple sclerosis.

PURPOSE: The literature suggests that individuals with multiple sclerosis (MS) engage in less physical activity than non-diseased individuals. That conclusion, however, depends upon the validity of scores from measures of physical activity among the MS population. This study evaluated the validity of scores from two self-report surveys, a pedometer, and an accelerometer and during seven days of free-living conditions among individuals with MS. METHOD: Participants were 30 individuals (28 females, two males) with an established definite diagnosis of MS. The participants wore a pedometer and a single-axis accelerometer during the waking hours of a 7-day period. After the 7-day period, participants returned to the lab and completed a self-administered physical activity questionnaire and then underwent a 7-day physical activity recall. RESULTS: There were strong correlations (a) between scores from the two self-report measures of physical activity and (b) between scores from the two objective measures of physical activity, and (c) weaker, but moderate-to-strong correlations between scores from the self-report and objective measures of physical activity. CONCLUSION: Our results support the quantification of physical activity among those with MS using validated self-report and objective measures.

Adult↗

PubMed2006

Effect of acute leg cycling on the soleus H-reflex and modified Ashworth scale scores in individuals with multiple sclerosis.

This study examined the effect of a single bout of unloaded leg cycling on the soleus H-reflex and modified Ashworth scale (MAS) in 27 individuals with multiple sclerosis (MS) who had spasticity of the leg muscles, but were not currently taking anti-spastic medications. The soleus H-reflex and MAS data were collected before and 10, 30, and 60 min after 20 min of unloaded leg cycling and a control condition. The acute bout of unloaded leg cycling resulted in concomitant and prolonged reductions in the soleus H-reflex and MAS scores compared with the control condition. This provides converging evidence for the anti-spastic potential of acute unloaded leg cycling in individuals with MS.

Adult↗

PubMed2006

Symptoms, self-efficacy, and physical activity among individuals with multiple sclerosis.

Using social-cognitive theory, we examined the associations among symptoms, self-efficacy, and physical activity in 196 individuals with multiple sclerosis (MS). Participants completed symptoms, self-efficacy, and physical activity measures and wore an accelerometer for 7 days. There was a moderate inverse correlation between symptoms and physical activity (varphi = -.42). Subsequent analyses indicated that symptoms had direct negative relationships with self-efficacy (gamma = -.32) and physical activity (gamma = -.24), and self-efficacy had a direct positive relationship with physical activity (beta = .57). This study provides initial support for symptoms as a correlate of physical activity in individuals with MS. Monitoring symptoms during a physical activity program and altering the exercise prescription during symptom exacerbation might be a method for increasing exercise adherence.

Activities of Daily Living↗

PubMed2006

Correlates of physical activity among individuals with multiple sclerosis.

BACKGROUND: There is accumulating evidence that individuals with multiple sclerosis (MS) are less physically active than nondiseased populations. One method for increasing the level of participation in physical activity among MS patients involves the identification of factors that correlate with physical activity and that are modifiable by a well-designed intervention. PURPOSE: This study adopts a social cognitive perspective and examines self-efficacy, enjoyment, social support, and disability as correlates of participation in physical activity among individuals with MS. METHODS: We recruited 196 individuals with a diagnosis of MS from the Midwest region of the United States. The participants completed a battery of questionnaires and then wore a belt with an accelerometer for a 7-day period. The data were analyzed using covariance modeling. RESULTS: Enjoyment (gamma=.38, p<.001), social support (gamma=.15, p<.05), and disability (gamma=.18, p<.01) had statistically significant direct relations with self-efficacy, and self-efficacy (beta=.29, p<.001) and enjoyment (gamma=.28, p<.001) had statistically significant direct relations with physical activity. CONCLUSIONS: Future researchers should consider examining self-efficacy and enjoyment as possible components of an intervention that is designed to increase physical activity participation in MS patients.

Disability Evaluation↗

PubMed2005

Accuracy of two electronic pedometers for measuring steps taken under controlled conditions among ambulatory individuals with multiple sclerosis.

Pedometers are inexpensive and user-friendly devices that might be practical for measuring physical activity among individuals with multiple sclerosis (MS). This study involved an evaluation of the accuracy of two pedometers against actual steps taken under controlled laboratory conditions (five minute bouts of walking at five different treadmill speeds [41, 54, 67, 80, and 94 m x min(-1)]) among 23 individuals with MS who were ambulatory without an aide. Both pedometers exhibited good accuracy with the 67, 80, and 94 m x min(-1) speeds, but poor accuracy with the 41 and 54 m x min(-1) speeds. Those results support the quantification of physical activity using pedometers among those with MS who are ambulatory without an aide.

Adult↗

PubMed2005

Physical activity and multiple sclerosis: a meta-analysis.

Using meta-analytic procedures, this study involved a quantitative synthesis of the difference in physical activity among individuals with multiple sclerosis (MS) compared with nondiseased and diseased populations and then examined factors (i.e., moderators) that explain variation in the overall difference in physical activity. We searched MEDLINE, PsycINFO and Current Contents Plus using the key words physical activity, exercise and physical fitness in conjunction with multiple sclerosis; conducted a manual search of bibliographies of the retrieved papers; and contacted study authors about additional studies. Overall, 53 effects were retrieved from 13 studies with 2360 MS participants and yielded a weighted mean effect size (ES) of -0.60 (95% CI = -0.44, -0.77). The weighted mean ES was heterogenous, Q = 1164.11, df = 52, P < 0.0001. There were larger effects with objective versus self-report measures of physical activity, nondiseased versus diseased populations and primary progressive versus relapsing remitting MS. The cumulative evidence suggests that individuals with MS are less physically active than nondiseased, but not diseased, populations.

Female↗

PubMed2004

Physical activity and executive control: implications for increased cognitive health during older adulthood.

Electrocortical and behavioral responses of low, moderate, and high physically active older adults were compared with a younger control group on neutral and incompatible conditions of a flankers task. Compared to younger adults, high and moderate active older adults exhibited increased event-related potentials component P3 amplitude for the incompatible condition at the frontal electrode site. For the neutral condition, only low active older adults exhibited decreased amplitude at the central-parietal site, compared to younger adults. P3 latency revealed the longest latencies for low active older adults, followed by moderate active, high active, and younger adults, respectively. Reaction time (RT) data revealed that younger adults exhibited faster RT compared to all three older groups. Results suggest that physical activity may improve executive control function in older adults by affecting the distribution of P3 amplitude, which has been related to memory and attentional processes, and by decreasing P3 latency, which relates to the speed of cognitive processing.

Aged↗

PubMed2003

Acute cardiovascular exercise and executive control function.

Acute cardiovascular exercise effects on cognitive function were examined using an executive control task by comparing neuroelectric and behavioral performance at baseline with post-exercise in 20 undergraduates. A within-subjects design was used to assess the P3 component of an event-related brain potential (ERP) and behavioral performance using a task that varied the amount of executive control required. The baseline session involved participation on the Eriksen flankers task followed by a graded maximal exercise test to measure cardiovascular fitness. The exercise session consisted of a 30-min acute bout of exercise on a treadmill followed by the Eriksen flankers task after heart rate returned to within 10% of pre-exercise levels. Across midline recordings sites, results indicated larger P3 amplitude following acute exercise compared to baseline. Shorter P3 latency was observed during the baseline Eriksen flankers task for the neutral compared to the incompatible condition; an effect not found following the acute bout of exercise. These findings suggest that acute bouts of cardiovascular exercise affect neuroelectric processes underlying executive control through the increased allocation of neuroelectric resources and through changes in cognitive processing and stimulus classification speed.

Adult↗