K. Bo Foreman

Intramuscular adipose tissue, sarcopenia, and mobility function in older individuals.

Objective. Intramuscular adipose tissue (IMAT) and sarcopenia may adversely impact mobility function and physical activity. This study determined the association of locomotor muscle structure and function with mobility function in older adults. Method. 109 older adults with a variety of comorbid disease conditions were examined for thigh muscle composition via MRI, knee extensor strength via isometric dynamometry, and mobility function. The contribution of strength, quadriceps lean tissue, and IMAT to explaining the variability in mobility function was examined using multivariate linear regression models. Results. The predictors as a group contributed 27–45% of the variance in all outcome measures; however, IMAT contributed between 8–15% of the variance in all four mobility variables, while lean explained only 5% variance in only one mobility measure. Conclusions. Thigh IMAT, a newly identified muscle impairment appears to be a potent muscle variable related to the ability of older adults to move about in their community.

Barriers to Exercise in People With Parkinson Disease

Background Exercise is known to reduce disability and improve quality of life in people with Parkinson disease (PD). Although barriers to exercise have been studied in older adults, barriers in people with chronic progressive neurological diseases, such as PD, are not well defined. Objective The purpose of this study was to identify perceived barriers to exercise in people with PD. Design The study had a cross-sectional design. Methods People who had PD, dwelled in the community, and were at stage 2.4 on the Hoehn and Yahr scale participated in this cross-sectional study (N=260; mean age=67.7 years). Participants were divided into an exercise group (n=164) and a nonexercise group (n=96). Participants self-administered the barriers subscale of the Physical Fitness and Exercise Activity Levels of Older Adults Scale, endorsing or denying specific barriers to exercise participation. Multivariate logistic regression analysis was used to examine the contribution of each barrier to exercise behavior, and odds ratios were reported. Results Three barriers were retained in the multivariate regression model. The nonexercise group had significantly greater odds of endorsing low outcome expectation (ie, the participants did not expect to derive benefit from exercise) (odds ratio [OR]=3.93, 95% confidence interval [CI]=2.08–7.42), lack of time (OR=3.36, 95% CI=1.55–7.29), and fear of falling (OR=2.35, 95% CI=1.17–4.71) than the exercise group. Limitations The cross-sectional nature of this study limited the ability to make causal inferences. Conclusions Low outcome expectation from exercise, lack of time to exercise, and fear of falling appear to be important perceived barriers to engaging in exercise in people who have PD, are ambulatory, and dwell in the community. These may be important issues for physical therapists to target in people who have PD and do not exercise regularly. The efficacy of intervention strategies to facilitate exercise adherence in people with PD requires further investigation.

Diagnosis of Fall Risk in Parkinson Disease: An Analysis of Individual and Collective Clinical Balance Test Interpretation

Background and Purpose: Parkinson disease (PD) results in an increased frequency of falls relative to the frequency in neurologically healthy people. The purpose of this study was to compare the accuracy of PD fall risk diagnosis based on one test with that based on the collective interpretation of multiple tests. Participants: Seventy people with PD (mean age=73.91 years) participated in this study. Method: Clinical balance tests were conducted during the initial examinations of people with PD. Validity indices were calculated for individual tests and compared with validity indices calculated for a combination of multiple tests. Results: Thirty-six participants reported a fall history. Analysis of individual tests revealed broad variations in validity indices, whereas the collective interpretation of multiple tests improved sensitivity and negative likelihood ratios. Discussion and Conclusion: Collective interpretation of clinical balance tests resulted in fewer false-negative results and more substantial adjustments to the posttest probability of being a “faller” than the interpretation of one test alone. These results should be confirmed in a prospective examination of fall risk in PD.

Factors Associated With Exercise Behavior in People With Parkinson Disease

Background The benefits of exercise for reducing disability in people with Parkinson disease (PD) are becoming more evident. Optimal benefit, however, requires regular and sustained participation. Factors associated with engaging in regular exercise have received little scientific scrutiny in people with PD. Objective The purpose of this study was to explore factors associated with exercise behavior in patients with PD using the International Classification of Functioning, Disability and Health (ICF) as a guiding framework. Design This was a cross-sectional study. Methods The participants in this study were 260 patients with PD from 4 institutions. Participants were designated as “exercisers” or “nonexercisers” based on responses to the Stages of Readiness to Exercise Questionnaire. Exercise status was validated using the Physical Activity Scale for the Elderly and an activity monitor. Factors potentially associated with exercise behavior included measures of body structure and function, activity, participation, environmental factors, and personal factors. Their relative contributions were analyzed using logistic regression and quantified with odds ratios. Results One hundred sixty-four participants (63%) were designated as exercisers. Participants with high self-efficacy were more than twice as likely to engage in regular exercise than those with low self-efficacy (adjusted odds ratio=2.34, 95% confidence interval=1.30–4.23). College educated and older participants also were more likely to exercise. Disabling influences of impairments, activity limitations, and participation restrictions were not associated with exercise behavior. Limitations The cross-sectional nature of the study limited the ability to make causal inferences. Conclusions Self-efficacy, rather than disability, appears to be strongly associated with whether ambulatory, community-dwelling people with PD exercise regularly. The results of this study suggest that physical therapists should include strategies to increase exercise self-efficacy when designing patient intervention programs for patients with PD.

Accuracy of Fall Prediction in Parkinson Disease: Six-Month and 12-Month Prospective Analyses

Introduction. We analyzed the ability of four balance assessments to predict falls in people with Parkinson Disease (PD) prospectively over six and 12 months. Materials and Methods. The BESTest, Mini-BESTest, Functional Gait Assessment (FGA), and Berg Balance Scale (BBS) were administered to 80 participants with idiopathic PD at baseline. Falls were then tracked for 12 months. Ability of each test to predict falls at six and 12 months was assessed using ROC curves and likelihood ratios (LR). Results. Twenty-seven percent of the sample had fallen at six months, and 32% of the sample had fallen at 12 months. At six months, areas under the ROC curve (AUC) for the tests ranged from 0.8 (FGA) to 0.89 (BESTest) with LR+ of 3.4 (FGA) to 5.8 (BESTest). At 12 months, AUCs ranged from 0.68 (BESTest, BBS) to 0.77 (Mini-BESTest) with LR+ of 1.8 (BESTest) to 2.4 (BBS, FGA). Discussion. The various balance tests were effective in predicting falls at six months. All tests were relatively ineffective at 12 months. Conclusion. This pilot study suggests that people with PD should be assessed biannually for fall risk.

Capturing ambulatory activity decline in Parkinson's disease.

Background and Purpose: Relatively little is known about the natural evolution of physical activity–related participation restrictions associated with Parkinsons disease (PD). We examined this issue prospectively, using continuous monitoring technology to capture the free-living ambulatory activity of persons with PD engaging in life situations. We specifically sought (1) to explore natural, long-term changes in daily ambulatory activity and (2) to compare the responsiveness of ambulatory activity parameters to clinical measures of gait and disease severity. Methods: Thirty-three persons with PD participated (Hoehn and Yahr range of 1–3). Participants wore a step activity monitor for up to 7 days at baseline and again at 1-year follow-up. Mean daily values were calculated for parameters indicative of amount, intensity, frequency, and duration of ambulatory activity. Clinical measures included the Unified Parkinson Disease Rating Scale, the 6-Minute Walk, and Maximal Gait Speed. Parametric tests for paired samples were used to investigate changes in ambulatory activity parameters and clinical measures. Results: Participants had significant declines in the amount and intensity of daily ambulatory activity but not in its frequency and duration (P < 0.007). Declines occurred in the absence of changes in clinical measures of gait or disease severity. The greatest 1-year decline occurred in the number of daily minutes participants spent engaging in at least moderate-intensity ambulatory activity. Conclusion: Continuous monitoring of ambulatory activity beyond mere step counts may serve as a distinct and important means of quantifying declining ambulatory behavior associated with disease progression or improved ambulatory behavior resulting from rehabilitation and medical and/or surgical interventions in persons with PD.

Comparative Utility of the BESTest, Mini-BESTest, and Brief-BESTest for Predicting Falls in Individuals With Parkinson Disease: A Cohort Study

Background The newly developed Brief–Balance Evaluation System Test (Brief-BESTest) may be useful for measuring balance and predicting falls in individuals with Parkinson disease (PD). Objectives The purposes of this study were: (1) to describe the balance performance of those with PD using the Brief-BESTest, (2) to determine the relationships among the scores derived from the 3 versions of the BESTest (ie, full BESTest, Mini-BESTest, and Brief-BESTest), and (3) to compare the accuracy of the Brief-BESTest with that of the Mini-BESTest and BESTest in identifying recurrent fallers among people with PD. Design This was a prospective cohort study. Methods Eighty participants with PD completed a baseline balance assessment. All participants reported a fall history during the previous 6 months. Fall history was again collected 6 months (n=51) and 12 months (n=40) later. Results At baseline, participants had varying levels of balance impairment, and Brief-BESTest scores were significantly correlated with Mini-BESTest (r=.94, P<.001) and BESTest (r=.95, P<.001) scores. Six-month retrospective fall prediction accuracy of the Brief-BESTest was moderately high (area under the curve [AUC]=0.82, sensitivity=0.76, and specificity=0.84). Prospective fall prediction accuracy over 6 months was similarly accurate (AUC=0.88, sensitivity=0.71, and specificity=0.87), but was less sensitive over 12 months (AUC=0.76, sensitivity=0.53, and specificity=0.93). Limitations The sample included primarily individuals with mild to moderate PD. Also, there was a moderate dropout rate at 6 and 12 months. Conclusions All versions of the BESTest were reasonably accurate in identifying future recurrent fallers, especially during the 6 months following assessment. Clinicians can reasonably rely on the Brief-BESTest for predicting falls, particularly when time and equipment constraints are of concern.

Kinetic Gait Analysis Using a Low-Cost Insole

Abnormal gait caused by stroke or other pathological reasons can greatly impact the life of an individual. Being able to measure and analyze that gait is often critical for rehabilitation. Motion analysis labs and many current methods of gait analysis are expensive and inaccessible to most individuals. The low-cost, wearable, and wireless insole-based gait analysis system in this study provides kinetic measurements of gait by using low-cost force sensitive resistors. This paper describes the design and fabrication of the insole and its evaluation in six control subjects and four hemiplegic stroke subjects. Subject-specific linear regression models were used to determine ground reaction force plus moments corresponding to ankle dorsiflexion/plantarflexion, knee flexion/extension, and knee abduction/adduction. Comparison with data simultaneously collected from a clinical motion analysis laboratory demonstrated that the insole results for ground reaction force and ankle moment were highly correlated (all >0.95) for all subjects, while the two knee moments were less strongly correlated (generally >0.80). This provides a means of cost-effective and efficient healthcare delivery of mobile gait analysis that can be used anywhere from large clinics to an individuals home.

The course of the frontal branch of the facial nerve in relation to fascial planes: an anatomic study.

Background: Despite a wealth of literature describing the anatomy of the temporal region, controversy still exists over the depth of the frontal branch of the facial nerve as it travels over the zygomatic arch. It is commonly stated that the frontal branch travels within the superficial musculoaponeurotic system (SMAS) as it crosses the zygomatic arch. Clinically, however, it is apparent that the nerve runs at a deeper level as it crosses the arch, allowing for safe elevation and division of the SMAS to a point at or above the superior border of the zygomatic arch. The purpose of this study was to define the path of the frontal branches along fascial planes and to clarify the relationship of the fascial layers of the cheek and temporal region. Methods: Eighteen fresh-frozen cadaver hemifaces were dissected in a layer-by-layer fashion to evaluate the relationship between the nerve and the fascial planes above and below the zygomatic arch. Histologic evaluation was performed on six hemifaces. Results: In all dissections, the frontal branch traveled within the innominate fascia as it crossed the zygomatic arch into the temporal region. A fascial transition zone was identified in a region 1.5 to 3.0 cm above the zygomatic arch and 0.9 to 1.4 cm posterior to the lateral orbital rim, where the frontal branches crossed from the innominate fascia to run within the superficial temporal fascia. Conclusion: As the frontal branch crosses the zygomatic arch, it is within the innominate fascia, a plane deep to the SMAS and superficial temporal fascia.

The long-term contribution of muscle activation and muscle size to quadriceps weakness following total knee arthroplasty

Purpose: Many older individuals have persistent quadriceps strength impairments after a total knee arthroplasty (TKA). A combination of muscle atrophy and neuromuscular activation deficits apparently contributes to residual strength impairments. The purpose of this short report is to describe the contribution of quadriceps muscle activation and muscle volume to impaired muscle strength in older individuals an average of 21 months following a TKA. Methods: Seventeen individuals (males: 3, females: 14; mean age: 68 yrs ± 8.7; BMI: 33 ± 4.8 kg/m2; number of TKA: 24; average postoperative months: 21 ± 11.3) recruited from an orthopaedic surgeons practice provided their written consent and participated in this study. Quadriceps strength (MVIC) and voluntary quadriceps muscle activation (QA) were measured with use of a burst‐superimposition technique in which a supramaximal burst of electrical stimulation is superimposed on an MVIC. Quadriceps volume (QV) was assessed from magnetic resonance images of the quadriceps. Results: The mean quadriceps strength was 107.3 Nm ± 36.4 (range: 43.22 ‐ 205.2). The mean QA (as described with a central activation ratio) was 0.97 ± 0.04 (range: 0.83 ‐ 1.00). The mean QV was 1093 cm3 ± 311.80 (range: 653.66 ‐ 1706.56). QA and QV explain 85% of the variance in quadriceps strength (R2 = .85, p < 0.001), with QV having the greatest contribution to strength (R2 = .77, p < 0.001). Conclusions: QV is a much stronger predictor of quadriceps strength than QA in individuals more than 1 year following TKA. Activation levels contributed little to strength one year following TKA, compared to its profound contribution in the first few postoperative months. Physical therapy interventions focused on improving muscle size in this population should be considered more relevant than countermeasures addressing neuromuscular activation.