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Biomedical subjects

Steven L Wolf

Publications and source records attributed to Steven L Wolf.

At least 37 records · Page 2Linked to original sources
PubMed2005

The EXCITE trial: attributes of the Wolf Motor Function Test in patients with subacute stroke.

The Wolf Motor Function Test (WMFT) has been used in rehabilitation studies of chronic stroke patients, but until now its psychometric properties have not been evaluated in patients with subacute stroke. Two hundred twenty-nine participants with subacute stroke (3-9 months postinjury) at 7 research sites met inclusion criteria for the EXCITE Trial and were randomized into immediate or delayed (by 1 year) constraint-induced movement therapy treatment. All evaluations were undertaken by assessors standardized in the administration of the WMFT and masked to treatment designation. Participants were also assessed using the Fugl Meyer Motor Assessment (FMA). Delayed group members had measurements repeated 2 weeks following baseline assessment to determine learning or exposure effects. The results demonstrate that the WMFT differentiated higher from lower functioning participants across sites; scores were uninfluenced by hand dominance or affected side. Women exhibited slower performance times than men. The Functional Ability scale (FAS) portion of the WMFT also revealed lower scores among lower functioning participants and women. Minimal changes were observed after repeating the WMFT among delayed group participants 2 weeks later. The FMA revealed similar results when the total group was divided into higher and lower functional levels at its midpoint score of 33. The WMFT discriminates higher from lower functioning participants tested across research sites. Comparable findings using the FMA support the criterion validity of the WMFT.

Acute Disease↗
PubMed2004

The influence of Tai Chi training on the center of pressure trajectory during gait initiation in older adults.

OBJECTIVE: To determine if a program of intense Tai Chi exercise that has been shown to reduce the risk of falling in older adults improves postural control by altering the center of pressure (COP) trajectory during gait initiation. DESIGN: Before-after trial. SETTING: Biomechanics research laboratory. PARTICIPANTS: Twenty-eight older adults transitioning to frailty who participated in either a 48-week intervention of intense Tai Chi training or a wellness education (WE) program. INTERVENTIONS: Eight Tai Chi forms emphasizing trunk rotation, weight shifting, coordination, and narrowing of lower-extremity stance were taught twice weekly. WE program participants met once a week and received lectures focused on health. Main outcome measures The COP was recorded during gait initiation both before and after the 48-week intervention by using a forceplate sampling at 300 Hz. The COP trajectory was divided into 3 periods (S1, S2, S3) by identifying 2 landmark events. Displacement and average velocity of the COP trace in the anteroposterior (x) and mediolateral (y) directions, as well as smoothness, were calculated. RESULTS: Tai Chi training increased the posterior displacement of the COP during S1 and improved the smoothness of the COP during S2. CONCLUSIONS: Tai Chi improved the mechanism by which forward momentum is generated and improved coordination during gait initiation, suggesting improvements in postural control.

Aged↗
PubMed2004

Intra-subject reliability of parameters contributing to maps generated by transcranial magnetic stimulation in able-bodied adults.

OBJECTIVE: This study evaluated the reliability of several parameters contributing to topographic motor cortical maps of the extensor digitorum communis (EDC) within able-bodied participants, across 3 sessions and from both hemispheres with greater precision than previously reported. METHODS: Nine healthy right-handed males aged 44-75 years were studied at 3 separate sessions, spaced 7-14 days apart. Transcranial magnetic stimulation (TMS) was used to elicit motor evoked potentials (MEP) in the contralateral EDC. Closely spaced surface electrodes were used to record the MEPs. RESULTS: TMS-related parameters did not demonstrate a significant difference within participants across sessions and between hemispheres, with the exception of the hotspot distance, center of gravity distance, and normalized map volume. Hotspot and COG distances were determined from the Euclidean equation to calculate the distance in x,y coordinates traveled over sessions: one to two (distance A) and two to three (distance B). The hotspot distance, center of gravity distance and normalized map volume demonstrated a significant difference between right and left hemispheres, within participants. Adjusting for time and examining mean changes for hemispheres across sessions revealed that there was a 9-fold greater movement over sessions in the left hemisphere among these variables. CONCLUSIONS: TMS-related parameters are reliable within participants across 3 sessions. These data should be useful for planning and interpreting TMS studies using a healthy or patient population before and after an intervention.

Adult↗
PubMed2004

Can Tai Chi improve vestibulopathic postural control?

OBJECTIVES: To evaluate the rationale and scientific support for Tai Chi as an intervention for vestibulopathy and to offer recommendations for future studies. DATA SOURCES: A computer-aided search, including MEDLINE and Science Citation Index, to identify original Tai Chi studies published in English; relevant references cited in the retrieved articles were also included. STUDY SELECTION: A preliminary screening selected all randomized controlled trials (RCTs), non-RCTs, case-control studies, and case series that included Tai Chi as an intervention and had at least 1 outcome variable relevant to postural stability. DATA EXTRACTION: Authors critically reviewed studies and summarized study designs and outcomes in a summary table. DATA SYNTHESIS: Twenty-four Tai Chi studies met screening criteria. No studies specifically studying Tai Chi for vestibulopathy were found. Collectively, the 24 studies provide sometimes contradictory but generally supportive evidence that Tai Chi may have beneficial effects for balance and postural impairments, especially those associated with aging. Ten RCTs were found, of which 8 provide support that Tai Chi practiced alone, or in combination with other therapies, can reduce risk of falls, and/or impact factors associated with postural control, including improved balance and dynamic stability, increased musculoskeletal strength and flexibility, improved performance of activities of daily living (ADLs), reduced fear of falling, and general improvement in psychologic well-being. Studies using other designs support the results observed in RCTs. CONCLUSIONS: At present, few data exist to support the contention that Tai Chi specifically targets the impairments, functional limitations, disability, and quality of life associated with peripheral vestibulopathy. There are, however, compelling reasons to further investigate Tai Chi for vestibulopathy, in part because Tai Chi appears useful for a variety of nonvestibulopathy etiologic balance disorders, and is safe. Especially needed are studies that integrate measures of balance relevant to ADLs with other psychologic and cognitive measures; these might help identify specific mechanisms whereby Tai Chi can remedy balance disorders.

Humans↗
PubMed2004

Temporal and spatial features of gait in older adults transitioning to frailty.

Examining gait characteristics in older adults who are transitioning to frailty enhances our understanding of movement control in this fall-prone population and helps to better target preventive interventions. This work presents data on temporal and spatial gait parameters of a group of older adults who have been operationally defined as "transitionally frail". Gait speed, cadence, stride length, stance, swing, double-support, and horizontal heel velocity at heel contact were measured in 50 transitionally frail older adults while walking at a self-selected pace. These data suggest that the temporal and spatial gait features of these older adults differ substantially from published results from other older adults.

Aged↗
PubMed2004

Changes in serial optical topography and TMS during task performance after constraint-induced movement therapy in stroke: a case study.

The authors examined serial changes in optical topography in a stroke patient performing a functional task, as well as clinical and physiologic measures while undergoing constraint-induced therapy (CIT). A 73-year-old right hemiparetic patient, who had a subcortical stroke 4 months previously, received 2 weeks of CIT. During the therapy, daily optical topography imaging using near-infrared light was measured serially while the participant performed a functional key-turning task. Clinical outcome measures included the Wolf Motor Function Test (WMFT), Motor Activity Log (MAL), and functional key grip test. Transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) were also used to map cortical areas and hemodynamic brain responses, respectively. Optical topography measurement showed an overall decrease in oxy-hemoglobin concentration in both hemispheres as therapy progressed and the laterality index increased toward the contralateral hemisphere. An increased TMS motor map area was observed in the contralateral cortex following treatment. Posttreatment fMRI showed bilateral primary motor cortex activation, although slightly greater in the contralateral hemisphere, during affected hand movement. Clinical scores revealed marked improvement in functional activities. In one patient who suffered a stroke, 2 weeks of CIT led to improved function and cortical reorganization in the hemisphere contralateral to the affected hand.

Aged↗
PubMed2004

The effects of constraint-induced therapy on precision grip: a preliminary study.

OBJECTIVE: This preliminary study examines the effects of a 2-week constraint-induced therapy (CIT) intervention on the force-producing capabilities of the hemiparetic hand during the performance of a functional dexterous manipulation task. METHODS: A 6-degree-of-freedom force/torque transducer that was embedded into the handle of a key allowed for the quantification of grasping forces and torques produced during the performance of a functional key-turning task. Clinical and kinetic data were collected from 10 subacute patients (3-9 months poststroke) who were participating in an ongoing national clinical study (EXCITE trial) examining the effects of CIT on upper extremity motor performance. Investigators were blinded to treatment designation. Five patients receiving treatment immediately completed 2 weeks of intensive CIT, whereas a group randomized to treatment 1 year later did not receive any therapy during a similar 2-week span. RESULTS: . Results indicated that 4 of the 5 patients in the CIT group, compared to the delayed group, showed significant clinical improvements in hand function, increased maximum precision grip force, improved force and torque regulation, and reduced variability in rate of force production during task performance. CONCLUSIONS: Improved force control may be a mechanism contributing to the observed improvements in dexterous function in those patients undergoing CIT.

Chronic Disease↗
PubMed2004

Tai Chi and vestibular rehabilitation effects on gaze and whole-body stability.

Tai Chi (TC) is a comparatively new intervention for peripheral vestibular hypofunction, which is often treated with vestibular rehabilitation (VR). We compared gaze stability (GZS), whole-body stability (WBS) and footfall stability (FFS) during locomotion among 26 people with vestibulopathy (VSP), randomized into two treatment arms (13 TC and 13 VR). Each intervention program was offered for 10 weeks. GZS improved more for VR than for TC, but WBS (and FFS) improved more for TC than for VR. There was a significant relationship between changes in GZS and WBS for the VR subjects (r=0.60, p=0.01), but not for TC subjects. There was a significant relationship between changes in WBS and FFS for both VR (r=0.65, p <0.01) and TC (r=0.58, p=0.02) groups; the relationship disappeared in the VR but not the TC group when controlling for GZS. These findings suggest that VR and TC both benefit patients with VSP but via differing mechanisms. Moreover, these data are the first to test the assumption that improving gaze control among patients with VSP perforce improves postural stability: it does not. We conclude that GZS is most improved in those who receive VR, but that TC improves WBS and FFS without improving GZS, suggesting patients with VSP can rely on non-gaze related mechanisms to improve postural control.

Female↗
PubMed2003

Intense tai chi exercise training and fall occurrences in older, transitionally frail adults: a randomized, controlled trial.

OBJECTIVES: To determine whether an intense tai chi (TC) exercise program could reduce the risk of falls more than a wellness education (WE) program in older adults meeting criteria for transitioning to frailty. DESIGN: Randomized, controlled trial of 48 weeks duration. SETTING: Twenty congregate living facilities in the greater Atlanta area. PARTICIPANTS: Sample of 291 women and 20 men aged 70 to 97. MEASUREMENTS: Demographics, time to first fall and all subsequent falls, functional measures, Sickness Impact Profile, Centers for Epidemiologic Studies-Depression Scale, Activities-specific Balance Confidence Scale, Falls Efficacy Scales, and adherence to interventions. RESULTS: The risk ratio (RR) of falling was not statistically different in the TC group and the WE group (RR=0.75, 95% confidence interval (CI)=0.52-1.08), P=.13). Over the 48 weeks of intervention, 46% (n=132) of the participants did not fall; the percentage of participants that fell at least once was 47.6% for the TC group and 60.3% for the WE group. CONCLUSION: TC did not reduce the RR of falling in transitionally frail, older adults, but the direction of effect observed in this study, together with positive findings seen previously in more-robust older adults, suggests that TC may be clinically important and should be evaluated further in this high-risk population.

Accidental Falls↗
PubMed2003

Selected as the best paper in the 1990s: Reducing frailty and falls in older persons: an investigation of tai chi and computerized balance training.

OBJECTIVES: To evaluate the effects of two exercise approaches, tai chi (TC) and computerized balance training (BT), on specified primary outcomes (biomedical, functional, and psychosocial indicators of frailty) and secondary outcomes (occurrences of fall). DESIGN: The Atlanta Frailty and Injuries: Cooperative Studies and Intervention Techniques, a prospective, randomized, controlled clinical trial with three arms (TC, BT, and education (ED)). Intervention length was 15 weeks, with primary outcomes measured before and after intervention and at 4-month follow-up. Falls were monitored continuously throughout the study. SETTING: Persons aged 70 and older living in the community. PARTICIPANTS: A total of 200 participants, 162 women and 38 men; mean age was 76.2. MEASUREMENTS: Biomedical (strength, flexibility, cardiovascular endurance, body composition), functional instrumental activities of daily living (IADL), and psychosocial well-being (Center for Epidemiological Studies for Depression scale, fear of falling questionnaire, self-perception of present and future health, mastery index, perceived quality of sleep, and intrusiveness) variables. RESULTS: Grip strength declined in all groups, and lower extremity range of motion showed limited but statistically significant changes. Lowered blood pressure before and after a 12-minute walk was seen following TC participation. Fear of falling responses and intrusiveness responses were reduced after the TC intervention compared with the ED group (P=.046 and P=.058, respectively). After adjusting for fall risk factors, TC was found to reduce the risk of multiple falls by 47.5%. CONCLUSION: A moderate TC intervention can impact favorably on defined biomedical and psychosocial indices of frailty. This intervention can also have favorable effects upon the occurrence of falls. TC warrants further study as an exercise treatment to improve the health of older people.

Accidental Falls↗
PubMed2003

Transcranial magnetic stimulation to assess cortical plasticity: a critical perspective for stroke rehabilitation.

Transcranial magnetic stimulation has gained increasing visibility as an evaluative and interventional tool during the past 15 years. Within the context of rehabilitation, transcranial magnetic stimulation has been applied to differentiate excitatory and inhibitory mechanisms and to assess cortical reorganization following specific interventions. This article reviews some of the more salient features of transcranial magnetic stimulation applications relevant to stroke rehabilitation, highlighting the strengths and weaknesses in this approach. Data derived from such studies may be profoundly over-interpreted. Information is provided showing the importance of utilizing fundamental principles of electrode placement and kinesiological electromyography to more accurately reflect and interpret data emerging from transcranial magnetic stimulation mapping studies, particularly as they apply to the interpretation of cortical reorganization following application of neurorehabilitative procedures.

Brain Mapping↗
PubMed2003

Treatment interventions for the paretic upper limb of stroke survivors: a critical review.

Despite a threefold increase in treatment interventions studies during the past 10 years, "best practice" for the rehabilitation of the paretic upper limb is still unclear. This review aims to lessen uncertainty in the management of the poststroke upper limb. Two separate searches of the scientific literature from 1966-2001 yielded 333 articles. Three referees, using strict inclusion and exclusion criteria, selected 68 relevant references. Cohort studies, randomized control trials, and systematic reviews were critically appraised. Mean randomized control trial quality (n = 33) was 17.1/27 (SD = 5.2, 95% CI = 15.2-19.0, range = 6-26). Mean quality of cohort studies (n = 29) was 11.8/27 (SD = 3.8, 95% CI = 10.4-13.2, range = 4-19). Quantitative syntheses were done using the Z-statistic. This systematic review indicated that sensorimotor training; motor learning training that includes the use of imagery, electrical stimulation alone, or combined with biofeedback; and engaging the client in repetitive, novel tasks can be effective in reducing motor impairment after stroke. Furthermore, careful handling, electrical stimulation, movement with elevation, strapping, and the avoidance of overhead pulleys could effectively reduce or prevent pain in the paretic upper limb. Rehabilitation specialists can use this research synthesis to guide their selection of effective treatment techniques for persons with impairments after stroke.

Humans↗
PubMed2003

Preliminary reliability and validity of a family caregiver conflict scale for stroke.

Recovery from stroke is a challenging process for stroke survivors and their families. Assessing family conflict may be useful in guiding interventions to reduce caregiver distress. The purpose of this study was to assess preliminary reliability and validity data for a 15-item family caregiver conflict scale [FCCS] for stroke. Construct validity was assessed using subscales from the family assessment device: communication, problem solving, general family functioning, and a perceived criticism scale. Data were pooled from three studies of caregivers of stroke survivors (total N=93). Internal consistency for the FCCS was adequate (>0.70). Higher family conflict was related to more ineffective family communication, general family functioning, and higher perceived criticism (p > or =0.05). Nonspouse caregivers reported more family conflict than spouse caregivers. The FCCS appears to have adequate internal consistency and construct validity and may provide information about family conflicts around stroke recovery and direction for family-focused interventions.

Adult↗
PubMed2002

Repetitive task practice: a critical review of constraint-induced movement therapy in stroke.

BACKGROUND: Constraint-induced (CI) movement therapy (also called forced use by some investigators and clinicians) has gained increasing popularity as a treatment mode for restoring function in the upper extremities of patients with stroke. The purpose of this article is to review the concept of constraint-induced movement therapy and provide a critical analysis of the existing data. REVIEW SUMMARY: The evidence to date offers encouragement for the application of this procedure for patients who have some movement recovery out of synergy. Success may be contingent on patient cooperation and intense repetitive use with applications of retraining through practice and shaping. The extent to which each of the latter elements influences the magnitude of recovery is still unclear. However, task novelty and challenge seem important to recovery of function. There are several methods used to map cortical changes after stroke. At this time, transcranial magnetic stimulation is the primary vehicle used to assess motor cortical reorganization after CI therapy in humans. CONCLUSIONS: Accumulating data indicate that the size of a cortical area representative of a muscle does expand and its center of gravity does change with CI therapy.

Journal Article↗
PubMed1981

Examination of electrode placements and stimulating parameters in treating chronic pain with conventional transcutaneous electrical nerve stimulation (TENS).

Conventional transcutaneous electrical nerve stimulation was applied to 114 patients diagnosed as having peripheral neuropathy (N = 18), peripheral nerve injury (N = 21), radiculopathy (N = 36) and musculoskeletal disorders (N = 39) to determine optimal electrode placements and stimulation parameters for pain relief. Treatment outcomes were assessed primarily through evaluation of the present pain intensity (PPI) rating scale, Immediate improvements in PPI scores occurred in patients in all these diagnostic categories. One month follow-up data on 25 subjects showed that improvement was of limited duration. No clear correlation between stimulation parameters or electrode placements and pain relief was ascertained. In certain instances (subjects with radiculopathy or peripheral nerve injury) a positive relationship existed between higher intensity stimulation and amelioration of pain. Greater pain relief was reported among patients with minimal previous medical or surgical treatment in every diagnostic group.

Adult↗
PubMed1980

Chronic back pain: electromyographic, motion and behavioral assessments following sympathetic nerve blocks and placebos.

Twenty patients with chronic low back pain received 12 lumbar sympathetic injections, in a series of 6 with bupivacaine and a series of 6 with saline. Changes in subjective pain intensity, EMG from paravertebral muscles, joint ranges of mobility, and daily activity levels were measured at multiple intervals throughout treatment and at 3 monthly follow-up intervals. The MMPI was administered before treatment, after treatment and at 3-month follow-up. Results revealed significant reductions in subjective pain intensity lasting 1 month after treatment which were not significantly different during bupivacaine and saline injection periods. Patients' MMPI profiles were indicative of reduced depression and an increase in ability to manage their lives. No significant changes were recorded with respect to EMG, joint range of mobility, or daily activity levels. Results were discussed in terms of a massive placebo effect and analgesia obtained through hyperstimulation of various tissue structures. They are consistent with the hypothesis that central postsynaptic mechanisms were predominant in these patients' chronic back pain states. Because subjective pain relief did not independently produce increasing function, it was recommended that deep analgesic injections or other pain relieving techniques be matched with behavior modification leading to functional rehabilitation.

Activities of Daily Living↗