Ruth Dickstein

Motor Imagery in Physical Therapist Practice

Motor imagery is the mental representation of movement without any body movement. Abundant evidence on the positive effects of motor imagery practice on motor performance and learning in athletes, people who are healthy, and people with neurological conditions (eg, stroke, spinal cord injury, Parkinson disease) has been published. The purpose of this update is to synthesize the relevant literature about motor imagery in order to facilitate its integration into physical therapist practice. This update also will discuss visual and kinesthetic motor imagery, factors that modify motor imagery practice, the design of motor imagery protocols, and potential applications of motor imagery.

How Does Explicit Prioritization Alter Walking During Dual-Task Performance? Effects of Age and Sex on Gait Speed and Variability

Background Previous studies have demonstrated that the performance of a secondary task during walking alters gait. Objective This study investigated the effects of task prioritization on walking in young and older adults to evaluate the “default” prioritization scheme used, the flexibility to alter prioritization and cortical resources allocated to gait and a secondary cognitive task, and any age-associated changes in these abilities. Design A cross-sectional study that explicitly altered the focus of attention was used to investigate the effects of prioritization in young and older adults who were healthy. Methods Gait speed and gait variability were evaluated in young adults (n=40) and older adults (n=17) who were healthy, both during usual walking and under 3 dual-task conditions: (1) no specific prioritization instructions, (2) prioritization of gait, and (3) prioritization of the cognitive task. Results Young adults significantly increased gait speed in the gait prioritization condition compared with gait speed in the no-instruction condition; a similar tendency was seen in the older adults. Gait speed was reduced when priority was given to the cognitive task in both age groups; however, this effect was less dramatic in the older adults. In the young adults, prioritization of gait tended to have different effects on gait speed among both men and women. In the older adults, but not in the young adults, all dual-task conditions produced increased gait variability, whereas prioritization did not alter this gait feature. Limitations The sample size and the relative homogeneity of the older adults could be considered as possible limitations of the study. Conclusions Even among young adults, the effects of secondary, cognitive tasks on gait speed are strongly influenced by prioritization. This finding was less significant in the older adults, suggesting that there is an age-associated decline in the ability to flexibly allocate attention to gait. Somewhat surprisingly, when prioritization was not explicitly instructed, gait speed in both young and older adults most closely resembled that of the condition when they were instructed to focus attention on the cognitive task.

Rehabilitation of Gait Speed After Stroke: A Critical Review of Intervention Approaches:

Purpose. Walking speed is a cardinal indicator of poststroke gait performance; however, no consensus exists regarding the optimal treatment method(s) for its enhancement. The most widely accepted criterion for establishing the contribution of treatment to walking speed is the gain in speed. The actual speed, however, at the end of the intervention (final speed) may be more important for functional community ambulation. This review examines the contribution of the prevailing methods for gait rehabilitation to final walking speed. Method. Walking speed information was derived from studies included in meta-analyses, systematic reviews, and clinical practice guidelines. Recent references, not included in the mentioned sources, were incorporated in cases when gait speed was an outcome variable. Final speed was assessed by the reported speed values and by inferring the capacity for functional community walking at the end of the intervention period. Results. Similar outcomes for final walking speed were found for the different prevailing treatment methods. Treatment gains were likewise comparable and generally insufficient for upgrading patients functional community walking capacity. Conclusions. Different treatment methods exist for poststroke gait rehabilitation. Their availability, mode of application, and costs vary, yet outcomes are largely similar. Therefore, choosing an appropriate method may be guided by a pragmatic approach. Simple “low technology” and conventional exercise to date is at least as efficacious as more complex strategies such as treadmill and robotic-based interventions.

Home-Based Motor Imagery Training for Gait Rehabilitation of People With Chronic Poststroke Hemiparesis

OBJECTIVEnTo test the feasibility and efficacy of a home-based motor imagery gait training program to improve walking performance of individuals with chronic poststroke hemiparesis.nnnDESIGNnNonrandomized controlled trial.nnnSETTINGnLocal facility.nnnPARTICIPANTSnParticipants (N=17) were community-dwelling volunteers with hemiparesis caused by a unilateral stroke that occurred at least 3 months before the study.nnnINTERVENTIONnParticipants received 15 minutes of supervised imagery gait training in their homes 3 days a week for 6 weeks. The intervention addressed gait impairments of the affected lower limb and task-specific gait training. Walking ability was evaluated by kinematics and functional scales twice before the intervention, 3 and 6 weeks after the intervention began, and at the 3-week follow-up.nnnMAIN OUTCOME MEASURESnSpatiotemporal, kinematic, and functional walking measurements.nnnRESULTSnWalking speed increased significantly by 40% after training, and the gains were largely maintained at the 3-week follow-up. The effect size of the intervention on walking speed was moderate (.64). There were significant increases in stride length, cadence, and single-support time of the affected lower limb, whereas double-support time was decreased. Improvements were also noted on the gait scale of the Tinetti Performance-Oriented Mobility Assessment as well as in functional gait. Sixty-five percent of the participants advanced 1 walking category in the Modified Functional Walking Categories Index.nnnCONCLUSIONSnAlthough further study is recommended, the findings support the feasibility and justify the incorporation of home-based motor imagery exercises to improve walking skills for poststroke hemiparesis.

Associations Between Treatment Processes, Patient Characteristics, and Outcomes in Outpatient Physical Therapy Practice

OBJECTIVEnTo identify how treatment processes are related to functional outcomes for patients seeking treatment for musculoskeletal impairments while controlling for demographic and health characteristics at intake.nnnDESIGNnProspective, observational cohort study. Treatment processes were not altered. Data were collected continuously from June 2005 to January 2008. Descriptive statistics were applied to compare patient characteristics, interventions, and outcomes between impairment categories. Ordinary least-squares multiple regressions were used to examine associations between patient characteristics at intake, treatment processes, and functional outcomes.nnnSETTINGnFifty-four community-based outpatient physical therapy clinics of Maccabi Healthcare Services, a public health plan in Israel.nnnPARTICIPANTSnA consecutive sample of 22,019 adult patients (mean age 51.2 y, standard deviation=15.7, range 18-96, 58% women) seeking treatment due to lumbar spine, knee, cervical spine, or shoulder impairments with functional measurements at intake and discharge.nnnINTERVENTIONSnNot applicable.nnnMAIN OUTCOME MEASUREnFunctional status at discharge.nnnRESULTSnExplanatory power ranged from 30% to 39%. Better outcomes were associated with patient compliance with self-exercise and therapy attendance, application of therapeutic exercise and manual therapy, and completion of 3 or more functional surveys during the episode of care. Worse outcomes were associated with women, electrotherapy for pain management, and therapeutic ultrasound for shoulder impairments. Mixed results were found for group exercise programs.nnnCONCLUSIONSnThe study of associations between treatment processes, patient characteristics, and outcomes helps to describe practice and can be used to suggest ways to improve outcomes in outpatient physical therapy practice.

Electromyographic activity of voluntarily activated trunk flexor and extensor muscles in post-stroke hemiparetic subjects

OBJECTIVEnTo study the EMG activity of selected trunk muscles during self-initiated voluntary flexion and extension of the trunk in post-stroke hemiparetic subjects, and to compare measurement results to corresponding findings in control subjects.nnnMETHODSnUsing a sample of 50 patients and 30 control subjects, bilateral EMG activity of the rectus abdominis (RA) and external oblique (EO) muscles was studied during direct trunk flexion, and activity of the lumbar erector spinae (ES) and latissimus dorsi (LD) was studied during straight trunk extension. Variables of timing, magnitude, and temporal synchronization between muscle activity on the paretic and non-paretic sides of the body in the patient group were compared with the same measurements taken from the left and right sides of the body in the control group.nnnRESULTSnActivity of the RA and LD muscles on the affected side of the body was reduced and delayed relative to the unaffected side in the patients and relative to the control subjects. Some deterioration was also observed in the function of the EO muscle, whereas the lumbar ES displayed normal activity on both sides of the body. Trunk velocity during both flexion and extension was slower in the patients than in the controls.nnnCONCLUSIONSnDespite the existence of ipsilateral as well as contralateral higher inputs to axial and to a lesser extent also to more lateral trunk muscles, the function of the superficial abdominal muscles and of the LD muscle is adversely affected by a contralateral stroke. Conversely, the lumbar ES, which can be categorized as local trunk extensors, seem to normally fulfill their anti-gravitational task on both sides of the body.

Light touch and center of mass stability during treadmill locomotion

PURPOSEnTo study the contributions of light fingertip touch on an earth-referenced object to body stability during treadmill locomotion.nnnMETHODnTwenty young healthy adults were tested in two blocks of five testing conditions while walking on the treadmill at 3 km/h. In each condition, subjects were tested with eyes open (EO) and with eyes closed (EC). In each block, four separate conditions of heavy (H) or light (L) touch to either a left or to a right force sensor mounted on the respective side rail, as well as one condition of no touch (N), were randomly applied. The 3D positions of the center of mass (COM) and the midpoint of the posterior aspect of each leg were monitored via a kinematic ultrasonic system, while the anterior-posterior (AP) acceleration of the COM was measured with a uniaxial linear accelerometer.nnnRESULTSnLight touch had a similar stabilizing effect as vision and as heavy touch on COM sway. Thus, COM sway and AP acceleration were comparable in conditions of eyes open and eyes closed as long as touch was applied. Conversely, without vision and touch, subjects drifted backwards, with complete disruption of the coordinated stepping pattern.nnnCONCLUSIONSnSomatosensory fingertip input from an external reference provides spatial orientation, which, similar to vision, enables the sustaining of body stability during treadmill walking.

Effects of explicit prioritization on dual task walking in patients with Parkinson's disease

Patients with Parkinsons disease (PD) have difficulties performing a dual task (DT) while walking and may use the posture second strategy. It is not clear if this is a result of motor or cognitive impairments. We examined the effects of explicit prioritization of walking or the cognitive task on gait speed (GS) and variability in 20 patients (Hoehn & Yahr stage: 2.3 ± 0.5) and 20 healthy older adults during usual-walking and under three DT (verbal-fluency) conditions: (1) no instruction for prioritization, (2) specific attention to the walking pattern (gait prioritization), and (3) specific attention to the cognitive task (prioritization of verbal-fluency). The Montreal Cognitive Assessment, the Frontal Assessment Battery, and the Trail Making Tests assessed cognitive status. The two groups did not differ on these cognitive tests. Compared to usual-walking, all subjects reduced their GS in the un-instructed DT condition. Compared to the un-instructed DT condition, both groups significantly (p < 0.001) increased GS when prioritizing walking and maintained about the same GS when prioritizing the cognitive task (p > 0.155). All three DT conditions increased gait variability in both groups (p < 0.001 usual-walking compared to uninstructed DT). Verbal-fluency tended (p = 0.073) to be influenced by prioritization in both groups. Task prioritization abilities were similar in the patients and controls, even though the patients generally walked more slowly. PD patients without cognitive impairment apparently utilize their cognitive resources in the same manner as healthy older adults. Both groups, however, use some form of the posture second strategy and naturally focus on the cognitive task.

TENS to the posterior aspect of the legs decreases postural sway during stance.

The purpose of this study was to examine the effect of Transcutaneous Electrical Nerve Stimulation (TENS) applied to the posterior aspect of the legs, on postural sway during stance. Thirty healthy subjects were tested while standing on a force platform under four stimulation conditions: no TENS, bilateral TENS, and unilateral left and right TENS. Thirty-second long tests, employing detection threshold amplitudes, were performed in three blocks. In each block, the four conditions were applied both with and without vision in a random order. The results indicate that the application of TENS brought about a decrease in postural sway as expressed by average sway velocity, in addition to a decrease in the absolute values of maximal and minimal medio-lateral and anterior-posterior velocity. Thus, similar to sub-threshold random electrical noise, it appears that the application of low-amplitude TENS to the lower limbs decreases postural sway during stance. Considering the ease of TENS application and the high prevalence of postural disorders, the potential clinical significance of this observation is to be determined by further studies.

EMG activity in selected target muscles during imagery rising on tiptoes in healthy adults and poststroke hemiparetic patients

The authors sought to gain further knowledge about activation of target muscles during imagery engagement in a motor task. Six hemiparetic patients and 9 healthy participants performed 3 real rises on tiptoes and then, after pausing, 3 imagery rises on tiptoes. Metronome beats guided the rate of rises and descents. Electromyographic (EMG) activity from the medial gastrocnemius and the rectus femoris muscles were monitored bilaterally throughout the performance of both tasks. In 3 healthy participants and 3 individuals with hemiparesis, EMG activity was related to the imagery task in at least 1 of the target muscles. Conversely, in the other participants, motor imagery practice was not accompanied by task-related EMG activity in the monitored muscles. In all cases, the increment in activation level during motor imagery practice was very low in comparison with that of real performance. The findings were not unequivocal; therefore, EMG activity may sometimes, but not always, be recorded during motor imagery practice both in healthy individuals and in poststroke hemiparetic participants. Further research is needed to align motor imagery practice with the objectives of motor rehabilitation.