Constraint-induced Movement Therapy: Another form of NDT or Something Completely Different?

Constraint-induced Movement Therapy: Another form of NDT or Something Completely Different? Carolee J. Winstein, PhD, PT, FAPTA University of Southern California NDTA Conference: Orlando Florida, May 5-8, 2004

Concepts and Evidence • What is CI therapy? • How important is the ‘constraint’? • Protocol design and training • How important is the ‘intensity’ of training? • What are the essential ingredients of ‘training’ • Task-specific training and functional goals • Common elements of NDT and CI therapy

Constraint-induced movement therapy • Developed at the University of Alabama Birmingham (Edward Taub, Director, CI Therapy Research Group) • Began with basic research done with monkeys in which somatic sensation was surgically abolished in one forelimb resulting in somatosensory deafferentation. • After somatosensory deafferentation, monkeys do not use the forelimb in the free situation (problem is nonuse). • Hypothesis that the nonuse was a learning mechanism termed ‘learned nonuse’. • Two general types of techniques were effective in overcoming the nonuse in the monkeys.

Constraint-induced movement therapy…. • The procedures of CI therapy are relatively simple: • For the arm, therapy involves ‘promoting use of the more affected UE for a target of 90% of waking hours by employing one of several methods for restraining or reducing use of the less-affected UE for 2-3 weeks (depending on the severity of the deficit)’ • Training of the more-affected UE is given 6 hrs daily for 10 consecutive weekdays during that period (ie, massing of practice or concentrated, repetitive training). • For the lower extremity (LE) the less-affected LE is not restrained, but the more affected LE is given intensive training for 7 hrs per day over a period of 3 weeks. Taub et al., PM&R Clinics of North America, Feb 2003 Supplement

Critical Concept: Learned nonuse • CI therapy is intended to help stroke patients overcome ‘learned nonuse’ of the paretic arm by discouraging the use of the unaffected or less affected arm in combination with intensive training of the paretic arm.

Learned nonuse theory developed from observations in animal research • Mott & Sherrington (1895) • Taub (1980) • Taub et al., (1994) • only when the “normal” limb was restricted, did the animal begin to use the deafferented limb.

Development of Learned Nonuse: Hypothesis

Overcoming Learned Nonuse: Hypothesis

Evidence for learned nonuse and effectiveness of CIT • Learned nonuse theory is based on deafferentation experiments in monkeys. • Four randomized clinical trials of CIT: although the authors reported positive results, the effect sizes calculated without covariates yielded no statistically significant differences. • In one study, patients with sensory disorders and hemineglect showed a differential effect. • Learned nonuse theory requires further exploration. • Only one study attempted to measure learned nonuse (Sterr et al., 2002) Van der Lee, J Rehab Med, 2003

Learned nonuse: Outcome measures • Motor Activity Log (MAL) • Structured subjective interview with self-reported ranking of the amount and quality of affected arm use for 30 specified tasks (e.g., open a drawer; use a fork for eating) • Clinimetric properties not well established (see van der Lee, LTE, Stroke, 31: 983-c, 2000). • In 2 of the articles claimed to confirm the stability of the MAL over a 6-week placebo treatment and follow-up period, no data were presented (ie., Taub et al., 1998; Taub & Wolf, 1997). • The possibility that reported changes on the MAL are the result of a Hawthorne effect remains unchallenged.

Motor Activity Log: “Amount” • 0 - did not use my weaker arm • 1 - occasionally tried to use my weaker arm (very rarely) • 2 - sometimes used my affected arm, but did most of the activity with my stronger arm (rarely). • 3 - used my weaker arm about half as much as before the stroke (half prestroke). • 4 - used my weaker arm almost as much as before the stroke (3/4 prestroke) • 5 - used my weaker arm as much as before the stroke (same as prestroke). 30 different questions: “In the last week, how often did you…..use your weaker arm to turn on a light with a light switch”?

Motor Activity Log: “How well” • 0 - the weaker arm was not used at all for that activity (never) • 1 - the weaker arm was moved during that activity, but was not helpful (very poor). • 2 - the weaker arm was of some use during that activity, but needed some help from the stronger arm, moved very slowly, or with difficulty (poor). • 3 - the weaker arm was used for the purpose indicated, but movements were slow or were made only with some effort (fair). • 4 - the movements made by the weaker arm were almost normal, but not quite as fast or accurate as normal (almost normal) • 5 - the ability to use the weaker arm for that activity was as well as before the stroke (normal). “When you used your weaker arm to….turn on a light with a light switch, how well did it work”?

MAL interview—”How much” first; then “how well”

Actual Amount of Use Test (AAUT) • Covert video of set task scenarios • Movement assessed for • Use of affected limb (yes or no) • Quality of movement (Functional Rating Scale)

Is the behavior automatic and spontaneous?

What is the evidence? • Critical concept is that the ‘constraint’ is a means to force use of the affected limb just as in the monkey experiments (see Friel et al., 2000). • Only one study in humans has compared two interventions with the same intensity: “The contrast between the intervention conditions was focused on the presence or absence of forced use.” (van der Lee et al., 1999, p. 2370) • Forced use of the upper extremity in chronic stroke patients: Results from a single-blind randomized clinical trial.

Van der Lee et al., 1999 • Two groups: Randomly assigned • “forced-use therapy (immobilization of unaffected arm combined with intensive training) • Equally intensive bimanual training based on NDT • Treatment for a period of two weeks • Inclusion criteria • Chronic stroke • Min 20 deg active wrist extension; 10 deg finger extension • ARA test score <51/57 • Ability to walk indoors without a stick (no major balance problems) • No severe aphasia or cognitive problems (>22 MMSE)

Results… • 31 allocated to ‘forced use’; 31 to ‘bimanual training’ • Mean intake: FU BI • ARA: 32.1 28.8 (total 57) • FMA: 51.1 45.1 (total 66) • Hemineglect 3 4 • Sensory disorder 16 12 • MAL (amount) 2.2 1.7 • One week after treatment: significant difference between groups for ARA score and MAL amount of use score • ARA 39.2 30.0 • MAL 2.9 2.2

Results…continued • One year follow-up effects only for ARA • Group FU BI • ARA 38.5 30.7 • MAL 2.5 1.8 (NS) • Using 10% of range as MCID, the differences in treatment effect for ARA and MAL were clinically relevant for patients with sensory disorders and hemineglect, respectively.

Take home message.. • Van der Lee et al., 1999 showed a small but lasting effect of ‘forced use therapy’ on the dexterity of the affected arm as measured by the ARA in comparison with bimanual training. • In patients with sensory disorders, this effect was clinically relevant; positive effect was found on the subjective amount of use of the affected arm in ADL (measured by MAL) especially in patients with hemineglect. However, this effect was no longer found during follow-up (no persistence).

Protocol design and training.. • Differences across the four published RCT studies in stroke Author Chronicity N • Taub et al., 1993 chronic 4 exp/5 ctl • Van der Lee et al., 1999 chronic 31 exp/31 ctl • Dromerick et al., 2000 acute 11 exp/9 ctl • Page et al., 2002 subacute 4 exp/5 ctl exp = experimental, ctl = control

What were the protocol differences? • Experimental interventions, respectively: • CI signature protocol (restraint 90% waking hours, 6 hr of supervised task practice 5 d/wk, 2 weeks) • Immobilization of unaffected arm + intensive arm function training 6 hr/day, 5 d/wk, 2 weeks (groups of 4 patients together). • Discouragement to use unaffected hand (padded mitten) 6 hr/day + occupational therapy and CIM circuit training 2 hr/day, 5 d/wk, 2 weeks • 0.5 hr PT and 0.5 hr OT including ‘Shaping’ 3x/wk, 10 wks + restraint during 5 hrs of frequent arm use, 5d/wk 10 weeks.

What were the control group differences? • Control interventions, respectively: • Procedures to focus attention on the involved extremity. • Intensive bimanual arm function training, 6 hr/d, 5 d/wk, 2 weeks (based on NDT). • Standard occupational treatment + circuit training (bilateral) 2 hr/d, 5 d/wk, 2 weeks. • 0.5 hr PT and 0.5 hr OT including PNF 3x/wk 10 wks; second control group received no treatment at all

Protocols based on specific research questions and implicit assumptions • How best to achieve the reversal of learned nonuse, elicit expression of latent behavior, and encourage use of the affected arm in the real world? (Taub et al.,1993) • Practice should be aimed at functional goals; how much does immobilization of unaffected limb add to this for encouraging use and improved dexterity of the affected arm? (van der Lee et al., 1999) • Is a modified CIM protocol feasible in acute stroke in humans? (Dromerick et al., 2000) • Is a modified CIT protocol feasible in subacute stroke? (Page et al., 2002)

Intensity and dose of training? • Signature CIT protocol is 60 hrs of supervised training delivered 6 hr/day, 5 d/wk, over 2 weeks • Van der Lee et al., 1999—same dose and intensity of training as signature CIT protocol. • Dromerick et al., 2000—2 hr/day, 5 d/wk, over 2 weeks = 10 hrs of training • Page et al., 2002—3 hr/wk x 10 wks = 30 hrs of training

Contrast in intensity between groups • Highest in Taub et al., 1993 • A positive relationship has been found between effect sizes and the contrast in intensity of training (Kwakkel et al., 1997; Duncan, 1997; Richards & Pohl, 1999) • This potential confounder was taken into account in the design of two studies (Van der Lee et al., 1999; Dromerick et al., 2000) • Two studies applied much less intensive training schedules (Dromerick et al., 2000; Page et al., 2002) • One study directly compared effects of 3 hr/day vs 6 hr/day CIMT ‘shaping training’ (Sterr et al., 2002)

Sterr et al., APMR, 83: 2002 • 18 chronic hemiparetic patients (15 remained, 13 stroke, 2 TBI) • Random assignment to 1 of 2 treatment groups • Signature CIMT protocol using the ‘shaping procedure’. • Only difference between groups was 3 vs 6 hr/day of shaping training. • 6 hr group (n =7), 3 hr group (n = 8).

Outcome measures: MAL, WMFT • MAL (20 items; 15 affected, 5 unaffected rating), baseline MAL ~ 2 AOU, 1.8 QOU. • WMFT—16 timed tasks, standardized with published validity and reliability. • Results: baseline, pre, post, 1 month FU (weekly) • MAL, 6 hr baseline-FU = 2.0 units AOU, 1.6 QOU • MAL, 3 hr baseline-FU = 1.2 units AOU, 1.2 QOU • WMFT, median time gain pre-post 2.34 s, 6 hr • WMFT, median time gain pre-post 0.64 s, 3 hr • Note: Constraint time was the same for both groups

Components of re-training program • Besides the constraint, and intensity (dose), what are the components of ‘training’? • This is where the rubber meets the road!! • What is inside the ‘black box’? • Signature CI training defines two types of training: • Shaping or adaptive task practice (ATP), and standard Task practice (TP) are used with each participant as functional activities (e.g., writing, turning pages, rotation of rolodex file) are repeated.

Shaping • Derives its name from the behavioral training technique developed by Skinner and others. • A form of operant conditioning in which the probability of experimenter determined behaviors are ‘elicited’ through reinforcement (reward or punishment). • The learner is relatively passive in this process while performance is progressively ‘shaped’ as the behavioral objective (task goal) is approached in small steps through reinforcement or reward (positive feedback) • Using this approach, a motor objective (task goal) is approached in small steps by successive approximations (ie, parts of the task), the task is made more difficult in accordance with motor capability, or the speed of the performance is progressively increased.

Shaping….continued • Typically, each functional activity or its part is practiced for a set of 10 trials, and explicit feedback is provided regarding the participant’s performance with each trial.

An open question… • A point of debate concerning the degree to which ‘shaping’ clearly describes the fundamental training procedure that is used with CI therapy. • The debate is focused on defining the goal of this training: • To modify behavior (elicit arm movements) • Improve skill in performing functional motor tasks with the affected limb

Morris et al., 1997 • “shaping is very similar to training techniques commonly used by physical and occupational therapists giving patients task practice. The main difference is that with shaping, patients or subjects are given explicit feedback concerning even small improvements in performance” (p. 39) and errors are ignored.

Descriptions have changed…. • Specific training protocols described in 1994 have evolved to more recent versions in 2003 • “CI therapy is typically administered one-on-one by a therapist who continuously monitors patient performance, provides positive reinforcement to the patient, and shapes the difficulty of the task upwards.” (Taub & Uswatte, 2003, p 38)

What is there to debate? • If the goal is to modify behavior, feedback is more reward-like and less informational in content; it is provided frequently and immediately, and it does not include error information. • In sharp contrast, if the goal is to enhance skilled learning, feedback is more informational than reward-like in content; it is provided less frequently with practice and with some delay, and it provides information on errors to enhance motor learning.

No test of relative effectiveness… • To our knowledge, there has not been any systematic direct comparison of the relative effectiveness of these two fundamentally different approaches for training-feedback protocols in stroke rehabilitation.

Further concerns… • Shaping implies the learner is a relatively passive player in the process and yet we know that learning involves active participation, motivation and attention. • A conditioned response depends on the reward and can be extinguished if the schedule of reinforcement is not maintained. This suggests that shaped responses will dissipate with time and predicts limited persistence of the training.

Task Practice • Less structured than ‘shaping’ procedures. • Tasks are not set up to be carried out as individual trials of discrete movements • They involve functionally based activities performed continuously for a period of 15-20 minutes (e.g., setting the table; wrapping a present). • Progression: in successive periods of task practice, the spatial requirements of the activity or other parameters (such as duration) can be changed to require more demanding control of limb segments for task completion. • Feedback about overall performance is provided at the end of the 15-20 minute period.

Black Box—Functional Task Practice • Task Practice (functional tasks practiced as a whole, e.g., wrapping a present; setting the table) • “Shaping” (adapted task practice) • Factors that are not clearly delineated in CI therapy protocols • Determining where to start is critical (thresholding is essential for the right amount of challenge) • Determining how to progress is essential and takes a skilled clinician • Choosing tasks is critical to motivation and patient participation

Examples of the “small well” type task…

Discovery/learning of new strategy (implicit)…

Behavioral Issues: Reminders • Behavioral Contract • Caregiver Contract • Daily Diary/Review of Daily Diary • Homework • Compliance Device in Mitt—measures the actual time the mitt is worn

Constraint-induced Movement Therapy: Another form of NDT or Something Completely Different?