Dual Task Practice in Parkinson's Disease
Condition: Parkinson's Disease
MeSH terms: Parkinson Disease
Study type: Interventional
Phase: Phase 3

Summary: 
      The ability to perform two or more tasks together is impaired in Parkinson's Disease (PD).
      Based on pilot work we hypothesize that dual tasking is amenable to training in PD and will
      not compromise safety. In the proposed study we will therefore collect high level evidence on
      whether 6 weeks of integrated dual task gait training is more effective than consecutive task
      practice. The investigators will use a randomized, single blind study design and conduct the
      same protocols in two academic centers (Katholieke Universiteit Leuven and Radboud
      Universiteit Nijmegen). The investigators intend to test an experimental condition which
      consists of focused dual task training in the home using a novel program of personalized
      cognitive tasks. The aim of dual task training is to teach motor-cognitive task integration
      and achieve optimal levels of automaticity and functionality. The control arm will receive
      gait practice and separate cognitive training of the same intensity, but offered
      consecutively. We will test the hypothesis that dual task training (integration) will have
      more pronounced effects on complex gait than consecutive task training.

      Sub-analysis will be conducted on patients with and without freezing of gait. The
      investigators expect that integrated dual task training may be less effective in patients
      with freezing, due to the increased fall risk and impaired cognitive profiles.

      Overall, this project will provide evidence to support future directions for motor learning
      and innovative rehabilitation targets.
    

Detailed description: 
      Purpose:

      The ability to perform two or more tasks together - for instance walking and talking - is
      impaired in Parkinson's Disease (PD). As a result, dual tasking might evoke gait
      deterioration with an increased risk of falling in PD. In the European guideline for
      physiotherapy, it is therefore recommended to advise PD patients to avoid dual tasking.
      However, based on clinical experience and pilot work we argue that rather than avoiding, dual
      tasking should be trained and this may enhance safety.

      At present, there is little clinical evidence about the effectiveness of attention-related
      exercise in PD. The RESCUE-trial showed sustained reductions of dual task interference after
      a short period of combined single and dual task cued gait training without increasing fall
      risk. These effects were cue-related and not contrasted with an active control group. Dual
      task training with a variable locus of attention showed very effective in comparison to
      single task training in achieving retention and transfer effects in balance-impaired older
      people. This randomized study also showed that dual tasking led to greater improvements of
      cognitive function compared to single task intervention. In addition, recent study showed
      dual task training to be surprisingly effective in mild to moderately affected patients with
      dementia, who were randomly assigned to dual tasking or unspecific exercise.

      Given the positive effects of these clinical studies, the effectiveness of dual task training
      needs to be urgently addressed in PD patients, in whom both motor and cognitive problems are
      apparent. The fact that patients with freezing of gait (FOG) are associated with a surplus
      decline of attention and have a higher fall risk, begs the question whether dual task
      training is equally effective in this important clinical subgroup. Therefore, we propose to
      obtain high level evidence on whether dual task gait training is as effective and safe in
      PD-patients with FOG. The overall purpose of this project is to guide future directions for
      innovative rehabilitation targets.

      Research objectives:

        1. To determine whether intensive and integrated dual task gait training leads to sustained
           improvements in complex gait performance and is more effective than consecutive task
           training. The study will focus on influencing the ability to resist dual task
           interference, the ability to transfer learning effects to an untrained but related task
           and the ability to retain the learning increments after a period without training (12
           weeks).

        2. To test whether integrated training of dual task walking is a safe intervention in PD
           and does not increase fall risk.

        3. To determine whether disease stage or disease profile (with and without FOG) and
           cognitive factors predict the effect of dual task training.

      Design:

      The design will consist of a multicentered single blind randomized controlled trial in which
      PD patients are either allocated to a control group (Consecutive Task Training, "CTT") or to
      an experimental group (Integrated Dual Task Training, "IDT"). Patients in both arms of the
      study will continue their usual care (including standard physiotherapy) as normal. In case
      patients receive physiotherapy, we will inform the therapists involved and make sure that we
      ascertain the contents of normal care and avoid overlap. The trial will be conducted in two
      countries Belgium and the Netherlands, which are similar in terms of language and healthcare
      facilities.

      Randomization:

      The overall timeline of the study is 3 years. Subjects will undergo a control period of six
      weeks without intervention. This allows us to investigate the effects of repeated measures.
      Subsequently, patients will be randomized to one of the two groups within each center: 1) IDT
      or 2) CTT. All subjects will participate in an intensive, progressive training protocol
      consisting of 18 sessions (3 per week for 6 weeks) and up to one hour per session. Assessors
      will be unaware of group allocation. Randomization will be stratified with respect to
      subgroups (i.e. with or without FOG and Hoehn & Yahr stage II and III) to ensure adequate
      representation and diversity. A computerized block randomization will be performed per
      centre. Freezers will be defined by a score >1 on the New Freezing of Gait Questionnaire.

      Power calculation:

      Based on the literature and our previous experience, we anticipate that DTT will improve with
      an average of 20% and STT with 5% of baseline dual task gait speed (during a novel task).
      Assuming an alpha of 0.05, we calculated our sample size with dual task gait speed as the
      main outcome. On the basis of the RESCUE data, (including patients with >5% DT interference)
      we found a mean dual task gait speed of 0.766 m/s and SD=0.21. Based on these figures we
      estimated that the total sample size would be N=108 (54 per centre). Incorporating a loss to
      follow-up of about 5% brings the final figure up to 60 patients per centre to be recruited
      over a period of two years (N=120).

      Intervention:

      Integrated dual task training will be conducted at home by a physiotherapist, especially
      trained in the intervention. It will consist of gait training (straight-line gait, turning
      and manoeuvring round the house) while using a standardised cognitive exercise protocol with
      an MP3 player. To address the correct level of learning, the levels of task complexity will
      be matched to the patient's baseline characteristics, considering the following components:
      baseline DT interference, previous fall risk and presence of FOG. Given the cognitive
      deterioration in PD, implying a reduced learning capacity, a fixed priority training
      (attention priority on both tasks) will be implemented, aimed to improve better and safe
      walking when distracted by other attention demands. Every session will also include training
      of a functional dual task, relevant for each patient. Progression of treatment will be
      standardized. Treatment will consist of 18 sessions over a period of 6 weeks. Homework will
      be conducted with the partner for safety reasons. Intervention will be additional to regular
      care (including physiotherapy). A follow-up period of 12 weeks without training will be used
      to test retention.

      Consecutive task training will be conducted at home by a physiotherapist. It will consist of
      traditional gait training(straight-line gait, turning and maneuvering). Patients will get
      separate training of cognitive tasks while sitting, using the same program via an MP3 player
      as described above. Every session will also include training of a functional task, relevant
      for each patient, but dual tasking will be positively discouraged. Functional training will
      thus consist of carrying out task components separately. Progression and intensity of
      treatment will be the same as IDT.

      Co-interventions:

      During the 6 weeks of IDT or CTT, all other interventions (medication, allied health care
      etc) will be kept as stable as possible. Any changes in treatment will be monitored.

      Subjects:

      Patients will be recruited by a movement disorders specialist at each medical center
      involved. The following clinical descriptive outcomes will be collected: Disease duration,
      Hoehn & Yahr stage, Unified Parkinson's Disease rating scale, New Freezing of Gait
      Questionnaire, Cognitive scores, Beck's Depression Index, and general gait performance (2
      minute walk test).

      Test procedure:

      Testing will be conducted by an independent therapist at each centre. Patients will be
      followed up over a period of 24 weeks in total. Four testing moments will be foreseen: 1) one
      baseline test at study entry and the second baseline tests after a 6 week control period
      without intervention; 2) one test after 6 weeks of training and 3) one test after 12 weeks
      follow-up without training. All spatiotemporal gait outcomes with and without DT will be
      measured during normal speed conditions and therefore will require transport of the patients
      to the gait laboratory. Clinical testing will also be conducted in this environment. Both
      centers use the same GAITRite Walkway System in their gait laboratory, which is considered to
      be the 'gold standard' instrumented system for measuring spatiotemporal gait parameters. The
      untrained secondary task will be an Auditory Stroop task delivered by a wireless headphone. A
      microphone will record the verbal responses of the patients, allowing detailed measurement of
      the reaction times of patients' responses. This system is currently used in one of the
      centers (Katholieke universiteit Leuven). Secondary task performance will be measured during
      sitting as well as walking.

      Tests:

        1. DT gait performance will be evaluated by measuring gait speed while performing the
           untrained cognitive task, i.e. the Auditory Stroop.

        2. Safety will be assessed by determining fall rate ascertained by a weekly telephone call.

        3. We will also test cognitive performance during a trained dual task (Digit Span Backward)
           and during a functional task (using a mobile phone). At baseline, the appropriate level
           of cognitive challenge for each patient will be determined. We will measure gait and
           secondary task performance separately and calculate dual task interference outcomes.

      Other outcomes will be

        -  Single task gait performance: speed, stride length and cadence;

        -  Single task cognitive performance (during sitting);

        -  Activities-specific Balance Confidence scale (measure of function);

        -  Tests of executive function and attention;

        -  Freezing of Gait Questionnaire

        -  ADL scale

        -  PDQ39 Quality of LIfe scale
    

Intervention name(s): physical therapy
Intervention type(s): Behavioral
Intervention description(s): Physical therapy consisting of gait training 3 times a week for 6 weeks
Other intervention name(s): Exercise
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Keywords: Parkinson's disease; Gait; Rehabilitation; Cognition; Freezing of gait