This chapter details the PDSAFE intervention and its delivery. Background information is provided to support the conceptual development of the intervention, the protocol is presented using the TIDieR (Template for Intervention Description and Replication)41 and descriptive statistics demonstrate the content of the intervention delivered over the intervention period.
Background for intervention design
A role for exercise in the treatment of both the physical and cognitive/behavioural symptoms of Parkinson’s has been advocated and is supported by the European Physiotherapy Guidelines for Parkinson’s Disease.42 In reviewing 70 clinical trials, the guidelines suggest that there is strong evidence that specific physiotherapy interventions help to improve transfers, balance, gait, physical capacity and movement functions,42 all isolated falls risk factors. A recent Cochrane review43 stated that the overall aim of physiotherapy intervention is to optimise independence, safety and well-being, thereby enhancing quality of life; however, the intervention that is most effective at achieving this remains unclear.
Evidence suggests that a multidimensional intervention to reduce falls, incorporating balance, functional strength and strategy training, and thus appreciating the need for motor, cognitive and behavioural training, may be more effective than interventions focusing on independent risk factors such as postural control and/or functional strength alone.19
The PDSAFE intervention is delivered in the home, tailored to an individual’s specific falls mechanism and functional presentation and personalised to rehabilitate the primary strategy or strategies that contributed to the fall(s) (). Not only does this allow the protocol to align with all components of the International Classification of Functioning, Disability and Health (ICF)44 as a person-centred approach, it also follows the consensus-based clinical practice recommendations for falls management in Parkinson’s.45 From this, personalised exercise prescription, within a menu of exercises, allows an individualised programme to be designed specific to the falls-related risk factors (impairments) that contribute to the primary ‘problematic’ strategy (as recommended by the European Physiotherapy Guidelines for Parkinson’s Disease42). The specific ‘impairment’ training enables physiological improvements in Parkinson’s symptoms and deficits, which allow functional training and strategy task practice in everyday life (see ). In this way, the rehabilitation of the falls-related strategy and its contributing falls risk factors not only works towards reducing the risk of similar falls again, but also embeds the training in everyday function and, therefore, is more likely to have a greater overall effect across all components of a participant’s life (and, thus, full ICF model).
Conceptual model of the PDSAFE falls prevention protocol intervention.
Intensity is maintained across all aspects of the frequency, intensity, time and type (FITT) principle (as published in the American College of Sports Medicine guidelines)46 to drive physiological adaptation. ‘Frequency’ is regulated to a minimum of three times per week, ‘intensity’ must be perceived as ‘moderately hard/hard’ for all activities of the programme, ‘time’ is set to a maximum of 60 minutes and ‘type’ of exercise is tailored and specific to each individual’s falls mechanism. With the consideration of all factors, it is therefore possible to design a multidimensional programme that does not lose intensity as a result of its many components. In addition, the high intensity, continuous progression and titrated support from intensive to independent practice maintains focus and adherence and encourages personal commitment and investment, as well as fostering an understanding and empowerment of the rehabilitation process for the individual. The addition of visual feedback both in therapy time and as a review through personalised DVDs also aids accurate independent practice and continuation of therapy. Thus, continuous progress and adaption to the neurodegenerative properties of the condition can be made to maintain safety.
In appreciation of the mechanisms of neurorehabilitation and exercise prescription, the PDSAFE intervention protocol is structured in a way that enables intensive, repetitive practice that is salient to an individual and their specific falls profile, thus meeting their needs for effective neuroplastic change. In addition, the embedding of the training in strategy task-related practice across all functional activities enables rehabilitation to take place across all levels of life participation and not just in relation to a specific task, goal or previous fall behaviour.
As a result of its unique structure and delivery, the PDSAFE intervention (see ) reflects the evidence base for falls prevention in Parkinson’s, meets the holistic recommendations of the ICF framework for practice and facilitates onward progression and independent self-management of the condition by the individual. The novelty lies in both the content (disease-specific exercises and strategies for instability, use of motor relearning and cognitive awareness) and delivery (personalised feedback using a DVD for adherence and self-management).
Intervention protocol
In line with the recommended methods of reporting intervention design, TIDieR41 is detailed in . The 12 items detailed in the checklist are an extension of the Consolidated Standards of Reporting Trials (CONSORT) 2010 statement – item 547 and the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 statement – item 1148 and are intended to improve the reporting of interventions.
The PDSAFE protocol description, as per TIDieR guidelines
For a visual representation of the intervention, please refer to the film available at: www.youtube.com/watch?v=emNr0REIm4A&list=PLT3AipgP4l_x7OVNryanVgtcvPZXVJyX1 (accessed 21 February 2019).
Delivery outcomes
Delivery of the PDSAFE intervention was over 2 years and 4 months. The intervention was delivered in a total of eight clinical sites across nine NHS trusts.
Therapists
Physiotherapists were recruited by each site. Trial requirements stated that each therapist should have experience in Parkinson’s or falls rehabilitation. It was initially designed that each site would have one treating therapist and a trained cover for periods of absence. However, owing to clinical workload and logistical delivery, a total of 18 therapists were trained over the study period. One lead therapist co-ordinated the team, delivered the training and development activities, and monitored the fidelity of intervention delivery.
Training, facilitated by the lead therapist, included attendance at one of the compulsory 2-day training events held on three separate occasions. In addition, therapists were asked to attend a virtual weekly meeting by telephone to discuss clinical cases and problem-solve within the boundaries of the intervention protocol. These sessions were chaired by the lead therapist, with a total of 122 telephone contacts made available over the intervention period. To maintain a high standard of clinical reasoning throughout the intervention period, therapists were also asked to attend (either physically or virtually) monthly ‘masterclasses’ on key clinical topics such as cognition and dual tasking, turning, FoG and balance. Alternating with masterclasses, therapists were asked to present case studies on key topics for team discussion. Twelve ‘masterclass’ topics (some were repeated for new therapists) and seven case study reviews were held over the intervention period.
Fidelity of the intervention was a priority to encourage uniformity of practice. The lead therapist observed each therapist in a treatment session with a participant, once a month for the first 3 months of delivery and then once every 3 months for the delivery period. Following the observation, a clinical reasoning discussion was completed and a report written. Therapists could also request additional joint sessions with the lead therapist if they had concerns or queries regarding a particular participant. This ensured that the PDSAFE intervention was uniformly delivered across all sites and by all therapists. A total of 75 fidelity sessions were held over the intervention period, with all therapists being assessed.
Intervention sessions
A total of 2587 sessions were delivered to the 291 intervention participants, with the majority of participants receiving the anticipated 12 sessions (mode = 12).
presents the total number of sessions received by participants allocated to the intervention arm of the trial. The majority of participants, 236 out of 238, received the exercise assessment and at least one supervised session. Two participants did not start because they had changed their mind and 19 received fewer than seven sessions; reasons for not fully engaging included admission to a nursing home, deteriorating health, commitment was too much and caring for others; in some cases, no reason was given.
Total number of intervention sessions received by participants.
All interventions sessions included a brief review of falls; warm-up exercises; review, practice and progression of a participant’s individual exercise programme; and strategy training in functional scenarios as a basic structure. Each therapist tailored the strategies treated, exercises prescribed and functional tasks practised from a menu for each participant.
Selection of strategies
Evidence from the literature and from previous studies of falls among patients with Parkinson’s, as well as expert opinion, were used to determine the most frequent falls mechanisms in Parkinson’s.19 Eight strategies were defined: avoiding tripping, dual tasking, freezing cues, moving in tight spaces, picking up an object, reaching, stepping backwards and turning. As described above, through the process of taking a detailed falls history, clinical assessment and advanced clinical reasoning, therapists determined the most likely ‘fall mechanism’ for each participant (levels 1 and 2 in ). For example, in the case of a participant who repeatedly reported catching their foot and falling, regardless of the task being undertaken or location, would be most likely to have a falls mechanism of tripping; thus, the strategy ‘avoiding tripping’ would be selected by the therapist.
Over the 291 participants who received the PDSAFE intervention, strategies were selected a total of 440 times, with a strategy being used in treatment a total of 3447 times over the period. This provides a large sample to consider the clinical reasoning process of the therapists selecting the strategies. demonstrates the number of times each strategy was selected as a potential falls mechanism corresponding to the number of times that strategy was used in a treatment session.
Stratification of strategies used in delivery of PDSAFE intervention.
Importantly, this allows description of the strategies selected as primary falls mechanisms and thus treated for the majority of the intervention period versus strategies that may have been selected as a secondary or subsequent strategy and thus treated less frequently or for a shorter period of time.
It is apparent that ‘avoiding tripping’ was the most widely used strategy. It was selected following assessment a total of 116 times, used 1110 times during treatment sessions and accounted for 26% of all strategies selected. The figures for ‘turning’ are similar [selected 107 times and used 938 times during treatment (26% of the total)]. ‘Freezing cues’ was also frequently selected as a strategy [selected 79 times and used 365 times (24% of the total)]. It is clear from that all other strategies were selected and used in treatment with similar frequencies to each other.
Selection of exercise prescription
Once the strategy or strategies most appropriate for addressing a participant’s falls mechanism had been selected, therapists used advanced clinical reasoning and assessment skills to determine the physical impairments and deficits in physical falls risk factors that were most likely to contribute to the fall mechanism (see ). For example, the participant described above, who frequently caught their foot and subsequently fell, was allocated the ‘avoiding tripping’ strategy. The therapist must consider a number of reasons why the participant has a tendency to catch their foot, such as weakness of the muscles used to lift the toes, failure to transfer weight onto the supporting leg appropriately because of hip weakness or reduced limits of postural control stability, or failure to achieve enough clearance from the ground because of weakness in the hip flexors. Through assessment, the therapist determines the most likely impairment and designs a functional strength and postural control exercise programme from the available menu that treats this impairment.
Evidence from the literature and from previous studies of falls among patients with Parkinson’s, as well as expert opinion, were used to determine what exercises were available on the menu for therapists to select from.19
shows the menu of exercises available for the therapist to select from when putting together an individual participant’s PDSAFE intervention.
Exercise menu for the PDSAFE intervention
Exercises were available on six levels; working through the levels enabled progression (level 4 in ) and maintenance of intensity for each exercise. All programmes had to include at least one balance and one strengthening exercise. A total of 1693 exercises were selected by all therapists over the intervention period with an average of six (range one to eight) exercises prescribed per participant across the period. shows a spread of all exercises being used over the intervention period.
Exercise use frequency across all of the intervention, in all participants.
demonstrates the predominance of the more dynamic postural control (compensatory step and lunge and heel/toe walking) and strengthening exercises over other exercises from the menu. The complex nature of the compensatory step and lunge exercise makes it suitable for the treatment of many of the falls risk factors associated with Parkinson’s; for example, high dynamic stepping actions help with motor control, compensatory stepping helps with the regain of an appropriate base of support from a loss of postural control or a trip by increasing stepping amplitude for those who freeze and expanding limits of stability for those who fall when reaching. The practice of stepping backwards with appropriate postural control and weight distribution will assist those who fall stepping backwards. A common symptom of the Parkinsonian gait is loss of foot clearance, heel strike and step length45 (hence the predominance of tripping as a falls mechanism); thus, the high frequency of the use of heel/toe walking to improve these impairments is also unsurprising. As each exercise programme had to include both strengthening and postural control exercises, the high frequency of selection of strengthening exercises can be attributed to the fact that the postural control menu contained fewer exercises that could be selected. This is less of a clinical reasoning observation and more related to the ratio of exercises in the menu.
Summary
The PDSAFE intervention was deeply rooted in evidence from both rehabilitation after falls and exercise prescription literature. The protocol was a holistic model encompassing all aspects of the ICF and its design allowed a personalised, sophisticated, complex intervention to be prescribed for each participant. ‘Personalised’, ‘intensive’ and ‘progressive’ were key parameters of the intervention, demanding a high level of commitment and collaboration between the therapist and the participant. The intervention was delivered to a high standard. All requirements of fidelity were met and the intervention was comparable across all sites. Delivery was significantly enhanced by the level of training and support provided to the delivery team and a high standard of clinical reasoning and protocol delivery was maintained. The majority of participants received the planned number of sessions. There was a slight rise in the number of participants receiving only seven or eight sessions as this is the point at which the therapists visited less frequently and participants were required to complete longer periods of independent practice. It is likely that this led to some participants withdrawing at this point because of the reduced support/motivation from the therapist. There was a clear predominance of some strategies, which is likely to reflect the demographic of the intervention group (i.e. more frequent fallers and people with Parkinson’s who freeze, plus those who have more advanced disease and thus are more likely to have difficulty turning: with axial rigidity, poor stepping and impaired cognition). The predominance of ‘avoiding tripping’, ‘turning’ and ‘freezing cues’ is in line with the reasons for falling provided by participants most frequently in the previous literature.26 The design of strategy selection leading to supported exercises to treat falls risk factors provided a protocol design that was deliverable, with all participants receiving both strategies and exercises as planned. Owing to the complexity of the exercises, some exercises are better able to be adapted for multiple impairments and thus are used more frequently. Previous studies19 have provided the same intervention for all participants, regardless of fall mechanism. The use of all the strategies and exercises demonstrates the need for a complex intervention and variability as ‘one size, clearly does not fit all’.
