Interventions incorporating physical and cognitive elements to reduce falls risk in cognitively impaired older adults: a systematic review protocol

Review question/objective The objective of this review is to identify the effectiveness of combined cognitive and physical interventions on the risk of falls in cognitively impaired older adults. Background Mild cognitive impairment (MCI) has been defined as “cognitive decline greater than that expected for an individual's age and education level but that does not interfere notably with activities of daily life”.1(p1262) Characteristics include problems with memory, planning, attention and visuospatial skills.2 Mild cognitive impairment affects between 3–19% of adults aged over 65 years.3 An estimated 15% of these go on to develop dementia every year3, although a high risk of progression has only been correlated with MCI patients with specific memory deficits. By 2025 there will be over a one million people in the UK with dementia2 and by 2050 an estimated 135 million worldwide.4 Cognitive impairment is a risk factor for falls.5 Prevalence of falls in the UK is comparable to that in other developed countries, with approximately one third of adults over 65 having experienced a fall.6,7 Older adults with a cognitive impairment (such as dementia) have an increased risk of falling compared with age matched individuals without a cognitive impairment, equating to a 70–80% chance of falling within a year.8 The economic impact on health services from the falls experienced by these individuals and the carers and families of older adults is considerable.9,10 In the 12 months following a fall, health and social care costs within the UK can increase by as much as four times.11 Estimates for the total cost of health care resulting from fall related injuries varies across the world, with figures ranging from AUS$558.5 million in New South Wales, Australia,7 to US$34 billion in the United States.12 Consequently, it is important to promote fall prevention initiatives within health services. Within the UK, the National Institute for Health and Care Excellence (NICE) provides clinical recommendations for falls prevention programs to incorporate multifactorial assessment and interventions, including strength and balance retraining, home hazard assessment and modification, vision assessment and referral, and medication review with modification/withdrawal.13 Multifactorial interventions target multiple risk factors for falls (i.e. reduced muscle strength, reduced visual acuity, poor proprioception, multiple medications, etc.).5 Current evidence on programs specifically aimed at cognitively impaired patients is sparse and requires further development.14–16 With many studies excluding participants with reduced cognition in order to produce a homogenous sample and limit attrition, clinicians have little evidence to draw on in practice. It has been suggested that, even in adults with no cognitive impairment, cognitive function should be addressed in falls rehabilitation.17 Exercise has been demonstrated to improve physical18 and cognitive19 function in dementia populations. However, the effectiveness of exercise in preventing falls in a dementia population is conflicting.20 Initially only limited effectiveness of physical training in older adults with cognitive impairment was reported.20 This has since been updated with a review in 2014 reporting significant reduction in falls following exercise interventions.14 However, both of these reviews included similar numbers of papers, indicating that further research has not been published in this patient population. Falls frequently occur during walking or transferring.5 Gait is controlled by a complex neuronal network of ascending information, cortical involvement and descending control.21 It has been demonstrated that adults with executive dysfunction have an altered gait patter and are more at risk of falling.22,23 Executive function refers to cognitive processes that orchestrate goal-directed activities and is involved in allocating attention in competing tasks.24 Activities such as walking whilst talking or performing another dual task involve executive function. To improve gait in this population, interventions could theoretically target and train both physical and cognitive ability. Combined interventions (dual task training and specific medications) have demonstrated positive results at improving executive function.25,26 Training the ability to maintain gait during multiple tasks is a viable theory to reduce the rate of falls in a population with cognitive impairment.17,27 Repetition and practice of cognitive tasks combined with physical training could improve the efficiency of allocating attention during a task such as walking and talking.27 Initial reports of animal studies have documented the neural benefits of combined physical and cognitive interventions.28 Theoretically, combining physical and cognitive exercises enables benefits to be gained from both interventions.27 It is these dual and combined interventions (i.e. exercise or physical activity, and cognitive rehabilitation or training) which this review aims to capture. This review is timely because standard falls interventions applied to people with cognitive impairment simply do not reduce falls.8 Combining and addressing cognitive components in standard falls rehabilitation programs is a novel and emerging area of health evidence. Literature is potentially widely published and difficult to identify due to the heterogeneity of search terms. A systematic search and synthesis of literature on combined cognitive and physical retraining in cognitively impaired populations in relation to falls has not been undertaken before. There has been a recent increase in the number of published studies investigating dual tasks or combined physical and cognitive interventions.29,30 Previous systematic reviews have focused on only older persons15,31, cognitive outcomes32,33, or physical function.27,34,35 At present no other systematic review has been undertaken to explore this combined intervention approach, in only older adults with cognitive impairment, regarding fall outcomes. This review will contribute towards increasing understanding of previous cognitive and physical retraining concepts within the literature, providing a coherent direction for developing interventions to address areas of deficit in cognitively impaired individuals which may reduce their risk of falling. Inclusion criteria Types of participants Older persons who are 65 years or older will be included. Studies where the majority of participants have been indicated through mean ages and standard deviations will also be eligible for inclusion. Participants who have been diagnosed or identified as having a cognitive impairment will be included in this review. The participants will be characterized as having a cognitive impairment through: 1. Diagnosis of a dementia or cognitive impairment or other condition which directly results in reduced cognition. 2. Reduced Mini Mental State Examination (MMSE) or other such global assessment of cognition, e.g. through the Montreal Cognitive Assessment (MoCA). Participants will not be limited by dementia diagnosis (i.e. Alzheimer's disease, vascular, mild cognitive impairment), but their cognitive impairment must be acquired and progressive in nature. Studies with a population of older adults with an increased risk of falls will be considered but will only be included if more than 75% of the total sample has reduced cognition identified in the criteria above. Types of intervention(s)/phenomena of interest This review will consider publications that describe multifactorial or multiple interventions where a physical and cognitive element has been noted by the authors or reviewers. It is the aim of this review to capture studies which have a combined physical and cognitive element in the intervention; however studies which have separate physical and cognitive components, or where the components have been specifically approached or tailored to the individual's cognitive level or impairment, will be included. Studies will only be included if this intent has been explicitly described as a quality of the intervention or by the reviewer's expert experience and opinion. Any physical intervention with the aim to reduce the number or risk of falls will be included, such as, but not limited to, exercise, physiotherapy, activity and fitness components. This review will include cognitive interventions, such as, but not limited to, dual task training, cognitive rehabilitation, memory tasks and verbal tasks. Delivery of the intervention will not limit inclusion of relevant studies into this review. Examples of delivery method include: group, 1:1, or technology assisted (telephone, email and internet). Types of outcomes Studies will only be included in this review if an outcome measure related to falls risk is used. The outcome measures must be measured before and after the investigated intervention. Outcome measures related to falls risk may include: specific falls risk measures (i.e. Physiological Profile Assessment), history and or details of occurrence of falls (i.e. falls diaries), reliable clinical outcome measures (i.e. Timed Up and Go test, Berg Balance Scale, gait speed), or clinical measures which relate to incidence or risk of falls (i.e. postural sway, gait parameters). Outcome measures related to falls (as stated above) will be included only if the studies state that the intervention is aiming to reduce falls. Types of studies This review will consider randomized control trials (RCT), controlled clinical trials, and experimental studies where randomization has been used. In the absence of these methods, comparative studies without randomization, cohort and case control studies will be considered for inclusion. Studies will only be included if they have repeated measures and compare an intervention against standard or no treatment. Search strategy The search strategy aims to find both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of MEDLINE and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases. The databases to be searched include: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, latest issue), the JBI Database of Systematic Reviews and Implementation Reports (JBISRIR), MEDLINE (1950 to present), EMBASE (1980 to present), AMED (1985 to present), CINAHL (1982 to present) and PsychINFO. Thirdly, the reference list of all identified reports and articles will be searched for additional studies. The search for unpublished studies will include an electronic search of trials registers: Current Controlled Trials (http://www.controlled-trials.com) and the National Institute of Health Clinical Trials Database (http://www.clinicaltrials.gov). Initial keywords to be used will be: dementia, cognitive impairment, memory loss, exercise, rehabilitation, and accidental falls. Assessment of methodological quality Papers selected for retrieval will be assessed by two independent reviewers (VB and VH) for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistical Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion with a third reviewer (FK). Data extraction Quantitative data will be extracted from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and objectives. Data synthesis Quantitative papers will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as odds ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard Chi-square. Where statistical pooling is not possible the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate. Subgroup analysis according to level of cognitive impairment and patient population will be conducted where possible. Cognitive impairment is not homogenous and it is anticipated that treatment suitability and effectiveness will vary depending on severity of cognitive impairment. Therefore completing sub-group analysis of this nature will provide information on the treatment's effectiveness dependent upon level of cognitive impairment and will assist in directing clinical recommendations. Participants will be divided into mild moderate and severe groups using validated cut-offs for the cognitive test utilized in assessment (i.e. MMSE, MOCA). For example, cognitive impairment levels are defined by MMSE scores: mild = 21–26, moderate = 11–20, and severe = <10.26 Underlying diagnosis of sample population will be used to categorize studies and pool results of similar conditions resulting in cognitive impairment. These categories will include: mild cognitive impairment and the different types of dementia (i.e. Alzheimer's disease, vascular dementia). Conflicts of interest The authors declare that there is no conflict of interest. Acknowledgements The authors would like to thank Fiona Bath-Hextall and the University of Nottingham Centre of Evidence Based Health Care: a Collaborating Centre of The Joanna Briggs Institute for their support with this review. The primary author (VB) is funded through the Alzheimer's Society on a Clinical Training Fellowship. This review contributes to a larger study of falls risk and balance in older adults with mild cognitive impairment at the University of Nottingham and Nottingham University Hospitals NHS Trust.