Falls in Parkinson’s Disease: A Complex and Evolving Picture
Fasano, A., Canning, C., Hausdorff, J., Lord, S., Rochester, L. 2017. Falls in Parkinson’s disease: A Complex and Evolving Picture. Movement Disorders, 32(11):1524-1536
Falls are a major determinant of reduced quality of life, reduced mobility, and reduced life expectancy in individuals with PD. Despite these factors, there is limited research on methods for anticipating and preventing falls. This article has gathered the available knowledge on fall risk factors, assessment of fall risk, prevention, and treatment.
Understanding Fall Risk (Who falls and why?)
Contrary to previous knowledge, falls happen across age groups for those who have PD. In fact, a recent study indicated a history of at least one (and often more) fall among PD patients younger than 50 years. Further, the single strongest predictor of a fall is a history of previous falls.
Approximately 70% of falls in PD patients occur as a result of actions such as turning, incorrect weight shifting, and inaccurate stepping, in addition to freezing of gait (FOG).
The Falls Task Force has identified PD-specific fall risk factors, which include:
- Cognitive (particularly executive functioning and/or attentional) impairment
- Disease severity
- Dual tasking
- Dyskinesias (impaired involuntary movement)
- Fall history
- Freezing of gait and festination
- Functional neurosurgery (i.e., DBS, STN)
- Higher total doses of levodopa
- Use of dopamine agonists and anticholinergics
- Postural abnormalities
- Postural instability
- Shuffling and short stride when walking
- Slow mobility
- Urinary incontinence
Due to the fact that one of the strongest predictors of future falls is previous falls, the quickest, easiest and most straightforward way for a clinician to assess fall risk is to ask patients if they have fallen in the last month. This has become relatively standard practice among providers who care for individuals with PD.
It is important to keep in mind, when assessing fall risk and fall factors, that all falls are not the same. When assessing falls, it is important to characterize the 3 Cs of falls:
Below are some of the existing and developing methods for assessing these factors.
Performance based tests of balance, gait, and mobility, such as:
- The Berg Balance Scale- focuses on static balance (i.e., standing)
- The Dynamic Gait Index -measures walking during challenging conditions such as stepping over an obstacle
- The Timed Up and Go (TUG)- quick in-vivo assessment in which a clinician measures the time it takes individuals to stand up, walk 3 meters, turn around and sit back down
- The Balance Evaluation Systems Test (BEST)- incorporates clinical components of the above 3 scales into a single test battery and has accurately predicted falls in PD patients during a 6-month period in a relatively recent study.
- Identifies specific targets for physical therapy and fall prevention.
- Body fixed sensors or inertial measurement units– small, lightweight and low cost devices that quantitatively assess gait features. This information is then used to assess fall risk (even among individuals who have never fallen before)
- One advantage is that they can be used to assess gait, balance and fall risk at home and when out in public, which is where falls typically occur.
- Preliminary research based on body fixed sensors has taught us that time of day and medication intake impact fall risk differentially throughout the day.
- Embedded home sensors– motion picture caption devices that can assess factors such as gait speed every time an individual passes through a hallway.
- These sensors can be mounted on keyboards, appliances, and pillboxes.
- The information can then be uploaded to an app and passed on to caregivers and clinicians and synchronized with other information to help with fall risk management.
- Wi-Fi technology- can assess someone’s location within their home, along with his or her posture and breathing to help characterize the nature and circumstances of any falls.
Preventing Falls: Current Evidence
Exercise Based Interventions:
The most recent research on the relationship between falls and exercise shows that benefits are observed immediately after exercise- based interventions at preventing falls and at follow up.
- Trials that have compared exercise to no exercise interventions showed reductions in fall rate for the exercise group when compared to the control group.
- The types of exercise studied in such trials include Tai Chi as well as other pragmatic, minimally supervised, home based strength and balance exercise programs intended to improve muscle strength and movement strategies.
- It is important to note that there are significant interaction effects, with those individuals with lower disease severity showing a decrease in falls, while those with higher disease severity tended to show an increase in falls.
- The take away: minimally supervised exercise programs targeting physical fall risk factors (reduced balance, reduced leg muscle strength, and FOG) are effective and beneficial for those with lower disease severity.
Another study looked at a supervised virtual reality (VR) intervention combined with treadmill walking (with an overhead harness for safety).
- Individuals were introduced to motor and cognitive challenges while walking on the treadmill (such as puddles and obstacles to step over as well as distractors and requirements to plan and execute a route in the virtual environment).
- At 6 month follow up, individuals who had received the VR intervention showed a 55% reduction in falls and fall risk when compared to a control group that did treadmill walking alone .
- One trial has shown that an acetyl cholinesterase inhibitor (i.e., rivastigmine 3-12 mg/day) delivered over 32 weeks significantly reduced falls in PD fallers by 45% when compared with a placebo group
- This was attributed to improved sleep variability and gait speed along with improved balance. No impact was found on FOG, cognition, or executive function.
- A second trial targeted individuals with PD who had signs and symptoms of orthostatic hypotension (i.e., lightheadedness when moving from sitting to standing)
- Showed that a prodrug of norepinephrine (droxidopa 300-1800 mg/day) delivered over 10 weeks resulted in 0.4 falls/week compared to 1.05 falls/week in the placebo group.
- The reduction in falls was attributed to decreased lightheadedness in the first week of treatment.
- A recent review shows that reactive step training reduced rate of falls in the general older population.
- In this study, an overhead harness was used for safety while individuals walked on treadmills and practiced navigating abrupt changes in speed or tripping obstacles.
- There is preliminary evidence that VR combined with treadmill training has positive benefits in improving motor-cognitive processes (i.e., navigating tricky situations that arise while walking) and thus reducing fall risk.
- There is clear evidence that exercise improves two key risk factors for falls: poor balance and decreased mobility.
- Exercise does not increase the overall risk of falls and exercise interventions delivered early in the PD disease process are effective in reducing falls.
- Minimally supervised exercise programs with a focus on challenging balance and attention are recommended, not only to prevent falls but also to maintain optimum mobility and enhance any possible neuroprotective effects of exercise. As disease severity and risk increases, then more highly supervised exercise is recommended.
- There is an urgent need for studies examining the effect of environmental modifications on falls in PD.
- Given the role of impulsiveness as a risk factor for falls in individuals with PD, it is important for future research to explore psychological/behavioral modification interventions aimed managing the relationship between high-risk activities and falls.