Parkinson's Disease: Moving ForwardPage 8 of 17

6. Fall Risk and Tests of Balance

It is not surprising that falls are common in those with Parkinson’s disease nor that injuries from falls are the most common reason for hospital admission. The estimated prevalence of falls in those with PD ranges from 40% to 90%, with about half of those falls occurring when walking (Kelly et al., 2012).

There are many significant consequences associated with falling, including fractures (particularly hip fractures), head trauma, head injuries, and even death. Falling may also cause fear of new falls, which can in turn reduce mobility and lead to osteoporosis, loss of independence, social isolation, and depression (Contreras & Grandas, 2012).

Because falls are associated with such serious complications for people with PD, healthcare providers should be familiar with practical and accurate measures for assessing and predicting falls as well as with interventions to decrease future falls (Duncan & Earhart, 2012). This is particularly important because numerous studies have shown that a wide range of healthcare providers are reluctant to incorporate fall prevention into their practice (Tinetti et al., 2008). In an attempt to discern why, Mary Tinetti and her colleagues at the Connecticut Collaboration for Fall Prevention surveyed healthcare providers near Yale University. The respondents (physical and occupational therapists, emergency department physicians and nurse managers, and primary and home care providers) gave the following reasons:

  • Ignorance of falling as a preventable condition
  • Competing time demands
  • Perceived lack of expertise
  • Insufficient reimbursement
  • Inadequate referral patterns among clinicians (Tinetti et. al., 2008)

The Tinetti researchers recommended evidence-based fall prevention strategies to the healthcare providers that included a reduction in medications, management of postural hypotension, management of visual and foot problems, hazard reduction, and balance, gait, and strength training. Healthcare providers were encouraged to incorporate assessments, treatments, and referrals into their practice, as appropriate to their discipline and setting. Following these interventions, a 9% decrease in fall-related injuries and an 11% decrease in fall-related use of medical services were noted in the intervention group (Tinetti et al., 2008).

Risk of Falls in Those with PD

Preventing falls is one of the most important unmet needs in PD, and strategies to prevent falls should focus on those at high risk for falling. A risk factor is something that increases a person’s risk or susceptibility for falling. The presence of one or more risk factors should prompt a referral to a healthcare provider familiar with assessment and treatment of balance disorders and to a physician or nurse practitioner familiar with medications that increase the risk of falling. Increased risk of falling is closely associated with certain pre-existing conditions, and fall risk increases proportional to the number of pre-existing conditions.

In fall intervention studies focusing on older adults, age and history of falls are the two risk factors most commonly used to define high risk. Also considered are gender, impaired balance and gait, visual impairment, and use of multiple medications or medications known to increase fall risk (Moyer, 2012). Musculoskeletal problems, neurologic diseases, psychosocial characteristics, functional dependency, and drug and alcohol abuse all contribute to an increased risk of falling (Baranzini et al., 2009).

For people with Parkinson’s disease, there are risk factors specific to PD. These include changes in posture, postural instability, freezing of gait, dyskinesias, gait changes, medication side effects, and decreased ability to react automatically to a loss of balance. Health and cognitive factors such as cognitive decline and depression can also greatly increase the risk of falling.

A Spanish study of 160 people with Parkinson’s disease who were being seen at a movement disorders clinic in Madrid found that fallers were older and had longer disease duration. They also had increased disease severity according to the UPDRS (part III) and the Hoehn and Yahr scale, and lower scores on the Schwab and England ADL test. In addition, fallers scored worse in the Mini-Mental State Examination and experienced a higher frequency of motor fluctuations, dyskinesia, and freezing of gait (Contreras & Grandas, 2012).

Recurrent Falls

In the general population of elders, a fall is considered recurrent when it occurs more than once in a given time period (usually 12 months). Using this definition, about 15% of people in the general older population are classified as recurrent fallers. Among people with PD, recurrent falls are more frequent, with one study reporting that more than 50% of the study participants fell recurrently. In another study involving a survey of 100 people with PD, 13% reported falling more than once a week, with most of these people falling multiple times a day (Allen et al., 2013).

Several risk factors for falls have been found to be more strongly associated with recurrent falls than single falls. Some of these factors are potentially modifiable, including cognitive impairment, freezing of gait, fear of falling, reduced mobility, reduced physical activity, and balance impairments. There is substantial variability in the falling rates reported in various studies, with the proportion of fallers (single and recurrent) ranging from 35% to 95%. Differences in the method of monitoring falls could contribute to this variability (Allen et al., 2013).

Despite the fact that recurrent falls are a substantial problem for people with PD, the scope of, and risk factors for, recurrent falls in PD are not clearly understood. Improving our understanding of recurrent falls is the first step toward developing effective interventions designed to reduce and manage these falls (Allen et al., 2013).

Cognitive Decline and Fall Risk

Several studies have examined the role of specific cognitive domains on fall risk. Lower scores on cognitive screening tests. such as the Mini-Mental State Examination and the Montreal Cognitive Assessment, were associated with an increased risk of falls. Lower scores on tests of attention, executive function, memory, and visual-spatial function have all been reported to be associated with an increased risk of falls in both cognitively intact and cognitively impaired individuals (Buracchio et al., 2011).

Difficulty with dual-task walking, a measure of divided attention and executive function in which individuals are given a secondary mental task while walking, has consistently been shown to be associated with an increased risk of falls (Buracchio et al., 2011). Impaired cognition may cause these problems because of a limited ability to perform either task or because of problems associated with allocating attention efficiently between the two tasks (Shumway-Cook & Woollacott, 2012).

An Israeli study looked at executive function, attention, and other cognitive domains in 256 community-living older adults with an average age of 76 years. Participants were free of dementia and had good mobility upon entrance into the study. Baseline cognitive function was established using computerized cognitive tests. Gait was assessed during single and dual-task conditions. Falls data were collected prospectively, using monthly calendars. The researchers found that among community-living older adults, the risk for future falls was predicted by executive function and attention tests conducted 5 years earlier, indicating that screening executive function will likely enhance fall risk assessment, and that treatment of executive deficits may reduce fall risk (Mirelman et al., 2012).

Fear of Falling

Fear of falling (FOF) has emerged as an important health concern in all older adults given its demonstrated association with restrictions in daily activity and in many cases activity avoidance. The substantial body of literature that has emerged addresses prevalence, risk factors, and consequences. Reported prevalence of FOF in the general population of elders is as high as 85%. Identified risk factors include having had a previous fall, increasing age, female gender, dizziness, depression and anxiety, and balance and gait disorders. Documented consequences of FOF include a decline in physical and mental performance, activity avoidance, and a loss of health-related quality of life (Foran et al., 2013).

A consequence of FOF is an increased risk of falling and there is a likelihood of additional falls, given reported rates of 29% and 92% of FOF among recent fallers with previous falls. Studies suggest that FOF is a psychological experience resulting in reduced physical activity leading to poor balance, mobility impairment, and social isolation. Such consequences may lead to increased likelihood for falling in the future (Foran et al., 2013).

Fear of falling is a common and potentially serious problem in people with Parkinson’s disease. Studies have consistently reported that community-dwelling individuals with PD have a greater FOF than age-matched healthy subjects. The level of fear is further increased in those who have had a fall history. Fear of falling is also a significant risk factor for predicting future falls. While some level of FOF has a protective role against falls, irrational fear—either too much or too little—may increase fall risk. One recent study noted that only those with excessive FOF had a higher risk of injurious falls (Mak et al., 2012).

Repeated falls may lead to avoidance of activity, physical deconditioning, and increased institutionalization. Therefore, interventions aiming to enhance balance confidence have the potential to reduce fall risk in appropriately targeted individuals with PD (Mak et al., 2012).

Depression and Falls

Depression is common and treatable in older adults, and outcomes improve with effective antidepressant therapy, which could lead to a decrease in the morbidity associated with falls. Older people who fall are twice as likely to be depressed compared with those who do not fall (Kerse, 2008). However, antidepressant use can also increase the risk of falls, both for those in the community and in residential care (Kerse et al., 2008).

A cross-sectional survey of Australians aged 60 and over investigated the association between depressive symptoms, medication use, falls, and fall-related injury. Both depression and the treatment for depression were independently associated with an increased risk of falls. Selective serotonin reuptake inhibitor (SSRI) use was associated with the highest risk of falls and injurious falls of all psychotropic agents (Kerse et al., 2008).

Polypharmacy and Falls

Polypharmacy is the use of multiple medications at one time, including over-the-counter (OTC) medications, dietary supplements, and herbal remedies. Polypharmacy includes prescribing more medications than are clinically indicated, using inappropriate medications, and using the correct medication for an inappropriate length of time. Polypharmacy is regarded as an important risk factor for falling, and several studies and meta-analyses have shown an increased fall risk in users of diuretics, type 1a anti-arrhythmics, digoxin, and psychotropic agents (Baranzini et al., 2009).

Due to concurrent prescription of several drugs, the risk of inappropriate drug combinations is increased in older adults. In addition, medication metabolism is affected by age-related changes, which increase both drug half-life and drug free fraction. Co-existing illnesses can also interact with medications. For all these reasons, older adults are at higher risk of experiencing adverse drug effects (Berdot et al., 2009).

Medication management in those with Parkinson’s disease is complicated by the number and schedule of medications, which can change dramatically as the disease progresses. One strategy is to use alternate treatment strategies such as transdermal patches and intestinal gel formulations.

Predicting Falls in Those with PD

Despite the relatively high prevalence of falls in the PD population, accurate and useful methods for predicting an impending future fall, especially during the early stages of the disease, remain elusive. Fall history, a well-known fall risk factor among older adults, has limited utility as a solitary predictive indicator. Although a meta-analysis of prospective studies of falling in PD found that 57% of individuals who had a history of falls in the past year fell during a 3-month surveillance period, so did 21% of individuals with no history of falls (Duncan et al., 2012).

Of perhaps more concern, fall incidence alone does not help to identify underlying contributors to postural instability specific to PD. People with PD, for example, may demonstrate impairment in areas of movement control such as sensory integration, keeping their center of mass within their base of support, coordination of anticipatory postural control tasks, as well as medication side effects such as dyskinesias (Duncan et al., 2012).

Falling in the Previous Year

In a meta-analysis of studies of falling in those with PD, the best predictor of falling was experiencing two or more falls in the previous year. Fallers scored worse in the Balance and Gait subscales of the Tinetti functional test and were slower in the Timed Get-Up-And-Go test (discussed later). There were no statistically significant differences in gait velocity, step length, and cadence between fallers and non-fallers (Contreras & Grandas, 2012).

The independent variables most associated with falls were the Tinetti Balance score and Hoehn and Yahr staging. The Tinetti Balance test predicted falls in patients with 71% sensitivity and 79% specificity, and Hoehn and Yahr staging predicted falls with 77% sensitivity and 71% specificity. No differences were observed between fallers and non-fallers in other drug treatments, age at onset of PD, symptoms of orthostatic hypotension, and cerebrovascular disease (Contreras & Grandas, 2012).

Most PD fallers had scored at Hoehn and Yahr stage III, or more. The transition from stage II to III, with the emergence of postural instability, appears to play a crucial role in the appearance of falls and is related to increased disability in many gait-dependent activities. Fallers had longer disease duration and increased disease severity based on the UPDRS, Hoehn and Yahr, and Schwab-England activities of daily living scores, and more frequently experienced motor fluctuations and dyskinesia. For the same reasons, fallers were treated with higher doses of levodopa and more frequently used COMT inhibitors (Contreras & Grandas, 2012).

A meta-analysis, conducted by Pickering and colleagues, noted that the best predictor of falls in individuals with PD is a history of 2 or more falls in the previous 6 months. However, simply asking about fall history does not provide information about factors associated with the cause of the falls (Duncan & Earhart, 2012).

Factors such as postural instability, gait difficulty, and other facets of mobility are significantly associated with falls in people with PD. As such, it is imperative that rehabilitation clinicians employ assessments that test mobility-related constructs in an effort to detect deficits in mobility prior to a fall. Gaining information about future fall risk allows for the implementation of effective rehabilitation programs to reduce fall risk and possibly prevent falls in people with PD (Duncan & Earhart, 2012).

Screening for Falls

Screening is a method for detecting dysfunction before an individual would normally seek medical care. Screening tests are usually administered to individuals who are without current symptoms but who may be at high risk for certain adverse outcomes. The purpose of screening is early diagnosis and treatment. Screening tools that address fall risk have been developed for use in various populations, including hospitalized older adults, adults in residential care, and community-dwelling older people.

Screening is an effective tool for quickly identifying patients at high risk for falling; however, finding an agreed-upon definition for screening is fraught with problems. For example, if a patient is asked “Have you fallen in the last year?” and the answer is no, the screen leads nowhere, even in the case of an older adult patient who has real risk factors for falls. It is important to observe the patient and have a screening tool that is quick and easy but also provides guidance about fall risk.

A practical approach for screening high-risk persons is to ask and assess: ask about history of falls, frequency and circumstances of falls, and mobility problems, then assess using a quick test such as the Timed Up and Go (TUG) test. The TUG test is performed by observing the time it takes a person to rise from an armchair, walk 10 feet, turn, walk back, and sit down again. The average healthy adult older than 60 years can perform this task in less than 10 seconds (Moyer, 2012).

Using Balance Tests to Predict Falls

The ability to predict future falls has improved through use of assessments that include measurements of postural stability during static and dynamic tasks. However, these assessments have some limitations when used in a clinical setting. Balance assessment tools often require special training of the tester, who must make subjective ratings of participant’s performance. In addition, administration of balance assessments can be time consuming. Because of these limitations, there is a need for measures that are objective, quick, and easy to administer. Adopting a measure with these qualities for clinical use must be based on the knowledge that such a measure is equally as accurate as more involved measures at predicting falls in people with PD (Duncan & Earhart, 2012).

A study at the Washington University School of Medicine’s Movement Disorders Center sought to determine how well four commonly used balance tests predicted falls in community dwelling adults over the age of 40 who had idiopathic PD. Participants were evaluated at baseline utilizing four balance tests (Berg Balance Test, Functional Gait Assessment, BESTest, and Mini-BESTest). Participants were followed for 12 months, with fall incidence determined through a participant’s report at 6 months and 12 months. Individuals were considered fallers if they reported two or more falls over the surveillance period of interest (0–6 months or 0–12 months). Individuals were considered non-faller s if they reported 0 or 1 fall during the surveillance period (Duncan et al., 2012).

Data from the study confirmed that a shorter followup period (6 months) consistently produced more accurate predictions than a longer followup period (12 months). In addition, at the 6-month followup all of the balance assessments studied provided clinically useful predictive accuracy. Comparisons suggested that the BESTest produced the greatest predictive accuracy. However, it is unclear whether the differences between the BESTest and the other balance measures are sufficiently large to merit use of one test over another in a clinical setting (Duncan et al., 2012).

Clinical Tests of Balance

A number of clinical tests are available for testing balance in patients with Parkinson’s disease. The Berg Balance Scale, the BESTest, the Tinetti Test, and the Timed Up and Go (TUG) are commonly used in hospitals and long-term care settings. The Pull Test, part of the UPDRS, is also used to test postural reactions in those with PD.

The Berg Balance Scale (BBS)

One of the most commonly used clinical tests of balance in people with PD is the Berg Balance Scale. The BBS, originally designed for use in the frail elderly, is a 14-item test that focuses on a variety of self-initiated tasks related to everyday function, such as sit-to-stand and functional forward reach. The Berg does not include tests of postural reactions or dynamic gait.

The Berg has excellent reliability and is somewhat correlated with severity of PD, as measured with the Unified Parkinson’s Disease Rating Scale. However, the Berg is not necessarily a good predictor of falls in those with neurologic impairment (Shumway-Cook & Woollacott, 2012). These particular limitations are important considerations when evaluating patients with mild neurologic deficits, who are easy to under-identify and therefore less likely to receive rehabilitation (King et al., 2012).

The Berg Balance Scale includes the following activities:

  • Sit to stand
  • Stand unsupported
  • Sit unsupported
  • Stand to sit
  • Transfers
  • Stand with eyes closed
  • Stand with feet together
  • Reach with outstretched arm
  • Retrieve object from floor
  • Turn to look behind
  • Turn 360 degrees
  • Alternate stepping on stool
  • Standing with one foot in front of the other
  • Standing on one foot

The BESTest

Documented limitations of the Berg have led many clinicians to do more than one validated balance assessment in order to identify deficits that may respond to treatment. A more comprehensive clinical balance test, the Balance Evaluation Systems Test (BESTest), is essentially a battery of balance and mobility tests borrowed from other validated tests such as the Berg and Dynamic Gait Index. The BESTest is a comprehensive clinical tool for evaluating six different balance control systems:

  • Biomechanical
  • Stability limits/verticality
  • Anticipatory
  • Reactive
  • Sensory orientation
  • Stability in gait

Such system-specific assessment is helpful in directing treatment and to ensure that a meaningful deficit is not overlooked. The BESTest has good inter-rater reliability and good validity in discerning fallers from nonfallers in patients with PD (King et al., 2012).

The BESTest, though comprehensive, valid, and reliable, is lengthy to administer and may not always be practical in a busy clinical setting. A shorter version of the BESTest—the Mini-BESTest—was developed using psychometric techniques to reduce redundancy and simplify scoring. This shorter version has excellent inter-rater and test-retest reliability and is similar in length to the Berg. However it is currently unknown how the Mini-BESTest compares with the Berg in detecting balance deficits in the PD population (King et al., 2012).

The items tested in the Mini-BEST examine one of four categories of balance: anticipatory, dynamic gait, reactive control, and sensory orientation. The Berg was not designed with such systems in mind but, if a system categorization were assigned to each item, the Berg items primarily evaluate anticipatory and sensory contributions to balance (King et al., 2012).

The following table compares individual items on the Berg and the Mini-BESTest. Items are ranked from most difficult to least, along with the percentage of participants with PD who did not have normal scores. Difficulty with the test was determined if the participant did not receive a perfect score.

Berg Test and Mini-Best Comparing Items by Difficulty

Berg Test item

% with difficulty

Mini-BESTest item

% with difficulty

System (Mini-BEST)

Turning to look behind

70.1

Rise to toes

86.6

Anticipatory

Standing with 1 foot in front

42.3

Single leg

81.4

Anticipatory

Reaching forward with outstretched arms

40.2

TUG (Timed Up and Go) with cognitive task

54.6

Gait

Standing on 1 foot

39.2

Pivot turn

51.5

Gait

Turn 360 degrees

30.9

Eyes closed/foam

46.4

Sensory

Placing alternate foot on stool

27.8

Obstacle during gait

46.4

Gait

Standing to sitting

11.3

Turn head with gait

41.2

Gait

Retrieving object from the floor

9.3

Incline eyes closed

33

Sensory

Sitting to standing

5.2

Backwards recovery

29.9

Postural

Standing with feet together

4.1

Lateral recovery

29.9

Postural

Transfers

4.1

Change pace gait

13.4

Gait

Standing with eyes closed

3.1

Forward recovery

13.4

Postural

Standing unsupported

3.1

Sit to stand

6.2

Anticipatory

Sitting unsupported

0

Eyes open stance

2.1

Sensory

There are two additional systems that the Mini-BESTest evaluates—dynamic gait and reactive postural control—providing more detail when analyzing balance and gait deficits.

Because dynamic gait (cognitive task with gait) and reactive postural control (response to perturbation) are the most difficult items for people with PD, clinicians may add additional tests such as the Dynamic Gait Index and the Pull Test (tested within the UPDRS).

The Tinetti Test

The Tinetti test is another commonly used balance assessment tool. It is a simple, widely used, qualitative test comprising two subscales, one to assess clinical balance and another to assess gait. The balance subscale consists of nine items, where lower scores indicate poor balance. The Tinetti test is a reliable and valid clinical test to measure balance and gait in elders and in patients with PD (Contreras & Grandas, 2012).

The first part of the tool, the Tinetti Balance Test, is scored on a scale of 0 to 16, and assesses:

  • Sitting balance
  • Sit to stand
  • Standing balance
  • Standing balance when nudged
  • Standing balance with eyes closed
  • Balance while turning, and stand to sit

The second part to the tool, the Tinetti Gait Test, is scored on a scale of 0 to 12, and assesses:

  • Initiation of gait
  • Step length and height
  • Step symmetry
  • Step continuity
  • Deviation from a straight path when walking
  • Trunk sway and stance when walking

When taken together, the maximum score on the Tinetti tests is 28; a client who scores between 19 and 24 is at risk for falls and a client who scores below 19 is at high risk for falls.

The Timed Up and Go (TUG)

The Get Up and Go test, the predecessor of the Timed Up and Go test (TUG), was developed by Mathias and Nayak as a tool to screen for balance problems, primarily in the frail elderly. The test measures how long it takes for a person to rise from a chair, walk 3 meters (about 10 feet) to a line on the floor, and return to the chair. The test correlates well with the Berg Balance Scale, the Barthel Index of activities of daily living, and gait speed tests. The Timed Up and Go modified the earlier version of the test by adding a timing component. An adult who is independent in balance and mobility can perform the TUG in less than 10 seconds (Shumway-Cook & Woollacott, 2007).

In a study of older adults with a range of neurologic pathologies, people taking 30 seconds or more to complete the TUG were more likely to need an assistive device, walk too slowly for community ambulation, and score lower on the Berg Balance scale. In contrast, a person completing the test in less than 20 seconds was more likely to be independent in daily living activities, score higher on the Berg Balance scale, and walk at a speed sufficient for community mobility (Podsiadlo & Richardson, 1991).

Shumway-Cook and Woollacott (2012) noted that the TUG can be used to predict the risk of falls in older adults. In a study, 30 community-dwelling frail elderly adults were tested using the TUG, and researchers found that those taking longer than 14 seconds to complete the task were at high risk for falls.

In the same study, the TUG was modified by adding a cognitive task (counting backward by threes) and a manual task (carrying a full cup of water). The addition of a secondary task increased the time need to complete the TUG by 22% to 25% (Shumway-Cook & Woollacott, 2012).

The Pull Test

The Pull Test is a measure of postural instability that is done in part III of the UPDRS. In the Pull Test, the patient is standing erect with eyes open and feet comfortably apart and parallel to each other. The tester stands behind the patient and applies a sudden, strong pull on the shoulders to see how well he or she compensates for a sudden imbalance. The Pull Test is positive if the person takes more than two steps back or would fall if not caught by the tester. A positive Pull Test indicates progression from Hoehn and Yahr stage II to stage III.