Abstract
Background Sensorimotor impairments following spinal cord injury (SCI) affect mobility and subsequently increase the risk of falls to patients. However, most of the fall data for these patients were retrospectively gathered.
Objectives This study prospectively assessed falls and intrinsic factors associated with falls in 89 independent ambulatory individuals with SCI over the course of 6 months. In addition, functional ability between participants who did and did not fall was compared.
Methods Participants were interviewed and assessed for their baseline data and functional ability using the Timed “Up & Go” Test and the Six-Minute Walk Test. Then they were interviewed by telephone to complete a self-report questionnaire once per week to gather fall data for 6 months. A stepwise multiple logistic regression was utilized to determine the effects of demographics and SCI characteristics on occurrence of falls. The functional data between participants who fell and those who did not fall were compared using the Mann-Whitney U test.
Results Thirty-five participants (39%) experienced at least 1 fall during 6 months (range=1–11). Two participants required medical attention due to patellar and sternum fractures after falling. Participants with an educational level of high school graduate or greater, an American Spinal Injury Association Impairment Scale C (AIS-C) classification, and a fear of falling (FOF) significantly increased their risk of falls approximately 4 times more than those who graduated primary education, had an AIS-D classification, and did not have FOF. Moreover, the functional abilities of participants who fell were significantly poorer than those who did not fall.
Limitations The sample size was calculated based on the primary objective (incidence of falls), which may not be sufficient to clearly indicate factors associated with falls for the participants.
Conclusions More than one third of the independent ambulatory participants with SCI experienced at least 1 fall during the 6-month period of the study. The findings suggest the importance of functional improvement on the reduction of fall risk in these individuals.
More than half of patients with spinal cord injury (SCI) have an incomplete lesion. Although 80% of these patients can regain ambulatory ability after rehabilitation, sensorimotor dysfunctions following SCI affect the quality and degree of ambulation and increase risk of falls in these individuals.1,2
Krause3 reported that individuals with SCI had a high rate of subsequent injuries due to a variety of causes, including falls. That study, however, considered injuries due to a variety of causes and did not investigate falls exclusively. Brotherton et al4 retrospectively surveyed falls in 119 independent ambulatory individuals with SCI and found that 75% (n=89) sustained at least 1 fall in a year. After falls, 18% of these individuals experienced fractures, and 45% had restricted ability to function independently in the community and engage in productive activities.4 The researchers also found that exercise frequency and walker use significantly reduced the risk of falls.5 However, the data were retrospectively gathered using a mail survey and subjectively reported by the participants, with a large number of nonresponders (46%). Later, Amatachaya et al6 reported that 74% of independent ambulatory individuals with incomplete SCI experienced at least 1 fall in 6 months (range=1–24), and 1 individual had a metatarsal fracture that required limited weight bearing for 2 weeks. However, the study recruited only 23 independent ambulatory individuals with incomplete SCI and reported incidence of falls as a factor relevant to functional alteration after discharge.6 Recently, Phonthee et al7 also retrospectively gathered data on falls and found that 34% of independent ambulatory individuals with SCI experienced falls during 6 months before participation in the study (range=1–6) and that individuals who experienced a fall had better functional ability than those who did not fall. The researchers suggested that better functional ability may increase the integration of walking while performing daily activities that expose people to a high risk of falls.7
Until now, most studies relating to falls in independent ambulatory people with SCI retrospectively reported the data3,4,7 or recruited a small number of participants.6 Moreover, participants in these studies3,4,6,7 indicated impairments of balance and walking ability as major causes of falls. However, the data were subjectively reported by the participants, which might have reduced the strength of the findings. Therefore, a further study using prospective fall data collection with the incorporation of objective assessments relating to falls would ensure the validity of the findings and direct the application of proper rehabilitation strategies to improve safety issues for the patients.
The impairments of balance and walking ability can be quantitatively measured using the Timed “Up & Go” Test (TUG) and the Six-Minute Walk Test (6MWT). The TUG incorporates many complex tasks that reflect ability of dynamic balance control. The 6MWT is one of the most thorough measures, and the results correlate with many walking ability tests, such as the Walking Index for Spinal Cord Injury II (WISCI-II) and the 10-Meter Walk Test (10MWT).8–10 This study prospectively assessed the incidences, circumstances, consequences, and intrinsic factors associated with falls in independent ambulatory people with SCI over 6 months and compared the functional ability between participants who fell and those who did not fall using the TUG and 6MWT.
Method
Participants
This study prospectively monitored data on falls over 6 months in a cohort of independent ambulatory individuals with SCI from several communities in Thailand. The participants had an SCI either from traumatic causes or nonprogressive diseases at a subacute or chronic stage of injury. In addition, they needed to be at least 18 years of age and have the ability of independent walking over at least 17 m with or without a walking device (Functional Independence Measure [FIM] locomotor subscale score of 5–7).8 Exclusion criteria included the inability to read Thai and having an SCI from a progressive disease or other medical conditions that might affect ambulatory ability, such as visual deficits, pain in the musculoskeletal system with a pain scale more than 5 out of 10 on a visual analog scale, leg length discrepancy, or deformities in the joints of the lower extremities. Eligible participants provided written informed consent prior to taking part in the study.
Ninety-one independent ambulatory patients with SCI agreed to participate in this study. However, 2 individuals were lost during the follow-up period because they had changed their telephone numbers; therefore, 89 participants completed the study (Fig. 1). Most of the participants were men, had a chronic or mild severity of SCI (American Spinal Injury Association Impairment Scale D [AIS-D]) from a nontraumatic cause, and required a walking device. Table 1 presents baseline demographics and characteristics of SCI of the participants.
Flowchart of study participants.
Baseline Demographics and Spinal Cord Injury Characteristics of the Participants
Protocols of the Study
Participants were interviewed and assessed for baseline demographics, SCI characteristics, and self-perceived health status using a self-report questionnaire (Appendix) that was developed from data of previous studies.4,6,7 Then, the content validity of the questionnaire was judged subjectively through the method of expert panel discussion using 4 rehabilitation experts (2 physical therapists, a nurse, and a physician) who had extensive clinical experience in treating patients with neurological conditions. Subsequently, the questionnaire was preliminarily tested in 10 independent ambulatory patients with SCI. Thereafter, some items were deleted, modified, or rearranged to improve the clarity and completeness of the questionnaire. Then participants were assessed for their functional ability using the TUG and 6MWT. Details of the tests are below.
TUG.
Participants were instructed to stand up from a chair with armrests; walk around a traffic cone, which was located 3 m away from the chair; and return to the sitting position in the chair, at a maximum and safe speed, with or without a walking device.11,12 The amount of time from the command “go” until the participant's back was against the backrest was recorded.
6MWT.
Participants were required to walk along a rectangular walkway for as long as possible in 6 minutes. During the test, participants were allowed to rest as needed, without stopping the timer, and continued walking as soon as they could. Every 1 minute during the test, participants were informed about the time left and offered encouragement. The distance covered in 6 minutes was recorded.8,9
Following the test, participants received a fall diary (see part 3.1 in the Appendix) to daily record data relating to falls at home, and the researcher (S.P.) telephoned them weekly to interview and summarize the data for the week. Data on the occurrence of falls, including date, time, place, circumstances, and consequences, were gathered during the telephone interviews. To ensure information accuracy, the findings were confirmed by caregivers or relatives. If there was any conflicting information between the participant and caregiver, the researcher relied on the data that were consistent with those in the fall diary. For the purposes of this study, a fall was defined as an unplanned, unexpected, or unintentional event that occurred during standing, walking, or changing posture and resulted in a person coming to rest on the ground or other lower or supporting surface.5,6
Data Analysis
Descriptive statistics were applied to explain baseline demographics, SCI characteristics, and findings of the study. The data between participants who fell and those who did not fall were compared using the Mann-Whitney U test for continuous variables and the chi-square test for categorical data. The stepwise multiple logistic regression analysis was utilized to determine effects of independent variables (including age, sex, living arrangements, having a caregiver, level of education, cause of SCI, level of SCI, severity of SCI, the requirement of a walking device, current perceived health when compared with a previous year, and fear of falling [FOF]) on the occurrence of falls. The results were reported as an adjusted odds ratio (aOR) with corresponding 95% confidence intervals (95% CI) and Beta (β) coefficients with the standard error around the Beta coefficient. The aOR provides information about the increase or decrease in the possibility of falls given that the independent variable has occurred when controlling for other independent variables in the model. An aOR of less than 1 indicates a decrease in the chance that the fall will occur given that the independent variable occurs (a protective factor). On the contrary, an aOR of greater than 1 indicates an increase in the chance that the fall will occur given that the independent variable occurs (a risk factor). The Beta coefficients represent the log of the aOR or the influence of independent variables on the occurrence of falls.13 The level of significance was set at P<.05.
Role of the Funding Source
This study was supported by funding from the Faculty of Associated Medical Sciences, the Improvement of Physical Performance and Quality of Life (IPQ) research groups, and the Graduate School, Khon Kaen University, Khon Kaen, Thailand.
Results
Incidence, Circumstances, and Consequences of Falls
Thirty-five participants experienced at least 1 fall in 6 months (range=1–11) (Fig. 1), and the total number of falls was 98. Table 2 presents circumstances of falls in which most of the falls occurred while walking within the house and its immediate surroundings (n=74) (areas of falls within the house included the bedroom [n=11], bathroom [n=15], walkway in the house [n=14], and kitchen [n=2]), during the morning to afternoon time (5:00 am–4:59 pm). Participants indicated lower-limb muscle weakness and environmental hazards (ie, uneven surface [n=10], slippery floor [n=18], and obstacle on the floor [n=14]) as major causes of falls (Tab. 2). Most participants reported no serious consequences after falling. Two participants, however, had fractures: one participant had a patellar fracture that needed rehospitalization for 14 days with limited weight bearing, and another participant had a sternum fracture that required readmission for 5 days (Fig. 2).
Fall Data: Time, Place, Circumstances, and Factors Inducing Falls as Perceived by the Participants
Physical, functional, and psychological consequences of falls.
Factors Associated With Falls
Data of stepwise logistic regression analysis indicated that living arrangements, having a caregiver, level of education, level of SCI, severity of SCI, the requirement of a walking device, current perceived health when compared with a previous year, and FOF were the best predictors for the occurrence of a fall (Tab. 3). Among these variables, at least high school graduation, having an AIS-C classification, and having FOF significantly increased risk of falls by approximately 4 times compared with those who graduated primary education, had an AIS-D classification, and did not have FOF (P<.05) (Tab. 3).
Data on Factors Associated With Falls in Independent Ambulatory Participants With Spinal Cord Injurya
Functional Ability in Participants Who Fell and Those Who Did Not Fall
TUG.
The TUG data of 6 participants were considered outliers (the data that were more than 1.5 times of the interquartile range: Q1–Q3);14 thus, the data were analyzed in 83 participants. The findings indicated that individuals who fell required a significantly longer time to complete the TUG compared with those who did not fall (P<.05) (Fig. 3A).
Data of functional tests in fallers and nonfallers for the (A) Timed “Up & Go” Test and the (B) Six-Minute Walk Test with P values from the Mann-Whitney U test.
6MWT.
The 6MWT data of 2 participants were considered outliers; thus, the data were analyzed in 87 participants. The findings suggest that individuals who did not fall could walk a significantly longer distance, within a 6-minute period, than those who fell (P<.05) (Fig. 3B).
Discussion
This study prospectively investigated falls and associated factors in 89 independent ambulatory individuals with SCI. The findings showed that 39% of the participants experienced at least 1 fall during 6 months (range=1–11/participant). The falls mostly occurred while participants were walking, during morning to afternoon hours, and within the house and its immediate surroundings (Tab. 2). After falls, 2 participants had fractures that needed medical attention. Participants with an educational level of at least high school graduation with an AIS-C classification and FOF significantly increased their risk of falling by approximately 4 times compared with those who graduated primary school, had an AIS-D classification, and did not have FOF (P<.05) (Tab. 3). The TUG and 6MWT data indicated that participants who fell had significantly poorer functional ability than those who did not fall (P<.05) (Fig. 3).
The incidence of falls found in this study was less than that reported previously.4,6 The differences may relate to study design, follow-up period, and sample size. The present study used prospective fall data collection every week for 6 months. A prospective design allows data gathering, from exposure to outcome, that can establish a temporal relationship of the observed events.15 However, frequent follow-up of the fall data may lead to the “Hawthorne effect,” which commonly occurs when individuals know that they are being observed and temporarily change their behavior.15 This may be a reason that the incidence of falls found in this study (39%) was less than that of previous reports (74%–75%).4,6 However, the findings were similar to those recently reported (34%) in a study using retrospective face-to-face interviews to gather fall data during a 6-month period.7
The sensorimotor deterioration following SCI and inappropriate environmental conditions may have limited the ability of the individuals to participate in the community. Therefore, the falls frequently occurred at home (within the house and its immediate surroundings). In addition, the time of falls was associated with the duration of the performed exercises and physical activities (subjective data from the self-report questionnaire). After falling, 2 participants experienced fractures that needed medical attention. The finding was in agreement with those of previous studies that also reported that individuals had experienced fractures after falls.4,6,7 The findings emphasize the serious consequences after falls and the need for a proper rehabilitation strategy or management to improve safety issues, particularly while walking in actual environments, of these individuals.
The findings indicate that participants who achieved at least high school graduation and had an AIS-C classification and FOF significantly increased their risk of falling by approximately 4 times compared with those who completed primary school education and had an AIS-D classification and FOF (P<.05) (Tab. 3). Regidor et al16 reported that educational level is associated with attention to health status. Individuals with a high educational level may increase attention to their health status and thus move more frequently in order to improve their functional ability. However, sensorimotor dysfunctions following SCI may distort their ability to move safely; hence, they may increase their exposure to fall opportunities. This assumption was associated with the subjective data that the participants indicated the impairments of balance control and lower-limb muscle strength and environmental hazards as major causes of falls (Tab. 2). Similarly, Brotherton et al5 also found that a high educational level (at least a bachelor's degree) significantly increased unadjusted odds ratios for the fall risk of independent ambulatory individuals with SCI.
Having an AIS-C classification and FOF also significantly increased the risk of falls (P<.05) (Tab. 3). A level of severity is associated with a degree of sensorimotor impairments and a level of functioning. Harkema et al17 reported that individuals with an AIS-C classification had significantly poorer balance and functional ability than those with an AIS-D classification as determined using the Berg Balance Scale, 10MWT, and 6MWT. A lower level of functioning also may increase the level of FOF and decrease a person's confidence in his or her ability to engage in a daily activity. In other words, fear of falling frequently occurs in individuals with low levels of functioning that subsequently reduces their self-confidence in movement control.18,19 Low levels of functioning also have been recognized as a risk factor for falls in elderly people and individuals with stroke and SCI.5,20,21 Brotherton et al5 found that exercise frequency significantly reduced risk of falls in independent ambulatory individuals with SCI. The researchers suggested that the implementation of an exercise program may help to improve health status, reduce the number of medical conditions, and increase confidence in the ability to engage in community activities, and thus the individuals have decreased risk of falls.5
The findings of the TUG and 6MWT also emphasize the importance of good functional ability on the reduction of fall risk in these individuals (Fig. 3). The TUG incorporates many complex tasks (ie, standing up, walking, turning, and sitting down) that may reflect daily activities and balance control while walking more accurately than the 10MWT.9 The longer time required to complete the TUG (Fig. 3A) indicates that the participants who fell had poorer balance control than those who did not fall.11,12 A long-distance walking test, such as the 6MWT, is a thorough investigation for functional endurance and a good predictor of habitual walking9,22,23
Guimaraes and Isaacs24 found that during a short-distance walking test, such as the Six-Meter Walk Test, individuals who fell showed a trend toward increased step length variability (ie, unsteadiness or inconsistency and arrhythmicity of stepping). On the contrary, while performing the 6MWT, participants who fell demonstrated significantly greater gait variability than those who did not fall in which the gait unsteadiness, or variability, had been indicated as an important predictor for the increased risk of falls.25 Van Hedel et al10 also found that the results of the TUG and 6MWT had good to excellent correlation with other walking tests such as the 10MWT (r=.89 for the TUG and ρ=−.95 for the 6MWT) and the WISCI II (ρ=−.76 for the TUG and ρ=.60 for the 6MWT). However, the findings in this study were different from those reported by Phonthee et al,7 who found that the TUG and 6MWT data of the individuals who fell were significantly better than those of the individuals who did not fall. The different findings may relate to the study designs in which the measurements of functional ability were executed before (for a prospective study) and after (for a retrospective study) falls. Therefore, a further investigation to indicate functional alteration of individuals who did and did not fall with SCI may help to support the findings.
Currently, there is a trend toward considerably decreasing the rehabilitation period of these patients (from 115 days in 1974 to 36 days in 2005).26,27 Therefore, it is likely that patients cannot reach an optimal level of ability at the time of discharge27 and have increased risk of falling and subsequent injury. Thus, the present findings emphasize the importance of the exploration for rehabilitation strategies or management to improve ability of movement control and safety for these patients. However, the data contain several noteworthy limitations. The study used frequent prospective follow-up fall data with confirmation from caregivers or relatives in order to improve data accuracy. However, frequent follow-up periods may affect a natural lifestyle (eg, frequent follow-up could increase conscious awareness of movements that influences the incidence of falls). Also, the sample size was calculated based on the primary objective (to investigate incidence of falls), which may not be sufficient to clearly indicate factors associated with falls for the participants. Furthermore, the data of the functional tests (TUG and 6MWT) indicate functional impairments, not the impairments of the body systems, affecting falls. Thus, a further study using unscheduled follow-up of the fall data in a greater number of participants with the assessments of system impairments influencing falls (ie, muscle strength, sensation, and spasticity) may strengthen the findings.
Appendix.
Questionnaire for Fall Data Collection of Independent Ambulatory Individuals With Spinal Cord Injurya
a The questionnaire may not be used or reproduced without written permission from the authors.
Footnotes
All authors provided concept/idea/research design and data analysis. Ms Phonthee and Dr Amatachaya provided writing. Ms Phonthee provided data collection. Dr Amatachaya provided fund procurement and facilities/equipment. Dr Saengsuwan provided consultation (including review of manuscript before submission). The authors thank Mr Ian Thomas for his help in preparing the manuscript.
This study was approved by the Khon Kaen University Ethics Committee for Human Research.
This study was supported by funding from the Faculty of Associated Medical Sciences, the Improvement of Physical Performance and Quality of Life (IPQ) research groups, and Graduate School, Khon Kaen University, Khon Kaen, Thailand.
- Received November 20, 2012.
- Accepted April 8, 2013.
- © 2013 American Physical Therapy Association
References
Issue highlights
