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PHYS THER
Vol. 80, No. 12, December 2000, pp. 1174-1187
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Research Reports

Turning Difficulty Characteristics of Adults Aged 65 Years or Older

Mary T Thigpen, Kathye E Light, Gwenda L Creel and Sheryl M Flynn

MT Thigpen, PT, MHS, NCS, is a doctoral student in an interdisciplinary program in the College of Health and Human Performance and the College of Health Sciences, Department of Physical Therapy, University of Florida, Box 100154, Gainesville, FL 32610 (USA) (bobnmaryt{at}AOL.com). Address all correspondence to Ms Thigpen
KE Light, PT, PhD, is Associate Professor, Department of Physical Therapy, University of Florida
GL Creel, PT, MHS, NCS, is Lecturer and Professor, Department of Physical Therapy, University of Florida
SM Flynn, PT, MHS, is a doctoral student in an interdisciplinary program in the College of Health and Human Performance and the College of Health Sciences, Department of Physical Therapy, University of Florida


Submitted April 17, 2000; Accepted May 29, 2000


   Abstract
 
Background and Purpose. Falls that occur while walking have been associated with an increased risk of hip fracture in elderly people. This study's purpose was to describe movement characteristics in older adults that serve as indicators of difficulty in turning while walking. Subjects. Three groups were assessed: young adults who had no difficulty in turning (age range=20–30 years, n=20) (YNDT group), elderly adults who had no difficulty in turning (age range=65–87 years, n=15) (ENDT group), and elderly adults who had difficulty in turning (age range=69–92 years, n=15) (EDT group). Methods. All subjects were videotaped performing a self-paced 180-degree turn during the Timed "Up & Go" Test. Movement characteristics of each group were identified. Four characteristics were used to identify difficulty in turning: (1) the type of turn, (2) the number of steps taken during the turn, (3) the time taken to accomplish the turn, and (4) staggering during the turn. Results. In general, the EDT group took more steps during the turn and more time to accomplish the turn than the YNDT and ENDT groups did. Although the only turning strategy used by the YNDT group was a pivot type of turn, there was an almost total absence of a pivot type of turn in the EDT group. No differences were found among the groups on the staggering item, yet the EDT group was the only group in which staggering was present. We believe these changes observed in the 4 characteristics only in the EDT group are indicators of difficulty in turning while walking. Conclusion and Discussion. These indicators of difficulty may be useful for the early identification of individuals aged 65 years or older who are having difficulty in turning and may well serve as the basis for the development of a scale for difficulty in turning in older adults. Preliminary findings indicate the need for further study into the reliability, validity, and sensitivity of measurements obtained with such a scale.

Key Words: Elderly • Hip fracture • Turning difficulty • Walking


   Introduction
Top
 Abstract
 Introduction
Method
 Results
 Discussion
 Conclusions
 References
 
Research on the causes of hip fractures has concentrated on the mechanisms of reduced bone strength, with much less attention being given to the characteristics of the falls that lead to hip fractures. Studies have shown that there are some types of falls that are more likely than other types of falls to cause fractures.1–3 Cumming and Klineberg2 examined the association between history of falls and risk of hip fracture in 412 older adults (age range=65–100 years), and they identified characteristics of falls related to hip fracture. They found that individuals who fell while performing a standing turn test were 7.9 times more likely to have a subsequent fall resulting in a hip fracture.

Because falling during turning while walking has been identified as predictive of subsequent hip fracture, we believe that it is logical to identify and quantify the movement dysfunction related to this fall-provoking activity.4–6 Individuals who are at risk for falling may be identified earlier, and more effective interventions might be possible.

The purpose of our study was to identify and describe the movements that occur during turning while walking in adults aged 65 years or older and, specifically, the movements that characterize turning difficulty in older adults.


   Method
Top
 Abstract
 Introduction
 Method
Results
 Discussion
 Conclusions
 References
 
Subjects

Volunteers were recruited to comprise 3 groups: (1) young adults who had no difficulty in turning while walking (8 men and 13 women; mean age=24.2 years, SD=3.6, range=20–30) (YNDT group), (2) elderly adults who had no difficulty in turning while walking (7 men and 8 women; mean age=74.9 years, SD=6.0, range=65–87) (ENDT group), and (3) elderly adults who had difficulty in turning while walking (5 men and 10 women; mean age=80.1 years, SD=7.0, range=69–92) (EDT group).

YNDT group.
The first 21 eligible volunteers who met the study criteria were selected randomly from a group of 60 University of Florida students and staff. Subjects were recruited via notices posted at various sites on campus. To be included in the study, the subjects had to be between the ages of 20 and 30 years and, according to self-report, without any current or chronic medical problems such as cardiac, respiratory, metabolic (eg, diabetes), or musculoskeletal (eg, lower-extremity [LE] fractures, injuries, or disease) pathologies. The subjects had to be independent and community dwelling and had to report having a lifestyle with a moderate level of activity. They could not be involved in competitive athletics. The subjects had to report having no difficulties in turning while walking when screened with a questionnaire designed to assess turning difficulty (Fig. 1). Subjects who were overtly obese or thin, as defined by the American College of Sports Medicine (ACSM) Guidelines for Exercise Testing and Prescription7; showed extremes in height (not less than 1.5 m [5 ft] or greater than 1.8 m [6 ft]); or exhibited or reported active or residual physical disability were excluded. Table 1 shows the group's baseline characteristics.


Figure 1
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[in a new window] 		Figure 1. Turning difficulty questionnaire.

 

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[in a new window] 		Table 1. Group Characteristics for Age, Sex, Living Situation, Number of Medications, and Number of Comorbiditiesa

 
ENDT group.
The first 15 people who met the study criteria were selected from a group of 25 volunteers recruited from community civic organizations, University of Florida faculty, and health fairs in the local mall and local retirement centers. Fitness screens, posters, and lectures to local groups were used to recruit subjects. To be included in the study, the subjects had to be 65 years of age or older, independent, and community dwelling. They had to report having a lifestyle with a moderate level of activity. They could not be involved in competitive athletics. The subjects had to report having no difficulties with mobility, activities of daily living, or turning while walking by answering "No" to all items on the turning difficulty questionnaire (Fig. 1). Subjects who were overtly obese or thin, as defined by the ACSM Guidelines for Exercise Testing and Prescription7; showed extremes in height (not less than 1.5 m [5 ft] or greater than 1.8 m [6 ft]); exhibited or reported active or residual physical disability (eg, chronic obstructive pulmonary disease, congestive heart failure, Parkinson disease); or scored 24 or less on the Folstein Mini Mental State Examination8 were excluded. A score of less than 24 on the Folstein Mini Mental State Examination is highly suggestive of cognitive impairment and is considered a risk factor for falling.8 Chronic comorbidities reported by this group included hypothyroidism, osteoporosis, hypertension, and arrhythmia. Medications used by these subjects included antihypertensives, cardiac medications, anticoagulants, nonsteroidal anti-inflammatory drugs, and Synthroid.* Table 1 shows the group's baseline characteristics. Three volunteers were excluded because they answered "Yes" to questions 1, 3, or 6 of the turning difficulty questionnaire (Fig. 1), 2 volunteers decided not to participate, and 5 volunteers were excluded due to comorbidities such as angina, chronic obstructive pulmonary disease, and the flu.

EDT group.
The first 15 people who met the study criteria were selected from a group of 31 volunteers recruited from community civic organizations, University of Florida faculty, and health fairs in the local mall and local retirement centers. To be included in the study, the subjects had to be 65 years of age or older and have no history of acute neurologic or musculoskeletal pathologies within last 12 months, chronic cardiopulmo-nary conditions, or severe residual physical disability. The subjects had to report difficulty with turning while walking by answering "Yes" to the questions 1, 3, or 6 of the turning difficulty questionnaire (Fig. 1) and be able to ambulate 6 m (20 ft) independently. Subjects who were overtly obese or thin, as defined by the ACSM Guidelines for Exercise Testing and Prescription7; showed extremes in height (not less than 1.5 m [5 ft] or greater than 1.8 m [6 ft]); exhibited or reported active or residual physical disability (eg, chronic obstructive pulmonary disease, congestive heart failure, Parkinson disease); or scored 24 or less on the Folstein Mini Mental State Examination were excluded. Chronic comorbidi-ties reported by this group included osteoarthritis, depression, coronary artery disease, throat cancer, hypertension, transient ischemic attacks, asthma, and osteoporosis. Medications used by the subjects in this group included antihypertensives, cardiac medications, antidepressants, anticoagulants, and nonsteroidal anti-inflammatory drugs. Table 1 shows this group's baseline characteristics. Three volunteers were excluded due to having scores of less than 24 on the Folstein Mini Mental State Examination, 3 volunteers decided not to participate, and 10 volunteers were excluded due to comorbidities, including chronic obstructive pulmonary disease, Guillain-Barré syndrome, stroke, basilar artery insufficiency, and recent cardiac surgery.

Procedure

To observe the subjects turning while walking using a standardized format, each subject was asked to perform the Timed "Up & Go" Test.9,10 This test is used to measure (in seconds) the time taken by an individual to stand up from a chair with a 48-cm seat height, walk a distance of 3 m to a line on the floor, turn, walk back to the chair, and sit down again. Each subject was given one practice trial and then asked to perform 3 test trials.

A turn was defined as the beginning and end of the 180-degree reversal of direction at the turn line on the floor while walking. The last heel-strike prior to initiation of the reversal of direction was designated the beginning of the turn. The heel-strike of the first step progressing in a direct line back to the chair was designated the end of the turn.

Subjects were videotaped performing a practice trial and then 3 more successive trials of the Timed "Up & Go" Test. Before testing began, pilot work with 2 cameras, one in the sagittal plane and one in the frontal plane, was done to determine whether 2 cameras were necessary for this analysis. Two major limitations using 2 cameras were identified: (1) the use of 2 video cameras required at least 54 m2 (600 ft2), and (2) the use of 2 video cameras and consequent time for analysis of 2 videotapes were impractical when considering potential clinical application. Although clear observation of movement characteristics such as head and trunk lateral tilt were lost with the use of only a sagittal-view camera, several key movement characteristics were easily identified with this camera placement. Therefore, we used one stationary video camera mounted on a tripod and placed perpendicularly to and 9 m from the marked pathway. The view included the entire path from the chair to the line on the floor. For maximum accuracy, the image was kept as large as possible, with a full view of the subject performing the entire Timed "Up & Go" Test. On the command "Go," a light flash was used to time reference the film frame. A yardstick was placed in the field as a scaling reference for distance.

The videotapes of the turn were viewed using a video-cassette player with stop-action and frame-by-frame slow-motion capabilities. For every subject, each trial of the Timed "Up & Go" Test was time coded to .01 second for timing of the entire test and of the turn. Observation of the subject's body movement while performing the turn was viewed in the sagittal plane of movement.

Data Reduction

When describing human movement, body action can be characterized for relatively few body segments, each of which can be regarded as a rigid body.11 Because these segments are linked, and consequently lack independent movement, they can be evaluated in relationship to one another.11,12 Therefore, body movement during turning was evaluated by observing 3 body components individually: (1) the upper extremities (UEs), (2) the axial (head-trunk) region, and (3) the LEs.13 The turning movement was first observed as a total-body movement, and then the individual body segments during specific events of the turn were evaluated more closely. These segments were observed individually and in relationship to one another at 3 designated events during the turn sequence (ie, heel-strike entering turn, mid-turn, and heel-strike leaving turn).

We used what we considered to be basic principles of movement analysis to evaluate turning during walking. These principles were (1) identification of where the movement begins and ends, (2) identification of where most of the movement occurs, (3) identification of the main movement components and their sequence, (4) identification of the timing of this sequence, and (5) identification of the type of movement occurring (ie, discrete, serial, or continuous).14,15

Following methods described by VanSant,13 the principal investigator (MTT) viewed the videotapes for each group and then recorded descriptive observations of characteristic movements in a logbook for each trial of every subject. The principal investigator concentrated first on the axial region only and wrote descriptions of movements of the head and trunk for each trial of each subject and compared these descriptions for similarities and differences. When similarities of action were apparent, a more general category of axial movements could be established to serve as a common characteristic of axial movement during turning. This process was repeated using observations of the UEs and the LEs. After this phase of observational analysis, the principal investigator again reviewed the videotapes of each group and recorded the frequency of occurrence of these descriptive movement characteristics. At least half of the trials in each group had to demonstrate a movement behavior for it to be considered a common characteristic of the group. This criterion was chosen because the movement observations were not dichotomous; therefore, observation of a characteristic occurring in 50% or more of the trials was a clear majority. The written descriptions of these characteristics were refined throughout the observational process and finally served as categorical descriptors of each body action component.

To further investigate and recognize the similarities and differences among the groups, movement characteristics other than body action components were also analyzed. Basic temporospatial aspects of turning during walking such as the number of steps taken during the turn and the time taken to accomplish the turn were measured using both the slow-motion and stop-action capabilities of the VCR system and a time-code processor. The turn of each trial was also categorized according to the 3 basic motor learning task classifications: discrete, serial, and continuous.14 Refer to Table 2 for descriptions of these task classifications.


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[in a new window] 		Table 2. Percentage of Occurrence Across 3 Trials Per Subject for Task Classificationa

 
Data Analysis

Description of turning while walking in adults.
Based on all 3 test trials for all subjects, the percentage of trials in which each category of body component action was observed was calculated in order to portray the frequency of occurrence of each type of component action (Tabs. 3Go–5). The percentages of trials observed in the categories describing basic temporospatial aspects of turning, type of turn, and type of task were also calculated (Tabs. 2, 6, and 7).


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[in a new window] 		Table 3. Percentage of Occurrence Across 3 Trials Per Subject for Upper-Extremity (UE) Movement Characteristicsa

 

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[in a new window] 		Table 4. Percentage of Occurrence Across 3 Trials Per Subject for Axial Movement Characteristicsa

 

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[in a new window] 		Table 5. Percentage of Occurrence Across 3 Trials Per Subject for Lower-Extremity (LE) Movement Characteristicsa

 

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[in a new window] 		Table 6. Percentage of Occurrence Across 3 Trials Per Subject for Temporospatial Features of Turna

 

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[in a new window] 		Table 7. Percentage of Occurrence Acress 3 Trials Per Subject for Type of Turn Useda

 
Description of difficulty in turning while walking in older adults.
Characteristics exclusive to the EDT group and deviating from characteristics consistently identified in the YNDT and ENDT groups were considered indicators of difficulty. These movements were observed only in the EDT group and appeared to reflect impaired stability during turning. Based on trends observed in all test trials across the 3 groups, the principal investigator created 4 major categories that she believed most readily identified indictors of difficulty in turning while walking. These categories were: (1) the type of turn (or strategy) used to accomplish the turn, (2) the number of steps taken during the turn, (3) the time taken to accomplish the turn, and (4) staggering during the turn. An ordinal scale of measurement incorporating the 3 major trends observed across the groups was then developed for each category (Fig. 2).


Figure 2
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[in a new window] 		Figure 2. The 4 characteristics developed to reflect a continuum from "no difficulty" to "definite indicators of difficulty" while turning during walking.

 
Reliability of categorical descriptions.
In order to establish the reliability of categorizing descriptions, test trial 3 for each subject in the ENDT and EDT groups was evaluated by 2 physical therapists (mean number of years of experience=12.5, range=7–18) with expertise in the evaluation of geriatric patients. The principal investigator trained the 2 raters to identify the categories of movement characteristics that had been developed in the data reduction process. The raters were given category definitions and definitions for each level on the ordinal scale descriptor within each category. Key wording was discussed and clarified for the raters. Videotape examples of a characteristic's absence or presence were reviewed and discussed. The raters then independently viewed and rated, in random order, the third trial of each subject in the ENDT and EDT groups. To evaluate the descriptions for clarity and appropriateness, the raters' scores were evaluated for percentage of agreement using the kappa statistic.16(pp516–523) Items with less than 60% agreement were flagged and discussed with the raters. Based on group discussion, the category descriptions were refined and revised. The raters then reanalyzed the videotapes of the subjects using the revised descriptions and achieved greater than 60% agreement on each characteristic. Using a 3-point ordinal scale, these 4 characteristics are designed to recognize a continuum of movements within each characteristic that reflect no difficulty to definite difficulty in turning while walking. They are presented in Figure 3.


Figure 3
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[in a new window] 		Figure 3. Indicators of difficulty in turning while walking in older adults.

 
Differences among the 3 groups.
The differences among the 3 groups in the 4 categories was then determined by the principal investigator using trial 3 from each group. The intrarater reliability of the principal investigator for the category descriptions was evaluated using another set of 30 randomly ordered trials, with a 2-week interval between tests. Intratrater reliability for the final 4 categories was tested by the use of the intraclass correlation coefficient (ICC), which provides an estimate of the average correlation between all possible pairs of ratings. The calculation is based on an analysis of variance (ANOVA), which estimates the amount of variance attributable to the subjects, the raters, and unexplained error. Once intrarater reliability was established, the principal investigator evaluated trial 3 for each group using the 4 difficulty categories. Actual times and actual number of steps among the 3 groups were compared using a one-way ANOVA. The type of turn and staggering categories were compared using a Kruskal-Wallis analysis.


   Results
Top
 Abstract
 Introduction
 Method
 Results
Discussion
 Conclusions
 References
 
Description of Turning While Walking in Adults

Description of component actions.
Similarities and differences in the subjects' turning while walking resulted in 3 categories of UE action, 4 categories of axial action, and 6 categories of LE action. The action categories are delineated for the UE, axial, and LE components and the frequency with which each category of body action appeared across trials is presented in Tables 3 through 5. In the UE component, asymmetrical arm swing was the most common pattern in the YNDT group, arms symmetrically by sides was the most common pattern in the ENDT group, and arms raised symmetrically was the most common pattern in the EDT group. In the axial region, the most frequently observed pattern in the YNDT group was backward trunk lean just prior to the turn, and the most frequently observed pattern in the ENDT and EDT groups was vertical alignment before and during the entire turn. In the LE component, an early pivot approach with the body already rotated 90 degrees by the time the turn line was reached was the most common pattern seen in the YNDT group, with 100% of the group using a pivot type of strategy. The mixed strategy (a combination of steps and partial pivots) was the most common pattern in the ENDT group, while the remaining 44% of the group used 1 of the 4 full-pivot types of strategies. The mixed strategy was also the most common pattern observed in the EDT group, with only 2% of the group using a full-pivot strategy.

Description of basic temporospatial aspects of turning.
Table 8 shows the number of steps taken during the turn for all 3 trials and the time taken to accomplish the turn for the second and third trials for all 3 groups. Descriptive statistics for the number of steps taken during the turn, the time to taken to accomplish the turn, and the Timed "Up & Go" Test time are presented in Table 9. The percentage of occurrence of categories of number of steps taken during the turn and the time taken to accomplish the turn for all trials in all groups are presented in Table 6.


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[in a new window] 		Table 8. Quantitative Raw Data for All Groups for Number of Steps, Time to Turn, and Time to Perform the Timed "Up & Go" Testa

 

View this table:
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[in a new window] 		Table 9. Descriptive Statistics by Group for Number of Steps in the Turn, Time to Accomplish the Turn, and Time to Perform the Timed "Up & Go" Test During Trial 3a

 
Description of type of turn and type of task.
Three major categories of turns were observed and consequently were used as a descriptive category. The frequency with which each type of turn appeared across trials for each group is presented in Table 7. All subjects in the YNDT group used a pivot type of turn, whereas only 58% of the ENDT group used that type of turn. The remaining 42% of the ENDT group demonstrated a mixed type of turn, with a mixture of partial pivots combined with extra steps where no full pivot occurred. The EDT group demonstrated an almost total absence of the full-pivot type of turn, with only one subject demonstrating a pivot turn. Sixty-five percent of the EDT group used the mixed type of turn as observed in the ENDT group; the remaining 30% showed a complete absence of any type of pivot, demonstrating a series of multiple steps or weight shifts to accomplish the turn. Table 7 shows the frequency with which each type of turn appeared across trials for each group. The turns of each group were also categorized according to the 3 basic motor learning task classifications: discrete, serial, and continuous. Table 2 shows the frequency with which each task classification appeared across trials for each group. The type of turn used was found to be related to the task classification. Pivot turns were 100% discrete movements, whereas 90% of mixed turns were classified as serial. Ninety percent of the stepping turns were classified as continuous, with the reversal of direction accomplished simply by gradually changing direction while walking. The remaining 10% of the stepping turns were classified as serial.

Description of Difficulty in Turning While Walking in Adults—Differences Among the 3 Groups

Using the criterion that at least half of all the trials of all subjects in each group must demonstrate a movement for it to be considered a common characteristic of the respective group, 4 characteristics emerged to reflect common movement behaviors across the 3 groups. The 4 categories were: (1) the type of turn or strategy used to accomplish the turn, (2) the number of steps or weight shifts taken during the turn, (3) the amount of time taken to accomplish the turn, and (4) the presence or absence of staggering during the turn.

Reliability of categorical descriptions.
The percentage of agreement between raters was evaluated and reevaluated using these 4 categories. The kappa values for the final percentage of agreement between raters on the 4 characteristics were: .78 for type of turn, .67 for number of steps taken during the turn, .90 for time taken to accomplish the turn, and .71 for staggering during the turn.

Intrarater reliability of the principal investigator.
An ICC (2,0) was used to establish the principal investigator's intrarater reliability on the 4 movement characteristic categories designed to identify indicators of difficulty in turning. The principal investigator's ICCs on each characteristic were: .99 for type of turn; .90 for number of steps taken during the turn; .96 and .67 for time taken to accomplish the turn, based on measurements obtained with the time-code processor and the stopwatch, respectively; and 1.00 for staggering during the turn. When the total of the 4 categories was evaluated, the ICC was .87 (using stopwatch measurements). These values indicated good to excellent intrarater agreement.16

Time taken to accomplish the turn.
Mean values and standard deviations for the time taken to accomplish the turn during trial 3 were compared among the 3 groups using a one-way ANOVA with Scheffé's comparisons. Differences (F=38.4, P<.0001) were found between the groups. Post hoc tests showed that the time taken to accomplish the turn was less in the YNDT group (1.43±0.25 seconds) than in the ENDT group (2.23±0.73 seconds) (P=.03) and the EDT group (3.18±1.03 seconds) (P<.0001). Comparisons also showed that the time taken to accomplish the turn was less in the ENDT group than in the EDT group (P<.0001). A power analysis showed that ß<.99.

Number of steps taken during the turn.
Mean times for the number of steps taken during the turn during trial 3 were compared among the 3 groups using a one-way ANOVA with Scheffé's comparisons. Differences (F=29.5, P<.0001) were found between the groups. Post hoc tests showed that the number of steps taken during the turn was less in the YNDT group (1.3±0.4 steps) than in the ENDT group (2.7±1.4 steps) (P=.005) and the EDT group (4.7±2.1 steps) (P<.0001). Comparisons also showed that the number of steps taken during the turn was less in the ENDT group than in the EDT group (P<.0001). A power analysis showed that ß<.99.

Timed "Up & Go" Test scores.
Mean times for the total Timed "Up & Go" Test were also compared among the 3 groups using a one-way ANOVA with Scheffé's comparisons. Differences (F=35.7, P<.0001) were found between the groups. Post hoc tests showed that the time for the total Timed "Up & Go" Test was less in the YNDT group (8.54±1.36 seconds) and the ENDT group (9.62±2 seconds) than in the EDT group (14.98±3.41 seconds) (P<.0001, respectively). No differences were observed between the YNDT and ENDT groups for the time for the total Timed "Up & Go" Test. A power analysis showed that ß<.99.

Staggering and type of turn characteristics.
A Kruskal-Wallis test was used to assess whether differences existed among the 3 groups in the staggering category and the type of turn category. Differences (H=26.8, P<.0001) were found in the type of turn used among the 3 groups. To determine the significance of pair-wise differences between groups, the pair-wise comparison was tested against a minimum significant difference. The YNDT group (sum rank=325.5, mean rank=15.5) and the ENDT group (sum rank=378.0, mean rank=25.2) were found to be significantly different, the YNDT group and the EDT group (sum rank=622.5, mean rank=41.5) were found to be significantly different, and the ENDT group and the EDT group were found tbe significantly different. No differences (P>.05) were observed among the groups in the staggering category.

Summary of Characteristics Within Each Group

YNDT group.
Characteristics observed in the YNDT group included no staggering during the turn; turning 180 degrees at the turn line by pivoting on one foot or both feet simultaneously, keeping the head, trunk, and hips aligned while achieving complete reversal of direction; having 2 or fewer steps within the actual turn; and accomplishing the turn in less than 2.50 seconds. There was no variability within the 3 trials of each subject; the turn was basically performed in the same manner across all 3 trials. Minimal variability in certain characteristics was observed and consisted of arm placement during the turn, including arms by the sides, arms symmetrically elevated 20 to 30 degrees, or reciprocal arm swing during the turn; asynchronous sequencing of both feet to pivot; approaching the turn line straight on or actually beginning to rotate the body prior to reaching the turn line; and achieving a backward trunk lean prior to the actual turn.

ENDT group.
In contrast to the YNDT group, the characteristics observed in the ENDT group were less homogenous and more variable. Approximately 50% of the ENDT group matched the characteristics observed in the YNDT group, using a pivot strategy with 1 to 2 steps to accomplish the turn in 2.49 seconds or less with no sign of imbalance. The other 50% of the ENDT group demonstrated characteristics not seen in the YNDT group: use of more steps (3–4) to accomplish the turn, only partially pivoting on one foot in combination with extra steps or weight shift, and moderate to marked changes in speed during the turn, including coming to a complete stop. The intersubject variability in choice of strategies, number of steps, time to accomplish the turn, and use of arms/trunk/legs was minimal, but increased compared with the YNDT group. Minimal variability was observed within the 3 trials of 8 subjects, primarily in the categories of number of steps taken and time to make the turn. This variability was present only in the subjects who used a mixed type of turn; no variability was observed in those subjects who used a pivot type of turn.

EDT group.
The EDT group demonstrated indicators of difficulty that were characteristic only of this group. Almost 100% of the trials of the EDT group showed a complete absence of pivoting while turning. The EDT group was the only group that demonstrated staggering during the turn. The frequency with which staggering occurred across trials for the EDT group is presented in Table 10. Other characteristics particular to this group included use of multiple steps (5 or more) to achieve the turn; marked hesitancy, pauses, or stops entering, during, or leaving the turn; and increased time spent in the turn (>.3 seconds). The EDT group also demonstrated some of the characteristics observed in the ENDT group such as use of 3 to 4 steps to accomplish the turn, use of a mixed strategy, and mild to moderate hesitancy and change of speed during the turn. The ENDT group also demonstrated arms raised symmetrically in guard fashion away from the trunk in 49% of the trials. Although this frequency did not meet the 50% observed criterion that was set, it is noteworthy and warrants further investigation.


View this table:
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[in a new window] 		Table 10. Percentage of Occurrence Across 3 Trials Per Subject for Staggering During Turna

 
Summary of the 3 groups.
Overall, these results indicate that the EDT group took more steps during the turn than the YNDT and ENDT groups, took more time to accomplish the turn than the YNDT and ENDT groups, and did not use a pivot type of turn to accomplish the turn. Although no differences were found among the groups for the staggering category, the EDT group was the only group in which staggering was present.


   Discussion
Top
 Abstract
 Introduction
 Method
 Results
 Discussion
Conclusions
 References
 
Falls and fall-related injuries are a major health hazard to older adults. Because falling during turning while walking has been identified as a fall characteristic strongly associated with hip fracture, a functional assessment that accurately measures difficulty in turning would be a useful clinical tool for early recognition of those individuals who are at risk for falling. The main purpose of this study was to describe movement behaviors in elderly people that serve as indicators of degree of difficulty in turns during walking.

Indicators of Difficulty

Four categories of movement during turning were identified that were unique to a sample of older adults (EDT group) who reported having difficulty in turning while walking: (1) staggering during the turn, (2) the absence of pivoting during the turn, (3) using 5 or more steps or weight shifts to accomplish the turn, and (4) taking 3 seconds or longer to accomplish the turn (Fig. 2). We consider these characteristics to be indicators of difficulty for turning while walking.

All of the subjects in the YNDT group demonstrated a pivot turn, accomplished in less than 2.5 seconds, using 2 or fewer steps, whereas only 8 of the 15 subjects in the ENDT group demonstrated a pivot turn. The remaining 7 subjects in the ENDT group demonstrated a mixed strategy consisting of partial pivots plus extra steps (3–5 steps) and took slightly longer to accomplish the turn (2.5–2.99 seconds). Age and sex did not appear to be factors influencing these differences within the ENDT group. This different approach to turning in the ENDT group when compared with the YNDT group could be considered a developmental change in older adults. VanSant13 proposed that motor development is a lifelong process and that age-related change in movement patterns that may not be attributed directly to learning may occur throughout the human life span, not just during childhood. However, half of the subjects in the EDT group, who reported experiencing definite difficulty in turning while walking, demonstrated this same mixed type of turn. We believe that this shift to a modified turning strategy is an early indicator of underlying problems associated with difficulty in turning while walking.

One issue that we believe should be considered when studying these groups' differences is the potential lack of reliability of self-reports on the 6-item questionnaire used to identify individuals having difficulty in turning while walking. Other investigators have reported inconsistencies between self-report indexes and functional assessment indexes when elderly subjects are studied. Seeman et al17 reported improved sensitivity in elderly subjects, with minimal to no functional deficits, when using standardized performance measures rather than self-report indexes. Alexander et al18 had similar findings when investigating bed rise difficulty in elderly women. Elderly women with no apparent difficulty in rising from bed by self-report, by total rise time, and by total difficulty scale scores nevertheless showed differences in bed rise motion strategy when compared with young adults. Alexander et al hypothesized that conceivably these minor changes in strategy may emerge in response to subtle changes in balance over time. Minor changes occurring slowly over time may be imperceptible to the individual. Guralnik et al6 also found support for this concept, stating that decline or recovery from many age-related chronic conditions may continue for years and that detecting change may be difficult or impossible using self-reports. If this is the case, then these changes observed in the ENDT group could serve as early indicators of difficulty, which could provide the clinician with the opportunity to evaluate and address these potential functional limitations.

Simplification strategy used for loss of coordination.
We consider the almost total absence of a pivot type of turn in 95% of the trials in the EDT group to be an important finding and possibly the most definitive, readily observable indicator of difficulty. This finding is in contrast to the presence of a pivot type of turn in 100% of the trials in the YNDT group and 58% of the trials in the ENDT group. The EDT group, in our view, changed strategies to accomplish the turn. The YNDT and EDT groups used 2 distinctly different strategies to accomplish the same goal. The use of a slower stepping strategy in the EDT group rather than a ballistic pivoting strategy observed in the YNDT and ENDT groups may reflect a shift from feedforward to feedback mechanisms. The pivot turn is a fast, open-looped movement requiring feedforward mechanisms, whereas the multiple stepping turn is a slower, more closed-looped movement appearing to have increased feedback requirements. Spirduso19 argued that simplification is a major strategy used by older adults who are experiencing losses of coordination. To compensate for their losses, they make simpler, smaller, or slower movements that accomplish the same goals that were previously met by more complicated coordinated movements. Understanding the specific mechanisms underlying this change in movement strategy is not within the scope of this article, but certainly warrants further investigation.

Staggering as an indicator of instability.
Another characteristic unique to the EDT group was staggering. Although the criterion of 50% observed frequency was not met, staggering was selected as an indicator of difficulty for 3 reasons: (1) staggering is well supported as an indicator of instability during standing, walking, and turning in place,4,6,20–23 (2) staggering was observed only in the EDT group, and (3) the EDT group was mostly composed of independent, community-dwelling individuals who reported some difficulty in turning, with none reporting an inability to turn or a need for assistance in turning. Staggering may increase as the overall level of upright mobility and independence declines. This trend was observed in our data with 3 of the 4 subjects who staggered demonstrating all 4 indicators of difficulty and taking longer than 16 seconds to perform the Timed "Up & Go" Test.

Mean Times for Timed "Up & Go" Test

Using the Timed "Up & Go" Test, Podsiadlo and Richardson10 identified 3 groups among their sample of older subjects (mean age of 75 years): (1) Subjects who took less than 10 seconds on the Timed "Up & Go" Test were freely independent in mobility, (2) subjects who took between 10 and 20 seconds to complete the test were independently mobile with some limitations, and (3) subjects who took 30 seconds or more to complete the test needed the assistance of others for many mobility tasks. The mean time on the Timed "Up & Go" Test for our ENDT group (self-reported no difficulty in turning) was 9.62 seconds, compared with a mean time of 14.98 seconds for the EDT group (self-reported difficulty in turning). Based on each group's mean time and range of times, we can categorize our ENDT and EDT groups according to Podsiadlo and Richardson's findings, with our ENDT group meeting criteria for a freely independent group and our EDT group meeting criteria for an independently mobile group with some limitations. This observation leads us to propose that the self-report of difficulty in turning while walking may also serve as an indicator of a loss in overall mobility that might otherwise escape notice.

Future Directions

The 4 categories developed to identify difficulty in turning while walking may serve well as the basis for a scale for difficulty in turning in older adults. Preliminary findings support the need to study the reliability, validity, and sensitivity of measurements used to characterize difficulty in turning while walking. A longitudinal study assessing the sensitivity of the scale to changes in patient status would greatly enhance the usefulness of the scale. Additionally, this type of scale may be appropriate for other populations with turning difficulties, regardless of age. Further study with specific populations would be necessary to establish this type of instrument validation.

Clinical Limitations

Although analysis of turning while walking using the 4 categories of difficulty is a safe, simple test that is easy to administer, problems remain. A clear understanding of the turn and its variables is essential, in our opinion, for rating subjects accurately. In addition, at least one observation per item is required for scoring, with an initial observation required simply to identify the beginning and end of the turn. Videotaping of a patient might be necessary for reliable scoring, but might not reflect clinical practice.


   Conclusions
Top
 Abstract
 Introduction
 Method
 Results
 Discussion
 Conclusions
References
 
The purpose of our study was to identify and describe the movements that occur during turning while walking in adults and, specifically, the movements that characterize turning difficulty in older adults. Our most compelling finding was the absence of a pivot strategy to accomplish the turn in the group of elderly subjects who had reported difficulty in turning. Determining the causes of this change in strategy is not within the scope of this work and requires further analysis. We plan to use the results of this study as a basis for the development of a turning difficulty scale to be used with older adults. We believe this type of scale has potential as a useful assessment tool with geriatric patients and warrants future development and testing of the instrument.


   Footnotes
 
Ms Thigpen, Dr Light, and Ms Creel provided concept/research design, subjects, and project management. Ms Thigpen and Dr Light provided writing, and Ms Thigpen and Ms Creel provided institutional liaisons. Ms Thigpen, Ms Creel, and Ms Flynn provided data collection, and Ms Thigpen and Ms Flynn provided data analysis. Dr Light provided facilities/equipment, and Dr Light and Ms Flynn provided consultation (including review of manuscript before submission). The authors acknowledge Kathy Cook, PT, and Florida Sunshine Rehab, Gainesville, Fla, for provision of subjects and facilities/equipment. They also acknowledge Jim Cauraugh, PhD, Carolyn Hanson, PhD, and Denis Brunt, PhD, for consultation.

This study was approved by the University of Florida Health Center Institutional Review Board.

* Knoll Laboratories, Div of Knoll Pharmaceutical Co, 3000 Continental Dr N, Mount Olive, NJ 07828. Back


   References
Top
 Abstract
 Introduction
 Method
 Results
 Discussion
 Conclusions
 References
 

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