Reliability of measurements obtained with a modified functional reach test in subjects with spinal cord injury.

Balance has been studied in various ways: by

recording biomechanical descriptions of

balance reactions,[1-4] by examining physiological

components of balance,[5-9] and by investigating

changes in the ability of a person to balance across the

life span.[8,10-13] These studies provide a basis for

understanding human performance. Often, the measurements

obtained in research settings are not practical for

routine clinical application.

Most studies of balance have been performed with

subjects in the standing position, but studies of sitting

balance have also been reported.[14-17] Most studies of

sitting balance have used instrumentation similar to that

used for studies of standing balance.[14,15] Some balance

tests that are less dependent on instrumentation have

been introduced, but these measures are designed for

persons who can ambulate.[18,19] Only a few tests exist for

clinical balance assessment of nonstanding individuals.

One such test is the Seated Posture Control Measure,[16,17]

which is designed to document a child's posture in his or

her seating system and to assess his or her ability to

function. Unfortunately, the test is quite long (36 items)

and may not be generalizable to persons with a variety of

impairments, including persons with spinal cord injury

(SCI).[16,17]

The Functional Reach Test (FRT)[20] can be used to

measure standing balance. In our view, the FRT is fast

and easy to use. A study using the FRT with 217 elderly

male veterans (aged 70-104 years) demonstrated that

the test provides highly reliable measurements of balance

and can be used to predict the risk of falling.[21] The

FRT also can be used to estimate physical frailty[22] and to

demonstrate change in response to treatment.[23] In the

study by Weiner et al,[23] 28 inpatient male veterans were

tested every 4 weeks during a regular physical therapy

program, and increases in functional reach and other

mobility measures were documented. No control was

placed on the therapy received. Studies of FRT have also

demonstrated strong reliability and validity.[20-23]. The

FRT, therefore, possesses attributes that can make it a

meaningful and accessible test.

Measures that can be used to predict outcomes

regarding the balance of patients with SCI are not available.

Therapists cannot be certain that prescribed wheelchairs

or cushions provide patients with the most stable

positions from which they can function (ie, the best

balance). Defining positions that are stable and the effects

of equipment on stability would be helpful because

persons with paralysis are challenged to maintain their

balance during a variety of functional activities.

For the purposes of our study, we defined sitting balance

as the ability of a person to maintain control over

upright posture during forward reach without

stabilization. Any reaching task will be a challenge to upright

control for persons with partial or complete paralysis of

the trunk and arms. The primary purpose of our study

was to determine whether the FRT could be modified for

a group of individuals with SCI to provide reliable

measurements of sitting balance. A secondary purpose

was to determine whether the modified FRT could

measure differences in functional reach among different

levels of SCI.

Method

Subjects

Thirty male subjects participated in this study. The

subjects were between 18 and 45 years of age (X=30.8,

SD=7.2). Subjects were placed in groups based solely on

level of injury. All subjects had complete lesions

according to the American Spinal Injury Association's (ASIA)

Impairment Scale.[24] The sessions, therefore, were

classified as either ASIA A or ASIA B, because both

classifications are for complete motor injuries. The difference

between the categories is in sensation. There is no

sensation below the level of the lesion in ASIA A lesions,

but sensation can be partially spared in ASIA B lesions.

We chose these type categories of lesions to ensure that

there would be no lower-extremity motor function to

allow the subject to weight bear on the feet when

reaching forward in sitting. All subjects were recruited

from the following sources: scheduled medical

appointments for Magee Rehabilitation Hospital's

(Philadelphia, Pa) SCI follow-up system, teams that participated

in wheelchair sports tournaments, and persons

readmitted to Magee Rehabilitation Hospital for intensive

rehabilitation. All subjects were seen at least 1 month after

completion of their initial phase of rehabilitation.

Subjects were selected based on their SCI diagnosis and

assigned to one of three groups: group 1 (n=10)

consisted of subjects with C5-6 tetraplegia, group 2 (n=10)

consisted of subjects with T1-4 paraplegia, and group 3

(n=10) consisted of subjects with T10-12 paraplegia.

To be included in our study, subjects had to be able to sit

independently of a seating system with only a backboard

for support. The subjects' upper extremities had to be

without deformities, and each subject had to be able to

assume and maintain 90 degrees of shoulder flexion.

Muscle force (manual muscle testing), range of motion,

and the presence of musculoskeletal deformities in the

upper extremity used in reaching were examined at the

time of the testing. The presence of inadequate muscle

force to maintain shoulder flexion during reaching (as

measured by a break test of the shoulder flexors),

inadequate range of motion, or musculoskeletal

deformity meant elimination from the study. Spasticity, a

common sequela in persons with SCI, was not part of the

inclusion or exclusion criteria. Spasticity was not

measured in any subjects.

Instrumentation

A yardstick was attached horizontally to a wall by

Velcro[R](*) or tape. The method of attachment varied,

depending on the site of data collection. According to

Duncan et al,[20] the method used to attach the yardstick

is not crucial. All subjects sat on a narrow mat table or a

padded weight bench, which were of similar width

(about 61 cm [24 in]). The same backboard was used and

kept at the same angle of 80 degrees for all subjects. This

angle allowed all subjects to sit back and relax between

trials. The backboard used in this study is also typically

used for supporting sitting activities during

rehabilitation of patients with SCI (Figure).

[FIGURE ILLUSTRATION OMITTED]

Procedure

Informed consent was obtained once subjects were

determined to be eligible for the study. The procedure

for the collection of data closely followed the procedure

described by Duncan et al.[20] Once each subject was

positioned on the mat table, the yardstick was placed

along the subject's shoulder at the level of the acromion.

Subjects sat in the same position for each trial. Their

hips, knees, and ankles were positioned with 90 degrees

of flexion, and there was 5.08 cm (2 in) of clearance

between the popliteal fossa and the mat table. Foot

support was provided, if necessary, with a rubber floor

mat to ensure proper sitting position. The backboard

was placed behind each subject for support (Figure).

Initial reach was measured with each subject resting

against the backboard with an upper-extremity flexed to

90 degrees. The anatomical landmark used to measure

reach was the ulnar styloid process. Because the subjects

with tetraplegia in our study could not make a fist, this

landmark was used instead of the third metacarpal,

which was used in the original studies of FRT.[20-23] The

ulnar styloid process is a prominent landmark and was

proximal enough to allow accurate measurements to be

taken for all subjects. Subjects used the nonreaching

upper extremity for counterbalance only (eg, no weight

bearing or holding on was allowed). The subjects were

guarded for safety, and the trial was repeated if the

subject required assistance to recover to the backboard.

Two sites were used for data collection. Limitations of

the physical facilities at one of the data collection

locations necessitated that all 8 subjects who were tested

there use their left upper extremity. The remaining 22

subjects who were tested at the other facility used their

right upper extremity. All methods were otherwise the

same between the sites.

Each subject had two practice trials of maximal forward

reach, followed by three trials during which data were

collected. The mean of these three trials was recorded.

Following the initial three trials, each subject left the

testing area for 10 minutes and then returned to

undergo repeated testing using the same procedure. A

single rater (SML) collected all data for this study.

Data Analysis

Test-retest reliability was studied using the intraclass

correlation coefficient (ICC[3,2]) because there was a

single rater.[25] Calculations were performed using a

spreadsheet software package.[dagger] Because a secondary

purpose of our study was to determine whether the

modified FRT could measure differences among levels

of lesion, a one-way analysis of variance (ANOVA) was

used to test for differences among the means for reach

in the three groups. A Newman-Keuls test was used to

discern differences among group means and to ensure

that Type I error was minimized.[25]

Results

Mean reach data for the subjects are presented in the

Table. The results indicated that the reliability of

measurements obtained with the modified FRT was very

strong. The ICCs for test-retest reliability of

measurements of average reach length were .94 for group 1, .85

for group 2, and .93 for group 3. There were no

differences between the subjects who used their right

upper extremity and the subjects who used their left

upper extremity to perform the reaches.

The modified FRT was also tested for its ability to

distinguish level of lesion. Mean maximal reach was 14.7

cm (SD=7.6, range=3.3-27.4) for group 1, 15.5 cm

(SD=4.3, range=7.6-21.3) for group 2, and 22.9 cm

(SD=5.6, range=14.7-99.2) for group 3. A one-way

ANOVA was used to determine that subjects with lower

levels of lesion had a longer reach compared with

subjects with higher levels of lesion. The Neuman-Keuls

test demonstrated that reach differed only between

groups 1 and 3 and groups 2 and 3. There was no

difference in reach between groups 1 and 2.

Discussion

Forward reach in a sitting position can be measured

reliably via a ruler attached to a wall alongside a patient

with SCI. The modified FRT achieved ICCs for test-retest

reliability similar to those documented in the original

FRT studies.[20-23] Generalizability of test-retest reliability

is weak because only one rater was available for data

collection. Further study using an interrater design may

allow differences to be generalized to a greater number

of situations.

The modified FRT appears to be useful for determining

differences in reach among different levels of lesion in

persons with SCI. The modified FRT measured

differences in reach between groups 1 and 3 and groups 2 and

3. There was no difference in the ability: to reach

between groups 1 and 2, but mean reach was greater in

group 3 compared with groups 1 and 2. This finding

appears to be reasonable because people with lower

levels of paraplegia tend to have greater functional

capabilities than people with higher levels of lesion do.

The subjects in group 3 had abdominal and back

extensor muscles that were unaffected by their SCI, which

apparently, gave them a greater advantage in movement

control.

The modified FRT did not appear to detect differences

between the subjects with tetraplegia (group 1) and the

subjects with higher levels of paraplegia (group 2).

Although the subjects with higher levels of paraplegia

had more unaffected muscles than the subjects with

tetraplegia did, reach outcomes were similar. Further

study is needed.

Although our study indicates that reliability exists for

measurements obtained with the modified FRT, more

research is needed to establish validity. Face validity is

the assessment of how well a test appears to measure

something specific. In our study, subjects with varying

amounts of paralysis were asked to reach forward and

move without any assistance from their base of support.

We believed that each subject had to move to the limits

of his stability without loss of balance. We contend that

it is important for a test to measure what clinicians and

patients believe can affect the patients' functional

performance. According to Campbell[26] in her discussion of

face validity, better performances may occur when

patients are challenged appropriately by a test, and

poorer performances occur when patients believe that

the test has no meaning for their problem. Face validity

appears to be present in the modified FRT because

subjects felt the challenge to their stability and had to

make great effort not to fail or a fall would occur.

Future research is needed to obtain evidence that the

modified FRT can be used to predict future outcomes

(predictive validity) or current balance status. We believe

that the modified FRT should be compared with measures

of established criterion-related validity.

Strengthening validity may demonstrate that the modified FRT is

a proper method to answer clinical or research

questions.

Studies using the modified FRT would improve its

usefulness. Because patients with SCI sit on different

support surfaces (cushions and wheelchairs),

comparisons could be made only among different products.

Measurement of functional reach may cause clinicians to

prescribe equipment based on its effects on sitting

balance.

Conclusion

This study examined the use of the FRT for a population

that cannot stand: persons with complete SCI. The

modified FRT can become a highly useful test because it

is easy and fast to perform and adaptable to many

environments. The purpose of this study was to test

whether the FRT could provide reliable

measurements in persons who are unable to stand. Before the measurements

can be shown to be useful, research on their

validity is needed.

Table

Maximal Functional Reach

          Maximal

Subject   Functional

No.(a)    Reach (cm)(b)



   1       14.10 (5.55)

   2        8.48 (3.34)

   3       14.61 (5.75)

   4       27.53 (10.84)

   5       19.91 (7.84)

   6       22.12 (8.71)

   7        3.40 (1.34)

   8       12.70 (5.00)

   9        2.54 (3.21)

  10       15.04 (5.92)

  11       17.78 (7.00)

  12       15.77 (6.21)

  13        7.62 (3.00)

  14       20.32 (8.00)

  15       21.39 (8.42)

  16       11.63 (4.58)

  17       12.93 (5.09)

  18       17.35 (6.83)

  19       12.80 (5.04)

  20       17.48 (6.88)

  21       29.12 (11.46)

  22       27.31 (10.75)

  23       19.91 (7.84)

  24       24.03 (9.46)

  25       17.15 (6.75)

  26       28.37 (11.17)

  27       28.37 (11.17)

  28       23.93 (9.42)

  29       15.24 (6.00)

  30       14.71 (5.79)

(a) Group 1 (C5-6 tetreplegia): subjects 1-10; 2 (T1-4 paraplegia):

subjects 11-20; group 3 (T10-12 paraplegia): subjects 21-30.

(b) Measurements in inches shown in parentheses.

(*) Velcro USA Inc, 406 Brown Ave., Manchester, NH 03108.

[dagger] Microsoft Excel 5.0, Microsoft Corp, One Microsoft Way, Redmond, WA

98052.

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