The effect of walking with an assistive device and using a wheelchair on school performance in students with myelomeningocele.

Controversy exists over the preferred method of mobility in school for children with myelomeningocele. These children, particularly those with lumbar-level lesions, frequently are encouraged to use crutch walking as the primary method of mobility at school, despite evidence that energy cost is high. [1] Advocatesfor ambulation with an assistive device maintain that walking is necessary to improve bowel and bladder function, prevent contractures and obesity, and increase bond density. [2] DeSouza and Carroll, [3] however, have reported that 50% of these children who have been independent ambulators will stop walking between the ages of 10 and 20 years. Alternatively, those who advocate the use of wheelchairs postulate that children with myelomeningocele who use wheelchairs learn earlier and become more skilled in activities of daily living, can move faster and compete better in sports, and are more likely to be continent and independent in bowel and bladder function. [4] In addition to lower-extremity paralysis, children with myelomeningocele may have cognitive, perceptual, or attentional deficits or upper-extremity dysfunction that affects academic performance. [5-7] Consequently, the decision on method of mobility at school must take into account not only physical status but also factors related to education and career preparation.

Compared with normal walking, ambulation with assistive devices consumes more oxygen per kilogram of body weight per meter traveled, independent of presence or absence of physical disability, type of disability, and age. [1,8-11] Williams et al [8] investigated the energy requirements for crutch walking and wheelchair propulsion in 15 children with myelomeningocele (8 children used crutches, 1 child used a walker, and 6 children used no upper-extremity aids). The authors found oxygen consumption ([Vo.sub.2]) per meter was significantly higher during ambulation than during wheelchair propulsion. Ambulation for the children with myelomeningocele was found to be 218% less energy efficient than that for nondisabled children. In contrast, wheelchair propulsion was as fast and as energy efficient as normal walking.

Agre et al [9] examined [Vo.sub.2] during crutch walking and wheelchair propulsion in 33 children with myelomeningocele. They found that, for children with functional levels of L-2 or higher, walking at the slowest speed measured (ie, 26.6 m/min) required an amount of energy equal to the children's maximal aerobic capacity. For childrenwith L3-4 levels, 85% of maximal aerobic capacity was required. These results indicate that a rapid onset of fatigue will occur at this level ofexertion. Crutch walking at a velocity of 53 m/min required 42% more energy expenditure than that required in propelling a wheelchair. At a velocity of 66 m/min, the usual speed of walking for nondisabled children, energy expenditure was only 9% greater for children with myelomeningocele when propelling a wheelchair than for nondisabled children during walking. Agre and associates suggested that, for some children, using wheelchairs when moving from one place to another may prevent excessive fatigue, thereby preserving energy for other activities.

Less invasive alternatives to the oxygen-collection apparatus used to measure [Vo.sub.2] are measures of energy efficiency based on heart rate. The physiological cost index (PCI) is a reliable measure of energy efficiency in walking that is based on the linear relationship of heart rate to [Vo.sub.2] and work. [12] The PCI is calculated by dividing the increase in heart rate attributable to walking by the sped of walking and is expressed in beats per meter. Butler et al [13] reported a mean PCI of 0.40 beats per meter for children without motor problems as compared with PCIs greater than 1.00 beats per meter for children with physical disabilities.

Based on the results of several studies of nondisabled, male, college-aged subjects, it is reasonable to assume that children with myelomeningocele whose walking is equivalent to heavy exercise may have compromised cognitive and fine motor performance, particularly when they are in upper-elementary and middle-school grades when walking speed and distance increase. Gutin and DiGennaro [14] found accurance in performance of arithmetic problems decreased hwen preceded by exercise of up to 97% of maximum heart rate (HRmax). In another study, [15] exercise for up to 10 minutes was found to enhance performance of fundamental arithmetic procedures; more than 10 minutes of exercise resulted in decreased accuracy. The effect of exercise on response to visual stimuli was examined by Salmela and Ndoye, [16] who concluded that exercise at 60% of HR-max caused a form of "central stressor interference" leading to the inability to process cues and focus attention. Spano and Burke [17] found performance of fine motor tasks decreased significantly when preceded by exercise above 75% of HRmax. Williams et al [18] reported both reaction time and movement speed were impaired immediately after exercise,although recovery occurred after serveral trials. If ambulation with asistive devices has an adverse effect on the academic performance of students with myelomeningocele, perhaps the emphasis on independent ambulation in school needs to be reconsidered.

The purpose of this study was to examine the effect of walking with an assistive device on three measures of school performance in three students with myelomeningocele. The following question was addressed using an alternating-condition, single-subject research design: For each student, is there a difference between the effect of ambulation with an assistive device and the effect of wheelchair propulsion on school performance, as measured by tests of reading fluency, visuomotor accuracy, and manual dexterity?

Method

Subjects

A 15-year-old boy (subject 1) from a middle school and a 10-year-old girl (subject 2) nad a 9-year-old boy (subject 3) from elementary schools in west-central Wisconsin participated in the study. Informed consent was obtained from one or both parents, and letters granting permission to carry out the study were obtained from administrators of each school district. To be included in the study, each subject had to meet the following criteria: (1) age 9 years or older, (2) diagnosed as having myelomeningocele with a lumbar-level lesion, (3) able to walk with crutches or a walker for most activities at home and school and to use a wheelchair proficiently, and (4) enrolled in a school program that required the ability to move between classrooms with nondisabled students. Subjects must also have shown a PCI greater than 1.00 beats per meter while walking with crutches or a walker. The PCI was determined by having each potential subject walk 200 m at maximal speed while heart rate was recorded every 25 m using an Exersentry heart rate monitor (*1) and time was recorded using a stopwatch. None of the subjects had medically diagnosed cardiac or respiratory problems. Characteristics of the subjects are presented in Table 1.

Instrumentation

Three tasks were selected as a sampling of skills necessary for school performance: reading fluency, visuomotor accuracy, and manual dexterity. Reading fluency, that is, accurate and automatic word recognition, is a prerequisite for reading comprehension. [19] Reading fluency was measured from an audiocassette recording of the student reading a word passage selected by the teacher.

Visuomotor accuracy was assessed using the Motor Accuracy Test-Revised (MAC-R) from the Southern California Sensory Integration Tests. [20] The MAC-R requires the child to trace with a red pen a printed, curved black line shaped similar to a butterfly. Points equaling the length (in inches) that the child's drawn line deviates from the printed black line, multiplied by a constant based on how far the drawn line is from the printed line, are subtracted from a score of 200, resulting in an accuracy score. The MAC-R assesses the status of a visuomotor response involving the ability to see and direct attentionto a printed line and coordinate the fine motor movement required to draw over the line. The MAC-R was selected as a measure of school performance representing skills used in printing and writing.

The manual dexterity task selected was the Purdue Pegboard Assembly subtest, which requires the child to use one hand to pick up and place a peg in a hole in the pegboard, and then to use the other hand to pick up and place a washer on the peg, followed by a cap, followed by another washer to make a complete four-piece assembly. [21] The Assembly subtest measures manual dexterity related to rapid, skilled bilateral

[TABULAR DATA OMITTED]

movements involved in manipulating objects. This subtest was selected as a measure of the type of manual dexterity required to perform various industrial arts and home economics activities.

Prior to beginning data collection, interrater reliability was determined by administering each of the three tests to five students not involved in the study. The first author and a teache rscored each test separately. All items were administered and scored according to instructions from the appropriate test manuals. Agreement of 80% or higher was designated as acceptable to begin the study. The following percentages of agreement were obtained for the three measures prior to beginning the study: reading fluency=98.8%, MAC-R=97%, and Purdue Pegboard Assembly subtest=100%. Interrater reliability during the study also was determined once for each subject. For all three subject, 100% agreement was obtained for both the Assembly subtest and reading fluency. On the MAC-R, 98% agreement was obtained for the first and third subjects and 99% agreement was obtained for the second subject.

Procedure

A three-phase, alternating-condition, single-subject design (phase 1=wheelchair propulsion, phase 2=ambulation with crutches or a walker, phase 3=wheelchair propulsion) was used. The three students began the study using only wheelchair mobility at school for 1 week. At the start of the second week, the students switched to only ambulation with crutches or a walker at school. At the beginning of the third week, the students changed back to only wheelchair mobility. Data were collected daily for 3 weeks or until a total of 15 measurements for each dependent variable had been recorded. Testing was scheduled so that it would not interfere with academic activities. Tests were administered during one of the last three periods of the day or immediately after school. For all three phases of data collection, subject 1 was tested during the last school period of the day, subject 2 was tested 1 hour before dismissal, and subject 3 was tested immediately after school.

Prior to the start of data collection, each student participated in a practice session to become familiar with the test procedures. The test procedures were identical for all three phases. For testing, the first author accompanied the student from his or her classroom to a designated testing room. For each student, the distance was predetermined and represented the student from his or her classroom to a designated testing room. For each student, the distance was predetermined and represented the student's usual between-class distance (Tab. 1). Upon entering the testing room, each student, walked or wheeled to an appropriately sized desk or table that allowed the student to sit in either his or her wheelchair or a straight-backed chair with erect posture, elbows and forearms resting on the tabletop, knees under the table, and feet on the floor or on wheelchair footplates. Each day, the order of presentation of the three tests was randomly determined. The test instrument was placed on the table in front of the student, and, after receiving instructions, the student began the task. A stopwatch was used to time the test activities. The tester's instructions to the student for each activity were written out and used daily with all three students to ensure uniformity of the test procedures.

Oral reading material was obtained from each student's reading teacher and copied on 21.6-x27.9-cm (8-1/2-x11-in) paper prior to beginning the study. The reading test was presented to the students with identical daily instructions. Each day a 100- to 200- word passage was given to the student to read with the instruction: "This is a story about [a brown horse]. Read it aloud now so we can find out what happens." The oral reading was recorded by an audiocassette recorder, which was placed on the table in front of the child. The MAC-R was administered and scored according to the instruction manual for the Southern California Sensory Integration Tests, [20] with the following exceptions: The test was administered only for the dominant hand, and the test's maximum performance time of 2 minutes was used to ensure that all children would be able to complete the test. The Assembly subtest was administered and score according to the Purdue Pegboard Examiner Manual instructions. [21] The MAC-R and the Assembly subtest also were presented to all of the students using identical daily instructions. During each test session, the students were encouraged verbally to give their best performance, and a reward system was used in which they earned points each day for following instructions, completing the tasks, and cooperating with the examiner. If the students accumulated enough points by the end of phase 3, they received a predetermined item (eg, favorite audiotape).

Data Analysis

Data considered of the number of correct words read per minute for reading fluency, the accuracy score for the MAC-R, and the number of pieces assembled per minute for the Purdue Pegboard Assembly subtest. Each student's scores for the three tests were plotte don separate standard line graphs. Data were analyzed using the graphic presented the graphic presentation and visual analysis method described by Ottenbacher. [22]

To further analyze data, the two--standard-deviation band method, a semistatistical procedure, was used. Using the method described by Ottenbacher, [22] a line two standard deviations above and below the mean score for phase 1 was extended to the data points for phase 2, and a line two standard deviation above and below the mean score for phase 2 was extended to the data points for

[TDO]

phase 3. When at least two successive data points in either phase 2 or phase 3 feel outside the extended two--standard-deviation bands, the difference between condition was considered to be statistically significant. To test for serial dependency prior to statistical analysis, autocorrelation co-efficients were calculated for each dependent variable. None f the correlations were significant.

Results

Reading Fluency

Mean reading fluency scores and standard deviations for each of the subjects during each of the phases are presented in Table 2. Subject 1 achieved his highest mean score during phase 2, subject 2 achieved her lowest mean score during phase 2, and subject 3 had mean scores that decreased progressively from phase 1 to phase 3. Among the subjects, the greatest mean difference in reading fluency between phase 2 and phases 1 and 3 was 7.8 words per minute. The number of words read correctly by the three subjects during each session and the results of the two-standard-deviation band analysis are presented in Figure 1. None of the subjects had two consecutive scores that were outside the two--standard-deviation band in either phase 2 or phase 3 (Fig. 1). The results indicate that reading fluency was not affected significantly by the mode of mobility.

Visuomotor Accuracy

Mean MAC-R scores and standard deviations for the three subjects during each of the phases are presented in Table 2. All three subjects had lower mean scores during phase 2 than during the other phases. Each subject's MAC-R scores and the results of the two--standard-deviation band analysis are presented in Figure 2. For subject 1, one data point in phase 2 was on the line, and the remaining four data points were below the two--standard-deviation band. All five data points in phase 3 were above the two--standard-deviation band. For subjects 2 and 3, five consecutive data points in phase 2 were below the two--standard-deviation band, and five consecutive data points in phase 3 were above the two--standard-deviation band. These results indicate that visuomotor accuracy was significantly lower during phase 2 than during phases 1 and 3 for all three subjects.

Manual Dexterity

Mean Purdue Pegboard Assembly subject scores and standard deviations for the three subjects during each phase are presented in Table 2. Subjects 1 and 2 achieved their lowest mean score during phase 2, and the largest mean difference was 3.2 units. For subject 3, the mean score increased in each successive phase. The number of pegboard pieces assembled correctly per session and the results of the two--standard-deviation band analysis are presented for each subject in Figure 3. For subject 1, two consecutive data points in phase 2 were below the two--standard-deviation band by 0.4 of a pegboard piece, and three consecutive data points in phase 2 were above the two--standard-deviation band. These results demonstrate that the subjects' performance in the test for manual dexterity was significantly lower during phase 2 than during phases 1 and 3. For subject 2, no consecutive data points were outside the two--standard-deviation band, indicating there was no difference in performance between the two methods of mobility. For subject 3, two consecutive data points in phase 2 were above the two--standard-deviation band, indicating a significantly higher performance during phase 2 than during phase 1.

Discussion

The performance measure that was affected by the method of mobility among all three students was visuomotor accuracy, as measured by the MAC-R. This finding is in accordance with findings that fine motor performance and ability to focus attention may be affected by submaximal exercise. [14,15] Additionally, the mean difference of 6.9 between MAC-R scores for phases 2 and 3 for subject 1; the mean differences of 6.1 and 6.25 between scores for phases 1 and 2 and phases 2 and 3, respectively, for subject 2; and the mean difference of 6.0 between scores for phases 1 and 2 for subject 3 are greater than the standard error of measurement for the 2-minute MAC-R, which is 5.24. [20] This finding suggests that the mean differences between phase 2 and phases 1 and 3 are too great to be attributed solely to intrasubject variability and measurement error.

The decrease in MAC-R scores that occurred during phase 2 of this study may be an example of superimposing a handicap on a deficit, as described by Leonard and Freeman. [23] Fine motor skills, ability to concentrate, and visual perception have been found to be deficient in children with myelomeningocele. [6,24-28] The three children in this study, when ambulating with an assistive device, appear to have an increased risk for poor school performance in activities requiring visuomotor coordination and the ability to comprehend printed detail.

The effect of the two methods of mobility on performance on the Purdue Pegboard Assembly subtest was not consistent across subjects. The scores of subject 1 decreased during phase 2, whereas the scores of subject 2 were not affected by the method of mobility. Although subject 3 demonstrated a significant increase in performance during phase 2, examination of means and celeration lines of the three phases clearly indicates that a practice effort occurred. Scores increased steadily on an almost daily basis, regardless of mobility mode. The difference in manual dexterity results among the three subjects was not expected, based on our findings for the MAC-R and the findings of previous studies [8-15] in which fine motor performance decreased with high-intensity exercise. Gardner and Broman, [29] however, suggest that the Assembly subtest is not very discriminating and may not present a challenge for children the age of the subjects in this study. The Assembly subtest does not appear to require as much precision as the MAC-R and perhaps was not as demanding for the subjects, despite the effects of exercise stress.

Performance in reading fluency was not significantly by method of mobility. This finding also was not expected, based on studies [12-14] in which an increased amount of exercise led to a decrease in cognitive performance. The phase in this study may have been too short for observable changes in oral reading to occur, because the subjects were still learning to read (Vicki E Snider, PhD, personal communication, April 3, 1989). Our procedures did not allow us to determine whether the results reflected the immediate effect of walking or propelling a wheelchair to the test site, the cumulative effect of walking or using a wheelchair the entire day, or a combination of both effects. Certain subject characteristics regarding energy consumption, however, are pertinent to this question. During the 200-m walk used to determine the PCI, the mean heart rates of subjects 1 and 2 exceeded 60% of estimated HRmax, and the mean heart rate of subject 3 exceeded 75% of estimated HRmax. For all three subjects, heart rates during PCI testing had increased to mean levels by the time subjects had walked a distance equal to the distance they walked to the test room. The PCI results suggest that all three subjects expended excessive energy walking to the test room and that the immediate effects of ambulating with assistive devices contributed to the difference in performance between phase 2 and phases 1 and 3.

In this study, the PCI proved a clinically feasible measure. We recommend including the PCI as part of a physical therapy assessment for children who walk with assistive devices, because it provides a measure of a child's energy cost while walking and possibly can be used to document the effectiveness of fitness programs. A high PCI can alert a therapist that the student is using excessive energy and that school performance may be at risk.

An important limitation of this study is the very limited generalizability of findings from three subjects. Additional studies that directly measure classroom performance are needed to investigage the effect on academic performance of ambulating with assistive devices. Another limitation is the possibility of examiner bias, because the examiner was aware of each subject's method of mobility. We believe that the potential for examiner bias was addressed by determining interrater reliability once for each subject during data collection.

Conclusions

The results of this study suggest that therapist and educators should be aware that increased energy consumption when ambulating with assistive devices may have a potentially negative effect on certain apsects of educational performance. Regardless of their view on mobility methods, physical therapist are encouraged to become involved in cooperative decision making with students, parents, classroom teachers, and physical education teachers regarding the selection of mobility methods and the need for program modifications. Combinations of assistive-device ambulation and wheelchair propulsion and adaptations in schedules are examples of how mobility methods can be successfully integrated into school programs. Providing children who have myelomeningocele with creative and challenging fitness programs at a young age and teaching them to assume resposibility for fitness maintenance may maximize energy efficiency during ambulation with assistive devices. Children who use wheelchairs at school may be encouraged to participate in walking programs at home or in the community. Through collaborative efforts, the mobility and physical fitness of students with myelomeningocele can be maintained without the disability having an adverse impact on education.

Acknowledgment 

We thank Dennis DePace, PhD, for his advice and assistance, Vicki E Snider, PhD, for her assistance with the reading measure; John Stallard for providing PCI information; and the three students, their parents, and their school districts for their participation and cooperation.

References

[1] Waters RL, Lunsford BR. Energy cost of paraplegic locomotion. J Bone Joint Surg [Am]. 1985;67:1245-1250.

[2] Rosenstein BD, Greene WB, Herrington RT, Blum AS. Bone density in myelomeningocele: the effects of ambulatory status and other factors. Dev Med Child Neurol. 1987;29:486-494.

[3] DeSouza LJ, Carroll N. Ambulation of the braced myelomeningocele patient. J Bone Joint Surg [Am]. 1976;58:1112-1118.

[4] Liptak GS, Bloss JW, Briskin H, et al. The management of children with spinal dysraphism. J Child Neurol. 1988;3:3-20.

[5] Knowlton DD, Peterson K, Putbrese A. Team management of cognitive dysfunction in children with spina bifida. Rehabilitation Literature. 1985;46:259-263.

[6] Sand PL, Taylor N, Hill M, et al. Hand function in children with myelomeningocele. Am J. Occup Ther. 1974;28:87-90.

[7] Tew B. The "Cocktail Party Syndrome" in children with hydrocephalus and spina bifida. Br J Disord Commun. 1979;14:89-101.

[8] Williams LO, Anderson Ad, Campbell J, et al. Energy costs of walking and of wheelchair propulsion by children with myelodysplasia: comparison with normal children. Dev Med Child Neurol. 1983;25:617-624.

[9] Agre JC, Findley TW, McNally MC, et al. Physical activity capacity in children with myelomeningocele. Arch Phys Med Rahabil. 1987;68:372-377.

[10] Cerny K, Waters R, Hislop H, Petty J. Walking and wheelchair energetics in persons with paraplegia. Phys Ther. 1980;60:1133-1139.

[11] Lough LK, Nielsen DH. Ambulation of children with myelomeningecele: parapodium versus parapodium with Orlau swivel modification. Dev Med Child Neurol. 1986;28:489-497.

[12] MacGregor J. The evaluation of patient performance using long-term ambulatory monitoring technique: the domiciliary environment. Physiotherapy. 1981;67:30-33.

[13] Butler P, Engelbrecht M, Major RE, et al. Physiological cost index of walking for normal children and its use an indicator of physical handicap. Dev Med Child Neurol. 1984;26:607-612.

[14] Gutin B, DiGennaro J. Effects of a treadmill run to exhaustion on performance of simple addition. Research Quarterly. 1968;39:958-964.

[15] Gupta VP, Sharma TR, Jaspal SS. Physical activity and efficiency and mental work. Percept Mot Skills. 1974;38:205-206.

[16] Salmeal JH, Ndoye OD. Cognitive distortions during progressive exercise. Percept Mot Skills. 1986;63:1067-1072.

[17] Spano JF, Burke EJ. Effects of three levels of work intensity on performance of a fine motor skill. Percept Mot Skills. 1976;42:63-66.

[18] Williams LRT, Pottinger PR, Shapcott DG. Effects of exercise on choice reaction latency and movement speed. Percept Mot Skills. 1985;60:67-71.

[19] Snider VE, Tarver SG. The effect of early reading failure on acquisition of knowledge among studednts with learning disabilities. Journal of Learning Disabilities. 1987;20:1-7.

[20] Ayres AJ. Southern California Sensory Integration Tests. Los Angeles, Calif: Western Psychological Services; 1972.

[21] Tiffin J. Purdue Pegboard Examiner Manual. Chicago, Ill: Scientific Research Associates Inc; 1968.

[22] Ottenbacher KJ. Evaluating Clinical Change: Strategies for Occupational and Physical Therapist Baltimore, Md: Willimas & Wilkins; 1986.

[23] Leonard CO, Freeman JM. Spina bifida: a new disease. Pediatrics. 1981;68:136-137.

[24] Grimm RA. Hand function and tactile perception in a sample of children and myelomeningocele. Am J Occup Ther. 1976;30:235-240.

[25] Mazur JM, Menelaus MB, Hudson I, Stillwell A. Hand function in children with spina bifida cystica. J Pediatr Orthop. 1986;6:422-427.

[26] Miller E, Sethi L. The effect of hydrocephalus on perception. Dev Med Child Neurol. 1971;13(suppl 25):77-82.

[27 Shaffer J, Friedrich WN, Shurtleff DB, Wolf L. Cognitive and achievement status of children with myelomeningocele. J Pediatr Psychol. 1985;10:325-336.

[28] Tew B, Laurence KM. The effects of hydrocephalus on intelligence, visual perception and school attainment. Dev Med Child Neurol. 1975;17(suppl 35):129-134.

[29] Gardner RA, Broman M. The Purdue Pegboard: normative data on 1,334 school children. Journal of Clinical Child Psychology. 1979;1:156-162.

Commentary

Although we often assume that the sole domain of physical therapy is the motor function of our patients, in reality our focus is the person who has a movement limitation. Our traditional reluctance to broaden our scope of concern to the entire realm of functioning of the patient in his or her relevant environment has often led to poorly conceptualized treatment plans and less-than-optimal outcomes. In spite of the frequent interdisciplinary nature of our work in school systems, and other community environments, many pediatric physical therapists have been slow to place mobility goals in the proper social and educational perspectives.

Frank and colleagues are to be commended for examining the effects of ambulation with an assistive device and wheelchair propulsion on preacademic performance of children with myelomeningocele. As physical therapists, we need to know how our clinical decisions regarding the method of functional ambulation affect energy consumption and performance in cognitive and fine motor domains. Although we have been trained that our physical therapy goals should emphasize increasingly normalized functioning, with a strong emphasis on ambulation, the cost-benefit ratio of ambulation may not always be advantageous to our patients.

Discussion regarding the controversy over real-life trade-offs of different functional movement options for children is now becoming more apparent in the physical therapy literature. For example, Fetters [1] has noted that an improvement in upper-extremity control in children with cerebral palsy may be associated with a functional loss in head and trunk control. Thus, the improvement in one area of function may have a negative rippling effect on other parts of the body. The proper evaluation of our programs must include a comprehensive assessment of the overall advantages and advisability of our treatments.

The results of this study also point out the necessity of evaluating the patient in the context of the relevant environment. Longitudinal studies in developmental psychology consistently support the importance of viewing the child's development in a transactional framework, emphasizing the interdependence of different domains and the interdependence between the child and his or her environment in the accomplishment of daily tasks. Functional performance is characteristic of the child in a context (eg, educational setting), not independent of context. The child may have the capability to ambulate with assistive devices, but the actual performance of the child may differ because of the difficulty of the task or the adverse effects on other important aspects of the child's life. Assessment procedures in special education have begun to shift from individual discipline-referenced assessments in isolated contexts to assessments of performance in the classroom environment using input from many professionals and parents. [2] Functional assessment procedures in physical therapy must continue to merge toward this transactional framework by recognizing the potential discrepancies between capability and the patient's functional performance, the interdependency across all domains or behavior, and the pervasive role of environmental conditions on functional performance. The dependency of functional performance on the demands and support of the environment is not a new theme in patient-outcome studies. Declines in functional performance between the rehabilitation clinic setting and the home setting have been a consistent finding in adult rehabilitation follow-up studies. [3,4]

In their study, Franks and colleagues used an alternating-condition, single-subject research design on three children with myelomeningocele. Of course, there are significant limitations in the generalization of these findings to other children, and further studies must be undertaken to replicate these preliminary results. In addition, the impact of the assisted ambulation phase was noted consistently across the three subjects only with the visuomotor accuracy scores. How this isolated preacademic loss in function may affect academic performance and future learning over the course of an academic year cannot be answered by this study. In effect, how serious these deficits may be to the long-term academic learning of the child is unclear. This study, however, clearly raises the possibility that a decrement in performance may occur in children who are asked to use large amounts of energy just to functionally ambulate within an educational environment. Much more research addressing this important issue must be undertaken in the educational environment, as well as in most of our practice settings in physical therapy.

In summary, the implications of this study may cause us to step back from our often aggressive posture toward functional ambulation at all costs. If assisted ambulation is not energy efficient, time efficient, or safe or leads to an interruption in social, emotional, or cognitive growth, then alternate means of mobility must be considered. Is not the aim of the physical therapist to promote overall development rather than to promote ambulation at a significant cost? Is not efficient, independent mobility the real functional goal for children and their families?

Stephen M Haley, PhD, PT Assistant Profesor Department of Rehabilitation Medicine Tufts University School of Medicine New England Medical Center Hospitals 750 Washington St, #75 K/R Boston, Ma 02111

References

[1] Fetters L. Measurement and treatment in cerebral palsy: an argument for a new approach. Phys Ther. 1991;71:244-247.

[2] York J, Rainford B, Giangreco MF. Transdisciplinary teamwork and integrated therapy: clarifying the misconception. Pediatric Physical Therapy. 1990;2:73-79.

[3] Haworth RJ, Hollings EM. Are hospital assessments of daily living activities valid? Int J Rehabil Med. 1979;1:59-62.

[4] Strub N, Levine RE. Self-care: a comparison of patients' institutional and home performance. OTJR. 1989;7:53-56.

Author Response

We thank Dr Haley for his thoughtful commentary. We appreciate this opportunity to expand our position.

We certainly agree with Dr Haley that further studies are needed to determine the effect of ambulation with assistive devices on academic performance not only for children with myelomeningocele, but for children with any physical disability. We also recognize the limitation of single-subject research when generalizing findings from one or a few subjects. In group designs, generalizability is accomplished through random selection of relatively large samples from homogeneous populations. Children receiving physical therapy services, however, are often from heterogeneous populations with low incidences of physical disability. Findley et al [1] found only 77 adolescents between the ages of 10 and 16 years who had myelomeningocele in the entire state of Minnesota, when age and the presence of myelomeningocele were the only qualifying criteria. According to Ottenbacher, [2] through replication across subjects, therapists, and settings, generalizability can be achieved. Systematic replication with school-aged children who have myelomeningocele and clinical replication with school-aged children who have other conditions requiring ambulation with assistive devices (eg, cerebral palsy) by public school therapists are needed.

Regular multidisciplinary team assessment could be performed with all children who use ambulation aids for mobility while at school, regardless of diagnosis. It is appropriate to seek teachers' perspectives regarding the effects of crutch walking on classroom performance. They are aware of how the students come to class (eg, Do they look tired? Are they always late?) and whether there are differences in performance between the beginning and end of class. Ongoing single-subject studies as described by Ottenbacher [2] could be a part of the annual individualized educational program evaluation process in schools. Frequent physiological cost index testing should be performed, especially at critical periods such as during growth spurts and when a student is advancing to middle school. Additional testing using other instruments that are more sensitive to the effects of exercise stress is also indicated. More important, perhaps, is assessment of a student's performance on materials that are part of classroom curricula, administered at specific times after the student has arrived at class. Such testing would be in a functional context and would measure relevant academic performance, as Dr Haley suggests. Liptak et al [3] describe two main goals in the management (including physical therapy) of children with myelomeningocele that are applicable to children using assisted ambulation: preventing dysfunction from becoming a disability and preventing a disability from becoming a handicap.

Catherine A Franks, MS, PT

Robert J Palisano, ScD, PT

Joan C Darbee, MS, PT

References

[1] Findley TW, Agre JC, Habeck R, et al. Ambulation in the adolescent with myelomeningocele, I: early childhood predictors. Arch Phys Med Rehabil. 1987; 68:518-522.

[2] Ottenbacher KJ. Evaluating Clinical Change: Strategies for Occupational and Physical Therapists. Baltimore, Md: Williams & Wilkins; 1986.

[3] Liptak GS, Bloss JW, Briskin H, et al. The management of children with spinal dysraphism. J Child Neurol. 1988;3:3-20.

CA Franks, MS, PT, is a doctoral student in the Motor Development Program, University of Wisconsin, Madison, WI 53702. Address all correspondence to Ms Franks at 3411 Country Club Ln, Altoona, WI 54700 (USA).

RJ Palisano, ScD, PT, is Associate Professor, Programs in Physical Therapy, Hahnemann University, Philadelphia, PA 19102.

JC Darbee, MS, PT, is Clinical Assistant Professor, Programs in Physical Therapy, Hahnemann University.

This study was completed in partial fulfillment of the requirements for Ms Frank's Master of Science degree in Pediatric Physical Therapy at Hahnemann University.

Partial funding was provided by Grant #G008530031 to Ms Franks from the US Department of Education.

Institutional approval for this study was obtained from the Chippewa Falls Area School District, the Eau Claire Area Schools, and Ladysmith-Hawkins Public Schools.