A Study on the Validity and Reliability of 6-Metre Timed Walk in Stroke Patients. Sau Ping Helen Lam PT, HHH

Transcription

1 A Study on the Validity and Reliability of 6-Metre Timed Walk in Stroke Patients. Sau Ping Helen Lam PT, HHH

2 INTRODUCTION Stroke is also known as cerebro-vascular accident (CVA). Survivors can experience loss of vision and / or speech, confusion and paralysis. Stroke is so called because of the way it strikes people down (WHO, 2005). Stroke is common in the sixth, seventh and eighth decades of life (WHO, 1989).

3 Annually, 15 million people worldwide suffer a stroke. Of these, 5 million die and another 5 million are left disabled permanently (WHO, 2005).

4 In Hong Kong, stroke is among the five leading causes of death (Hong Kong Hospital Authority, 2005). The Hong Kong Hospital Authority has reported that in 2004, there were 9,269 patients admitted to public and private hospitals due to stroke and 1,234 of them died (Hong Kong Hospital Authority, 2005).

5 One of the goals most frequently desired by patients who have had a stroke is that of walking again (Bohannon, 1986a). But it is often that clinicians note that some patients are able to walk without help, but physiotherapists comment that the gait is clinically abnormal (Wade, Wood, Heller, Maggs, and Hewer, 1987).

6 To monitor the walking progress of stroke patients, to bridge the gap between clinicians and physiotherapists in assessing patients gait, and to meet an increased demand for evidence that supports the effectiveness of physiotherapy techniques, we need valid and reliable measures to monitor treatment outcomes (Holden et al, 1986).

7 LITERATURE REVIEW Many measures can be used to document the walking progress of stroke patients, but the measurement of gait speed is particularly useful (Bohannon, 1986a). It is simple and quick. By using a stopwatch and tape measure, it can be done in the clinic/ hospital or at home easily (Green, Forster, and Young, 2002). The patient is timed when he walks with his own preferred walking aid over a set distance (Wade, 1992).

8 The validity of gait speed test in stroke patients has been established in many studies. Gait speed relates strongly to 1. cadence (steps/min) (Bohannon, 1986a; Bohannon,1987; and Bohannon, 1989), 2. the standardized knee extensor strength of the paretic leg (Bohannon, 1986a; Bohannon, 1989; and Bohannon, and Andrews, 1990), and 3. the type of walking aids used (Wade et al, 1987).

9 The most commonly used gait speed test is 10-metre timed walk (10MTW). The validity and reliability of 10MTW have been established in stroke patients (Wade et al, 1987; Maeda, Yuasa, Nakamura, Higuchi and Motohashi, 2000; Green et al, 2002; and Liston, and Brouwer, 1996).

10 But it may be time consuming for busy medical professionals to carry out the test. Some stroke patients may also find it exhausting. Besides, in space limited areas such as Hong Kong, it is not always possible to have a 10-metre long walkway for carrying out the test, especially during domiciliary services.

11 Some medical professionals have started using a walk test of shorter distance, the 6-metre timed walk (6MTW) (Hill, Goldie, Baker, and Greenwood, 1994; and Evans, Goldie, and Hill, 1997). But the validity and reliability of 6MTW have not been well established in stroke patients.

12 Aims to investigate the validity of 6MTW in stroke patients (by correlating 6MTW with cadence, standardized knee extensor strength, type of walking aids used, and 10MTW); to investigate the reliability (test-retest and intertester) of 6MTW in stroke patients.

13 METHODS Subjects: In-patients and day-patients receiving physiotherapy, with principal diagnosis of stroke, in Haven of Hope Hospital, from August 05 to March 06, were studied.

14 Test for Validity of 6MTW: A 10-metre walkway was marked out on the floor along the corridor outside the Physiotherapy treatment rooms. Red tape markers were placed at the 0-, 2-, 8-, and 10- metre points along the walkway (Figure 1).

15 Figure1. Patient undertaking the 6-Metre Timed Walk

16 The investigator used a stopwatch to time the patient over the central 6 metres and recorded the number of steps. The first and last 2 metres of the walk were not timed or counted because of changes in velocity. Gait speed (metres/min) and cadence (steps/min) were calculated from these data (Figure 1).

17 The isometric knee extensor strength of the paretic leg was tested using a dynamometer and standardized against the body weight. The type of walking aid (none, stick, small quadripod, large quadripod or frame) the patient was using during the timed walk was recorded. 10MTW was tested like the 6MTW, but on a 14-metre walkway, marked next to the 10-metre walkway, measuring the central 10 metres.

18 Test for Reliability of 6MTW: Test-retest reliability: Together with the validity test, the principal investigator instructed each subject to perform totally two 6MTWs. Inter-tester reliability: The co-investigator instructed each subject to conduct a third 6MTW on the next day. The 6MTW with the fastest time achieved on the day before was used together with the third walk to calculate the inter-tester reliability.

19 RESULTS Forty- five stroke patients (27 male and 18 female; mean age yrs) took part in this study. Significant correlations were found between 6MTW and cadence, standardized knee extensor strength, walking aids used, and 10MTW (rho = 0.924, 0.553, , and respectively, p < ). The ICC coefficients of test-retest and inter-tester reliability were (p = 0.000) and (p = 0.000) respectively.

20 DISCUSSION In the present study, 6MTW is found to be a valid and reliable outcome measure in stroke patients. The significant correlation between 6MTW and knee extensor strength gives us an inspiration of resistance training of the knee extensor muscles in order to improve the walking ability of the patient.

21 6MTW is simple and cost-effective. Regular measurement of this walk test can thus be easily incorporated into the operation of stroke rehabilitation. It can be used to judge the effectiveness of therapy and the walking progress of the patients.

22 Physiotherapists can use the result of the test in the early period post-stroke to help them in discharge planning too. It was previously found that stroke patients walked at 18m/min or less were likely to require inpatient rehabilitation whereas those who walked at 36m/min or faster were likely to be discharged home from the acutecare hospital (Salbach et al, 2001).

23 Physiotherapists can also use the result of the test to set rehabilitation goals for patients. For ambulatory patients who have to cross streets, they have to achieve a gait speed of at least 72m/min. Street lights in Hong Kong are timed assuming a velocity of at least 72m/min to safely cross the street (Transport Department, 1986). This is similar to the standard set in the United States (Hoxie and Rubenstein, 1994).

24 LIMITATIONS Because of the time limit, only a limited number of patients (45) were recruited. Therefore, it is not possible to divide the subjects into subgroups for analysis. The findings are only generalized to similar patients at similar stage after stroke.

25 FURTHER STUDIES Investigations on the inter-location reliability (hospital vs home) and the tester reliability of 6MTW within the home environment in stroke patients are suggested.

26 Thank you God bless