Contrary to common belief, sitting balance and selective

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1 Additional Exercises Improve Trunk Performance After Stroke: A Pilot Randomized Controlled Trial Neurorehabilitation and Neural Repair Volume 23 Number 3 March/April The American Society of Neurorehabilitation / hosted at Geert Verheyden, PhD, Luc Vereeck, MSc, Steven Truijen, PhD, Mark Troch, MSc, Christophe LaFosse, PhD, Wim Saeys, MSc, Els Leenaerts, MSc, An Palinckx, MSc, and Willy De Weerdt, PhD Background. Sitting balance and the ability to perform selective trunk movements are important predictors of functional outcome after stroke. However, studies evaluating the effect of exercises aimed at improving trunk performance are sparse. Objective. To examine the effect of additional trunk exercises on trunk performance after stroke. Methods. An assessor-blinded randomized controlled trial was carried out at an inpatient stroke rehabilitation center. In total 33 participants were assigned to an experimental group (n = 17) or a control group (n = 16). In addition to conventional therapy, the experimental group received 10 hours of individual and supervised trunk exercises; 30 minutes, 4 times a week, for 5 weeks. Trunk performance was evaluated by the Trunk Impairment Scale (TIS) and its subscales of static and dynamic sitting balance and coordination. A general linear repeated measures model was used to analyze the results of our study. Results. No significant differences were found pretreatment between the 2 groups for the collected demographic variables, stroke-related parameters, clinical measures, number of therapy sessions received, and primary outcome measure used. Posttreatment, a significantly better improvement was noted in the experimental group compared to the control group for the dynamic sitting balance subscale only; measuring selective lateral flexion initiated from the upper and lower part of the trunk, (P =.002, post hoc power calculation =.90, effect size = 1.16). Conclusions. Our results suggest that, in addition to conventional therapy, trunk exercises aimed at improving sitting balance and selective trunk movements have a beneficial effect on the selective performance of lateral flexion of the trunk after stroke. Keywords: Stroke; Rehabilitation; Randomized controlled trial. Contrary to common belief, sitting balance and selective trunk movements remain impaired after stroke. 1 Trunk muscle strength measured by means of a hand-held dynamometer has shown to be significantly impaired in people with stroke in comparison to matched controls for lateral flexion to the affected and nonaffected side as well as forward flexion. 2 Studies using isokinetic dynamometry have also observed significantly lower muscle strength after stroke in comparison to age-matched healthy controls for trunk rotation and trunk flexion-extension. 3,4 More recently, a study using a clinical measurement tool also found significantly lower scores for trunk performance in people with stroke compared with age- and gender-matched healthy individuals. 5 There is convincing evidence that trunk performance is an important predictor of functional outcome after stroke. 6-8 A recent cross-sectional study showed a clear relation between trunk performance and measures of balance, gait, and functional ability after stroke. 9 Furthermore, trunk performance, assessed on admission to a rehabilitation center, was the most important prognostic factor of the Barthel Index score at 6 months after stroke; even more important than the Barthel Index score on admission itself. 10 Despite evidence demonstrating the importance of trunk performance after stroke, studies evaluating therapy aimed at improving trunk function are limited. Dursun et al, examined the effect of the use of an angular biofeedback device in training stroke patients with impaired sitting balance. 11 Mean time to achieve sitting balance in patients using biofeedback was significantly shorter than that of patients receiving conventional therapy. However there was no significant difference in level of sitting balance and independent ambulation between both groups at discharge. Dean and colleagues reported on the beneficial effect of practicing reaching tasks beyond arm s length on sitting ability and quality, reaching, and standing up, both in the acute and chronic phase after stroke. 12,13 Six months after stroke, participants in the experimental group showed a significantly larger maximum reach distance and peak vertical force through the affected foot during standing when treated early after stroke. 13 To the best of our knowledge, no study has evaluated a hands-on physiotherapy intervention for treating trunk performance after stroke. Therefore, it was the aim of this study to investigate the effect of additional exercises, aimed at improving sitting balance and selective trunk movements, on trunk performance after stroke. From the Department of Rehabilitation Sciences, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Belgium (GV, WDW); Division of Neuromotor and Psychomotor Physical Therapy, Department of Health Care Sciences, University College of Antwerp, Merksem, Belgium (LV, ST, WS, EL, AP); Scientific Unit Rehabilitation Centre Hof ter Schelde, Antwerpen, Belgium (MT, CL). Address correspondence to Geert Verheyden, PhD, University of Southampton, School of Health Sciences, the Stroke Association Rehabilitation Research Centre, Southampton General Hospital, Mailpoint 886, Tremona Road, Southampton, United Kingdom, S016 6YD. gv@soton.ac.uk. 281

2 282 Neurorehabilitation and Neural Repair Subjects Methods Participants were recruited from the rehabilitation center Hof ter Schelde (Antwerp, Belgium) if they attended the inpatient stroke rehabilitation program and had a hemiparesis that was stroke related. Stroke diagnosis was confirmed by the consultant appointed at the rehabilitation center on the basis of CT or MRI imaging. Patients who suffered from an earlier stroke were only allowed in the study if they were fully recovered. In case of aphasia, patients relatives were asked to give informed consent. Patients were excluded from the study if they were 80 years of age or older, were not able to understand the instructions, had other disorders that could affect motor performance, or obtained a maximum trunk performance score at the start of the study. Trunk performance was evaluated by means of the Trunk Impairment Scale (TIS). 14 Figure 1 shows the flow diagram from the study. Over an 8-month period (September 2004 to April 2005), 102 patients were attending the stroke rehabili tation program. A total of 69 patients were ineligible for inclusion and thus 33 patients were assigned to an experimental or control group. Design The design of this study was an assessor-blinded randomized controlled trial. Prior to the initial evaluation, participants were divided by simple randomization into an experimental or control group. Randomization was done by a person who was not involved in the assessment or treatment of the patients. Seventeen participants were assigned to the experimental group (conventional rehabilitation program and 10 hours of additional trunk exercises over a period of 5 weeks) and 16 were assigned to the control group (conventional rehabilitation program). There were no dropouts during the course of the study, but 2 patients in the experimental group had 3 and 4 fewer hours of additional therapy sessions because of early discharge from the rehabilitation center (20 and 21 days after inclusion in the study). In the control group, 3 patients were discharged after 21, 23, and 25 days, respectively. All participants were evaluated before discharge from the rehabilitation center and included in the analysis. Ethical approval for the study was given by the ethics committee at the rehabilitation center where the study was conducted. Intervention Patients in the experimental and control groups received the conventional multidisciplinary stroke rehabilitation program provided by the rehabilitation center. The conventional treatment program is patient-specific and consists mainly of physiotherapy, occupational therapy, and nursing care. Neuropsychological and speech therapy are provided if needed. Therapists combine elements from different neurological Figure 1 Flow Diagram for Subject Assignment in the Study Total number of subjects attending inpatient rehabilitation program over an 8-month period (n = 102) Ineligible for inclusion (n = 69) age > 80 years: 28 communication problems: 11 comorbidities affecting motor performance: 27 maximum trunk performance score at the start of the study: 3 Experimental group (n = 17) Conventional therapy program plus 10 hours of trunk exercises Evaluated pretreatment Posttreatment assessment (n = 17) after 5 weeks of therapy (2 subjects were discharged early but included in the analysis) Number of patients before randomization (n = 33) treatment concepts but the main emphasis is on the neurodevelopmental treatment concept and on motor relearning strategies. In addition to the conventional treatment, patients from the experimental group received 30 minutes of extra training, 4 times a week, for 5 weeks. In total, 10 hours of additional training were given. The additional exercises consisted of selective movements of the upper and lower part of the trunk in supine and sitting. Supine exercises, with the legs bent and the feet resting on the treatment table, included selective anterior-posterior movements of the pelvis, extension of the hips (bridging), and rotation of the trunk initiated from the upper and lower part of the trunk. Exercises in a sitting position included: flexion and extension of the trunk (the patient flexes and extends the trunk without moving the trunk forwards or backwards); flexion and extension of the lumbar part of the spine (this involves selective anteflexion and retroflexion of the lower part of the trunk); flexion and extension of the hips with the trunk extended (with an extended trunk, the movement is initiated in the hips and the patient brings the extended trunk forwards and backwards); Control group (n = 16) Conventional therapy program Evaluated pretreatment Posttreatment assessment (n = 16) after 5 weeks of therapy (3 subjects were discharged early but included in the analysis)

3 Verheyden et al / Exercises to Improve Trunk Performance After Stroke 283 lateral flexion of the trunk initiated from the shoulder and pelvic girdle (from the shoulder girdle means that the patient touches the exercise table with one elbow and returns to the starting position, from the pelvic girdle means that the patient lifts one side of the pelvis and returns to the starting position); rotation from the upper and lower part of the trunk (from the upper part of the trunk means that the patient moves each shoulder forwards and backwards, from the lower part of the trunk means that the patient, while sitting in the upright position, moves each knee forwards and backwards); and finally shuffling forwards and backwards on an exercise table (the participant shifts the weight from one side to the other and moves forwards and backwards on the exercise table). Exercises were gradually introduced and the number of repetitions was determined by the therapist on the basis of the patients performance. Assessment The Tinetti Scale was used to document the patients balance and gait performance. The balance subscale consists of 9 balance tasks. The score ranges from 0 to 16 points. The gait subscale evaluates 7 gait maneuvers and is scored on a scale from 0 to 12 points. Consequently the total Tinetti score ranges between 0 and 28 points, with a higher score indicating a better performance. The Tinetti Scale has been developed for the elderly but it has also been reported in stroke patients. 15,16 Every participant was also graded on the Functional Ambulation Category to evaluate the level of dependency during walking. The grades range from 0 (requiring continuous support from 2 persons) to 5 (being able to walk indoors and outdoors without supervision). Reliability for the Functional Ambulation Category score has been reported in the literature. 17,18 The primary outcome measure used in this study was the TIS and its subscales. The TIS assesses static sitting balance, dynamic sitting balance, and trunk coordination on a scale ranging from 0 to 23 points, a higher score indicating a better trunk performance. The subscale static sitting balance evaluates if a patient can maintain a sitting posture with both feet on the floor and with the legs crossed. Furthermore, the patient is asked to cross the nonaffected leg over the hemiplegic leg while keeping the trunk upright and stable. The dynamic sitting balance subscale evaluates lateral flexion initiated from the upper and lower part of the trunk. Adequate movement and possible compensations are scored on a dichotomous scale. Finally, trunk coordination is assessed by asking the patient to selectively rotate the upper and lower part of the body. Again adequate rotation and compensations are evaluated. The maximum score on the subscales of the TIS are 7, 10, and 6 points, respectively. Adequate psychometric properties for the TIS in stroke patients are reported elsewhere. 14 Statistical Analysis Variables collected to describe our sample were age, gender, time since stroke onset, type of stroke, paretic side, Tinetti balance, gait and total score, Functional Ambulation Category score, amount of physiotherapy and occupational therapy received during the 5-week period, and initial score on the TIS and its subscales. Patient s characteristics measured on a continuous scale were examined to evaluate normal distribution of data. This was done by the Kolmogorov- Smirnov test and visual inspection of the data by means of histograms. Because only one variable, the score on the static sitting balance subscale of the TIS, showed consistent and significant skewness, it was decided to use parametric statistics to analyze the data. To examine the effect of our randomization procedure, differences between all variables mentioned above for the experimental and control groups were evaluated by means of independent t test or chi-square test for continuous or dichotomous measures, respectively. For continuous measures, equality of variances was assessed by means of Levene s test and according P values reported. To analyze the results of our study, a general linear repeated measures model was used. The pretreatment and posttreatment results were entered as within-subjects variable time, the experi-mental and control groups were included as between-subjects factor condition. P values for the variable time would indicate whether there is a significant change between pretreatment and posttreatment assessment. A significant interaction of time*condition would mean that the change between pretreat ment and posttreatment evaluation is significantly different between the experimental and control groups. Post hoc power calculation was performed together with the determination of the effect size and number needed to treat. Data analysis was performed using SPSS for Windows version The level of significance for all analyses was set at P <.05. Results In total, 33 patients were included in the analysis, of which 17 were in the experimental group and 16 were in the control group. Characteristics of both groups are shown in Table 1. No significant differences were found between subjects in the experimental and control groups for the collected demographic variables, stroke-related parameters, clinical measures, number of physiotherapy and occupational therapy sessions received over the 5-week period, and primary outcome measure used in this study. Results of the general linear repeated measures model are presented in Table 2. All P values for the variable time were significant, indicating that our sample of stroke patients clearly improved over the 5-week period for the score on the total TIS and the static sitting balance, dynamic sitting balance, and coordination subscales. The interaction parameter of time*condition was only significant for the score on the dynamic sitting balance subscale of the TIS (P =.002). Patients in the experimental condition improved significantly better compared to the control group. Mean (SD) score on the dynamic sitting balance subscale for the experimental group was 5.12

4 284 Neurorehabilitation and Neural Repair Table 1 Characteristics of the Two Groups Variable Experimental Group (n = 17) Control Group (n = 16) P Value Age (mean [SD] years) 55 (11) 62 (14).122 a Gender (women/men) 6/11 7/9.619 b Time since stroke onset (mean [SD] days) 53 (24) 49 (28).697 a Type of stroke (ischemia/hemorrhage) 15/2 13/3.576 b Paretic side (left/right) 8/9 9/7.598 b Tinetti balance (mean [SD] score) 9.65 (4.87) 8.75 (5.6).626 a Tinetti gait (mean [SD] score) 6.94 (3.34) 5.94 (4.23).454 a Tinetti total (mean [SD] score) (7.94) (9.62).539 a Functional Ambulation Category (mean [SD] score) 2.65 (1.32) 2.19 (1.68).388 a Physiotherapy (mean [SD] sessions) 23 (4) 24 (6).646 a Occupational therapy (mean [SD] sessions) 22 (4) 24 (6).208 a Trunk Impairment Scale (mean [SD] score) (3.76) (5).515 a Static sitting balance (mean [SD] score) 6.06 (1.64) 6 (1.75).921 a Dynamic sitting balance (mean [SD] score) 5.12 (2.18) 6.44 (2.76).136 a Coordination (mean [SD] score) 3 (1.28) 2.75 (1.24).572 a a Evaluated by means of independent t test. b Evaluated by means of chi-square test. Table 2 Outcome Measures in the Experimental and Control Groups Pretreatment Posttreatment P Value Outcome Measures Experimental Control Experimental Control Time Time*Condition Trunk Impairment Scale (range 0-23) (3.76) (5) 19 (2.78) 18.5 (3.12) < Static sitting balance (range 0-7) 6.06 (1.64) 6 (1.75) 6.59 (1.28) 6.69 (.6) Dynamic sitting balance (range 0-10) 5.12 (2.18) 6.44 (2.76) 8.59 (1.41) 7.69 (2.34) < Coordination (range 0-6) 3 (1.23) 2.75 (1.24) 3.82 (1.43) 4.13 (1.15) < Values are presented as mean (SD). P values are the result of the general linear repeated measures model. (2.18) pretreatment and 8.59 (1.41) posttreatment. For the control group, mean (SD) dynamic sitting balance subscale scores changed from 6.44 (2.76) pretreatment to 7.69 (2.34) posttreatment. No significant between-group differences were noted for the other subscales or the total score of the TIS. Post hoc calculations for the total TIS and its subscales are presented in Table 3 and include power, effect size, mean difference, and numbers needed to treat. Analysis for the dynamic sitting balance subscale revealed a sufficient power of 0.90, which is above the suggested value of 0.80 by Cohen. 19 An effect size of 1.16 was calculated for the dynamic sitting balance subscale. The mean difference in effect between the 2 interventions (with or without additional trunk exercises) was 2.22 (95% CI ), being >22% of the highest possible score of this subscale. When a minimum of 10% change was chosen as a clinically significant change, the numbers needed to treat were This would mean that 2.25 patients after stroke are needed for each patient improving at least 10% during inpatient rehabilitation. Power, effect size, and mean difference for the TIS total score and static sitting balance and coordination subscale scores were all lower than the values for the dynamic sitting balance subscale. Numbers needed to treat for the TIS total score and static sitting balance subscale score were greater than for the dynamic sitting balance. A negative number needed to treat was found for the coordination subscale, which is probably related to the relatively greater improvement of the control group compared to the experimental group on this subscale. Discussion It was the aim of this study to evaluate the effect of additional trunk exercises on trunk performance after stroke. We used an assessor-blinded randomized controlled trial and compared an experimental group, which received conventional therapy plus 10 hours of trunk exercises, with a control group, which received conventional therapy only. Our results suggest that extra task-specific practice of exercises aiming to improve

5 Verheyden et al / Exercises to Improve Trunk Performance After Stroke 285 Table 3 Post Hoc Calculations Numbers Needed to Outcome Measures Power Effect Size Mean Difference (95% CI) Treat (>10% Improvement) Trunk Impairment Scale (range 0-23) (-1, 3.52) 3.68 (>4 points improvement) Static sitting balance (range 0-7) (-0.92, 0.60) (>1 points improvement) Dynamic sitting balance (range 0-10) (0.86, 3.58) 2.25 (>2 points improvement) Coordination (range 0-6) (-1.25, 0.15) 5.91 (>1 points improvement) trunk performance resulted in short-term improvement above what was found by conventional therapy only, on the dynamic sitting balance subscale of the TIS. The dynamic sitting balance subscale evaluates selective lateral flexion of the upper and lower part of the trunk. 14 Stability during selective trunk movements, appropriate shortening and lengthening of the trunk, and eventual compensations are evaluated. Over a 5-week period, the mean scores on the dynamic sitting balance subscale in the experimental group improved from 5.12 to 8.59 and in the control group from 6.44 to That is an improvement of 34.7% and 12.5% of the total score range, respectively. This means the experimental group improved almost 3 times more than the control group. Post hoc power and effect size calculations were high (0.90 and 1.16, respectively) and number needed to treat was low (2.25), which supports the significance of our findings. Significant within-group differences were found for the total TIS and all 3 subscales. For the static sitting balance subscale, this a notable result because the mean score on the static sitting balance subscale for both groups pretreatment was already 6 out of a maximum of 7 points. There is evidence in the literature that the subscales of the TIS contain a hierarchy. In a sample of 40 stroke patients, static sitting balance appeared to be easier than dynamic sitting balance, and dynamic sitting balance in its turn easier than coordination. 5 This hierarchy possibly explains why our study demonstrated a beneficial effect for the experimental group compared to the control group for dynamic sitting balance only, and not for static sitting balance, coordination, or the total TIS. On the one hand, values for the static sitting balance scores were pretreatment already at a sub-maximal level. On the other hand, 10 hours of training may not have been enough to result in a difference for the more intricate coordination items of the TIS. According to Kwakkel et al, 15 hours of extra therapy is needed to achieve a clinically relevant increase in Barthel Index score. 20 These arguments could then explain why no significant difference was seen for the total TIS. Our additional trunk program, which was conceptualized by expert therapists in the field of neurological rehabilitation with many years of experience, included exercises in supine and sitting positions. The purpose of this therapy program was to treat the trunk as functional and in line with the daily rehabilitation setting. It could be argued that the additional treatment was similar to some of the items measured in the TIS and therefore significant results are no surprise. However, the TIS is a scale designed on the basis of stroke literature, existing scales, and opinion of experts in the field of neurological rehabilitation. Therefore, items of the TIS are indeed related to clinical practice. It is our opinion that this is one of the strengths of this study, which presents an interaction between a therapy approach and a scientific tool applicable in clinical practice. The question remains if this beneficial effect also means functional improvement. With the results from our study, this cannot be answered today. However, there is strong evidence in the stroke literature that trunk performance is an important predictor of functional outcome. 6-8 Studies have shown a significant relation between trunk performance measured early after stroke or on admission to the rehabilitation center and functional ability measured at discharge from the rehabilitation center and even 6 months after stroke. 6-8 A recent multi-center study has shown that the TIS and the static sitting balance subscale of the TIS on admission to the rehabilitation center (median days post stroke, 20) are the most important predictors of Barthel Index score at 6 months after stroke. With an explained variance of 50% and more, the TIS total and static sitting balance subscale score were even more important predictors than Barthel Index score itself on admission to the rehabilitation center. 10 This could mean that if trunk performance could be improved early on in the rehabilitation process, better functional improvement at discharge and 6 months after stroke might be expected. The study of Dursun et al gives further support for this hypothesis. 11 In their study, ambulatory patients who received biofeedback in addition to conventional therapy had a significantly shorter rehabilitation period. In addition, Dean et al reported a carry-over effect from a reaching intervention in sitting toward standing up but not to walking. 13 Future research should address if regaining sitting balance and trunk performance early after stroke could determine early discharge and enhance long-term functional outcome after stroke. It is our opinion that this is where the clinical applicability of our results are situated. As mentioned before, the TIS is based on clinical experience and its content can be a guide toward examining which exercises are beneficial early after stroke. The results of the intervention are encouraging but the exercise program probably needs fine-tuning when studying people in the acute phase after stroke. With regard to future studies, we would further encourage the development of task-specific and

6 286 Neurorehabilitation and Neural Repair well-defined interventions such as those presented in this study. We would like to argue that the present study contributes to the field of knowledge of effects, which arise from tasks, directly related to and trained in the experimental exercise program There are limitations that warrant caution when generalizing the results of our study. First, this study included only a small number of participants. Future studies with a larger number of participants are therefore needed to confirm our results. Second, neither the patients nor the physiotherapists who delivered the interventions were blinded, which may have introduced a bias to our study. Unfortunately this was impossible to organize with regard to the nature and setting of the study. Furthermore, our study only analyzed the results between pretreatment and posttreatment assessment. We did not perform a follow-up assessment. Future studies should evaluate long-term effects of additional exercises. Finally, our control group did not receive placebo therapy and therefore received less therapy in comparison to the experimental condition. However it is suggested that placebo physiotherapy is impossible in most clinical studies. 24 Including a group of patients who receive 10 hours of additional but usual physiotherapy exercises as a control group would be favorable for a next study. Implications Although several studies reported the importance of trunk performance after stroke as a predictor of functional outcome, evidence concerning the beneficial effect of exercises to improve trunk performance after stroke is sparse. The results of the present study indicate that additional trunk exercises have a positive effect on the ability to perform lateral flexion initiated from the upper and lower part of the trunk. These findings are directly applicable to clinical practice. Future work is needed with regard to functional implications of our results. This could be examined by means of functional scales or 3-dimensional measurements of functional movements such as forward reach, lateral reach, or turning. References 1. Verheyden G, Nieuwboer A, De Wit L, et al. Time course of trunk, arm, leg, and functional recovery after ischemic stroke. Neurorehabil Neural Repair. 2008;22: Bohannon RW, Cassidy D, Walsh S. Trunk muscle strength is impaired multidirectionally after stroke. Clin Rehabil. 1995;9: Tanaka S, Hachisuka K, Ogata H. Trunk rotatory muscle performance in post-stroke hemiplegic patients. Am J Phys Med Rehabil. 1997;76: Tanaka S, Hachisuka K, Ogata H. Muscle strength of trunk flexionextension in post-stroke hemiplegic patients. Am J Phys Med Rehabil. 1998;77: Verheyden G, Nieuwboer A, Feys H, Thijs V, Vaes K, De Weerdt W. Discriminant ability of the trunk impairment scale: a comparison between stroke patients and healthy individuals. Disabil Rehabil. 2005;27: Franchignoni FP, Tesio L, Ricupero C, Martino MT. Trunk control test as an early predictor of stroke rehabilitation outcome. Stroke. 1997;28: Duarte E, Marco E, Muniesa JM, et al. Trunk control test as a functional predictor in stroke patients. J Rehabil Med. 2002;34: Hsieh CL, Sheu CF, Hsueh IP, Wang CH. Trunk control as an early predictor of comprehensive activities of daily living function in stroke patients. Stroke. 2002;33: Verheyden G, Vereeck L, Truijen S, et al. Trunk performance after stroke and the relationship with balance, gait and functional ability. Clin Rehabil. 2006;20: Verheyden G, Nieuwboer A, De Wit L, et al. Trunk performance after stroke: an eye-catching predictor of functional outcome [published online ahead of print December 18, 2006]. J Neurol Neurosurg Psychiatry. 2007;78: Dursun E, Hamamci N, Dönmez S, Tünzünalp O, çakci A. Angular biofeedback device for sitting balance of stroke patients. Stroke. 1996;27: Dean CM, Shepherd RB. Task-related training improves performance of seated reaching tasks after stroke: a randomised controlled trial. Stroke. 1997;28: Dean CM, Channon EF, Hall JM. Sitting training early after stroke improves sitting ability and quality and carries over to standing up but not to walking: a randomized trial. Aust J Physiother. 2007;53: Verheyden G, Nieuwboer A, Mertin J, et al. The Trunk Impairment Scale: a new tool to measure motor impairment of the trunk after stroke. Clin Rehabil. 2004;18: Tinetti M. Performance-orientated assessment of mobility problems in elderly patients. J Am Geriatr Soc. 1986;34: Corriveau H, Hébert R, Raîche M, Prince F. Evaluation of postural stability in the elderly with stroke. Arch Phys Med Rehabil. 2004;85: Collen FM, Wade DT, Bradshaw CM. Mobility after stroke: reliability of measures of impairment and disability. Int Disabil Stud. 1990;12: Stevenson TJ. Using impairment inventory scores to determine ambulation status in individuals with stroke. 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