Toward improving the specificity of perturbation-based training through assessment of dynamic balancing responses: a series of N-of-1 studies in subacute stroke.

Perturbation-based balance training (PBT) has been shown to improve reactive balancing abilities in chronic stroke. To inform future investigations in the subacute phase of stroke, the objective of this series of N-of-1 studies was to investigate the range of balancing responses to unexpected mechanical perturbations applied to the pelvis during walking on an instrumented treadmill before and after PBT training. Three subacute stroke subjects were assessed on each occasion with clinical tests and biomechanical measurements following perturbations applied in forward, backward, inward and outward directions. After 15 daily sessions of PBT, most clinical mobility outcomes showed improvements in all three subjects. Assessment of reactive balancing also showed improvements in all subjects when responding to perturbations in backward and inward directions whereas the changes following perturbations in forward and outward directions were subject-specific. The results suggest that PBT should be individually tailored to target balance deficiencies identified through a serial biomechanical assessment.

A comparison of three balance-assessment scales for patients after stroke with various levels of balance disorder.

It is often difficult for the clinician to choose the most appropriate balance-assessment measure. We wanted to facilitate this decision based on the stroke patient's functional abilities. The aim of our study was to compare three established scales [Berg Balance Scale (BBS), mini-BESTest (MBT) and Functional Gait Assessment (FGA)] in terms of responsiveness, floor and ceiling effects at different levels of ambulation as defined by the Functional Ambulation Classification (FAC). The 18-month prospective study included 88 patients after cerebral stroke, who were able to walk independently or with assistance of one person (FAC 2-6). BBS showed the highest relative gain in the FAC 2-3 group (17% of maximum scale score); in the other two groups (FAC 4-5 and FAC 6), MBT showed the highest relative gain (16 and 13%, respectively), followed by FGA (11 and 10%, respectively). Among the patients with initial FAC 2-3, a floor effect occurred with FGA, while a ceiling effect occurred with BBS among patients with initial FAC 6. Gain in FGA correlated slightly more with improvement detected by MBT (r = 0.60) than with BBS (r = 0.50). We can conclude that BBS seems to be suitable for stroke patients with initial FAC 2-5, whereas MBT and FGA for those with FAC 4-6.

Assessment of dynamic balancing responses following perturbations during slow walking in relation to clinical outcome measures for high-functioning post-stroke subjects.

BACKGROUND: Generating appropriate balancing reactions in response to unexpected loss of balance during walking is important to prevent falls. The purpose of this study was to assess dynamic balancing responses following pushes to the pelvis in groups of post-stroke and healthy subjects. METHODS: Forty-one post-stroke subjects and forty-three healthy subjects participated in the study. Dynamic balancing responses to perturbations triggered at heel strike of the left or right leg, directed in the forward, backward, inward and outward directions during slow treadmill walking were assessed. Responses of the healthy group provided reference values used to classify responses of the post-stroke group into two subgroups; one within the reference responses ("inside" subgroup) and the other that falls out ("outside" subgroup). A battery of selected clinical outcome measures (6-Minute Walk Test, 10-Meter Walk Test, Timed-Up-and-Go test, Four Square Step Test, Functional Gait Assessment, Functional Independence Measure and One-legged stance test) was additionally assessed in the post-stroke group. RESULTS: The "inside" subgroup of post-stroke subjects was able to appropriately modulate centre-of-pressure and ground-reaction-force both under the impaired and non-impaired leg in response to perturbations. The "outside" subgroup of post-stroke subjects showed limited modulation of centre-of-pressure and ground-reaction-force under the impaired leg; instead stepping strategy was used in which the non-impaired leg was placed such as to make a longer step (forward perturbation), to make a shorter step (backward perturbation) or to make a cross-step (outward perturbation). Consequently, peak centre-of-mass displacements following perturbations were significantly higher in the "outside" subgroup compared to the "inside" subgroup. Responses in both subgroups following inward perturbations did not differ. Majority of clinical outcome measures moderately correlated with the peak centre-of-mass displacements for forward perturbations and exhibited weak correlations for other perturbation directions. CONCLUSIONS: Substantial number of post-stroke subjects, that were considered to be independent walkers, have reduced capabilities to execute appropriate balancing responses following perturbations commencing on the hemiparetic leg and may thus benefit from perturbation-based training. Timed-Up-and-Go and Functional Independence Measure tests may provide an indication on the abilities of each subject to counteract unexpected loss of balance. However, a reliable assessment should be done through perturbation-based measures.

Multi-Exergames to Set Targets and Supplement the Intensified Conventional Balance Training in Patients With Stroke: A Randomized Pilot Trial.

People who survive a stroke usually suffer movement disorders resulting in involuntary abnormal movements. Intensive and repetitive physiotherapy is often a key to functional restoration of movements. Rehabilitation centers have recently offered balance training supported by exergames in addition to conventional therapy. The primary objective was to investigate different types of balance training (multi-exergaming and conventional) in addition to a conventional 6-week physiotherapy program. Furthermore, we examined the choice of an appropriate exergame to target balance training. We designed a randomized pilot trial. Hospital inpatients with stroke aged 33-65 were recruited and randomized into 2 groups by drawing lots; a control group receiving 1 week of conventional balance training and an exergaming group 1 week of multiple-game exergaming, comprising single leg exercises, weight shifting, balancing and standing up. Center of pressure was monitored for the exergaming group and clinical data were collected (non-blinded assessment) using Four Square Step Test, Timed Up and Go, 10 m Walk Test, Romberg, Sharpened Romberg, Clinical Test for Sensory Interaction in Balance in both groups. Statistical tests were used to find significant (p < 0.05) differences and Cohen's U3 for effect sizes. Recruited participants (20/30) met the inclusion criteria and were randomized; 10 per group. 1 participant of the exergaming group was excluded from center of pressure analysis. Both groups demonstrated substantively and statistically significant improvements of functional balance, in particular the exergaming group (FSST p = 0.009, U3 = 0.9 and 10 MWT p = 0.008, U3 = 0.9). However, significant differences between the groups were found in tests with eyes closed, Sharpened Romberg test (p = 0.05) and standing on the right leg (p = 0.035). The center of pressure area decreased up to 20% for the exergaming group. Both types of additional balance training demonstrated comparable outcomes, however, the multi-exergaming could target specific motor control disorders by the selection of exergames according to Gentile's taxonomy. We may not prioritize exergaming due to the low statistical power of clinical outcomes. However, exergaming enables independent balance training, which is feasible without strenuous physiotherapy and may thus be crucial for future home or telerehabilitation services. Clinical Trial Registration: www.clinicaltrials.gov/, identifier NCT03282968.

Algorithm for selection of balance assessment tools in post-stroke patients.

The aim of the study was to design an algorithm of selecting the balance assessment tool in patients after stroke, which could be used in a subacute rehabilitation setting. A retrospective study was carried out to analyse results of standardized balance measurements in three groups of stroke patients classified by Functional Ambulation Category (FAC) (FAC 1 or 2, non-functional ambulation; FAC 3 or 4, ambulatory dependent; FAC 5 or 6, ambulatory independent). Balance functions were evaluated in 62 out of 70 patients (88.6%) at admission and discharge with at least with one standardized assessment tool. In 21 patients (30%), two or more assessment tools were used. From admission to discharge significant changes in balance functions in the non-functional ambulatory group were detected by Postural Assessment Scale for Stroke (PASS) (P = 0.003), in the ambulatory dependent group with PASS (P = 0.025) and Berg Balance Scale (BBS) (P = 0.009) and in the ambulatory independent group with the Timed Up and Go Test (P = 0.002) and Functional Gait Assessment (P = 0.029). In a post-stroke rehabilitation most commonly used BBS and PASS are sensitive enough in non-functional ambulatory and ambulatory dependent patients, though they do not reflect the overall balance function. In ambulatory independent patients, significant changes in balance functions can be detected only with the assessment tools that include the measurements of dynamic balance. Based on the findings, the algorithm for the selection of balance assessment tools in post-stroke rehabilitation setting was formulated according to FAC.

A novel robot-assisted training approach for improving gait symmetry after stroke.

Gait asymmetry as a consequence of hemiparesis is known as a serious long-term disability, where typical compensatory gait movements are used by stroke subjects in order to cope with their daily activities. This study presents a gait symmetry training approach consisting of the adaptive robot assistance with the combination of the visual feedback integrated in Balance Assessment Robot for treadmill walking (BAR-TM). The support algorithm is based on gait temporal parameters that change the level of assistive support, which was triggered at different gait subphase events. The presented approach was evaluated on a post-stroke subject in a large number of training sessions. The results have shown significant improvement of gait symmetry indicating that the proposed rehabilitation method has significant potential that should be explored in further studies.

Rasch validation and comparison of Slovenian, Croatian, and Italian versions of the Mini-BESTest in patients with subacute stroke.

We aimed to verify by Rasch analysis whether the Mini-BESTest, a balance measure, confirms its main psychometric properties in patients with subacute stroke undergoing rehabilitation in three different countries (Slovenia, Croatia, and Italy), and to examine the stability of item hierarchy and difficulty across the three national versions through a differential item functioning analysis. We investigated 159 patients with subacute stroke consecutively admitted to three rehabilitation facilities after screening for an intensive, tailored rehabilitation program. Balance function was tested within 36 h from admission and after ∼25 days. As no differential item functioning was found between admission and discharge data or among countries, all data were pooled. Rasch criteria for the functioning of rating scale categories were fulfilled. In terms of internal construct validity, all items except item #14 (Cognitive Get Up & Go; infit value=1.42) showed an acceptable fit to the Rasch model. The patient ability-item difficulty matching was very good. Reliability indices were high. The Principal Component Analysis of standardized residuals confirmed the unidimensionality of the test. On the basis of the item calibration, raw scores of the Mini-BESTest were transformed into linear estimates of dynamic balance and six statistically detectable levels of balance ability were defined. Good psychometric features of the Mini-BESTest were confirmed. The three different national versions showed stability in item hierarchy, indicating equivalence of their cross-cultural adaptations. Problems with item #14 in these patients warrant further study.

Telerehabilitation using virtual reality task can improve balance in patients with stroke.

PURPOSE: The objective of the telerehabilitation is a continuation of the rehabilitation process on patients' home. The study also compares the balance training in clinical environment with the telerehabilitation approach when the physiotherapists and physicians can follow the progress remotely. METHOD: In this paper, the preliminary study of the pilot project with virtual reality (VR)-based tasks for dynamic standing frame supported balance training is presented. Six patients with stroke participated in the study. The patients performed the balance training 3 weeks, 2 weeks in the clinical settings and 1 week in the home environment, five times a week, and each time for up to 20 minutes. Objective effectiveness was demonstrated by parameters as track time, number of collisions and the clinical instruments Berg Balance Scale (BBS), Timed Up & Go (TUG), 10-m walk test and standing on the unaffected and affected extremity. The outcomes were compared to the balance training group without VR and telerehabilitation support. A 2-way ANOVA was used to explore the differences between the both stroke groups. RESULTS: In patients who were subject to VR supported balance training, the BBS demonstrated improvement for 15%, the TUG for 29%, the 10-m walk for 26%, stance time on the affected and unaffected extremity for 200 and 67%, respectively. The follow-up demonstrated that the patients preserved the gained functional improvement. The VR task performance time and number of collisions decreased to 45 and 68%, respectively. Besides, no statistical differences were found between the telerehabilitation approach with VR supported balance training and conventional balance training in clinical settings either regarding the overall mean level or regarding the mean improvement. CONCLUSIONS: The telerehabilitation approach in VR supported balance training improved balance in stroke patients and had similar effect on patients' postural functional improvement as conventional balance training in clinical settings. However, when balance training is continued on patient's home instead of the hospital, it would eventually decrease the number of outpatients' visits, reduce related costs and enable treatment of larger number of patients.

Improving balance in subacute stroke patients: a randomized controlled study.

The aim of the study was to compare the efficacy of balance training in a balance trainer, a newly developed mechanical device for training balance, with conventional balance training in subacute stroke patients. This was a randomized controlled study. Fifty participants met the inclusion criteria and 39 finished the study. The participants were randomly divided into control and balance trainer groups. The first had conventional balance training while the second trained balance in the balance trainer. All the participants trained balance 20 min per day, 5 days per week for 4 weeks and had additional 25 min of physiotherapy. Balance was assessed by the Berg Balance Scale, one-leg standing, Timed Up and Go (TUG) Test and 10 m walk. There was significant improvement in Berg Balance Scale (P<0.001), TUG (P<0.001) and 10 m walk (P=0.001) in both the groups, whereas no differences were found in any of these measures between the two groups either regarding overall average level or regarding average improvement. Both the groups improved significantly in standing on the healthy (P=0.001) as well as the impaired lower limb (P=0.005), whereby no significant differences were observed between the groups. Within both groups, significantly fewer subjects needed assistance of a physiotherapist for the 10 m walk and the TUG test at the end than at the beginning of the study (P=0.016). It can be concluded that both conventional balance training and training balance in the balance trainer equally improved balance in subacute stroke patients. The balance trainer cannot replace a physiotherapist but it is a safe and efficient supplementary method.

Normative based clinical tool for objective evaluation of postural responses.

The paper presents a novel normative based method and apparatus for objective assessment of postural responses during unexpected perturbation in clinical environment. A modified standing frame (based on BalanceTrainer) for standing-balance training in a fall-safe balancing environment equipped with electrical actuators to provide unexpected perturbations in eight directions during quiet standing was used. Ground reaction forces were recorded under both feet and center of pressure was calculated to derive postural response indicators. The set-up normative was based on consistent patterns assessed in seven neurologically intact volunteers. In clinical investigation the postural responses in two incomplete spinal cord injured persons and hemiparetic stroke patient were contrasted to the normative response. Thus the characteristic direction dependent deficiencies were identified and numerically evaluated. On the basis of our findings we may suggest that the method may become effective when substantial direction dependent quantitative evaluation of postural responses are required in clinical & home environment.