Movement Control after Stroke : Studies on Sit-to-walk and on the Relations between Clinical and Laboratory Measures

Aims: The principal aims of this research were 1) to extend existing knowledge of the everyday sit-to-walk (STW) transfer in subjects with stroke and in matched controls by exploring temporal, kinematic, and kinetic aspects, and 2) to investigate the relations between some clinical and laboratory measures of postural control and locomotion in stroke rehabilitation and research. Methods: Ten community-living subjects with stroke (mean age 59 years) and ten matched controls were enrolled in the STW studies (Studies I, II, and IV). In the study regarding relations between clinical and laboratory measures the same samples (part of Study II) and also 20 outpatient subjects with stroke (mean age 50 years) participated (Study III). Data collections were performed in laboratory environments with clinical assessment instruments, video cameras, force plates and a movement analysis system. Results: 1) Study I: A temporal aspect of STW was studied. Four phases were defined. The subjects with stroke used significantly more time during the 2nd STW phase, defined from seat-off to the loading peak of the 1st swing leg. Study II: A movement aspect of STW was investigated. The stroke subjects generated significantly less centre of mass momenta in horizontal and vertical directions, and the momenta peaks occurred significantly earlier than in the controls. Study IV: A force aspect of STW was explored. The subjects with stroke generated significantly larger propulsive impulse beneath the (non-paretic) stance buttock and significantly more braking impulses were exerted by both buttocks and particularly by the stance foot. 2) Part of Study II: A strong correlation was found between the clinical measure Fluidity Scale and the laboratory measure Fluidity Index. Study III: Moderate correlations were shown between Berg Balance Scale, ratings of weight distribution during quiet stance, and force measures. Conclusions: The findings of the STW studies show a changed force interaction between the lower extremities post-stroke, likely influencing movement patterns and temporal characteristics of the everyday transfer. The results are considered to reflect compensatory motor strategies. The results of the studies on relations between some clinical and laboratory measures indicate that the strength of the relation is multidimensional.

Movement Control after Stroke : Studies on Sit-to-walk and on the Relations between Clinical and Laboratory Measures

Aims: The principal aims of this research were 1) to extend existing knowledge of the everyday sit-to-walk (STW) transfer in subjects with stroke and in matched controls by exploring temporal, kinematic, and kinetic aspects, and 2) to investigate the relations between some clinical and laboratory measures of postural control and locomotion in stroke rehabilitation and research. Methods: Ten community-living subjects with stroke (mean age 59 years) and ten matched controls were enrolled in the STW studies (Studies I, II, and IV). In the study regarding relations between clinical and laboratory measures the same samples (part of Study II) and also 20 outpatient subjects with stroke (mean age 50 years) participated (Study III). Data collections were performed in laboratory environments with clinical assessment instruments, video cameras, force plates and a movement analysis system. Results: 1) Study I: A temporal aspect of STW was studied. Four phases were defined. The subjects with stroke used significantly more time during the 2nd STW phase, defined from seat-off to the loading peak of the 1st swing leg. Study II: A movement aspect of STW was investigated. The stroke subjects generated significantly less centre of mass momenta in horizontal and vertical directions, and the momenta peaks occurred significantly earlier than in the controls. Study IV: A force aspect of STW was explored. The subjects with stroke generated significantly larger propulsive impulse beneath the (non-paretic) stance buttock and significantly more braking impulses were exerted by both buttocks and particularly by the stance foot. 2) Part of Study II: A strong correlation was found between the clinical measure Fluidity Scale and the laboratory measure Fluidity Index. Study III: Moderate correlations were shown between Berg Balance Scale, ratings of weight distribution during quiet stance, and force measures. Conclusions: The findings of the STW studies show a changed force interaction between the lower extremities post-stroke, likely influencing movement patterns and temporal characteristics of the everyday transfer. The results are considered to reflect compensatory motor strategies. The results of the studies on relations between some clinical and laboratory measures indicate that the strength of the relation is multidimensional.

How many trials are needed in kinematic analysis of reach-to-grasp? : A study of the drinking task in persons with stroke and non-disabled controls

Background: Kinematic analysis of the 3D reach-to-grasp drinking task is recommended in stroke rehabilitation research. The number of trials required to reach performance stability, as an important aspect of reliability, has not been investigated for this task. Thus, the aims of this study were to determine the number of trials needed for the drinking task to reach within-session performance stability and to investigate trends in performance over a set of trials in non-disabled people and in a sample of individuals with chronic stroke. In addition, the between-sessions test–retest reliability in persons with stroke was established. Methods: The drinking task was performed at least 10 times, following a standardized protocol, in 44 non-disabled and 8 post-stroke individuals. A marker-based motion capture system registered arm and trunk movements during 5 pre-defined phases of the drinking task. Intra class correlation statistics were used to determine the number of trials needed to reach performance stability as well as to establish test–retest reliability. Systematic within-session trends over multiple trials were analyzed with a paired t-test. Results: For most of the kinematic variables 2 to 3 trials were needed to reach good performance stability in both investigated groups. More trials were needed for movement times in reaching and returning phase, movement smoothness, time to peak velocity and inter-joint-coordination. A small but significant trend of improvement in movement time over multiple trials was demonstrated in the non-disabled group, but not in the stroke group. A mean of 3 trials was sufficient to reach good to excellent test–retest reliability for most of the kinematic variables in the stroke sample. Conclusions: This is the first study that determines the number of trials needed for good performance stability (non-disabled and stroke) and test–retest reliability (stroke) for temporal, endpoint and angular metrics of the drinking task. For most kinematic variables, 3–5 trials are sufficient to reach good reliability. This knowledge can be used to guide future kinematic studies

ORIGINAL REPORT CORRELATION BETWEEN CLINICAL ASSESSMENT AND FORCE PLATE MEASUREMENT OF POSTURAL CONTROL AFTER STROKE

Objectives: To explore the correlation between clinical assessment and force plate measurement of postural control after stroke when selected balance tasks are performed under similar spatial and temporal conditions, and to examine the inter-rater agreement of assessment of weight distribution during quiet stance in subjects with stroke. Design: A descriptive and correlational study. Methods: Clinical assessment of postural control using Berg Balance Scale, video recording for rating of weight distribution, and force plate measurement with the Vifor-system, were performed in 20 subjects with stroke. Results: Mean velocity of displacement of the centre of pressure in the anterior-posterior direction correlated moderately with scores from the Berg Balance Scale items “maintaining a position ” in the whole sample (r s = –0.50, p <0.05) as well as in a subgroup of subjects with stroke with submaximal Berg Balance Scale scores (r s = –0.62, p < 0.05). Moderate correlation was found between ratings of each of 3 physiotherapists and centre of pressure’s mean position in the frontal plane on the force plate, while the inter-rater agreement was poor. Conclusion: Clinical assessment of postural control and weight distribution showed moderate correlation with force plate measurement when the assessments were performed under similar conditions. The data suggest that the reliability of observational postural analysis needs to be improved

Neural and Nonneural Contributions to Wrist Rigidity in Parkinson's Disease : An Explorative Study Using the NeuroFlexor

Objective. The NeuroFlexor is a novel method incorporating a biomechanical model for the measurement of neural and nonneural contributions to resistance induced by passive stretch. In this study, we used the NeuroFlexor method to explore components of passive movement resistance in the wrist and finger muscles in subjects with Parkinson's disease (PD). Methods. A cross-sectional comparison was performed in twenty-five subjects with PD with clinically identified rigidity and 14 controls. Neural (NC), elastic (EC), and viscous (VC) components of the resistance to passive extension of the wrist were calculated using the NeuroFlexor. Measurements were repeated during a contralateral activation maneuver. Results. PD subjects showed greater total resistance (P < 0.001) and NC (P = 0.002) compared to controls. EC and VC did not differ significantly between groups. Contralateral activation maneuver resulted in increased NC in the PD group but this increase was due to increased resting tension. Total resistance and NC correlated with clinical ratings of rigidity and with bradykinesia. Conclusions. The findings suggest that stretch induced reflex activity, but not nonneural resistance, is the major contributor to rigidity in wrist muscles in PD. The NeuroFlexor is a potentially valuable clinical and research tool for quantification of rigidity

Motor performance after treatment of pilocytic astrocytoma in the posterior fossa in childhood

 Background:  Pilocytic astrocytoma is the most common brain tumour type in childhood located in the posterior fossa, and treated mainly with surgery. These tumours have low mortality, but knowledge concerning its long-term outcome is sparse.  Aims:  The aim was to investigate if patients treated for pilocytic astrocytoma in the posterior fossa had motor complications, including balance, motor and process skills.  Methods and results:  This descriptive single-centre study includes eight children and 12 adults, treated for pilocytic astrocytoma as children. Motor performance was investigated with Bruininks-Oseretsky Test of Motor Proficiency, Second Edition, and dynamic balance with the mini-balance evaluation systems test. Physiological cost index, six-minute walk test, hand grip strength and assessment of motor and process skills were also evaluated. Ten patients reported motor difficulties, mainly from the upper limbs. The motor performance test showed results within normal limits except for manual dexterity, which was significantly below mean (p = .008). In the dynamic balance test patients had significantly lower results compared with controls (p = .036). Physiological cost index, six-minute walk tests and hand grip strength showed results within normal limits. In the Assessment of Motor and Process Skills, patients over 16 years had significantly lower results compared with test norms for motor activities of daily living (ADL) and 30% of all patients scored below the cut-off level for difficulties with motor skills.  Conclusions:  Motor performance for patients treated for pilocytic astrocytoma in the posterior fossa in childhood is satisfactory but some patients display difficulties with balance, manual dexterity and ADL motor skills. Thus, it is important to identify those in need of motor follow-up and training

Inclination angles of the ankle and head relative to the centre of mass identify gait deviations post-stroke

Background: Whole-body movement adjustments during gait are common post-stroke, but comprehensive ways of quantifying and evaluating gait from a whole-body perspective are lacking. Research question: Can novel kinematic variables related to Center of Mass (CoM) position discriminate side asymmetries as well as coordination between the upper and lower body during gait within persons post-stroke and compared to non-disabled controls? Methods: Thirty-one persons post-stroke and 41 age-matched non-disabled controls walking at their self-selected speed were recorded by 3D motion capture. The Ankle-CoM Inclination Angle (A-CoMIA) and the Head-CoM Inclination Angle (H-CoMIA) defined the angle between the CoM and the ankle and the head, respectively, in the frontal plane. These angles and their angular velocities were compared between groups, and with regard to motor impairment severity during all phases of the gait cycle (GC) using a functional interval-wise testing analysis suitable for curve data. Upper and lower body coordination was assessed using cross- correlation. Results: The A-CoMIA was symmetrical between body sides in persons post-stroke but larger compared to controls. The angular velocity of A-CoMIA also differed when compared to controls. The H-CoMIA was consistently asymmetrical in persons post-stroke and larger than in controls throughout the stance phase. There were only minor group differences in the angular velocity of H-CoMIA, with some side asymmetry in persons post-stroke. The A-CoMIA of the non-affected side, and the H- CoMIA, discriminated between persons with more severe impairments compared to those with milder impairments post-stroke. The variables showed strong cross- correlations in both groups. Significance: The A-CoMIA and Head-CoMIA discriminated post-stroke gait from non-disabled, as well as motor impairment severity. These variables with the advantageous curve analysis during the entire GC add valuable whole-body information to existing parameters of post-stroke gait analysis through assessment of symmetry and upper and lower body coordination.Rörelsekontroll efter stroke - kliniska och laboratoriebaserade utfallsmått och i relation till funktionell hjärnavbildningFörbättrad analys och tolkning av rörelsedata från personer med funktionshinder - innovativa statistiska metode