Jon Marsden

Cerebellar ataxia: pathophysiology and rehabilitation

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is ‘The trainee consistently demonstrates a knowledge of management approaches for specific impairments including spasticity, ataxia.’

Muscle paresis and passive stiffness: Key determinants in limiting function in Hereditary and Sporadic Spastic Paraparesis

Background People with Hereditary and Sporadic Spastic Parapresis (SP) walk with a stiff legged gait characterised by a lack of knee flexion. Objective We investigated the relationship between lower limb strength and stiffness and knee flexion during swing phase while walking in 20 people with SP and 18 matched controls. Methods Maximal isometric strength was measured using a dynamometer. Passive stiffness and spasticity was assessed during motor-driven slow (5°/s) and fast (60°/s) stretches at the ankle and knee while the subject was relaxed or preactivating the muscle. Walking was assessed using 3D motion analysis. Results Isometric muscle strength was decreased in people with SP with over a 50% reduction in strength being found in the ankle dorsiflexors. Passive stiffness, assessed during slow stretches, was 35% higher in the plantarflexors in people with SP (P < 0.05). Faster stretches induced large stretch evoked muscle activity and over a 110% increase in stiffness at the ankle and knee in people with SP reflecting the presence of spasticity (P < 0.05). However, stretch reflex size and stiffness was similar between the groups following identical stretches of the pre-activated muscle (P > 0.05). Lower knee flexion during swing phase was associated with reduced knee flexion velocity at the end of stance phase which in turn was associated with reduced plantarflexor strength and increased passive stiffness in the knee extensors. Conclusions The relative importance of muscle paresis and passive stiffness in limiting walking in SP suggests that these impairments should be the target of future therapies.

Foot and ankle impairments affect balance and mobility in stroke (FAiMiS): the views and experiences of people with stroke

Abstract Purpose: To explore the nature and impact of foot and ankle impairments on mobility and balance in community-dwelling, chronic stroke survivors. Methods: A qualitative research design using face to face semi-structured, audio recorded interviews. Thirteen community-dwelling stroke survivors, all of whom had self-reported foot and ankle impairments, were interviewed (female n = 6, mean age = 67 years, SD = 12 years, mean time since stroke = 4 years, SD = 6 years, right stroke n = 7, left stroke n = 6). A framework analysis approach was used to analyse and interpret transcribed interviews. Results: Three themes emerged: (1) Impact. The influence of foot and ankle impairments on mobility and balance. (2) Standing out. How participants felt they “stood out” because of their impairments and wanted to be normal. (3) Help. The specific help and advice participants received in managing their problems. Conclusions: Foot and ankle impairments such as pain, altered somatosensory input and weakness significantly contribute to problems with community ambulation, balance and fear of falling in people with chronic stroke. Specific foot and ankle impairments may also negatively contribute to perceptions of physical appearance and self-esteem. Therapeutic management approaches within clinical practice appear to focus mostly on the gross performance of the lower limb with little emphasis on the specific assessment or treatment of the foot or ankle. Implications for Rehabilitation Foot pain, sensory impairments and muscle weakness in the foot and ankle can impact on community ambulation, balance and fear of falling following stroke. Foot and ankle function post-stroke should be routinely assessed and monitored. Clinicians should be aware of the potentially distressing negative perceptions associated with altered gait patterns, footwear and orthotic use.

Balance dysfunction in hereditary and spontaneous spastic paraparesis

OBJECTIVE To determine how postural sway is affected in people with spastic paraparesis (pwSP) and the impact of different impairments. METHODS In 20 pwSP and 18 matched healthy controls standing postural sway was measured with eyes open and closed. Vibration threshold, isometric ankle and hip muscle strength and ankle stiffness with the participant at rest or preactivating the muscle was measured. RESULTS Antero-posterior (AP) and medio-lateral (ML) sway was higher in pwSP. Muscle strength was reduced and ankle stiffness increased in pwSP. Increased vibratory threshold was seen in 35% of participants. Higher total ankle stiffness (R2=0.44) was associated with lower AP sway with eyes open whilst hip abductor weakness was associated with increased ML sway with eyes open (R2=0.36) or closed (R2=0.47) or AP sway with the eyes closed (R2=0.48). CONCLUSIONS The degree of postural sway was related to muscle paresis of the hip abductors particularly in the ML direction and under conditions of reduced sensory input. People with higher total ankle stiffness have less AP sway suggesting that this may help to stabilise the body.

An observational study of implicit motor imagery using laterality recognition of the hand after stroke.

Abstract Objective: To explore the relationship between laterality recognition after stroke and impairments in attention, 3D object rotation and functional ability. Design: Observational cross-sectional study. Setting: Acute care teaching hospital. Participants: Thirty-two acute and sub-acute people with stroke and 36 healthy, age-matched controls. Main outcome measures: Laterality recognition, attention and mental rotation of objects. Within the stroke group, the relationship between laterality recognition and functional ability, neglect, hemianopia and dyspraxia were further explored. Results: People with stroke were significantly less accurate (69% vs 80%) and showed delayed reaction times (3.0 vs 1.9 seconds) when determining the laterality of a pictured hand. Deficits either in accuracy or reaction times were seen in 53% of people with stroke. The accuracy of laterality recognition was associated with reduced functional ability (R2 = 0.21), less accurate mental rotation of objects (R2 = 0.20) and dyspraxia (p = 0.03). Conclusion: Implicit motor imagery is affected in a significant number of patients after stroke with these deficits related to lesions to the motor networks as well as other deficits seen after stroke. This research provides new insights into how laterality recognition is related to a number of other deficits after stroke, including the mental rotation of 3D objects, attention and dyspraxia. Further research is required to determine if treatment programmes can improve deficits in laterality recognition and impact functional outcomes after stroke.

Sensory–motor rehabilitation therapy for task-specific focal hand dystonia: A feasibility study:

Introduction Medical treatments have limited long-term effect in task-specific dystonia. Whilst evidence supports the use of rehabilitation, no randomised controlled trials have been undertaken. This small-scale study determined the feasibility of implementing and evaluating a mixed sensory–motor task-specific dystonia rehabilitative programme. Methods Participants with writer’s or musician’s dystonia were recruited from a movement disorder and hand therapy clinic. Feasibility measures were recruitment rate, retention, session attendance, adherence to exercises. Self-report measures at 0, 3 and 6 months included: Arm Dystonia Disability Scale (ADDS), Tubiana and Chamagne Scale (TCS), Brief Illness Perception Questionnaire (BIPQ), Health Status (EQ-5D 5L), Clinical Global Impression Scale (CGI). Task performance was video-recorded at baseline and 6 months. At 6 months, interviews explored participant experiences of the intervention. Results Fifteen patients were recruited over 6 months (rate 2.5/month, musician’s dystonia = 8, writer’s dystonia = 7). Complete data sets were collected for twelve people(80%). The programme comprised a maximum six sessions plus daily home exercises. Nine completed the home programme at ≥75%. No adverse events were reported. Effect sizes at 3 and 6 months, respectively, were ADDS 3-month = 0.28, 6-month = 0.23; TCS 3-month = 0.13, 6-month = 0.53; BIPQ 3-month = 0.38, 6-month = 0.71; EQ-5D-5L 3-month = 0.34, 6-month = 0.59; video analysis at 6 months = 0.78. Eleven (92%) improved on the CGI. Interviews supported acceptability of the intervention. Conclusions This intervention was feasible to deliver with high retention, adherence and acceptability. Improvements occurred across measures. This informs the development of future randomised controlled trials.

The prevalence, distribution, and functional importance of lower limb somatosensory impairments in chronic stroke survivors: a cross sectional observational study.

Abstract Purpose: To investigate the prevalence and distribution of lower limb somatosensory impairments in community dwelling chronic stroke survivors and examine the association between somatosensory impairments and walking, balance, and falls. Methods: Using a cross sectional observational design, measures of somatosensation (Erasmus MC modifications to the (revised) Nottingham Sensory Assessment), walking ability (10 m walk test, Walking Impact Scale, Timed “Get up and go”), balance (Functional Reach Test and Centre of Force velocity), and falls (reported incidence and Falls Efficacy Scale-International), were obtained. Results: Complete somatosensory data was obtained for 163 ambulatory chronic stroke survivors with a mean (SD) age 67(12) years and mean (SD) time since stroke 29 (46) months. Overall, 56% (n = 92/163) were impaired in the most affected lower limb in one or more sensory modality; 18% (n = 30/163) had impairment of exteroceptive sensation (light touch, pressure, and pin-prick), 55% (n = 90/163) had impairment of sharp-blunt discrimination, and 19% (n = 31/163) proprioceptive impairment. Distal regions of toes and foot were more frequently impaired than proximal regions (shin and thigh). Distal proprioception was significantly correlated with falls incidence (r = 0.25; p < 0.01), and centre of force velocity (r = 0.22, p < 0.01). The Walking Impact Scale was the only variable that significantly contributed to a predictive model of falls accounting for 15–20% of the variance. Conclusion: Lower limb somatosensory impairments are present in the majority of chronic stroke survivors and differ widely across modalities. Deficits of foot and ankle proprioception are most strongly associated with, but not predictive, of reported falls. The relative contribution of lower limb somatosensory impairments to mobility in chronic stroke survivors appears limited. Further investigation, particularly with regard to community mobility and falls, is warranted. Implications for Rehabilitation Somatosensory impairments in the lower limb were present in approximately half of this cohort of chronic stroke survivors. Tactile discrimination is commonly impaired; clinicians should include an assessment of discriminative ability. Deficits of foot and ankle proprioception are most strongly associated with reported falls. Understanding post-stroke lower limb somatosensory impairments may help inform therapeutic strategies that aim to maximise long-term participation, minimise disability, and reduce falls.

An investigation of commonly prescribed stretches of the ankle plantarflexors in people with Multiple Sclerosis

BACKGROUND Stretches are often prescribed to manage increased limb stiffness in people with Multiple Sclerosis. This study determined the ankle plantarflexor torque magnitude that people with Multiple Sclerosis can apply during four commonly prescribed stretches and determined the relationship between the applied torque and functional ability. METHODS People with Multiple Sclerosis (N=27) were compared to healthy control participants (n=15). Four stretches were investigated; stretching in step standing; using a step; pulling the ankle into dorsiflexion and standing in a frame. Joint position and forces were measured using 3D motion analysis and torque transducers. Baseline ankle strength and stiffness was measured using motor driven ankle perturbations. FINDINGS People with Multiple Sclerosis (N=27) had higher stretch reflex amplitudes and lower strength compared to the control group (n=15). People with Multiple Sclerosis achieved less lengthening of the plantarflexor muscle-tendon complex when stretching but similar ankle torques compared to controls. While stretching people with Multiple Sclerosis showed greater muscle activation in the ankle plantarflexors. Stretches in weight bearing positions produced higher plantarflexor torques. People with Multiple Sclerosis with lower functional ability preferred the more supported stretches (ankle pull and standing frame). INTERPRETATION Stretches in weight bearing positions achieve higher ankle torques but this is in part due to increased postural activity in people with Multiple Sclerosis. Functional ability may limit stretch effectiveness.

Restorative and Rehabilitation Neurology

While there are many opportunities for the prevention or reversal of disease, health care systems worldwide are dominated by people with chronic diseases and conditions. In the USA for example, patients with chronic conditions account for nearly 80% of health care costs. In the UK, neurological damage accounts for 40% of people severely disabled and who require daily help, and for most of those with complex disabilities resulting from a combination of physical, cognitive and behavioural problems. Any health care system is thus confronted on a daily basis with a demand to meet this need from fi nite resources.