scholarly journals Vision does not always help stroke survivors compensate for impaired limb position sense

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Troy M. Herter ◽  
Stephen H. Scott ◽  
Sean P. Dukelow
Keyword(s):  
Position Sense ◽  
Visual Field Defects ◽  
Stroke Survivors ◽  
Visuospatial Neglect ◽  
Impaired Limb ◽  
Full Compensation ◽  
Systematic Shift ◽  
Opposite Limb ◽  
Neurologically Intact ◽  
Partial Compensation

Abstract Background Position sense is commonly impaired after stroke. Traditional rehabilitation methods instruct patients to visualize their limbs to compensate for impaired position sense. Objective Our goal was to evaluate how the use of vision influences impaired position sense. Methods We examined 177 stroke survivors, an average of 12.7 days (+/− 10 days (SD)) post-stroke, and 133 neurologically-intact controls with a robotic assessment of position sense. The robot positioned one limb (affected) and subjects attempted to mirror-match the position using the opposite limb (unaffected). Subjects completed the test without, then with vision of their limbs. We examined three measures of position sense: variability (Var), contraction/expansion (C/E) and systematic shift (Shift). We classified stroke survivors as having full compensation if they performed the robotic task abnormally without vision but corrected performance within the range of normal with vision. Stroke survivors were deemed to have partial compensation if they performed the task outside the range of normal without and with vision, but improved significantly with vision. Those with absent compensation performed the task abnormally in both conditions and did not improve with vision. Results Many stroke survivors demonstrated impaired position sense with vision occluded [Var: 116 (66%), C/E: 91 (51%), Shift: 52 (29%)]. Of those stroke survivors with impaired position sense, some exhibited full compensation with vision [Var: 23 (20%), C/E: 42 (46%), Shift: 32 (62%)], others showed partial compensation [Var: 37 (32%), C/E: 8 (9%), Shift: 3 (6%)] and many displayed absent compensation (Var: 56 (48%), C/E: 41 (45%), Shift: 17 (33%)]. Stroke survivors with an affected left arm, visuospatial neglect and/or visual field defects were less likely to compensate for impaired position sense using vision. Conclusions Our results indicate that vision does not help many stroke survivors compensate for impaired position sense, at least within the current paradigm. This contrasts with historical reports that vision helps compensate for proprioceptive loss following neurologic injuries.

Eye Movements of the Dogfish Squalus Acanthias L

1965 ◽  
Vol 43 (1) ◽  
pp. 107-130
Author(s):  
A. JOHN HARRIS
Keyword(s):  
Spinal Cord ◽  
Eye Movements ◽  
Squalus Acanthias ◽  
Free Swimming ◽  
Spontaneous Movements ◽  
Excitatory State ◽  
Blind Area ◽  
Full Compensation ◽  
Central Excitatory State ◽  
Partial Compensation

1. A method for recording the positions of the eyes of a free-swimming dogfish is described. 2. The eyes of the dogfish do not compensate completely for the lateral swinging of the head which occurs during swimming. The labyrinthine apparatus and the extraocular musculature are capable of providing complete compensation, but this compensation is opposed by influences from the spinal cord. 3. Full compensation during swimming would stabilize only objects at infinity. Partial compensation serves to stabilize a plane of reference close to the fish. 4. Eye movements, allied with the normal zig-zag progression of the fish, serve to eliminate the blind area behind the fish. 5. Other movements of the dogfish's eyes are discussed, and arranged in five categories. 6. Spontaneous movements of the eyes of resting dogfish are described, and related to the eye movements of swimming dogfish. The spontaneous movements are suggested to be manifestations of an otherwise subliminal central excitatory state affecting turning and swimming.

scholarly journals The Interaction of Rights of Relief and Unjustified Enrichment in Scots Law

2020 ◽  
Vol 24 (2) ◽  
pp. 202-231
Author(s):  
Euan West
Keyword(s):  
The Other ◽  
Precise Nature ◽  
Full Compensation ◽  
The Law ◽  
Unjustified Enrichment ◽  
Partial Compensation

In Scots law, a cautioner (i.e. a guarantor) who pays the guaranteed debt enjoys so-called “rights of relief” against the other parties liable for that debt: namely, a right to full compensation from the principal debtor (“total relief”) and a right to partial compensation from co-cautioners (“pro rata relief”). There has been an increasing tendency on the part of the Scottish courts to treat these rights of relief as a branch of the law of unjustified enrichment. This analysis, according to which a cautioner's payment of the guaranteed debt enriches the principal debtor and co-cautioners unjustifiably, thereby entitling the cautioner to redress, has been subject to academic criticism, with “enrichment” scholars arguing that rights of relief and unjustified enrichment are distinct areas of law. Building on the work of these scholars, this article explores the precise nature of the distinction between “enrichment” and “relief”, its implications for litigants faced with the choice whether to pursue a case on the basis of “relief” or “enrichment” and the extent to which these legal areas perform complementary roles.

scholarly journals Learning the spatial features of a locomotor task is slowed after stroke

2014 ◽  
Vol 112 (2) ◽  
pp. 480-489 ◽  
Author(s):  
Christine M. Tyrell ◽  
Erin Helm ◽  
Darcy S. Reisman
Keyword(s):  
Motor Learning ◽  
Spatial Pattern ◽  
Retention Test ◽  
Step Length ◽  
Treadmill Walking ◽  
Neurological Dysfunction ◽  
Stroke Survivors ◽  
Spatial Features ◽  
Walking Pattern ◽  
Neurologically Intact

The capacity for humans to learn a new walking pattern has been explored with a split-belt treadmill during single sessions of adaptation, but the split-belt treadmill can also be used to study longer-term motor learning. Although the literature provides some information about motor learning after stroke, existing studies have primarily involved the upper extremity and the results are mixed. The purpose of this study was to characterize learning of a novel locomotor task in stroke survivors. We hypothesized that the presence of neurological dysfunction from stroke would result in slower learning of a locomotor task and decreased retention of what was learned and that these deficits would be related to level of sensorimotor impairment. Sixteen participants with stroke and sixteen neurologically intact participants walked on a split-belt treadmill for 15 min on 5 consecutive days and during a retention test. Step length and limb phase were measured to capture learning of the spatial and temporal aspects of walking. Learning the spatial pattern of split-belt treadmill walking was slowed after stroke compared with neurologically intact subjects, whereas there were no differences between these two groups in learning the temporal pattern. During the retention test, poststroke participants demonstrated equal retention of the split-belt treadmill walking pattern compared with those who were neurologically intact. The results suggest that although stroke survivors are slower to learn a new spatial pattern of gait, if given sufficient time they are able to do so to the same extent as those who are neurologically intact.

scholarly journals Effects of a Robot-aided Somatosensory Training on Proprioception and Motor Function in Stroke Survivors

2020 ◽  
Author(s):  
I-Ling Yeh ◽  
Jessica Holst-Wolf ◽  
Naveen Elangovan ◽  
Anna Vera Cuppone ◽  
Kamakshi Lakshminarayan ◽  
...  
Keyword(s):  
Position Sense ◽  
Chronic Stroke ◽  
Tactile Feedback ◽  
Just Noticeable Difference ◽  
Current Evidence ◽  
Stroke Survivors ◽  
Spatial Error ◽  
Upper Limb Function ◽  
Age Range ◽  
Proprioceptive Function

Abstract Background- Proprioceptive deficits after stroke are associated with poor upper limb function, slower motor recovery, and decreased self-care ability. Improving proprioception should enhance motor control in stroke survivors, but current evidence is inconclusive. Thus, this study examined whether a robot-aided somatosensory-based training requiring increasingly accurate active wrist movements improves proprioceptive acuity and motor performance in chronic stroke. Methods - Twelve adults with chronic stroke completed a 2-day training (age range: 42 – 74 years; median time-after-stroke: 12 months; median Fugl-Meyer UE: 65). Retention was assessed at Day 5. Grasping the handle of a wrist-robotic exoskeleton, participants trained to roll a virtual ball to a target through continuous wrist adduction/abduction movements. During training vision was occluded, but participants received real-time, vibro-tactile feedback on their forearm about ball position and speed. Primary outcome was the just-noticeable-difference (JND) wrist position sense threshold as a measure of proprioceptive acuity. Secondary outcomes were spatial error in an untrained wrist tracing task and somatosensory-evoked potentials (SEP) as a neural correlate of proprioceptive function. Ten neurologically-intact adults were recruited to serve as non-stroke controls for age, gender and hand dominance (age range: 44 to 79 years; 6 women, 4 men).Results – Participants significantly reduced JND thresholds at posttest and retention (F(2, 38) = 4.54, p = 0.017, ηp2 = 0.20) in both groups. A higher pretest JND threshold was associated with a higher threshold reduction at posttest and retention (r = -0.86, -0.90, p ≤ 0.001) among the stroke participants. Error in the untrained tracing task was reduced by 22% at posttest, yielding an effect size of w = 0.13. Stroke participants exhibited significantly reduced P27-N30 peak-to-peak SEP amplitude at pretest (U = 11, p = 0.03) compared to the non-stroke group. SEP measures did not change systematically with training.Conclusion - This study provides proof-of-concept that non-visual, proprioceptive training can induce fast, measurable improvements in proprioceptive function in chronic stroke survivors. There is encouraging but inconclusive evidence that such somatosensory learning transfers to untrained motor tasks.Trial Registration Clinicaltrials.gov; Registration ID: NCT02565407; Date of registration: 01/10/2015; URL: https://clinicaltrials.gov/ct2/show/NCT02565407

Effects of Elastic Therapeutic Taping on Joint Position Sense of the Ankle in Stroke Survivors

2019 ◽  
Vol 98 (9) ◽  
pp. 830-834
Author(s):  
Roghayeh Mohammadi ◽  
Mojtaba Abdollahi Khorasgani ◽  
Maryamasadat Tabatabaei ◽  
Namrata Grampurohit
Keyword(s):  
Position Sense ◽  
Joint Position Sense ◽  
Stroke Survivors ◽  
Joint Position

Delays in Grip Initiation and Termination in Persons With Stroke: Effects of Arm Support and Active Muscle Stretch Exercise

2009 ◽  
Vol 101 (6) ◽  
pp. 3108-3115 ◽  
Author(s):  
Na Jin Seo ◽  
William Z. Rymer ◽  
Derek G. Kamper
Keyword(s):  
Muscular Activity ◽  
Functional Independence ◽  
Stroke Survivors ◽  
Dominant Hand ◽  
Flexor Muscle ◽  
Active Muscle ◽  
Muscle Stretch ◽  
Arm Support ◽  
Flexor Muscles ◽  
Neurologically Intact

Stroke survivors' difficulty in releasing grasped objects may be attributable not only to impaired finger extension but also to delays in terminating activity in the gripping flexor muscles. This study was undertaken 1) to quantify the time needed to initiate and terminate grip muscular activity following stroke and 2) to examine effects of arm support, grip location, and active muscle stretch on the delays recorded in the paretic hand. Delays in initiation and termination of finger flexor muscle activity in response to an auditory stimulus were measured for both paretic and nonparetic hands of ten stroke survivors with chronic hemiparesis and the dominant hand of five neurologically intact subjects. Additionally, the delays for the paretic hand were recorded while an external arm support was used and after 30 min of active muscle stretch. We found that delays in grip initiation and termination were greatest for the paretic hand (1.9 and 5.0 s), followed by the nonparetic hand (0.5 and 1.6 s), and least for the control hand (0.2 and 0.4 s). Arm support reduced delay in grip termination 37% for the paretic hand. Repeated active muscle stretch resulted in 24% reduced delay in grip initiation and 32% increased delay in grip termination for the paretic hand. Therapies and interventions reducing these delays may improve the ability to grasp and release objects and thus increase functional independence for stroke survivors.

scholarly journals Assessing Proprioceptive Function: Evaluating Joint Position Matching Methods Against Psychophysical Thresholds

2014 ◽  
Vol 94 (4) ◽  
pp. 553-561 ◽  
Author(s):  
Naveen Elangovan ◽  
Amanda Herrmann ◽  
Jürgen Konczak
Keyword(s):  
Position Sense ◽  
Matching Task ◽  
Joint Position ◽  
Active Motion ◽  
Matching Methods ◽  
Position Errors ◽  
Orthopedic Injury ◽  
Threshold Testing ◽  
Opposite Limb ◽  
Proprioceptive Function

Background The importance of assessing proprioceptive function for rehabilitation after neurological or orthopedic injury has long been recognized. Yet, neither the validity nor the accuracy of the available tests is firmly established. Testing typically involves repeated matching of a given joint position with the same or opposite limb where the difference between the 2 positions indicates proprioceptive acuity. Objectives The aim of this study was to compare position sense acuity between ipsilateral and contralateral matching methods against a psychophysical threshold method to establish the accuracy and relationships between these models. Design A repeated-measures design was used. Method Assessment of forearm position sense for a 10-degree reference position in 27 young adults who were healthy. Results Psychophysical thresholds were revealed to be the most precise and least variable acuity measure. The mean (±SD) threshold (1.05°±0.47°) was significantly lower than mean position errors obtained by both joint position matching tasks (ipsilateral: 1.51°±0.64°; contralateral: 1.84°±0.73°)—a 44% to 75% difference in measurement accuracy. Individual participant position errors correlated poorly with respective thresholds, indicating a lack of concurrent validity. Position errors for both matching methods correlated only mildly with each other. Limitations The data represent performance of a healthy, young adult cohort. Differences between methods will likely be more pronounced in aging and clinical populations. Conclusions Threshold testing and joint position matching methods examine different physiological aspects of proprioceptive function. Because threshold testing is based on passive motion, it most closely reflects afferent sensory feedback processing (ie, proprioception). Matching methods require active motion and are consequently influenced by additional sensorimotor processes. Factors such as working memory and transmission between brain hemispheres also influence joint matching task outcomes.

scholarly journals Maximizing Telerehabilitation for Patients With Visual Loss After Stroke: Interview and Focus Group Study With Stroke Survivors, Carers, and Occupational Therapists (Preprint)

2020 ◽  
Author(s):  
Stephen Dunne ◽  
Helen Close ◽  
Nicola Richards ◽  
Amanda Ellison ◽  
Alison R Lane
Keyword(s):  
Health Care ◽  
Health Care Professionals ◽  
Good Practice ◽  
Occupational Therapists ◽  
Visual Exploration ◽  
Visual Field Defects ◽  
Stroke Survivors ◽  
Focus Group Study ◽  
Movement Strategies ◽  
The Impact

BACKGROUND Visual field defects are a common consequence of stroke, and compensatory eye movement strategies have been identified as the most promising rehabilitation option. There has been a move toward compensatory telerehabilitation options, such as the Durham Reading and Exploration (DREX) training app, which significantly improves visual exploration, reading, and self-reported quality of life. OBJECTIVE This study details an iterative process of liaising with stroke survivors, carers, and health care professionals to identify barriers and facilitators to using rehabilitation tools, as well as elements of good practice in telerehabilitation, with a focus on how the DREX package can be maximized. METHODS Survey data from 75 stroke survivors informed 12 semistructured engagement activities (7 focus groups and 5 interviews) with 32 stroke survivors, 10 carers, and 24 occupational therapists. RESULTS Thematic analysis identified key themes within the data. Themes identified problems associated with poststroke health care from both patients’ and occupational therapists’ perspectives that need to be addressed to improve uptake of this rehabilitation tool and telerehabilitation options generally. This included identifying additional materials or assistance that were required to boost the impact of training packages. The acute rehabilitation setting was an identified barrier, and perceptions of technology were considered a barrier by some but a facilitator by others. In addition, 4 key features of telerehabilitation were identified: additional materials, the importance of goal setting, repetition, and feedback. CONCLUSIONS The data were used to try to overcome some barriers to the DREX training and are further discussed as considerations for telerehabilitation in general moving forward.

scholarly journals Characterizing differential poststroke corticomotor drive to the dorsi- and plantarflexor muscles during resting and volitional muscle activation

2017 ◽  
Vol 117 (4) ◽  
pp. 1615-1624 ◽  
Author(s):  
Jacqueline A. Palmer ◽  
Ryan Zarzycki ◽  
Susanne M. Morton ◽  
Trisha M. Kesar ◽  
Stuart A. Binder-Macleod
Keyword(s):  
Muscle Contraction ◽  
Muscle Activation ◽  
Foot Drop ◽  
Stroke Survivors ◽  
Active Muscle ◽  
Corticomotor Excitability ◽  
Paretic Limb ◽  
Walking Recovery ◽  
Neurologically Intact ◽  
Plantarflexor Muscles

Imbalance of corticomotor excitability between the paretic and nonparetic limbs has been associated with the extent of upper extremity motor recovery poststroke, is greatly influenced by specific testing conditions such as the presence or absence of volitional muscle activation, and may vary across muscle groups. However, despite its clinical importance, poststroke corticomotor drive to lower extremity muscles has not been thoroughly investigated. Additionally, whereas conventional gait rehabilitation strategies for stroke survivors focus on paretic limb foot drop and dorsiflexion impairments, most contemporary literature has indicated that paretic limb propulsion and plantarflexion impairments are the most significant limiters to poststroke walking function. The purpose of this study was to compare corticomotor excitability of the dorsi- and plantarflexor muscles during resting and active conditions in individuals with good and poor poststroke walking recovery and in neurologically intact controls. We found that plantarflexor muscles showed reduced corticomotor symmetry between paretic and nonparetic limbs compared with dorsiflexor muscles in individuals with poor poststroke walking recovery during active muscle contraction but not during rest. Reduced plantarflexor corticomotor symmetry during active muscle contraction was a result of reduced corticomotor drive to the paretic muscles and enhanced corticomotor drive to the nonparetic muscles compared with the neurologically intact controls. These results demonstrate that atypical corticomotor drive exists in both the paretic and nonparetic lower limbs and implicate greater severity of corticomotor impairments to plantarflexor vs. dorsiflexor muscles during muscle activation in stroke survivors with poor walking recovery. NEW & NOTEWORTHY The present study observed that lower-limb corticomotor asymmetry resulted from both reduced paretic and enhanced nonparetic limb corticomotor excitability compared with neurologically intact controls. The most asymmetrical corticomotor drive was observed in the plantarflexor muscles of individuals with poor poststroke walking recovery. This suggests that neural function of dorsi- and plantarflexor muscles in both paretic and nonparetic limbs may play a role in poststroke walking function, which may have important implications when developing targeted poststroke rehabilitation programs to improve walking ability.

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