Nicholas O'Dwyer

Expression of emotion and quality of life after facial nerve paralysis.

Objective: To investigate the facial expression of emotion and quality of life in patients after long-term facial nerve paralysis. Study Design: Cross-sectional. Setting: Facial nerve paralysis clinic. Patients: Twenty-four patients with facial nerve paralysis and 24 significant others (partner, relative, friend). Intervention: Patients were assessed using Sunnybrook, Sydney, and House-Brackmann grading scales and SF-36, Glasgow Benefit Inventory, and Facial Disability Index quality-of-life measures. Results: When patients identified themselves as either effective or not effective at facially communicating each of Ekman’s primary emotions (happiness, disgust, surprise, anger, sadness, and fear), 50% classified themselves as not effective at expressing one or more of the six emotions. Significant others of the not effective patients rated the emotions as more difficult for their partner-patients to communicate facially than did the significant others of effective patients. The SF-36 quality-of-life survey revealed lower social functioning relative to physical functioning for not effective patients. From the Sunnybrook Facial Grading System, more synkinesis was found for those patients not effective at expressing happiness, less brow and eye movement for patients not effective at expressing sadness, and less voluntary movement for those not effective with surprise. Conclusion: Movement deficits associated with expressing specific emotions and an association with quality-of-life measures were identified in patients with long-term facial nerve paralysis who saw themselves as not effective at facial expression of emotions. To improve management of emotional expression in patients with facial nerve paralysis, a broader approach is recommended, linking the practitioner’s treatment goals with patient-driven outcome goals.

Loss of strength contributes more to physical disability after stroke than loss of dexterity

Objective: The major contributors to physical disability after stroke are considered to be the negative impairments of loss of dexterity (defined here as loss of the ability to co-ordinate muscle activity in the performance of any motor task) and loss of strength. The aims of this study were: (1) to determine the relative contributions of strength and dexterity to function during recovery after stroke; and (2) to determine the predictive value of initial strength, dexterity and function on long-term function after stroke. Design: A longitudinal descriptive study. Setting: The inpatient and outpatient rehabilitation departments of two metropolitan hospitals. Subjects: Twenty-two patients undergoing rehabilitation after acute stroke participated. Main outcome measures: Strength and dexterity of the elbow flexors and extensors were measured, along with arm function, at 3, 5, 7, 9, 11, 15, 19, 23 and 27 weeks after stroke. Results: Standard multiple linear regression analysis demonstrated that strength and dexterity in total contributed significantly to function at all times (r2 = 0.66-0.82, p < 0.0001). Furthermore, strength always made an additional separate contribution to function (r2 0.05-0.26, p<0.05). Function at week 3 was the best clinical predictor of function at week 27 (r2 0.55, p < 0.001). Conclusions: Loss of strength is a more significant contributor than loss of dexterity to physical disability after stroke. This suggests that, where significant weakness is present, exercise designed to increase strength will be required to decrease disability.

Relation between spasticity, weakness and contracture of the elbow flexors and upper limb activity after stroke: An observational study

Purpose. Understanding the relationship between the motor impairments and their impact on physical activity will allow rehabilitation after stroke to be based on scientific principles. The aims of this study were to determine: (i) the relative contribution of weakness and spasticity to contracture, and (ii) the relative contribution of all three impairments to limitations in physical activity during the first 12 months after stroke. Method. This longitudinal observational study charted the evolution of weakness (loss of maximal force), spasticity (stretch-evoked EMG) and contracture (loss of joint range) of the elbow flexors and limitations in upper limb activity (Motor Assessment Scale) for a year after stroke in 27 subjects who had suffered a first stroke. Spasticity was measured as abnormal reflex activity, weakness was measured as loss of maximum isometric torque, contracture was measured as the difference in range of motion between the affected and intact side, and limitations in physical activity were measured on a clinical scale. Results. The major independent contributors to contracture were spasticity for the first four months after stroke (p = 0.0001 – 0.10) and weakness thereafter (p = 0.01 – 0.05). However, the major and only independent contributor to limitations in physical activity throughout the year was weakness (p = 0.0001 – 0.05). Conclusions. For the first time, from a longitudinal study, the findings show that spasticity can cause contracture after stroke, consistent with the prevailing clinical view. However, weakness is the main contributor to activity limitations.

Reliability of the "Sydney," "Sunnybrook," and "House Brackmann" facial grading systems to assess voluntary movement and synkinesis after facial nerve paralysis.

OBJECTIVE: To investigate the extent of within-system reliability and between-system correlation for the “Sydney” and “Sunnybrook” systems of grading facial nerve paralysis, and to examine the interobserver reliability and agreement of the “House Brackmann” grading system. STUDY DESIGN: A fixed-effects reliability study in which 6 otolaryngologists viewed videotapes of patients with facial nerve paralysis. SETTING: University and medical Centers. PATIENTS: Patients with unilateral lower motor neurone facial nerve dysfunction greater than 1 year after onset, none of whom had undergone surgical reanimation procedures. INTERVENTION: Twenty-one patients with facial nerve paralysis were videotaped while they performed a protocol of facial movements. Six otolaryngologists viewed the videotapes and scored them with the Sydney and Sunnybrook systems, and then gave a House Brackmann grade. MAIN OUTCOME MEASURE: The 3 systems of grading facial nerve paralysis were evaluated and compared with the use of intraclass correlation coefficients, Pearsons weighted kappa, and percentage exact agreement values. RESULTS: The Sydney and the Sunnybrook systems had good intrasystem reliability and high intersystem association for the assessment of voluntary movement. Grading of synkinesis was found to have low reliability both within and between systems. The House Brackmann system had substantial reliability as shown by weighted kappa but had a percentage exact agreement of 44%. CONCLUSIONS: For clinical grading of voluntary movement, there is good correlation between ratings given on the Sydney and Sunnybrook systems, and within each system there is good reliability. The assessment of synkinesis was far less reliable within, and less related between, systems. Although the reliability of the House Brackmann system was found to be high, examination of individual grades revealed some wide variation between trained observers.

Reflex hyperexcitability and muscle contracture in relation to spastic hypertonia

Mechanisms of spasticity and possible therapeutic interventions continue to dominate research into motor disorders following cerebral lesions. However, the accumulated evidence suggests that this focus on spasticity may be out of step with its effects. In contrast, hypertonia remains an important problem. Further investigation into its link with muscle contracture is required and it needs to be clearly distinguished from reflex hyperexcitability in patients with spasticity.

Slowness to Develop Force Contributes to Weakness After Stroke

OBJECTIVE To examine weakness after stroke, in terms of both level and rate of torque generation. DESIGN Descriptive. T tests for dependent and independent samples and Pearsons product moment correlation coefficients were performed. SETTING A rehabilitation unit. PARTICIPANTS Ten stroke subjects, aged 56 to 81 years, undergoing rehabilitation. Ten neurologically normal subjects aged 55 to 78 years were the controls. OUTCOME MEASURES Peak isometric elbow flexor and extensor torque and time to 90% peak elbow flexor and extensor torque at 6 weeks and at 25 weeks after stroke. RESULTS At 6 weeks after stroke, subjects were only half as strong and took two to three times longer to produce torque compared to controls (p < or = .05). By 25 weeks after stroke, significant improvements in peak torque (p < or = .02) and time to 90% peak flexor torque (p < or = .05) were seen so that values were within normal limits. CONCLUSION Decreased rate of torque development compounds the problem of reduced peak torque, which may have significant implications for stroke patients, especially in situations where muscles are very weak or where force needs to be generated quickly.

Stochastic prediction in pursuit tracking: An experimental test of adaptive model theory

In this paper we test the proposition that in pursuit tracking, subjects compute stochastic (statistical) models of the temporal variations in position of the target and use these models to forecast target position for at least a response time interval into the future. A computer simulation of a human operator employing stochastic model prediction of target position is used to generate a synthetic pursuit tracking response signal. Actual pursuit tracking response signals are measured from 10 normal subjects using the same stimulus signal. Cross correlation and spectral analysis are employed to compute gain and phase frequency response characteristics for both synthetic and actual tracking data. The similarity of the gain and phase curves for synthetic and actual data provides compelling evidence in support of the proposition.

Mechanisms of muscle growth related to muscle contracture in cerebral palsy.

Over the past 15 years studies in experimental animals have shed considerable light on the mechanisms of longitudinal muscle growth. These studies reveal a crucial role for the functioning of muscle in determining its structure and thereby illuminate the problem of muscle contracture in cerebral palsy

Dependence of stretch reflexes on amplitude and bandwidth of stretch in human wrist muscle

Abstract The tonic stretch reflex was investigated using small-amplitude displacements (<4.2°) of the wrist while subjects maintained average contraction levels of 25% of maximum in flexor carpi radialis. The wrist displacements were designed to preclude voluntary following but at the same time were confined to the frequency range most relevant to voluntary movements. They included a broad-frequency band (0–12 Hz) signal as well as sets of narrow-band signals spanning the range from 0 to 10 Hz. The maximum frequency was set so as to remain within the linear encoding bandwidth of the reflex system and thereby minimize distortion. The effects of frequency bandwidth and amplitude of the displacement perturbations were tested in separate experiments. The coherence square, gain and phase between the EMG and angular displacement were calculated in order to characterize the stretch reflex under these conditions. It was found that the phase of the reflex response was dependent on both bandwidth and amplitude. For narrow-band displacements, the phase advance was about 30° greater over the frequency range tested than for broad-band displacements, suggesting that the reflex response may be influenced by the predictability of the perturbation. At the smallest amplitude of 0.3°, the peak phase advance was about 20° greater than at the largest amplitude of 4.2°. The gain was also higher and rose more steeply with frequency at smaller amplitudes. In the frequency range up to 12 Hz, the tonic stretch reflex responds most effectively to smaller-amplitude, more regular, higher-frequency inputs and this is consistent with a role for the reflex in counteracting small-amplitude oscillations, tremors and errors of voluntary movement.

Physiotherapy Rehabilitation of the Smile after Long-Term Facial Nerve Palsy using Video Self-Modeling and Implementation Intentions

OBJECTIVES: To improve smiling after long-term facial nerve palsy (FNP). Physiotherapy rehabilitation of an adapted (more symmetrical) smile was investigated in FNP subjects 1 year post-onset, using video self-modeling (video replay of only best adapted smiles) and implementation intentions (preplanning adapted smiles for specific situations). STUDY DESIGN AND SETTING: Prospective, blinded clinical trial. Facial-Nerve-Palsy Clinic. RESULTS: After video self-modeling: 1) reaction time (RT) to initiation of adapted smiles became 224 ms faster whereas RT for everyday (asymmetrical) smiles became 153 ms slower; 2) adapted smiles were completed 544 ms faster; 3) adapted smiles had higher overall quality, movement control, and symmetry ratings; and 4) Facial Disability Index scores also improved. Implementation intentions after video self-modeling ensured transfer of adapted smile to everyday situations. CONCLUSION: Following intervention the smile improved, with significant changes in availability, execution speed, and quality. SIGNIFICANCE: This study supports these rehabilitation techniques to maximize quality of smiling following FNP. EBM rating: B-2b