Muscle Shortening and Spastic Cocontraction in Gastrocnemius Medialis and Peroneus Longus in Very Young Hemiparetic Children.

OBJECTIVES: Muscle shortening and spastic cocontraction in ankle plantar flexors may alter gait since early childhood in cerebral palsy (CP). We evaluated gastrosoleus complex (GSC) length, and gastrocnemius medialis (GM) and peroneus longus (PL) activity during swing phase, in very young hemiparetic children with equinovalgus. METHODS: This was an observational, retrospective, and monocentric outpatient study in a pediatric hospital. Ten very young hemiparetic children (age 3 ± 1 yrs) were enrolled. These CP children were assessed for muscle extensibility (Tardieu scale XV1) in GSC (angle of arrest during slow-speed passive ankle dorsiflexion with the knee extended) and monitored for GM and PL electromyography (EMG) during the swing phase of gait. The swing phase was divided into three periods (T1, T2, and T3), in which we measured a cocontraction index (CCI), ratio of the Root Mean Square EMG (RMS-EMG) from each muscle during that period to the peak 500 ms RMS-EMG obtained from voluntary plantar flexion during standing on tiptoes (from several 5-second series, the highest RMS value was computed over 500 ms around the peak). RESULTS: On the paretic side: (i) the mean XV1-GSC was 100° (8°) (median (SD)) versus 106° (3°) on the nonparetic side (p = 0.032, Mann-Whitney); (ii) XV1-GSC diminished with age between ages of 2 and 5 (Spearman, ρ = 0.019); (iii) CCIGM and CCIPL during swing phase were higher than on the nonparetic side (CCIGM, 0.32 (0.20) versus 0.15 (0.09), p < 0.01; CCIPL, 0.52 (0.30) versus 0.24 (0.17), p < 0.01), with an early difference significant for PL from T1 (p = 0.03). CONCLUSIONS: In very young hemiparetic children, the paretic GSC may rapidly shorten in the first years of life. GM and PL cocontraction during swing phase are excessive, which contributes to dynamic equinovalgus. Muscle extensibility (XV1) may have to be monitored and preserved in the first years of life in children with CP. Additional measurements of cocontraction may further help target treatments with botulinum toxin, especially in peroneus longus.

Coefficients of impairment in deforming spastic paresis.

This position paper introduces an assessment method using staged calculation of coefficients of impairment in spastic paresis, with its rationale and proposed use. The syndrome of deforming spastic paresis superimposes two disorders around each joint: a neural disorder comprising stretch-sensitive paresis in agonists and antagonist muscle overactivity, and a muscle disorder ("spastic myopathy") combining shortening and loss of extensibility in antagonists. Antagonist muscle overactivity includes spastic cocontraction (misdirected descending command), spastic dystonia (tonic involuntary muscle activation, at rest) and spasticity (increased velocity-dependent reflexes to phasic stretch, at rest). This understanding of various types of antagonist resistance as the key limiting factors in paretic movements prompts a stepwise, quantified, clinical assessment of antagonist resistances, elaborating on the previously developed Tardieu Scale. Step 1 quantifies limb function (e.g. ambulation speed in lower limb, Modified Frenchay Scale in upper limb). The following four steps evaluate various angles X of antagonist resistance, in degrees all measured from 0°, position of minimal stretch of the tested antagonist. Step 2 rates the functional muscle length, termed XV1 (V1, slowest stretch velocity possible), evaluated as the angle of arrest upon slow and strong passive muscle stretch. XV1 is appreciated with respect to the expected normal passive amplitude, XN, and reflects combined muscle contracture and residual spastic dystonia. Step 3 determines the angle of catch upon fast stretch, termed XV3 (V3, fastest stretch velocity possible), reflecting spasticity. Step 4 measures the maximal active range of motion against the antagonist, termed XA, reflecting agonist capacity to overcome passive (stiffness) and active (spastic cocontraction) antagonist resistances over a single movement. Finally, Step 5 rates the residual active amplitude after 15 seconds of maximal amplitude rapid alternating movements, XA15. Amplitude decrement from XA to XA15 reflects fatigability. Coefficients of shortening (XN-XV1)/XN, spasticity (XV1-XV3)/XV1, weakness (XV1-XA)/XV1 and fatigability (XA-XA15)/XA are derived. A high (e.g., >10%) coefficient of shortening prompts aggressive treatment of the muscle disorder--e.g., by stretch programs, such as prolonged stretch postures -, while high coefficients of weakness or fatigability prompt addressing the neural motor command disorder, e.g. using training programs such as repeated alternating movements of maximal amplitude.

[Intensity in the neurorehabilitation of spastic paresis]. / Intensité et rééducation motrice dans la parésie spastique.

Neurorestoration of motor command in spastic paresis requires a double action of stimulation and guidance of central nervous system plasticity. Beyond drug therapies, electrical stimulation and cell therapies, which may stimulate plasticity without precisely guiding it, two interventions seem capable of driving plasticity with a double stimulation and guidance component: the lesion itself (lesion-induced plasticity) and durable behavior modifications (behavior-induced plasticity). Modern literature makes it clear that the intensity of the neuronal and physical training is a primary condition to foster behavior-induced plasticity. When it comes to working on movement, intensity can be achieved by the combination of two key components, one is the difficulty of the trained movement, the other is the number of repetitions or the daily duration of the practice. A number of recent studies shed light on promising recovery prospects, particularly using the emergence of new technologies such as robot-assisted therapy and concepts such as guided self-rehabilitation contracts.

[Does upper limb robot-assisted rehabilitation contribute to improve the prognosis of post-stroke hemiparesis?]. / La rééducation du membre supérieur assistée par robot contribue-t-elle à améliorer le pronostic de l'hémiparésie vasculaire ?

INTRODUCTION: Upper limb robot-assisted rehabilitation is a novel physical treatment for neurological motor impairments. During the last decade, this rehabilitation option utilizing technological tools has been evaluated in hemiparetic patients, mostly after stroke. STATE OF ART: Studies at acute and chronic stages suggested good tolerance and a significant and persistent reduction of motor impairment; a real impact on disability has been shown in acute/sub acute patients. PERSPECTIVES: Improved access to rehabilitation robots and an optimal use will probably be associated with higher efficiency of rehabilitative work in the paretic upper limb. CONCLUSIONS: Even if this treatment is still confined to a narrow circle of users, the device's biomechanical properties and clinical suggestions from the literature may show promise for the future of rehabilitation.

Estimating foot inertial parameters: a new regression approach.

BACKGROUND: Estimating the inertial parameters for the foot (mass, center of mass position and inertia tensor) is important for applications involving the ankle joint such as inverse dynamics or stiffness measurement techniques (e.g. Quick-release). Scaling equations relying on foot length and body mass are widely used. However, because of the complex foot geometry, such equations may represent an oversimplified solution. Our aim was to evaluate these approaches and propose a new method. METHODS: Thirty-four right feet (17 Males, mean age and weight 30 years, 75 kg; 17 Females, 32 years, 61.5 kg) were reconstructed using a 3D surface scanner and used as geometrical references. Associated inertial parameters were calculated directly on each reference assuming a uniform density distribution and were compared to corresponding scaling and multiple regression estimates. Finally, an alternative method, based on multiple non-linear regressions, was proposed considering both foot length (L) and ankle width (W). FINDINGS: Comparisons showed that reference mass and moments of inertia were greater than scaling predictions with mean difference up to 33 and 16% for mass and moments of inertia respectively. The maximum standard errors of estimate for scaled moments of inertia reached 26%. The alternative solution involving ankle width in the equations lowered the gap with reference data (8.7% max standard errors of estimate) for both genders. INTERPRETATION: This strategy, requiring two simple and accessible measurements, may offer a better practicality/relevance compromise for clinical routine use, in regards to existing scaling and regression equations.

[Neurorehabilitation in parkinsonian syndromes]. / Neurorééducation des syndromes parkinsoniens.

Parkinson's disease is a frequent and major source of motor disability, for which physical therapies currently involve less than a third of ambulatory patients and are thus underutilized when compared to chemical and surgical treatments. However, dopaminergic therapies alone prove unable to prevent worsening of motor disability after a number of years. There is rising interest about physical neurorehabilitative therapy for Parkinson's disease, for its symptomatic therapeutic properties, but also for its potential neuroprotective effects in the light of compelling, recent animal literature. The approach to therapy in an individual patient may be governed at the most basic level by the disease stage. For moderate stages of Parkinson's disease (ambulatory patients who have retained a certain degree of physical independence), therapy may focus on the teaching of exercises to the patient: strategies established in controlled studies when used over few weeks periods include motor strengthening programs in the lower limb, high intensity aerobic exercises, attentional strategies using in particular verbal instruction sets, sensory cueing, active axial rotation exercises and high-number repetition of specific tasks. A randomized protocol will soon evaluate the concept of asymmetric motor training, combining a strengthening program in extensor, abductor, external rotator and supinator muscles and a stretching program in their antagonists. For advanced stages (individuals with compromised sit-to-stand, ambulation and significant disability), the therapeutic focus may shift to the teaching of compensation strategies to the patient and the caregiver, both to lessen the effects of motor impairment and to optimize safety. A number of these compensatory strategies are reviewed, some being validated in controlled protocols. In idiopathic Parkinson's disease, clinicians must continue evaluating the symptomatic and perhaps neuroprotective value of physical treatment strategies used over the long term. In atypical parkinsonism, physical treatments often remain the only realistic methods to improve motor behavior and reduce functional deficiencies. The relatively short duration of the effects of physical therapies implies that such programs be pursued over long periods of time, or repeated frequently, for their benefits to be maintained over time.

Botulinum neurotoxin versus tizanidine in upper limb spasticity: a placebo-controlled study.

BACKGROUND: While spasticity is commonly treated with oral agents or botulinum neurotoxin (BoNT) injection, these treatments have not been systematically compared. METHODS: This study performed a randomised, double-blind, placebo-controlled trial to compare injection of BoNT-Type A into spastic upper limb muscles versus oral tizanidine (TZD), or placebo, in 60 subjects with upper-limb spasticity due to stroke or traumatic brain injury (TBI). Wrist flexors were systematically injected, while other upper limb muscles were injected as per investigator judgement. Participants were randomised into three groups: (1) intramuscular BoNT plus oral placebo; (2) oral TZD plus intramuscular placebo; (3) intramuscular placebo plus oral placebo. The primary outcome was the difference in change in wrist flexor modified Ashworth score (MAS) between groups. Other outcome measures included MAS at elbow and finger joints, Disability Assessment Scale (DAS) and adverse events (AE). RESULTS: BoNT produced greater tone reduction than TZD or placebo in finger and wrist flexors at week 3 (p<0.001 vs TZD; p<0.02 vs placebo) and 6 (p = 0.001 vs TZD; p = 0.08 vs placebo), and greater improvement in the cosmesis domain of the DAS at week 6 (p<0.01). TZD was not superior to placebo in tone reduction at either time point (p>or=0.09). The incidence of AE related to study treatment was higher with TZD than in the BoNT (p<0.01) or placebo groups (p = 0.001). CONCLUSIONS: BoNT is safer and more effective than TZD in reducing tone and disfigurement in upper-extremity spasticity, and may be considered as first-line therapy for this disorder.

Assessment: Botulinum neurotoxin for the treatment of spasticity (an evidence-based review): report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

OBJECTIVE: To perform an evidence-based review of the safety and efficacy of botulinum neurotoxin (BoNT) in the treatment of adult and childhood spasticity. METHODS: A literature search was performed including MEDLINE and Current Contents for therapeutic articles relevant to BoNT and spasticity. Authors reviewed, abstracted, and classified articles based on American Academy of Neurology criteria (Class I-IV). RESULTS: The highest quality literature available for the respective indications was as follows: adult spasticity (14 Class I studies); spastic equinus and adductor spasticity in pediatric cerebral palsy (six Class I studies). RECOMMENDATIONS: Botulinum neurotoxin should be offered as a treatment option for the treatment of spasticity in adults and children (Level A).

Neurophysiological modulation of the subthalamic nucleus by pallidal stimulation in Parkinson's disease.

OBJECTIVES: Current models of basal ganglia dysfunction in Parkinson's disease suggest a pivotal role of subthalamic nucleus (STN) hyperactivity. There is a direct excitatory output to the globus pallidus internus (GPi), which in turn hyperinhibits the motor thalamus and leads to a lack of cortical facilitation. The model, however, does not address the reciprocal influence of GPi on STN activity. METHODS: Measurement of immediate changes in STN single cell activity after GPi deep brain stimulation (DBS). RESULTS: An opposite effect of GPi DBS in the dorsal versus ventral STN was found. There was an almost exclusive reduction of firing rate in the dorsal region of the STN, whereas the cells in the ventral region exhibited facilitation similar to the recordings from the substantia nigra pars reticulata. CONCLUSION: Although these findings require confirmation, they suggest that the current theories of GPi DBS action, which do not include a GPi-STN modulation, are most likely incomplete.

Pathophysiology of impairment in patients with spasticity and use of stretch as a treatment of spastic hypertonia.

Paralysis, muscle shortening, and muscle overactivity are the three main disabling factors in patients with spasticity. Occurring after most central lesions, muscle overactivity and shortening are not equally spread throughout all muscles of the body. In an agonist-antagonist couple, there is invariably "greater" overactivity and shortening of one versus the other. This is the rationale for the use of targeted local treatments that train the weaker agonist and stretch and partially block the more overactive and shorter antagonist. Central paralysis, muscle shortening, and muscle overactivity are intertwined, and the three corresponding therapies, motor training, stretch, and local partial blocks, should be implemented in combination. This triple treatment is the main condition for any functional recovery. Muscle shortening occurs acutely after a central nervous system lesion; therefore its treatment should be implemented as rapidly as possible.

Physical modalities other than stretch in spastic hypertonia.

This article reviews various physical modalities that have been used in spastic hypertonia, particularly superficial heat and cold, diathermies (ultrasound, microwave, and short-wave irradiation), electrical stimulation (transcutaneous electrical nerve stimulation), implanted spinal stimulation (rectal stimulation), and massage (deep friction, superficial contact). The duration of the effects of most physical therapies is relatively short (e.g., cooling, heating, and massage), which often may limit their application to immediate prestretch or pre-exercise periods. The potential capacity of ultrasound therapy to improve the efficacy of chronic stretch in lengthening muscle may be a promising option. The neurodestructive potential of high intensity microwave for the personnel involved and controlled evidence of its value is required before this modality can be recommended in spasticity. Overall, controlled, double-blind studies are mandated to evaluate the long-term impact of repeated use of these short-term modalities on function and recovery in patients with spasticity.

Early morning off-medication dyskinesias, dystonia, and choreic subtypes.

BACKGROUND: Abnormal involuntary movements (dyskinesias) are common in patients with Parkinson disease (PD) as a consequence of the disease and dopaminergic replacement therapy. Early morning off-medication choreic dyskinesias have been recently reported after fetal dopaminergic cell transplantations in patients with advanced PD. OBJECTIVE: To determine the frequency and severity of the early morning off-medication dyskinesias in consecutive patients with advanced PD and an insufficient response to medical management before they undergo neurosurgery. METHODS: Consecutive patients with advanced idiopathic PD were examined and videotaped before undergoing neurosurgery that included pallidotomy, fetal transplantation, or deep brain stimulation. The examination took place in the morning in the practically defined off state, at least 12 hours after the last dose of dopaminergic drugs. Parkinson disease was characterized using the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr stage. Dyskinesias were rated with the Abnormal Involuntary Movements Scale and the Rush Dyskinesia Rating Scale. Patients' characteristics and medications were compared using the Wilcoxon rank sum and the Fisher exact tests. RESULTS: Of 68 consecutive patients (44 [65%] men and 24 [35%] women), 11 (16%) had early morning off-medication dyskinesia, with a 95% upper confidence limit of 24%. Focal dystonia was the most common off-medication dyskinesia, and occurred in 10 patients (15%), with a 95% upper confidence limit of 22%; and off-choreic dyskinesia occurred in 1 patient (1.5%), with a 95% upper confidence limit of 4%. There was no difference in PD medications between the patients with and those without dyskinesias. CONCLUSIONS: The most common form of off-medication dyskinesia seen in patients with advanced PD is dystonia. Early morning off-medication choreic dyskinesias are rare but do occur in patients with advanced PD before surgical intervention. The presence and type of off-medication dyskinesias should be monitored in clinical and surgical studies in patients with PD as part of the safety and evaluation of clinical benefits.

Short-term effects of dynamic lycra splints on upper limb in hemiplegic patients.

OBJECTIVE: To assess acceptability, effects on swelling, resting posture, spasticity, and active (AROM) and passive range of motion (PROM) of individually tailored upper limb Lycra garments, designed as dynamic splints to exert directional pull on certain limb segments, when worn for 3 hours by hemiplegic patients. DESIGN: Crossover trial. SETTING: Outpatient and inpatient rehabilitation center. PATIENTS: Convenience sample of 16 patients with hemiparesis and upper limb spasticity caused by a stroke more than 3 weeks before the study. INTERVENTIONS: Assessments performed at the start and end of a 3-hour period during a standard rehabilitation day when the patients were and were not wearing the garment. MAIN OUTCOME MEASURES: (1) Comfort assessed by questionnaire; (2) circumference of each limb segment; (3) resting posture at elbow and wrist; (4) spasticity at shoulder, elbow, and wrist using the Tardieu scale; and (5) AROM and PROM at shoulder, elbow, and wrist measured using a goniometer; (6) elbow proprioception using McCloskey's method; (7) visual neglect syndrome using the line bisection test. Differences between changes occurring with and without the garment were compared using Wilcoxon's signed rank test for ordinal variables (spasticity grading) and Student's t test for continuous variables (all other data). RESULTS: During 3 hours, garments worn on the arm by patients with hemiplegia (1) were comfortable, (2) improved wrist posture and reduced wrist and finger flexor spasticity, (3) reduced swelling in patients with swollen limbs (digit circumference decreased by 4%; p<.01), (4) improved PROM at shoulder (mean increase in range, 4.1 degrees +/- 13.0 degrees per shoulder movement; p<.01); and (5) impaired ability to flex fingers (range of voluntary flexion of digit III reduced from 107.3 degrees +/-79.6 degrees to 91.4 degrees +/-74.1 degrees; p<.05). CONCLUSION: Lycra garments, designed to produce continuous stretch of spastic muscles when worn for several hours each day, have rapid splinting and antispastic effects on wrist and fingers in patients with hemiplegia. These garments may help severely affected patients with major spasticity or painful swollen limbs.

Muscle spindle activity in the affected upper limb after a unilateral stroke.

Weakness, loss of dexterity and exaggerated reflex responses to proprioceptive and cutaneous stimuli are typical features of hemiparetic stroke. Since the extent to which altered fusimotor drive contributes to these deficits has not been established, this study was designed to assess fusimotor function in stroke patients by comparing three aspects of muscle spindle afferent behaviour (background discharge rate, responses to reflex inputs and responses to voluntary contractions) in 11 subjects affected by recent cerebrovascular lesions, with those in 18 healthy volunteers. The mean background discharge rates of muscle spindle afferents in the radial nerve when subjects attempted to relax the recorded limb completely were 6.6 +/- 5.3 Hz (n = 26) in patients and 6.4 +/- 6.1 Hz (n = 76) in control subjects. The variability of discharge rate of active afferents was also similar (0.12 +/- 0.07 and 0.09 +/- 0. 10, respectively). Reflex activation of fusimotor neurons was assessed using trains of electrical stimuli to the superficial radial nerve or to the palm of the hand, and using natural skin stimuli. Neither type of cutaneous stimulation affected muscle spindle afferent discharge in the absence of an EMG response. During deliberate voluntary contractions muscle spindle discharge rates were enhanced similarly in both the control and patient groups, indicating that volitional drives could access fusimotor neurons in the patients. Qualitatively, spindle behaviour was similar in patients and control subjects. These findings suggest that fusimotor function is not disturbed any more or less than skeletomotor function in hemiparetic patients and it is concluded that fusimotor dysfunction probably contributes little to their deficit.

Neuromuscular blockers.

The use of corrosive, injectable neuromuscular blockers has been a treatment option for many years; however, the more recent advent of botulinum toxin (BTX) treatment has revived interest in localized treatments. This article reviews the use of local anesthetics, alcohol, phenol, and BTX treatment for localized muscular overactivity syndromes.

Evidence for fusimotor drive in stroke patients based on muscle spindle thixotropy.

To study fusimotor function in stroke patients, we compared the amplitude of stretch reflexes elicited in flexor carpi radialis (FCR) after contraction of FCR with the wrist held flexed ('hold-short') or extended ('hold-long'). Seven subjects with impaired hand function and spasticity due to stroke, and seven healthy subjects were investigated. Surface electrodes recorded electromyographic activity of wrist flexors and extensors while subjects performed isometric wrist flexions with the wrist alternately in 15 degrees of flexion or extension. After contractions the wrist was moved passively to the mid-position, and stretch reflexes were elicited via controlled mechanical taps delivered over the FCR tendon. For both groups, the amplitude of the stretch reflex was greater after 'hold-short' than 'hold-long' contractions. This finding is consistent with the 'after-effects' of intrafusal fibre activation, and suggests that fusimotor neurones are activated during voluntary contractions of the paretic limb, just as in the limb of a healthy subject.

Bilateral optic disk pallor after unilateral internal carotid artery occlusion.

Bilateral pallor of the optic disks was observed in a 52-year-old man after dissection of an internal carotid artery. Diffuse pallor of the ipsilateral optic disk reflected infarction of the ipsilateral optic nerve and "bow-tie" atrophy of the contralateral optic disk reflected infarction of the ipsilateral optic tract. The findings were due to an occlusion of the internal carotid artery proximal to the origin of the ophthalmic artery, resulting also in insufficiency in the area of supply of the anterior choroidal artery.