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Evaluating patients with adult-onset gait instability can pose diagnostic challenges. In this case, a 62-year-old Ashkenazi Jewish woman with a history of surgically corrected hammer toes presented with chronic progressive lower extremity weakness, sensory impairment, and gait instability. Subsequently, the patient developed urinary urgency and mild cognitive difficulties. This case underscores the approach to diagnosing patients with gait difficulty by constructing a comprehensive differential diagnosis focusing on the neurologic localization of this case and exploring probable etiologies. Readers will deepen their comprehension of this neurologic process and its differential diagnoses to ultimately arrive at a final diagnosis.

Objective: To document the decline of upper and lower limb functions, mobility, and independence in daily living activities in adults with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) over a 2-year period., Methods: An exploratory longitudinal design was used. Nineteen participants were assessed on 2 occasions 2 years apart. Assessments included the Standardized Finger Nose Test, Nine-Hole Peg Test, Lower Extremity Motor Coordination Test, Berg Balance Scale, 10-m walk test (10mWT), 6-minute walk test (6MWT), Scale for the Assessment and Rating of Ataxia (SARA), and Barthel Index., Results: A significant decline was observed between baseline and follow-up for lower limb coordination, balance, walking abilities (10mWT and 6MWT), and overall disease severity (SARA). All differences were beyond measurement error documented in ARSACS. Results showed no significant decline for upper limb coordination and fine dexterity performance., Conclusion: Although ARSACS is a slow, progressive disease, results showed that mobility, balance, and lower limb performance significantly decreased over the 2-year period and that selected outcome measures were able to capture this decline beyond measurement errors., (© 2018 American Academy of Neurology.)

Objectives: The study was focused on leukoencephalopathies of unknown cause in order to define a novel, homogeneous phenotype suggestive of a common genetic defect, based on clinical and MRI findings, and to identify the causal genetic defect shared by patients with this phenotype., Methods: Independent next-generation exome-sequencing studies were performed in 2 unrelated patients with a leukoencephalopathy. MRI findings in these patients were compared with available MRIs in a database of unclassified leukoencephalopathies; 11 patients with similar MRI abnormalities were selected. Clinical and MRI findings were investigated., Results: Next-generation sequencing revealed compound heterozygous mutations in AARS2 encoding mitochondrial alanyl-tRNA synthetase in both patients. Functional studies in yeast confirmed the pathogenicity of the mutations in one patient. Sanger sequencing revealed AARS2 mutations in 4 of the 11 selected patients. The 6 patients with AARS2 mutations had childhood- to adulthood-onset signs of neurologic deterioration consisting of ataxia, spasticity, and cognitive decline with features of frontal lobe dysfunction. MRIs showed a leukoencephalopathy with striking involvement of left-right connections, descending tracts, and cerebellar atrophy. All female patients had ovarian failure. None of the patients had signs of a cardiomyopathy., Conclusions: Mutations in AARS2 have been found in a severe form of infantile cardiomyopathy in 2 families. We present 6 patients with a new phenotype caused by AARS2 mutations, characterized by leukoencephalopathy and, in female patients, ovarian failure, indicating that the phenotypic spectrum associated with AARS2 variants is much wider than previously reported., (© 2014 American Academy of Neurology.)

Poststroke spasticity (PSS) is associated with significant consequences for a patient's functional status and quality of life. Nonetheless, no uniform definition of spasticity exists that can be utilized across clinical research settings, and difficulties in validating proper assessment tools--both clinical and nonclinical--complicate the ability to evaluate and appropriately treat spasticity. Consequently, the current state of defining, assessing, and treating spasticity requires improved consistency and ongoing validation as clinical research efforts advance. When selecting clinical measures for PSS assessment (e.g., the Modified Ashworth, Tone Assessment, Tardieu, Modified Rankin, and Disability Assessment scales, and the Barthel Index), it is critical to understand the levels of impairment or functional limitation each tool assesses as well as their benefits and limitations. The use of quantitative methods--such as electrophysiologic, biomechanical, and imaging techniques--adjunctive to traditional clinical measures also allows for sensitivity in quantifying the abnormal muscle activity associated with spasticity. In addition to accurate evaluation and assessment of PSS, realistic treatment goal setting for patients as well as family members and caregivers is critical, because it promotes motivation and cooperation as well as proper management of expectations and can favorably affect recovery. Goal attainment scaling has been shown to help organize, focus, and clarify the aims of treatment, thereby enhancing the PSS rehabilitative process. Furthermore, integration of therapeutic modalities and treatment strategies, including both nonpharmacologic intervention and pharmacotherapy, is also important for improved outcomes.

Spasticity is defined clinically by increased muscle tone and tendon jerk hyperreflexia in patients who are at rest. However, the excitability of spinal circuits changes during movement, and this definition provides no insight into the extent to which spasticity and associated motor disturbances cause disability. Only a few spinal circuits have been shown to underlie the abnormalities of patients at rest. Movement can be restrained by pathologically enhanced muscle tone, and there is defective control of the feedback to active motoneurons through virtually all spinal reflex pathways. Spasticity does not necessarily require treatment: in fact, some patients rely on the increased muscle tone to help support otherwise weak muscle contractions for stance and locomotion. In addition, much of the increase in muscle tone arises from changes in muscle and motor units, independent of reflex mechanisms. Managing a patient with impairment after a stroke requires therapy tailored to that particular patient because the mechanisms contributing to the disability experienced by one patient may differ from those affecting another.

Among the estimated 20% to 40% of stroke survivors who develop spasticity, the burden of this condition on patients, caregivers, and society is substantial. Stroke survivors with spasticity may experience reductions in their ability to perform activities of daily living and in their health-related quality of life. The occurrence of spasticity in stroke survivors may also result in an increased burden on their caregivers, who exhibit poorer physical and emotional health as compared with the general population. The responsibilities that caregivers have to the stroke survivor--in terms of providing medical care, protecting from falls, and assisting with feeding and hygiene, among other tasks of daily living--must be balanced with their responsibilities to other family members and to themselves. Caregivers of stroke survivors often report a feeling of confinement with little opportunity for relief, and although social support can be helpful, it is frequently limited in its availability. In terms of the socioeconomic burden of spasticity after stroke, recent data point to a 4-fold increase in health care costs associated with stroke survivors with spasticity compared with stroke survivors without spasticity. Thus, it is important to reduce the burden of spasticity after stroke. Consequently, effective spasticity treatment that reduces spasticity and the level of disability experienced by stroke survivors will likely increase their functioning and their health-related quality of life and will also result in a diminished burden on their caregivers.

Poststroke spasticity (PSS)-related disability is emerging as a significant health issue for stroke survivors. There is a need for predictors and early identification of PSS in order to minimize complications and maladaptation from spasticity. Reviewing the literature on stroke and upper motor neuron syndrome, spasticity, contracture, and increased muscle tone measured with the Modified Ashworth Scale and the Tone Assessment Scale provided data on the dynamic time course of PSS. Prevalence estimates of PSS were highly variable, ranging from 4% to 42.6%, with the prevalence of disabling spasticity ranging from 2% to 13%. Data on phases of the PSS continuum revealed evidence of PSS in 4% to 27% of those in the early time course (1-4 weeks poststroke), 19% to 26.7% of those in the postacute phase (1-3 months poststroke), and 17% to 42.6% of those in the chronic phase (>3 months poststroke). Data also identified key risk factors associated with the development of spasticity, including lower Barthel Index scores, severe degree of paresis, stroke-related pain, and sensory deficits. Although such indices could be regarded as predictors of PSS and thus enable early identification and treatment, the different measures of PSS used in those studies limit the strength of the findings. To optimize evaluation in the different phases of care, the best possible assessment of PSS would make use of a combination of indicators for clinical impairment, motor performance, activity level, quality of life, and patient-reported outcome measures. Applying these recommended measures, as well as increasing our knowledge of the physiologic predictors of PSS, will enable us to perform clinical and epidemiologic studies that will facilitate identification and early, multimodal treatment.

Stroke survivors typically experience varying degrees of motor and neuropsychological deficits. Although these deficits are frequently treated as separate entities in the cognitive and physical rehabilitation settings, there is considerable interaction between them. Cognitive-motor interference, for example, refers to the simultaneous performance of cognitive and motor functions that results in diminished execution of one or both of the tasks. Studies have demonstrated that when performing dual tasks, poststroke patients will typically favor the cognitive function over the motor task. Furthermore, only certain cognitive functions will interfere with motor abilities, while the intensity of the motor task may magnify the detriment in dual-task performance. Moreover, mood disorders, particularly depression, have also been shown to interact substantially with physical functioning. Consequently, poststroke patients with depression experience greater reductions in their activities of daily living and worse rates of recovery. Recent neuroimaging studies suggest an association between white matter hyperintensities and both motor and neuropsychological poststroke deficits. The relationship between spasticity and cognition deficits needs to be further explored with regard to the deleterious consequences of poststroke spasticity on quality of life and overall motor function. These insights, among others, contribute to a growing, if embryonic, body of knowledge about poststroke motor/cognitive interaction that will ultimately inform developments in treatment and rehabilitation.

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).

Objective: To investigate whether repetitive transcranial magnetic stimulation (rTMS) can modify spasticity., Methods: We used high-frequency (5 Hz) and low-frequency (1 Hz) rTMS protocols in 19 remitting patients with relapsing-remitting multiple sclerosis and lower limb spasticity., Results: A single session of 1 Hz rTMS over the leg primary motor cortex increased H/M amplitude ratio of the soleus H reflex, a reliable neurophysiologic measure of stretch reflex. Five hertz rTMS decreased H/M amplitude ratio of the soleus H reflex and increased corticospinal excitability. Single sessions did not induce any effect on spasticity. A significant improvement of lower limb spasticity was observed when rTMS applications were repeated during a 2-week period. Clinical improvement was long-lasting (at least 7 days after the end of treatment) when the patients underwent 5 Hz rTMS treatment during a 2-week protocol. No effect was obtained after a 2-week sham stimulation., Conclusions: Repetitive transcranial magnetic stimulation may improve spasticity in multiple sclerosis.

Objective: To prospectively evaluate the effect of pump-infused intrathecal baclofen infusion (ITB) in therapeutic doses on sleep quality and on daytime and nighttime respiratory function in patients with severe spasticity., Methods: We prospectively evaluated 20 consecutive patients (mean +/- SD age 45 +/- 13 years). We assessed spasticity and obtained polysomnography, pulmonary function tests, and resting energy expenditure measurements 1 week before and at least 8 days after pump implantation. Patients stopped oral baclofen upon pump implantation but continued other medications unchanged. We report descriptive statistics as means +/- SD., Results: Most of the patients had multiple sclerosis (n = 9) or spinal cord injury (n = 8); there was one case each of cerebral palsy, hereditary spastic paraplegia, and Friedreich ataxia. Before and after ITB initiation, mean Ashworth scores were 2.75 +/- 0.85 and 1.15 +/- 0.36, and mean spasm scores were 3.75 +/- 0.55 and 1.00 +/- 0.56. ITB improved total sleep time (p = 0.05) and sleep efficiency (p = 0.01) and reduced periodic leg movements (p = 0.02). ITB did not modify sleep-related respiratory events, lung function tests, CO2 rebreathing response, or resting energy expenditure., Conclusion: Compared with oral baclofen, intrathecal baclofen infusion did not affect respiratory function and improved sleep continuity. Intrathecal baclofen infusion in therapeutic doses may act at the spinal level rather than at the supraspinal level.

Objective: To examine the modulation of non-reciprocal group I (Ib) inhibition during tonic contraction of antagonist muscles in patients with spasticity vs normal subjects., Methods: The authors studied 10 patients with spastic paraplegia due to cervical compression myelopathy and 16 age-matched normal subjects. Ib inhibition to soleus motoneurons was recorded as the change in size of the H-reflex of the soleus, evoked by conditioning stimulus to the nerve innervating the medial gastrocnemius muscle. The extent of inhibition was studied at rest and during tonic contraction of the pretibial muscles of variable strength., Results: In the resting state, the extent of inhibition in the patients did not differ from normal controls. During antagonist contraction, the extent of inhibition increased both in the normal subjects and patients. The increment was smaller in the patients, especially in those with severe spastic gait. The smaller increment in the inhibition was correlated with the time required to walk 10 m in the patients., Conclusion: The authors observed a lack of modulation of Ib inhibition during tonic antagonist contraction in patients with spasticity, especially those with gait disturbance. Disturbed central modulation of non-reciprocal (Ib) interneurons may be responsible for spasticity.

Background: Recently, six molecular subtypes of sporadic CJD (sCJD) have been identified showing differences regarding the disease course, neuropathologic lesion patterns, and sensitivity to diagnostic tools. Only isolated cases of the rare VV1 type have been reported so far., Objective: To describe the clinical characteristics and neuropathologic lesion profiles in nine cases., Methods: In the years 1993 until late 2003, 571 definite neuropathologically confirmed cases of sporadic CJD were identified in Germany. Of these, nine were homozygous for valine and displayed type 1 of the pathologic PrPSc in the brain (VV1 type)., Results: The authors describe eight men and one woman belonging to the VV1 type. All patients were relatively young at disease onset (median 44 years vs 65 years in all sCJD) with prolonged disease duration (median 21 months vs 6 months in all sCJD). During the initial stages, their main clinical signs were personality changes and slowly progressive dementia as well as focal neurologic deficits. None of the nine VV1 patients had periodic sharp-wave complexes (PSWCs) in the EEG. Only two out of seven displayed the typical signal increase of the basal ganglia on MRI, whereas signal increase of the cortex was seen in all patients. The 14-3-3 protein levels were elevated in CSF in all cases tested., Conclusions: The clinical diagnosis of the VV1 type of sCJD can be best supported by the 14-3-3 test and cortical signal increase on MRI. Because of the young age at onset vCJD is sometimes suspected as a differential diagnosis. MRI plays an important role in differentiating these two disease types and should be performed early during the disease course.

The authors describe a 38-year-old woman with stiff person syndrome (SPS) and gaze-holding nystagmus, limited abduction, vertical and horizontal ocular misalignment, deficient smooth pursuit, and impaired saccade initiation. There was no evidence of ocular myasthenia, indicating that abnormalities of ocular motor function can occur as a primary manifestation of SPS, perhaps from depletion of GABA.

The authors report a Chinese boy with a DYT1 gene mutation having muscle stiffness, severe painful muscle spasm, myoclonus, and dystonia compatible with stiff child syndrome. Autoantibodies to glutamic acid decarboxylase (anti-GAD) were absent. His asymptomatic mother had a DYT1 mutation. His asymptomatic sister has diabetes mellitus and antibodies to glutamic acid decarboxylase but no DYT1 mutation.

The authors describe two Japanese siblings with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) without spasticity, usually a core feature of this disorder. They had a novel homozygous missense mutation (T987C) of the SACS gene, which resulted in a phenylalanine-to-serine substitution at amino acid residue 304.

Oral and intrathecal baclofen (ITB) have been associated with epileptic seizures. The authors observed a higher incidence of epileptic seizures in 99 patients with multiple sclerosis (MS) treated with ITB vs a matched control group (7% vs 1%, p < 0.05). Three patients with MS on ITB developed status epilepticus. Seizures were often associated with additional triggering factors.

Objective: To investigate the adaptational changes in excitability of spinal neuronal circuits below the level of lesion from spinal shock to spasticity in patients with spinal cord injury (SCI)., Methods: More than 6 months after an acute SCI, clinical follow-up examinations were paralleled by electrophysiologic recordings with tibial nerve stimulation (M-wave, F-wave, H-reflex, and flexor reflex)., Results: During spinal shock, the loss of tendon tap reflexes and flaccid muscle tone were associated with low persistence of F-waves and loss of flexor reflexes, whereas H-reflexes were already elicitable. During the transition to spasticity, the reappearance of tendon tap reflexes and muscle tone and the occurrence of spasms was associated with the recovery of F-waves and flexor reflex excitability, whereas the H-to-M ratio remained about stable over months. At later stages (2 to 6 months after SCI) when clinical signs of spasticity became established, the electrophysiologic measures showed little change. In paraplegic patients, in contrast to tetraplegic patients, M-wave and flexor reflex amplitudes even decreased., Conclusions: The late decrease in M-wave and flexor reflex amplitude in paraplegic patients suggests a secondary impairment/degeneration of premotoneuronal circuits and of motoneurons. The divergent course of clinical signs of spasticity and their probable neuronal correlates indicates the occurrence of non-neuronal changes contributing to spasticity.

Objective: To compare human T-cell lymphotrophic virus type I (HTLV-I) seropositive and seronegative women for symptoms and signs of spasticity., Background: Infection with HTLV-I causes tropical spastic paraparesis/ HTLV-I-associated myelopathy (TSP/HAM). Certain populations, including female commercial sex workers (FSW), are at increased risk of developing this infection. Fewer than 5% of HTLV-I-seropositive persons develop TSP/HAM, which is typically associated with spasticity., Methods: Cross-sectional study of 255 registered FSW in Callao, Perú, involving a questionnaire detailing demographics and neurologic symptoms, standard neurologic examination, quantitative assessment of spasticity (QSA) of muscle tone, and serologic testing for HTLV-I. Participants and examiners were blinded to serology results., Results: On the questionnaire and neurologic examination, none of the 32 HTLV-I-seropositive or 223 seronegative women had signs or symptoms of spasticity. However, mean values on QSA were significantly higher among seropositive women (27.1 Newton-meters/radian [N-m/r]) than among seronegative women (21.6 N-m/r, p = 0.01), indicating a subclinical increase in lower extremity tone. With values of QSA divided into tertiles, and the first tertile serving as the comparison group, the odds ratio for seropositivity was 1.4 (95% confidence interval [CI] 1.0 to 2.0) in the second and 3.1 (95% CI 2.2 to 4.3) in the third tertile, after adjusting for age and place of birth., Conclusions: Although a standard neurologic evaluation could not distinguish between women with and without HTLV-I infection, QSA indicated significantly increased lower extremity tone in those with infection. Long-term follow-up will determine whether these subclinical findings in asymptomatic women progress to overt TSP/HAM.

We describe three siblings from an Italian family affected by an autosomal recessive spinocerebellar degeneration. Gait ataxia, presenting between 38 and 45 years, was the first symptom in all three patients. Dysarthria, dysmetria, brisk tendon reflexes, extensor plantar response, and scoliosis were constant features. Disease progression was slow. Electrophysiologic studies demonstrated a slight reduction in sural nerve sensory action potential in only one patient. Analysis of GAA expansion within the X25 gene showed that patients were homozygous for the expansion, with the shorter expanded allele ranging from 120 to 156 triplets. The size of the GAA expansion may be smaller than we previously described. Such minimal expansions may result in atypical forms of Friedreich's ataxia.

Cortical plasticity of the human brain permits functional recovery after brain injury even in the absence of neuronal recovery. We report the combined evaluation, including electrophysiology and functional magnetic resonance imaging, of the pattern of cortical and cerebellar reorganization, in a patient with mirror movements as a sequel of perinatal unilateral brain injury. Recovery resulted in motor control by the healthy hemisphere using direct ipsilateral corticospinal projections and the contralateral cerebellum.

We studied the effect of botulinum toxin A (BTXA) among patients with traumatic brain injury (TBI) and severe spasticity unresponsive to conservative management. Twenty-one consecutive adult patients with severe spasticity involving the wrist and finger flexor musculature were treated with BTXA injection (20 to 40 units per muscle) under EMG guidance. After injection, patients received passive range of motion (ROM) exercise, with modalities and casting as clinically indicated. Outcome measures, including wrist ROM and the modified Ashworth Scale (MAS), were assessed 2 to 4 weeks after injection. Among the respective acute and chronic groups, mean ROM improved 42.9 (p = 0.001) and 36.2 degrees (p < 0.001). Mean MAS rating improved 1.5 (p = 0.01) and 1.47 (p = 0.002) points. There were no significant adverse effects. BTXA, in conjunction with conventional modalities, significantly improves spasticity and ROM in the distal upper extremity musculature of patients with TBI.

Spasticity is a disorder of excess muscle tone associated with CNS disease. We hypothesized that botulinum toxin, a neuromuscular blocking agent, would reduce tone in spastic muscles after stroke. This randomized, double-blind, placebo-controlled, multicenter clinical trial evaluated the safety and efficacy of botulinum toxin type A (BTXA) in the treatment of chronic upper limb spasticity after stroke. Thirty-nine patients received IM injections of a total dose of either 75, 150, or 300 units of BTXA or placebo into the biceps, flexor carpi radialis, and flexor carpi ulnaris muscles. At baseline, patients demonstrated a mean wrist flexor tone of 2.9 and elbow flexor tone of 2.6 on the Ashworth Scale (0 to 4). Treatment with the 300-unit BTXA dose resulted in a statistically and clinically significant mean decrease in wrist flexor tone of 1.2 (p = 0.028), 1.1 (p = 0.044), and 1.2 (p = 0.026) points and elbow flexor tone of 1.2 (p = 0.024), 1.2 (p = 0.028), and 1.1 (p = 0.199) at weeks 2, 4, and 6 postinjection. In the placebo group, tone reduction at the wrist was 0.3, 0.2, and 0.0 and at the elbow was 0.3, 0.3, and 0.6 at weeks 2, 4, and 6 postinjection. BTXA groups reported significant improvement on the physician and patient Global Assessment of Response to Treatment at weeks 4 and 6 postinjection. There were no serious adverse effects. In this 3-month study, BTXA safely reduced upper extremity muscle tone in patients with chronic spasticity after stroke.

This multicenter, stratified, randomized, placebo-controlled, double-blind trial evaluated tizanidine for use in the United States for spasticity secondary to MS. The 15-week trial was divided into baseline (weeks 0 and 1), titration (2 mg to a maximum of 36 mg/d; weeks 2 to 4), and plateau (weeks 5 to 13) phases, followed by dose tapering (week 14) and a final visit (week 15). Primary efficacy parameters were scores on muscle tone (Ashworth Scale) and type and frequency of muscle spasms (patient diaries). All efficacy parameters were evaluated by the physician/assessor, and the physician/prescriber was responsible for all dosage adjustments. The patient, physician/assessor, and physician/prescriber made global evaluations of antispastic efficacy. Tizanidine produced a significantly greater reduction than placebo in spasms and clonus (patient diaries) but no significant differences in Ashworth scores. Patients and physician/prescribers, but not physician/assessors, gave significantly better scores in the overall assessment of efficacy and tolerability. No significant differences in other secondary efficacy parameters were noted. Adverse events were reported for 66 (61%) of the 109 placebo-treated patients and 101 (91%) of the 111 tizanidine-treated patients; 6 (6%) and 14 (13%) discontinued treatment, respectively. Patient and physician perception of improvement demonstrated more consistent differences between groups than did the Ashworth Scale, perhaps because of inexperience with this measure or failure to consider time between drug administration and assessment.

The therapeutic profile of a new antispastic drug cannot be defined solely on the basis of placebo-controlled studies. Its potential advantages must be evaluated in comparison with existing drugs. This review compares the efficacy and tolerability of tizanidine, a newer muscle relaxant, with that of baclofen and diazepam, the most widely used antispastic agents, for a variety of diagnoses and target symptoms associated with spasticity. More than 20 double-blind, comparative studies were conducted between 1977 and 1987. These included a total of 777 patients suffering from spasticity of various causes. The collected clinical data have been integrated into a combined analysis. Tizanidine emerges from this comparison as a valuable drug in the treatment of spasticity related to cerebral and spinal disorders.

Data from three placebo-controlled and 11 active-controlled studies of tizanidine were combined to permit analysis of the subsets, which were too small to evaluate within the individual studies. Overall analysis of placebo-controlled data confirms the effectiveness of tizanidine in reducing muscle tone in patients with spasticity of spinal cord origin. Subset analyses suggest that patients with more severe spasticity are more likely to respond, but age, sex, and race were not predictive of response. Comparisons of tizanidine with active controls showed no differences in efficacy compared with baclofen or diazepam. However, when compared with controls, patients treated with tizanidine did not experience increased weakness. Furthermore, patients tolerated tizanidine better than the control medications. More patients experienced adverse events during tizanidine treatment than did patients receiving placebo. The most common adverse events reported were dry mouth, somnolence, asthenia, and dizziness. Mild elevations in liver function tests were noted occasionally, but improved in all patients with dose reduction or withdrawal. Three patients from the double-blind database reported formed visual hallucinations. All three cleared; two continued tizanidine, and one discontinued.

Tizanidine, an imidazoline that acts as an agonist at alpha 2-adrenergic receptors, has been shown to be effective in reducing spasticity caused by MS. This multicenter study (14 sites) assessed the efficacy and safety of oral tizanidine in patients who had spinal cord injury of > 12 months' duration. Of the 124 patients admitted to the study, 78 completed it. Tizanidine was titrated to an optimized dosage in each patient to a maximum of 36 mg/d. Muscle tone, assessed by Ashworth score, was significantly reduced (p = 0.0001) by tizanidine treatment in comparison with placebo. Video motion analysis of the pendulum test showed improvement in the tizanidine-treated patients vs placebo (p = 0.04) and showed a significant correlation with the Ashworth score (p < 0.001). No significant alterations in muscle strength or vital signs were noted in either treatment group. The most common adverse events during tizanidine treatment were somnolence, xerostomia, and fatigue. It was concluded that, overall, tizanidine is effective in reducing spasticity in patients with spinal cord injury.

Recurrent inhibitory pathways are powerful modulators of motor neuron excitability. Renshaw cell activation can both inhibit homologous motor neurons and disinhibit antagonists. In spastic spinal-cord-injured patients, recurrent inhibition is consistently increased, and clinical reductions in spasticity are associated with reduced recurrent inhibition. In this study, we evaluated 12 spastic patients with amyotrophic lateral sclerosis (ALS) to see whether a similar mechanism was operating. In contrast to spinal-cord-injured patients, spastic patients with ALS showed strikingly reduced recurrent inhibition, as assessed by a conditioned H-reflex technique, which produces a response (H') whose amplitude is inversely correlated with activity in recurrent inhibitory pathways. The mean ratio of the maximum H' response to the maximum H-reflex response (H'/H ratio) was 0.55, significantly greater than the ratio seen in normal subjects. Amplitude of the H' correlated with amplitude of the Achilles tendon reflex. Thus, in patients with classical ALS, recurrent inhibition appears to be abnormally reduced compared with control subjects, suggesting a different physiology for spasticity in this setting than in spinal cord transection.

Spasticity results from various pathophysiologic abnormalities in spinal cord neuronal circuits. Noninvasive electrophysiologic techniques can be used to study these circuits in humans. The best correlation between briskness of reflexes and results of electrophysiologic testing is found with reduction in vibratory inhibition, a test that reflects presynaptic inhibition. For increase in muscle tone, the best correlation is found with reduction of Ib nonreciprocal inhibition. These test results, which are stable under controlled conditions, are influenced by myorelaxant drugs and may be used to analyze the mode of action of new products because the tests study specific circuits involving known neurotransmitters. Tizanidine reinforces presynaptic inhibition and two types of postsynaptic inhibition: Ia reciprocal and Ib nonreciprocal. It also markedly reduces flexor reflexes. These effects are explained by an action exerted on spinal interneurons deprived of their normal monoaminergic descending innervation. The spectrum of activity for tizanidine is thus broad, making it likely that tizanidine corrects more than one pathophysiologic abnormality. Because tizanidine reinforces presynaptic as well as Ib nonreciprocal inhibition, it may reduce both brisk tendon jerks and muscle hypertonia.

The relationship among tizanidine dose, plasma concentration, and antispastic action is linear in nature. Response to a given dose of this agent varies among patients, and determining the appropriate clinical dose requires individual titration.

This symposium is concerned with the treatment of spasticity and, in particular, with results from studies of tizanidine as a treatment for patients with MS and spinal cord injury. In this article, the definitions and pathophysiologies of spasticity are reviewed, and the issue of when and if to treat spasticity is evaluated. The merits of newer pharmacologic and invasive therapies are discussed relative to reduction of patient discomfort and the possibility of restored function.

We used oral motor examinations and quantitative perceptual speech analysis to study deviant speech dimensions in 44 patients with progressive supranuclear palsy (PSP). All patients had dysarthria with variable degrees of spasticity, hypokinesia, and ataxia; 28 patients had all three of these components, and 16 patients had only two components. Twenty-two patients (50%) had predominantly spastic components, 15 (34%) had predominantly hypokinetic components, six (14%) had predominantly ataxic components, and in one (2%) the spastic, hypokinetic, and ataxic components were equal. Stuttering occurred in nine patients (20%) and palilalia in five (11%). The finding of a mixed dysarthria with a combination of spastic, hypokinetic, and ataxic components might assist in diagnosis and is consistent with the widespread neuropathologic changes found in PSP.

Mechanisms underlying the development of spasticity after spinal cord injury are not understood. One spinal interneuron likely to be affected is the Renshaw cell, which acts to produce recurrent inhibition in motor neurons as well as inhibiting Ia interneurons. Descending pathways exert both excitatory and inhibitory control over Renshaw cell activity. We studied Renshaw cell activity in normal subjects and in patients with varying levels of spasticity after spinal cord injury using the conditioned H-reflex technique of Pierrot-Deseilligny and Bussel. A submaximal stimulus to the tibial nerve is presented prior to a supramaximal stimulus so that action potential collision permits an H reflex (H') to be elicited in response to the supramaximal stimulus. The amplitude of this H' reflex is affected by activity in recurrent inhibitory pathways. Patients with both complete and partial spinal cord lesions were studied; date of injury ranged from 1 month to 216 months prior to evaluation. In the 18 patients in whom H reflexes could be recorded, H' reflexes were absent in 13, in contrast to their uniform presence in normal subjects. We conclude that recurrent inhibition via Renshaw cell activity is increased in spinal cord injury, and that measures of recurrent inhibition may correlate well with some clinical measures of spasticity.

We report a case of progressive spastic paraparesis in a 45-year-old man with total portal-systemic shunting, which developed spontaneously due to congenital hepatic fibrosis. Cellular functions of the liver, except for an elevated blood ammonia level, were within normal limits, as is usual in congenital hepatic fibrosis. This case shows that spastic paraparesis following portal-systemic shunting may occur without liver failure.

We analyzed lumbosacral and cortical somatosensory evoked potentials in three spinal cord injury patients undergoing evaluation of intrathecal baclofen infusion for management of spasticity. The cauda equina propagating root wave (R wave) and conus medullaris postsynaptic responses (S and P waves) were analyzed before and during baclofen infusion. Baclofen abolished the concomitantly recorded H-reflex and markedly suppressed the P wave amplitude and area. The S wave amplitude and area were suppressed to a lesser degree. In contrast, there were no significant changes in cortical somatosensory evoked potentials.

To determine the usefulness of EMG-assisted botulinum toxin (BOTOX) injections for the treatment of spasmodic torticollis (ST), we randomized 52 ST patients into two groups and studied them prospectively. In one group [(E+C)RX, N = 28], the muscles were selected for BOTOX injection using both clinical and EMG examination and then injected with EMG assistance. In the second group [(C)RX, N = 24] the muscles were selected for BOTOX injection based solely on clinical examination and injected without EMG assistance. The percentage of patients showing any improvement after BOTOX as similar in both the (E+C)RX and (C)RX groups. A significantly greater magnitude of improvement was present in the (E+C)RX group, as well as a significantly greater number of patients with marked improvement. In particular, patients with retrocollis, head tilt, and shoulder elevation demonstrated additional benefit with EMG-assisted BOTOX injection. EMG assistance may be effective because the technique increases the ability to effectively identify and treat the deep cervical muscles.

Spontaneous activity on the EMG examination is traditionally ascribed to disease of the lower motor neuron when present in muscles well below the level of para- or quadriplegia despite the absence of any detectable peripheral nerve injury. It is uncertain whether it reflects transient paralysis of transmission (related to clinical spinal shock) or irreversible postsynaptic damage. We performed serial EMG studies of lower extremities and paraspinal muscles on eight young, previously healthy adults, commencing 2 to 9 weeks after acute cervical cord injury. All had stimulated single-fiber EMG (SFEMG) studies at 6-month intervals to determine whether irreversible postsynaptic damage of the anterior horn cell had occurred. MRI and nerve conduction excluded patients with evidence of distal cord injury or peripheral neuropathy. All patients had spontaneous activity in all muscles tested, persisting after spinal shock had resolved. Jitter was present on SFEMG in three of eight patients 6 months after injury. Four of five patients retested 12 months after injury had abnormal jitter, including three who initially had normal SFEMG studies. We conclude that there is electrophysiologic evidence of trans-synaptic distal cord dysfunction following acute spinal cord injury. SFEMG studies suggest that anterior horn cell dropout occurs during the 1st year after injury.

We studied reciprocal inhibition of H-reflexes in the forearm flexor and extensor muscles in 14 patients with spastic hemiplegia secondary to a focal cerebral lesion and 14 normal volunteers. In the spastic limb, the Hmax/Mmax ratio was increased in both flexor and particularly extensor wrist muscles. The 3 normal inhibitory phases of reciprocal inhibition between extensor and flexor forearm muscles were markedly reduced on the spastic side of patients. The early disynaptic phase showed the greatest alteration. Reduced or absent inhibition between forearm muscles associated with increased spinal motoneuron excitability may be typical to spastic hemiplegia.