The effect of changes in head posture on the patterns of muscle activity in cervical dystonia (CD)

Twelve patients with cervical dystonia (CD) and predominant rotation were studied to determine the effects of changes in head posture on the specific patterns of cervical muscle activity. Turns analysis was used to quantify muscle activity underlying head rotation, recorded simultaneously from the agonist and antagonist muscle pairs bilaterally (sternocleidomastoid [SCM] and splenius [SPL]). Muscle activity was compared between the uncompensated dystonic posture and during the maintenance of midposition. In addition, patients were separated into two groups (geste = 6; no geste = 6) based on whether they had a clinically efficacious geste to determine the effect of geste on patterns of cervical muscle activity. Muscle activity was measured during the maintenance of midposition with and without a clinical or simulated geste. Differences in muscle activity between the groups and postures were compared using repeated measure analysis of variance (ANOVA) analyses. The four muscles tested showed a significant difference in muscle activity in the uncompensated dystonic posture as a result of the increased activity in the agonist muscle pair (SCM and SPL responsible for the dystonic posture) (EMG amplitude: F[1,11] = 18.81, p = 0.0012; EMG frequency: F[1,11] = 32.07, p = 0.0001). Maintaining the head in the midposition was associated with a significant reduction in muscle activity compared with the uncompensated dystonic posture (EMG amplitude: F[1,9] = 6.36, p < 0.033; EMG frequency: F[1,9] = 10.96, p < 0.0091). This reduction in midposition muscle activity was significantly greater in the agonist muscle pair (EMG amplitude: F[1,10] = 19.70, p = 0.0013; EMG frequency: F[1,10] = 44.67, p < 0.0001). In the patients with clinically effective geste, there was no additional reduction in muscle activity observed in the midposition when they performed their geste (EMG amplitude: F[1,9] = 4.63, p = 0.060; EMG frequency: F[1,9] = 1.22, p = 0.298). These findings suggest that CD with rotation is characterized by predominantly increased agonist muscle activation. Patients with CD retain the ability to modulate this involuntary agonist muscle activity to maintain the head in the midposition. The maintenance of the midposition does not seem to be facilitated by geste.

Influence of COMT inhibition on levodopa pharmacology and therapy

Catechol O-methyltransferase (COMT) is an important enzyme that is linked directly to therapy with levodopa. Considering the demonstrated mechanism of action and pharmacologic profiles of COMT inhibitors, it is reasonable to hypothesize that these agents would improve the disability associated with Parkinson's disease. Two basic classes of COMT inhibitors are being studied in patients with PD: those that act exclusively extracerebrally or peripherally (e.g., entacapone) and those that cross the blood-brain barrier (e.g., tolcapone). With COMT inhibition, greater peripheral bioavailability of levodopa occurs in humans without an enhancement of peak plasma levels. It is reasonable to suggest that COMT inhibition will be associated with prolonged effects of levodopa in PD, without increased peak dose toxicity in the form of dyskinesias and hallucinations.

Georges Guillain's neurologic exploration of America

This is a study of the status of American neurology at the beginning of the 20th century as perceived by European neurologist Georges Guillain. Guillain trained in Paris, the international "Mecca" of neurology at that time. Whereas many Americans traveled and studied in Europe, very few European neurologists made the reverse journey to the United States. In 1902 Georges Guillain, age 26, traveled to the United States with the specific aim of evaluating neurologic services in America. Recent access to Guillain's personal travel journal and an article in French that he wrote after his return to Europe provide first-hand documentation of American neurology at the turn of the century from a European perspective. Using introductory references from his teacher, Pierre Marie, Guillain visited New York, Chicago, Boston, Philadelphia, and Baltimore. He studied hospitals, outpatient departments, laboratories, and universities, comparing them with institutions in his native France and other European capitals. Guillain was particularly struck by the creative energy of American neurologists, the broad-ranging programs in research and patient care, and the strong financial support provided by local philanthropists, universities, and governments. Guillain clearly foresaw the rising international role of American neurology and the prominence it would gain by the end of his career in the 1950s.

Highlights of the North American and European experiences

Two large, randomized, double-blind, placebo-controlled multicenter studies, one North American and one European, examined the efficacy and safety of 300 and 600 mg/day tolcapone in similar populations of patients (n = 379) with Parkinson's disease currently taking levodopa and experiencing motor fluctuations. Change in "on-off" function was the most important end-point assessment. The two studies found similar results. The percentage of "on" time improved significantly and "off" time was reduced. Daily levodopa dosage requirements decreased significantly. The most common and significant adverse event was increased dyskinesia; hallucinations were not frequently encountered.

5-Hydroxytryptophan-induced myoclonus in guinea pigs: mediation through 5-HT1/2 receptor subtypes

In guinea pigs, myoclonus can be induced by 5-hydroxytryptamine (5-HT, serotonin) precursors and synthetic 5-HT receptor agonists, yet the receptor subtype specificity of this behavior is not fully delineated. Guinea pigs were pre-treated with carbidopa (50 mg) followed by one of eight 5-HT antagonists: (-)-N-tert-butyl-3-[4-(2-methoxyphenyl) piperazin-1-yl]-2-phenyl propionamide ((-)-WAY 100135) (5-HT1A), N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]-ethyl]-N-(2-pyridyl)-cy clohexancarboxamide (WAY 100635) (5-HT1A), methiothepin mesylate (5-HT1/2), mesulergine hydrochloride (5-HT2A/2C), N[4-methoxy-3-(4-methyl-L-piperazinyl)phenyl]-2'-methyl-4'-(5-methyl-1,2 ,4-oxadizol-3-yl) (GR 127935) (5-HT1D), trans-4-[(3Z)3-(2-dimethylaminoethyl)oxyimino-3(2-fluorop hen yl) propen-1-yl]phenol, hemifumarate (SR 46349) (5-HT2), ondansetron hydrochloride (5-HT3), and [1-[2-[methylsulphonyl)amino]ethyl]-4-piperidinyl]methyl-5-fluoro-2-meth oxy-1H-indole-3-carboxylate (GR 125487) (5-HT4). Thirty minutes later, they received 5-hydroxytryptophan (5-HTP) (75 mg/kg, sc) and myoclonic jumping rates were assessed every 10 min for 200 min by a blinded observer. Repeated measures analysis of variance of drug-induced antagonism of 5-HTP-induced myoclonus revealed a significant effect for the 5-HT receptor antagonists methiothepin mesylate, GR127935, and mesulergine hydrochloride compared to placebo, and each of these drugs inhibited 5-HTP-induced myoclonus in a dose-dependent fashion. Based on the receptor profiles of the three effective antagonists, 5-HTP-induced myoclonus is influenced by the 5-HT1/2 receptor systems. The absence of a significant change with any other receptor subtype antagonist suggests that myoclonus is not related to diffuse activation of central serotonergic mechanisms.

Intravenous levodopa in hallucinating Parkinson's disease patients: high-dose challenge does not precipitate hallucinations

In five nondemented Parkinson's disease patients with daily visual hallucinations, we tested whether high-dose IV levodopa (LD) infusions precipitated hallucinations. Two infusion paradigms were studied, each with 1.5-mg/kg hourly dose for 4 hours--steady infusion and pulse infusion of the full hour dose over 5 minutes each hour. In both protocols, plasma LD levels changed significantly during the infusion protocol. The cumulative area under the curve was equivalent for the two infusions. All patients remained alert, and none developed visual hallucinations. The two patients with peak-dose dyskinesias on oral LD developed prominent dyskinesias during the infusion. Visual hallucinations do not relate simply to high levels of LD or to sudden changes in plasma levels.

Drug-induced movement disorders

Drug-induced movement disorders are often unrecognized, especially when not due to dopamine receptor blockers. This review discusses acute, subacute, and chronic syndromes. Pathophysiology relates almost always to dopaminergic transmission. Patient-dependent vulnerability and drug-dependent sensitivity are contributing factors. Young patients are more prone to acute reactions, and tardive or chronic conditions are more frequent in the elderly. Subclinical Parkinsonism can be unmasked by medication exposure. Treatment of tardive dyskinesia remains a challenging task for the clinician, but novel antipsychotics and dopamine depleting agents can be beneficial.

Metric properties of nurses' ratings of parkinsonian signs with a modified Unified Parkinson's Disease Rating Scale

We evaluated the ability of nurse clinicians to assess parkinsonian signs in older persons with a modified version of the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS). After completing a structured training protocol, three nurse clinicians and a neurologist with expertise in movement disorders administered a modified UPDRS to 75 older persons. The nurses repeated the assessment about 3 weeks later. Inter-rater agreement and short-term temporal stability were estimated for each item, the total modified UPDRS score, and for summary measures of bradykinesia, postural reflex impairment, rigidity, and tremor, and a global parkinsonian sign score. We performed our assessment in Catholic religious communities in the Chicago area, using consecutive subjects at four communities participating in the Religious Orders Study, a longitudinal, clinical-pathologic study of older persons. Our results showed that nurses were not a significant source of variability, with intraclass correlations exceeding 0.97 for all items, and they showed good to excellent agreement with the neurologist for most modified UPDRS items. Correlations between nurses and neurologist exceeded 0.90 for the total modified UPDRS, ranged from 0.76 to 0.95 for the four parkinsonian domain scores, and exceeded 0.90 for the global parkinsonian sign score. Nurses showed fair to good agreement with themselves over the 3-week interval for most modified UPDRS items. Correlations over the 3-week interval exceeded 0.90 for the total modified UPDRS score, ranged from 0.70 to 0.95 for the four domain scores, and exceeded 0.90 for the global parkinsonian sign score. Ratings of parkinsonian signs by nurse clinicians corresponded closely to those of a neurologist with expertise in movement disorders and showed good inter-rater agreement and temporal stability. With appropriate training, nurse clinicians can reliably administer the modified UPDRS.

Efficacy of a patient-training videotape on motor fluctuations for on-off diaries in Parkinson's disease

Patient on-off diaries are used in clinical trials, but a method to assure agreement between patient and examiner has never been developed. We tested whether a patient-teaching tape increased the rate of agreement between patient diary ratings and simultaneous neurologic assessment by a trained professional. A total of 32 consecutive patients who had Parkinson's disease with motor fluctuations independently completed a 4-h on-off diary (nine ratings) at the same time as an examiner. Those with < 80% agreement with the examiner (n = 20) were randomized to view either a training tape that showed motor fluctuations (experimental group) or-another videotape of general patient educational material (control group). All patients then underwent the same 4-h assessment of motor fluctuations. To test for long-term retention, they returned 1 month later and, without reviewing the videotape, underwent a final 4-h correlation assessment. After the training tape, the experimental group showed significant improvement, whereas the control group showed no improvement. Furthermore, another month later, the improvement in the experimental group was retained. Based on these findings, we suggest that future clinical trials assessing motor fluctuations incorporate this tape into their basic methodology.

Eye signs and tic disorders: Gilles de la Tourette's syndrome

BACKGROUND

Eye tics are among the most common manifested symptoms of tic disorders, including Gilles de la Tourette's syndrome (GTS).

METHODS

A review of medical literature or ocular signs and symptoms of tic disorders was conducted.

RESULTS

Tic disorders are characterized by repetitive and often disabling movements that primarily involve the eyes, face, neck, and voice apparatus. In addition, patients with tics may have eye problems related to medications used to control tics. Some eye signs are atypical in tic disorders and their presence may suggest alternate diagnoses.

CONCLUSION

Eye tics can be disabling and a optometrist should be familiar with ocular manifestations of tics and ocular dysfunction related to tic treatment, and also be aware of other neurologic conditions confused with tics.

Effect of stereotaxic intrastriatal cografts of autologous adrenal medulla and peripheral nerve in Parkinson's disease: two-year follow-up study

Studies in nonhuman primates with experimental parkinsonism have shown that intrastriatal cografts of autologous adrenal medulla and peripheral nerve yield greater behavioral improvement and graft survival than do adrenal medulla grafts alone. To test these observations, five patients with advanced Parkinson's disease were selected to receive unilateral intrastriatal adrenal medulla-intercostal nerve cografts. They were evaluated using the Core Assessment Program for Intracerebral Transplantation (CAPIT) protocol. Three of these patients also underwent quantitative motor testing for the measurement of upper limb bradykinesia (movement time; MT). Following right flank adrenalectomy, cografts consisting of small fragments of adrenal medullary tissue and minced intercostal nerve were stereotaxically implanted into three targets in the right striatum using computerized tomography guidance. Surgery was uneventful and postoperative magnetic resonance imaging revealed accurate placement of the grafts. No morbidity was encountered. Results of 24 months of clinical and quantitative motor assessments postoperatively are reported. Total UPDRS motor scores in the "off" state improved from a mean preoperative score of 39.5 to 32.1 at 3, 29.7 at 6, 27.6 at 9, 28.5 at 12, 31.4 at 18, and 26.5 at 24 months after surgery. Total timed motor test scores during the "off" state improved 17.9% at 6, 23.3% at 9, 18.2% at 12, 38.2% at 18, and 34.9% at 24 months postoperatively compared to baseline. Movement time showed statistically significant improvement (repeated measures ANOVA, P < 0.05) in the left arm (contralateral to surgery) in all three patients tested. These results indicate that stereotaxic intrastriatal implantation of autologous adrenal medulla-peripheral nerve cografts can be performed safely and clinical improvement from this procedure is sustained for a period of 24 months. The clinical improvement was paralleled by improvement in objective, quantitative motor testing.

What is the accuracy of the clinical diagnosis of multiple system atrophy? A clinicopathologic study

BACKGROUND

The presentation of symptoms for multiple system atrophy (MSA) varies. Because there are no specific markers for its clinical diagnosis, the diagnosis rests on the results of the neuropathologic examination. Despite several clinicopathologic studies, the diagnostic accuracy for MSA is unknown.

OBJECTIVES

To determine the accuracy for the clinical diagnosis of MSA and to identify, as early as possible, those features that would best predict MSA.

DESIGN

One hundred five autopsy-confirmed cases of MSA and related disorders (MSA [n=16], non-MSA [n=89]) were presented as clinical vignettes to 6 neurologists (raters) who were unaware of the study design. Raters identified the main clinical features and provided a diagnosis based on descriptions of the patients' first and last clinic visits.

METHODS

Interrater reliability was evaluated with the use of kappa statistics. Raters' diagnoses and those of the primary neurologists (who followed up the patients) were compared with the autopsy-confirmed diagnoses to estimate the sensitivity and positive predictive values at the patients' first and last visits. Logistic regression analysis was used to determine the best predictors to diagnose MSA.

RESULTS

For the first visit (median, 42 months after the onset of symptoms), the raters' sensitivity (median, 56%; range, 50%-69%) and positive predictive values (median, 76%; range, 61%-91%) for the clinical diagnosis of MSA were not optimal. For the last visit (74 months after the onset of symptoms), the raters' sensitivity (median, 69%; range, 56%-94%) and positive predictive values (median, 80%; range, 77%-92%) improved. Primary neurologists correctly identified 25% and 50% of the patients with MSA at the first and last visits, respectively. False-negative and -positive misdiagnoses frequently occurred in patients with Parkinson disease and progressive supranuclear palsy. Early severe autonomic failure, absence of cognitive impairment, early cerebellar symptoms, and early gait disturbances were identified as the best predictive features to diagnose MSA.

CONCLUSIONS

The low sensitivity for the clinical diagnosis of MSA, particularly among neurologists who followed up these patients in the tertiary centers, suggests that this disorder is underdiagnosed. The misdiagnosis of MSA is usually due to its confusion with Parkinson disease or progressive supranuclear palsy, thus compromising the research on all 3 disorders.

What are the obstacles for an accurate clinical diagnosis of Pick's disease? A clinicopathologic study

Several studies have evaluated the reliability and validity of the clinical diagnosis of Alzheimer's disease (AD) using well-defined neuropathologic criteria, but none has attempted to evaluate the diagnostic accuracy of Pick's disease. We determined the accuracy of the clinical diagnosis of Pick's by presenting 105 autopsy-confirmed cases of Pick's (n = 7) and related disorders (non-Pick's, n = 98) as clinical vignettes in randomized order to six neurologists who were unaware of the autopsy findings. The group of raters had moderate to fair agreement for the diagnosis of Pick's as measured by the kappa statistics. The sensitivity for the diagnosis of Pick's for the first visit (mean, 53 months after onset) and last visit (mean, 78 months after onset) was low (range, 0 to 71%), but specificity was near-perfect. Median positive predictive values at both visits were 83 to 85%. False-negative misdiagnoses mainly involved AD. False-positive diagnoses were rare and occurred with corticobasal degeneration (first visit) and with dementia with Lewy bodies (last visit). Pick's was also misdiagnosed by primary neurologists. The best clinical predictors for the early diagnosis of Pick's included "frontal" dementia, early "cortical" dementia with severe frontal lobe disturbances, absence of apraxia, and absence of gait disturbance at onset. However, the first neurologic evaluation in some of the Pick's cases took place in advanced stages of the disease. Our findings suggest that this disorder is underdiagnosed in clinical practice. Although the low sensitivity for the clinical diagnosis of Pick's is disappointing, our data suggest that when clinicians suspect Pick's, their diagnosis is almost always correct. Absence of awareness of the main features of this disorder and of specificity of the frontal lobe syndrome may partially explain the low detection of Pick's disease.

Teaching tape for the motor section of the Toronto Western Spasmodic Torticollis Scale

The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) assesses the character and severity of cervical dystonia (CD). We developed a teaching tape of the TWSTRS scoring for the motor symptoms of CD. The tape provides investigators with visual representations of each component of the motor section of the TWSTRS as agreed upon by three independently scoring raters. The rate of agreement for the nondichotomous components was always significant, with a Kendall's coefficient of concordance W ranging between 0.98 and 0.76 (p < 0.01 for all measures). For the two dichotomous components, a weighted kappa coefficient was also significant at 0.86 for lateral shift and 0.89 for sagittal shift (p < 0.01 for both measures). Scale deficiencies identified by the raters were an explicit definition of midline for assessment of range of motion, the absence of a separate scoring category assessing dystonic tremor, and the specification of duration for the effect of sensory tricks. These observations should be taken into account in future revisions of the TWSTRS and in refinements of other rating scales for CD.

Intact mirror-tracing and impaired rotary-pursuit skill learning in patients with Huntington's disease: evidence for dissociable memory systems in skill learning

Skill learning in early-stage Huntington's disease (HD) patients was compared with that of normal controls on 2 perceptual-motor tasks, rotary pursuit and mirror tracing. HD patients demonstrated a dissociation between impaired rotary-pursuit and intact mirror-tracing skill learning. These results suggest that different forms of perceptual-motor skill learning are mediated by separable neural circuits. A striatal memory system may be essential for sequence or open-loop skill learning but not for skills that involve the closed-loop learning of novel visual-response mappings. It is hypothesized that working memory deficits in HD resulting from frontostriatal damage may account broadly for intact and impaired long-term learning and memory in HD patients.

Tourette syndrome. Clinical rating and quantitative assessment of tics

An adequate rating scale for the measurement of tic severity must account for the multiple motor and phonic tics that increase and decrease over time. Available rating scales for Tourette syndrome have used historical information, direct observation, or both. Videotapes provide an objective means to quantify tics over time in a controlled environment. Videotapes also can be viewed multiple times for careful review of tic frequency and distribution. A unified rating scale, which integrates all elements of tic assessment is being developed, but is not currently available.

Jean-Martin Charcot and Silas Weir Mitchell

Although Charcot and Mitchell only met once or possibly twice in Paris (1873 and 1875), they interacted in multiple ways to influence one another's research and the development of nineteenth century neurology. Charcot strongly relied on, and openly credited, Mitchell's important contributions on the fragility of bones in locomotor ataxia when he postulated his own historic concepts on neuropathic arthropathies (Charcot joints). Mitchell likewise referred to Charcot in his texts and manuscripts, although his comments were not always complementary. Most notably, Mitchell publicly criticized Charcot for wrongfully claiming precedence over Americans (i.e., Mitchell himself) in the development of isolation therapy. The two men shared many specific neurologic interests, especially the effects of trauma and disorders affecting women, including hysteria. In the development of clinical neurology as a new scientific field, Charcot and Mitchell were both strong empiricists who distrusted theory but believed that clinical medicine, and specifically neurology, required continued infusion of new data from the laboratory sciences. Both men were exemplary teachers, Mitchell primarily a preceptor and supervisor of doctors outside the university system and Charcot the first European professor of clinical neurology and head of the celebrated School of the Salpêtrière.

Intact mirror-tracing and impaired rotary-pursuit skill learning in patients with Huntington's disease: evidence for dissociable memory systems in skill learning

Skill learning in early-stage Huntington's disease (HD) patients was compared with that of normal controls on 2 perceptual-motor tasks, rotary pursuit and mirror tracing. HD patients demonstrated a dissociation between impaired rotary-pursuit and intact mirror-tracing skill learning. These results suggest that different forms of perceptual-motor skill learning are mediated by separable neural circuits. A striatal memory system may be essential for sequence or open-loop skill learning but not for skills that involve the closed-loop learning of novel visual-response mappings. It is hypothesized that working memory deficits in HD resulting from frontostriatal damage may account broadly for intact and impaired long-term learning and memory in HD patients.

New strategies with dopaminergic drugs: modified formulations of levodopa and novel agonists

Most new pharmacological therapies in Parkinson's disease focus on the dopaminergic system. Drugs that enhance dopaminergic function fall into three primary categories: amino acid precursors to dopamine, agonists that stimulate dopamine receptors, and enzyme antagonists that prevent the metabolism of dopamine and hence permit more or prolonged neurotransmitter activity; the first two are discussed below. Within the first category, levodopa is the amino acid precursor to dopamine, and a number of modifications in its formulation have been developed to enhance dopaminergic activity. In the area of agonists, new agents pramipexole, ropinerole, and cabergoline have recently been developed to complement the currently available bromocriptine and pergolide, and these new drugs may be released in the United States.

Dopaminergic transplants in patients with Parkinson's disease: neuroanatomical correlates of clinical recovery

For the past 15 years, patients with Parkinson's disease have participated in clinical trials evaluating the efficacy of intrastriatal dopamine transplants. Principally, two donor tissues have been employed, the chromaffin cells of the adrenal medulla and fetal ventral mesencephalon. The clinical response following each type of transplant has been variable. In general, the magnitude and the duration of the clinical response is greater with fetal dopaminergic neurons than with adrenal medullary grafts. Postmortem studies of patients receiving adrenal medullary grafts or fetal nigral implants provide a neuroanatomical framework for the clinical response. Adrenal grafts survive poorly following implantation into the striatum, but they are capable of inducing sprouting of host-derived fibers within a the caudate nucleus. In contrast, robust survival of fetal nigral implants can be achieved within the human brain which can provide extensive reinnervation to the parkinsonian striatum. These findings are strikingly similar to what has been seen in rodent and nonhuman primate models of PD. This paper describes the neuroanatomical correlates of dopamine brain grafting in humans and elucidates the pattern of changes seen in dopaminergic systems which are associated with clinical benefit.