Novel THAP1 sequence variants in primary dystonia

BACKGROUND

THAP1 encodes a transcription factor (THAP1) that harbors an atypical zinc finger domain and regulates cell proliferation. An exon 2 insertion/deletion frameshift mutation in THAP1 is responsible for DYT6 dystonia in Amish-Mennonites. Subsequent screening efforts in familial, mainly early-onset, primary dystonia identified additional THAP1 sequence variants in non-Amish subjects.

OBJECTIVE

To examine a large cohort of subjects with mainly adult-onset primary dystonia for sequence variants in THAP1.

METHODS

With high-resolution melting, all 3 THAP1 exons were screened for sequence variants in 1,114 subjects with mainly adult-onset primary dystonia, 96 with unclassified dystonia, and 600 controls (400 neurologically normal and 200 with Parkinson disease). In addition, all 3 THAP1 exons were sequenced in 200 subjects with dystonia and 200 neurologically normal controls.

RESULTS

Nine unique melting curves were found in 19 subjects from 16 families with primary dystonia and 1 control. Age at dystonia onset ranged from 8 to 69 years (mean 48 years). Sequencing identified 6 novel missense mutations in conserved regions of THAP1 (G9C [cervical, masticatory, arm], D17G [cervical], F132S [laryngeal], I149T [cervical and generalized], A166T [laryngeal], and Q187K [cervical]). One subject with blepharospasm and another with laryngeal dystonia harbored a c.-42C>T variant. A c.57C>T silent variant was found in 1 subject with segmental craniocervical dystonia. An intron 1 variant (c.71+9C>A) was present in 7 subjects with dystonia (7/1,210) but only 1 control (1/600).

CONCLUSIONS

A heterogeneous collection of THAP1 sequence variants is associated with varied anatomical distributions and onset ages of both familial and sporadic primary dystonia.

Clinico-immunologic aspects of botulinum toxin type B treatment of cervical dystonia

In this multicenter study of 100 patients with cervical dystonia, we examined the immunogenicity of botulinum toxin type B (BTX-B) and correlated the clinical response with the presence of blocking antibodies (Abs) using a novel mouse protection assay. One-third of the patients who were negative for BTX-B Abs at baseline became positive for BTX-B Abs at last visit. Thus, the high antigenicity of BTX-B limits its long-term efficacy.

Development and initial validation of a screening tool for Parkinson disease surgical candidates

As there is currently no standardized assessment tool for evaluating Parkinson disease (PD) patients for deep brain stimulation (DBS), the authors developed the Florida Surgical Questionnaire for Parkinson Disease (FLASQ-PD). Part I of the study was a retrospective analysis of 174 patients presenting for a surgical screening. Part II was a multicenter study to assess the correlation of FLASQ-PD scores. The results of this study suggest that the FLASQ-PD may be a useful triage tool for screening PD patients for DBS surgery.

Cognitive slowing in Parkinson's disease resolves after practice

OBJECTIVE

To assess the effect of dopaminergic repletion on working memory in Parkinson's disease.

METHODS

The role of dopaminergic state on working memory in patients with Parkinson's disease was determined using the Sternberg item recognition paradigm, a continuous performance task that dissociates the motor and cognitive components of response time. Ten patients with Parkinson's disease were tested in an "on" state (on dopaminergic drug treatment) and a practical "off" state in two sessions held one week apart in counterbalanced order; 10 controls matched for age and education were studied at the same time points.

RESULTS

Patients with Parkinson's disease showed impaired working memory, independent of motor slowing. During session 1, the performance of the patients was worse than the controls, regardless of dopaminergic state. The patients showed a significant improvement in the cognitive component of task performance during the second session, such that they no longer differed from the controls. The performance of the control subjects remained stable over the two sessions.

CONCLUSIONS

Working memory performance of patients with Parkinson's disease did not change in association with dopaminergic state; rather, the performance improved over time. The pattern of improvement over time suggests a delay in proceduralising the task, similar to the deficits shown by such patients in procedural learning of other tasks.

Spasmodic torticollis and reproductive function in women

This investigation assessed a possible relationship between idiopathic spasmodic torticollis (ST) and reproductive function in women. Fifth decade ST onset, the peak decade for menopause, was over represented. Menstrual exacerbation of symptoms was significantly more common than in controls. Oral contraceptive use and pregnancy did not have adverse effects. Reproductive disorders and hysterectomy were significantly more common than in neurological and normal controls. The possibility that ST onset and severity may relate to reproductive state and hormonal factors warrants further investigation.

Impact on quality of life of botulinum toxin treatments for spasmodic dysphonia and oromandibular dystonia

OBJECTIVE

To determine the impact on quality of life of botulinum toxin treatments for common dystonias of the head and neck.

DESIGN

Cross-sectional survey study of a patient cohort treated with botulinum toxin injections for spasmodic dysphonia (SD) or oromandibular dystonia (OMD).

INTERVENTIONS AND OUTCOME MEASURES

The Glasgow Benefit Inventory was used to quantify the health benefit of treatment. Data were collected for demographics, time intervals relative to diagnosis, treatment duration, and frequency of injections. The groups were compared to determine whether differences existed in benefit from treatment. Correlation analysis was conducted for inventory scores and time intervals.

RESULTS

A total of 23 patients (5 with OMD and 18 with SD) completed the questionnaire. The mean total benefit score was +38.04 (possible range, -100 to +100) for the whole group (P<.001). The OMD group derived a nonsignificantly smaller benefit (+21.67 vs +42.59) (P =.07). The mean subscores for the combined group were +39.67, +26.81, and +42.75 for the general, social support, and physical health subscores, respectively (P< or =.001). The difference in mean subscores between the 2 groups was not statistically significant, although patients with OMD had a lower social support subscore (+6.67 vs. +32.41). No correlation was found between duration of therapy or frequency of injections and the Glasgow Benefit Inventory score.

CONCLUSIONS

Patients with OMD or SD derive considerable benefit when treated with botulinum toxin. The magnitude of benefit is largely independent of the time course of therapy. Treatment with botulinum toxin for these conditions is effective on the basis of quality-of-life criteria.

A randomized, controlled trial of remacemide for motor fluctuations in Parkinson's disease

BACKGROUND

Preclinical studies suggest that glutamate antagonists help ameliorate motor fluctuations in patients with PD treated with levodopa.

METHODS

In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study, the authors assessed the safety, tolerability, and efficacy of the glutamate receptor blocker remacemide hydrochloride in 279 patients with motor fluctuations treated with levodopa. The primary objective was to assess the short-term tolerability and safety of four dosage levels of remacemide during 7 weeks of treatment. Patients were also monitored with home diaries and the Unified PD Rating Scale (UPDRS) to collect preliminary data on treatment efficacy.

RESULTS

Remacemide was well tolerated up to a dosage of 300 mg/d on a twice daily schedule and 600 mg/d on a four times daily schedule. The most common dosage-related adverse events were dizziness and nausea, as observed in previous studies of remacemide. The percent "on" time and motor UPDRS scores showed trends toward improvement in the patients treated with 150 and 300 mg/d remacemide compared with placebo-treated patients, although these improvements were not significant.

CONCLUSION

Remacemide is a safe and tolerable adjunct to dopaminergic therapy for patients with PD and motor fluctuations. Although this study had limited power to detect therapeutic effects, the observed improvement is consistent with studies of non-human primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian signs and symptoms. Additional studies are warranted to confirm these results over an extended period of observation, and to explore the potential neuroprotective effects of remacemide in slowing the progression of PD.

Abnormalities of spatial and temporal sensory discrimination in writer's cramp

Clinical observations of patients with writer's cramp suggest that abnormalities of the sensory system may be a frequent finding in this disorder. Neurophysiological data from an animal model of focal dystonia have revealed cells in somatosensory cortex with enlarged and overlapping tactile receptive fields. However, psychophysical studies so far have been unable to document a clinical correlate supporting a similar enlargement of receptive fields in humans. We compared the fingertip discrimination of the orientation of fine spatial gratings between writer's cramp and control subjects and found a significant decrease in grating sensitivity in the patients, consistent with the possibility of enlarged tactile receptive fields. In addition, we duplicated previous experiments showing an abnormality of tactile temporal discrimination. The results provide psychophysical measures which may relate to the development of sensory cortical reorganization in patients with writer's cramp.

Remacemide: current status and clinical applications

Remacemide (RMC) is a non-competitive, low-affinity N-methyl-D-aspartate (NMDA) receptor antagonist that does not cause the behavioural and neuropathological side effects seen with other NMDA receptor antagonists. RMC and its active metabolite, AR-R 12495 AR, which has moderate affinity for the NMDA receptor, also interact with voltage-dependent neuronal sodium channels. Both agents show efficacy in a variety of animal models of epilepsy, parkinsonism and cerebral ischaemia. There is no evidence for teratogenicity or genotoxicity. RMC delays the absorption of L-dopa and elevates the concentrations of drugs metabolised by the hepatic cytochrome P450 3A4 isoform. RMC and AR-R 12495 AR have moderate protein binding and linear pharmacokinetics. Controlled studies show evidence of efficacy in treating epilepsy and Parkinson's disease. Post-surgical outcomes in RMC-treated patients at risk for intra-operative cerebral ischaemia are also encouraging. Adverse effects are related to the gastrointestinal and central nervous systems. RMC is a promising drug with numerous potential applications for both acute or chronic conditions associated with glutamate-mediated neurotoxicity.

Comparison of acute- and delayed-onset posttraumatic cervical dystonia

Head, neck, or shoulder trauma is an occasional antecedent event before the appearance of cervical dystonia. A clinically distinctive syndrome of acute-onset posttraumatic cervical dystonia characterized by markedly restricted range of neck motion, absence of phasic involuntary movements, and poor response to treatment has previously been described. Patients with cervical dystonia attending a movement disorder clinic were reviewed for history of trauma before onset of symptoms. Patients with symptom onset within 4 weeks of trauma were compared with patients who developed symptoms between 3 months and 1 year after trauma. Acute-onset cervical dystonia was characterized by markedly reduced cervical mobility; prominent shoulder elevation with trapezius hypertrophy in most patients, absence of involuntary movements, sensory tricks, or activation maneuvers; and poor response to botulinum toxin injection. By contrast, delayed-onset cervical dystonia was clinically indistinguishable from nontraumatic idiopathic cervical dystonia. Acute-onset posttraumatic cervical dystonia is similar to limb dystonia after peripheral trauma and may represent a form of nondystonic muscle spasm similar to torticollis associated with musculoskeletal injuries of the cervical spine and craniocervical junction.

High-frequency unilateral thalamic stimulation in the treatment of essential and parkinsonian tremor

Pharmacologic treatment for essential tremor and the tremor of Parkinson's disease is often inadequate. Stereotaxic surgery, such as thalamotomy, can effectively reduce tremors. We performed a multicenter trial of unilateral high-frequency stimulation of the ventral intermedius nucleus of the thalamus in 29 patients with essential tremor and 24 patients with Parkinson's disease, using a blinded assessment at 3 months after surgery to compare clinical rating of tremor with stimulation ON with stimulation OFF and baseline and a 1-year follow-up. Six patients were not implanted because of lack of intraoperative tremor suppression (2 patients), hemorrhage (2 patients), withdrawal of consent (1 patient), and persistent microthalamotomy effect (1 patient). A significant reduction in both essential and parkinsonian tremor occurred contralaterally with stimulation. Patients reported a significant reduction in disability. Measures of function were significantly improved in patients with essential tremor. Complications related to surgery in implanted patients were few. Stimulation was commonly associated with transient paresthesias. Other adverse effects were mild and well tolerated. Efficacy was not reduced at 1 year. Chronic high-frequency stimulation is safe and highly effective in ameliorating essential and parkinsonian tremor.

Botulinum toxin type B: a double-blind, placebo-controlled, safety and efficacy study in cervical dystonia

We enrolled and treated 122 patients with idiopathic cervical dystonia in a double-blind, placebo-controlled safety and efficacy study of botulinum toxin type B (BotB). Both A-responsive and A-resistant patients were enrolled. Patients received intramuscular injections of either BotB (2,500 U, 5,000 U, or 10,000 U) or placebo. The primary outcome measure of efficacy was the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at 4 weeks following study drug administration. Secondary measures of efficacy were TWSTRS-Severity, -Disability, and -Pain subscale scores, and Analog Pain Assessment, Investigator Global Assessment, Patient Global Assessment, and Sickness Impact Profile scores. Duration of effect was estimated with an intent-to-treat analysis of responders. Safety measures included clinical parameters, laboratory tests, and adverse events. The primary and most of the secondary analyses indicated a statistically significant treatment effect and a dose response. BotB is safe, well tolerated, and efficacious in the treatment of cervical dystonia at the doses tested.

An open-label study of botulinum toxin A for treatment of tardive dystonia

Tardive dystonia is a form of tardive dyskinesia for which there is little satisfactory treatment. We reviewed our experience at four movement disorder centers in the treatment of tardive dystonia with botulinum toxin A (BTX-A). Thirty-four patients with relatively localized tardive dystonia unresponsive to oral medications were treated with injections of BTX-A into dystonia muscles. Cervical dystonia was the most frequent manifestation of tardive dystonia in this group of patients. There was marked or moderate improvement in 29 of 34 patients. Eighteen of 24 patients with cervical dystonia showed either marked or moderate improvement. In this retrospective review, BTX-A provided useful symptomatic treatment for localized dystonia in patients with tardive dystonia unresponsive to other treatment. A controlled, prospective trial of BTX-A in tardive dystonia is warranted.

Comparison of clinical rating scales in treatment of cervical dystonia with botulinum toxin

Seventy-six consecutive patients with cervical dystonia. (CD) treated with botulinum toxin were assessed with the Tsui rating scale, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), and a global scale of improvement. Tsui, TWSTRS, and TWSTRS subscale scores all showed significant improvement. Tsui and TWSTRS score reduction rates correlated significantly with each other, and each correlated with the global scale. Analysis of these scales and TWSTRS subscales indicates that an objective scale of severity such as either the Tsui rating scale or TWSTRS severity subscale used in conjunction with the TWSTRS pain subscale adequately assesses improvement of CD following treatment with botulinum toxin.

Botulinum toxin A in the treatment of spasticity: functional implications and patient selection

OBJECTIVE

To explore the range of functional indications and benefit of botulinum toxin A (BTA) in spastic patients.

DESIGN

Case report of a series of patients selected for BTA treatment. Clinical information was collected in a prospective fashion on each patient.

SETTING

Freestanding acute rehabilitation hospital.

PATIENTS

39 consecutive patients with 40 limbs with acquired spasticity.

INTERVENTION

All 39 patients received BTA injections into muscles targeted for treatment based on functional indications.

MAIN OUTCOME MEASURES

Objective evaluation of outcome was measured by Ashworth Scale, goniometry, ambulation score, and brace wear scale. Subjective measures included patient self report of improvement and pain relief.

RESULTS

Mean BTA dose per limb was 180 units, mean number of muscles injected per limb was 2. Twenty-nine patients had subjective and/or objective improvement with treatment. Mean Ashworth Scale improvement was one point. Mean gain in active range of motion (AROM) was 17.0 degrees, and in passive range of motion (PROM) 18.4 degrees. Brace tolerance improved in 14 of 22 patients and pain relief occurred in 10 of 13 patients. There were no adverse effects, and there was no difference in duration of effect compared to dystonia patients.

CONCLUSION

BTA is a useful intervention in the treatment of spasticity, with the majority of patients demonstrating improvement on objective measures of tone and function, and reporting improvement on subjective measures. Careful patient selection will maximize functional benefit.

Stiff-man syndrome. Report of a case

Stiff-man syndrome is a well-described, but rare and often overlooked, neuromuscular syndrome of rigidity, spasm, and gait abnormality that is associated with several endocrinologic and autoimmune disorders. A patient exhibiting many typical features of stiff-man syndrome had intermittent symptoms for 22 years before the correct diagnosis was made. Similar to many described patients, she was diabetic, hyperthyroid, and had elevated islet cell, antithyroid, and glutamic acid decarboxylase antibody levels. The high frequency of diabetes mellitus among patients with stiff-man syndrome is emphasized, as is increasing evidence to suggest that elaboration of anti-glutamic acid decarboxylase and anti-islet cell antibodies may play a role in the pathophysiologic state of the disorder.

Limb dystonia following electrical injury

Electrical injuries of the extremities may cause paralysis, muscle atrophy, sensory deficit, causalgia, and reflex sympathetic dystrophy (RSD). Limb dystonia has rarely been reported following electrical injury to an extremity, although it may result from cerebral hemisphere electrical trauma. Following electrical injury to the upper extremity, three patients developed limb dystonia accompanied by severe pain and sensory symptoms in two patients and features of RSD in one patient. Two patients received botulinum toxin injections without functional benefit. The mechanism of dystonia following peripheral trauma is unknown but may relate to reorganization of central synaptic connections, possibly in the spinal cord.

Spontaneous calcific embolization to the supraclinoid internal carotid artery from a regurgitant bicuspid aortic valve

Calcific brain embolization leading to stroke is rarely recognized. We report a case of spontaneous embolization to the right cerebral circulation from a severely regurgitant, calcified bicuspid valve. Bicuspid aortic valves constitute the most common congenital heart abnormality, and have a tendency to become stenosed, regurgitant, calcified, or infected. The presence of heavy calcification in a noninfected bicuspid valve may lead to dislodgement of calcific embolic material which is not necessarily heralded by acute valvular rupture. Accurate localization of the calcific embolus to the right supraclinoid internal carotid artery was provided by spiral CT imaging in this case.

Pseudallescheria boydii infection of the central nervous system

Pseudallescheria boydii is a rare cause of central nervous system infection characteristically presenting as a neutrophilic meningitis or multiple brain abscesses. Factors predisposing to central nervous system infection with this fungus include immunosuppression and near drowning. The organism is infrequently cultured from fluid obtained by lumbar puncture, delaying clinical recognition and appropriate antifungal therapy. All untreated patients with P boydii infection of the central nervous system died. We describe a patient who developed a persistent neutrophilic meningitis with focal neurologic deficits due to P boydii 6 months after a freshwater aspiration pneumonia. We also review the characteristic clinical and pathologic features of previously reported cases and emphasize the importance of early detection and treatment in the management of this frequently intractable disease.

Movement disorders with neuroleptic drug treatment

Antipsychotic drugs produce several neurologic complications including acute dyskinesia, parkinsonism, neuroleptic malignant syndrome, akathisia, and tardive dyskinesia. Despite increased awareness of these syndromes, they continue to be underdiagnosed among patients receiving antipsychotic drugs. The clinical features, possible pathophysiologic mechanisms, and treatment of these conditions are discussed in this review.

Tardive dyskinesia

Tardive dyskinesia is an involuntary movement disorder associated with the prolonged use of antipsychotic drugs. The estimated prevalence rate is 10-15%. Elderly individuals are at greater risk than those below age 50. Although its cause is unknown, increased sensitivity to dopamine in the basal ganglia may contribute to the pathophysiology. No satisfactory treatment is currently available, restricted indications for chronic antipsychotic drug treatment, but early recognition of tardive dyskinesia, and prompt discontinuation of antipsychotic drugs when appropriate may reduce the incidence of this disorder.

Clonazepam and phenobarbital in tardive dyskinesia

Benzodiazepines have several advantages over other antidyskinetic drugs in treating tardive dyskinesia. The authors conducted a controlled study of clonazepam versus the active placebo of phenobarbital in 21 psychiatric patients with tardive dyskinesia. Both drugs significantly reduced dyskinetic movements: clonazepam had a stronger effect on orofacial dyskinesia, and phenobarbital was more effective for limbs and axial movements. Clonazepam was also more effective for drug-free patients and those receiving low doses of neuroleptics than for all patients given phenobarbital and for clonazepam patients taking high doses of neuroleptics. The authors suggest that future treatment studies focus on the effects of antidyskinetic drugs on distinct body regions.

Tardive dyskinesia: a clinical test of the supersensitivity hypothesis

Patients with tardive dyskinesia showed no significant difference in CSF HVA when compared with groups of schizophrenic or depressives. CSF cAMP in the tardive dyskinesia group was significantly lower when compared to schizophrenics but not depressives. These results do not support a dopamine-receptor supersensitivity hypothesis in permanent tardive dyskinesia.

Withdrawal syndromes associated with antipsychotic drugs

Withdrawal symptoms frequently follow abrupt discontinuation of antipsychotic compounds. In addition to other somatic symptoms, withdrawal-emergent dyskinesias may be observed. "Covert dyskinesia" refers to a masked form of tardive dyskinesia that becomes clinically detectable only after antipsychotic drugs are withdrawn or their dosage is reduced. Withdrawal dyskinesia appears under similar circumstances but disappears spontaneously in 6 to 12 weeks. Cholinergic overactivity and changes in dopamine-acetylcholine balance in the basal ganglia may underlie these withdrawal syndromes. The principal value of the concept of covert dyskinesia is in the secondary and tertiary prevention of tardive dyskinesia through early discovery and treatment.

Deanol acetamidobenzoate treatment in choreiform movement disorders

Deanol acetamidobenzoate was administered in double-blind, crossover fashion with placebo to five patients with tardive dyskinesia, three patients with Huntington's chorea, and one patient with posthemiplegic chorea. No significant effect on dyskinesia was observed. Preliminary administration of physostigmine salicylate to patients with tardive dyskinesia had a variable effect, while benztropine mesylate produced no change. Since the status of deanol as an effective precursor of acetylcholine is uncertain, further trials with putative cholinergic agents remain warranted in choreiform syndromes.

Tardive dyskinesia in young adults

The authors describe two cases of tardive dyskinesia in which severe axial dystonia and intense facial grimacing produced marked discomfort as well as social and physical disability. Both patients experienced the onset of psychiatric symptoms as young adults, showed a prompt response to antipsychotic drug therapy, and were subsequently left on maintenance treatment for indefinite periods. The severity of this frequently irreversible and disabling condition warrants careful consideration in the use of long-term antipsychotic drug treatment in the young psychiatric outpatient population.