Botulinum Toxin a for Chronic Daily Headache: A Randomized, Placebo-Controlled, Parallel Design Study

Sixty patients with headaches of more than 15 days per month were recruited for this double-blind, placebo-controlled, parallel study of botulinum toxin type A (BTX) for chronic tension type and chronic migraine headaches. The primary efficacy point was the number of headache-free days as assessed by diary for 12 weeks after BTX injection. Secondary efficacy points included global impressions, the use of abortive headache medications, and palpation. After recruitment, subjects kept diaries for 4 weeks prior to randomization, at which time they received either 200 U of BTX or matching placebo and were followed. After the week-12 evaluation, patients were offered 200 U of BTX (open label), and were similarly followed for another 12 weeks. The mean days with headache of the 60 subjects (49 female, mean age 47 ± 11 years) was 23 ± 7 out of 30. Both groups were demographically similar (58 completed). Over a 12-week period after injections, headache-free days had improved in the BTX group from week 8 to 12 ( P < 0.05), and strongly tended to improve over the entire 12-week period, 33 ± 23 vs. 24 ± 16 days without headache ( P = 0.07), but did not meet the a priori significance criteria. The subject global impressions ( P < 0.05), subject change in headache impressions ( P < 0.005), and investigator global impressions ( P < 0.001) all improved in the BTX group compared with placebo. Adverse events were mild and did not differ between groups. At week 24 (open label), headache-free days were less in the twice BTX injected group compared with the once injected group, 40 ± 26 vs. 26 ± 19 ( P < 0.05). BTX may help chronic daily headache and appears to have a cumulative effect with subsequent injections. The treatment was very well tolerated.

Placebo-controlled trial of lubiprostone for constipation associated with Parkinson disease

OBJECTIVE

To evaluate the efficacy and tolerability of lubiprostone (Amitiza) for constipation in Parkinson disease (PD) in a double-blind, randomized, controlled study.

METHODS

Patients with PD and clinically meaningful constipation (constipation rating scale score > 10 [range: 0-28]) were recruited from 2 academic movement disorder centers to participate in the study. After enrollment, patients were initially followed for 2 weeks and then were randomly assigned 1:1 to lubiprostone, and the dose was titrated up to 48 μg/day. They returned 4 weeks later for a final assessment. Data included stool diaries and global impressions (co-primary endpoints), demographics, Unified Parkinson's Disease Rating Scale scores, constipation scale scores, visual analog scale (VAS) scores, a stool diary, and adverse events.

RESULTS

Fifty-four subjects (39 male, mean age 67.0 ± 10.1 years, and mean duration of PD 8.3 ± 5.4 years) were randomly assigned to lubiprostone or placebo. One patient in the drug group discontinued the study because of logistics, and one patient in the placebo group discontinued the study because of lack of efficacy. A marked or very marked clinical global improvement was reported by 16 of 25 (64.0%) subjects receiving drug vs 5 of 27 (18.5%) subjects receiving placebo (p = 0.001). The constipation rating scale (p < 0.05), VAS (p = 0.001), and stools per day in the diary (p < 0.001) all improved with drug compared with placebo. Adverse events with drug were mild, most commonly intermittent loose stools.

CONCLUSION

In this randomized controlled trial, lubiprostone seemed to be well tolerated and effective for the short-term treatment of constipation in PD.

Evidence-based guideline update: treatment of essential tremor: report of the Quality Standards subcommittee of the American Academy of Neurology

BACKGROUND

This evidence-based guideline is an update of the 2005 American Academy of Neurology practice parameter on the treatment of essential tremor (ET).

METHODS

A literature review using MEDLINE, EMBASE, Science Citation Index, and CINAHL was performed to identify clinical trials in patients with ET published between 2004 and April 2010.

RESULTS AND RECOMMENDATIONS

Conclusions and recommendations for the use of propranolol, primidone (Level A, established as effective); alprazolam, atenolol, gabapentin (monotherapy), sotalol, topiramate (Level B, probably effective); nadolol, nimodipine, clonazepam, botulinum toxin A, deep brain stimulation, thalamotomy (Level C, possibly effective); and gamma knife thalamotomy (Level U, insufficient evidence) are unchanged from the previous guideline. Changes to conclusions and recommendations from the previous guideline include the following: 1) levetiracetam and 3,4-diaminopyridine probably do not reduce limb tremor in ET and should not be considered (Level B); 2) flunarizine possibly has no effect in treating limb tremor in ET and may not be considered (Level C); and 3) there is insufficient evidence to support or refute the use of pregabalin, zonisamide, or clozapine as treatment for ET (Level U).

Improvements in nocturnal symptoms with ropinirole prolonged release in patients with advanced Parkinson's disease

BACKGROUND

The 24-week, double-blind Efficacy and Safety Evaluation in PD-Adjunct (EASE-PD Adjunct) study randomized patients with advanced Parkinson's disease (PD) suboptimally controlled with levodopa to once-daily placebo or adjunctive ropinirole prolonged release (2-24 mg/day). We investigated the effect of ropinirole prolonged release on nocturnal symptoms in these patients.

METHODS

Total and grouped item PD Sleep Scale (PDSS) scores were analyzed post hoc in patients with baseline PDSS total scores ≤ 100 (troublesome nocturnal symptoms) and >100.

RESULTS

Baseline PDSS total score was ≤ 100 in 93 of 198 (47%) and 89 of 189 (47%) patients receiving ropinirole prolonged release and placebo, respectively; this subgroup displayed evidence at baseline of greater daily awake 'off' time, reduced night-time sleep and worse quality of life, than the PDSS >100 subgroup. Significant improvements with ropinirole prolonged release versus placebo in PDSS score from baseline to Week 24 last observation carried forward were observed for those with baseline PDSS ≤ 100 [adjusted mean treatment difference 9.0 (95% CI: 2.76, 15.33; P = 0.0051)], but not >100. The PDSS ≤ 100 subgroup demonstrated treatment benefits for PDSS groupings of motor symptoms on waking and global quality of sleep. Changes in daytime sleepiness were similar between treatment groups. The PDSS >100 subgroup demonstrated significant treatment benefit for global quality of sleep. The unadjusted odds ratio for a positive response with ropinirole prolonged release relative to placebo, for the PDSS ≤ 100 subgroup, was 2.90 (95% CI: 1.42, 5.95, P = 0.004).

CONCLUSIONS

Once-daily ropinirole prolonged release improves nocturnal symptoms in patients with advanced PD not optimally controlled with levodopa who suffer troublesome nocturnal disturbance.

Animal models of restless legs syndrome

Restless legs syndrome (RLS) is a common disease with prevalence up to 10% in the general population. It is mostly a subjective condition, making animal models intrinsically difficult. General increased activity (urge to move) and limb movements consistent with periodic limb movements of sleep, seen in most patients with RLS, are currently our best behavioral markers. Our best understanding of human RLS demonstrates reduced central nervous system (CNS) iron stores and dysfunction of dopaminergic systems, which most likely involves the spinal cord. Based upon this knowledge, animal manipulations, including destruction of the A11 diencephalic-spinal tract and iron deprivation, have resulted in animal behavior consistent with RLS. Dopamine receptor type 3 knockout mice also show general increased activity. Pharmacologic blockade of dopamine receptors in rodents has also caused movements resembling periodic limb movements of sleep in older rodents but not in younger animals. More sophisticated animal modeling is needed to facilitate our understanding of RLS.

Practice Parameter: Treatment of Parkinson disease with motor fluctuations and dyskinesia (an evidence-based review): [RETIRED]

Objective: To make evidence-based treatment recommendations for the medical and surgical treatment of patients with Parkinson disease (PD) with levodopa-induced motor fluctuations and dyskinesia. To that end, five questions were addressed. 1. Which medications reduce off time? 2. What is the relative efficacy of medications in reducing off time? 3. Which medications reduce dyskinesia? 4. Does deep brain stimulation (DBS) of the subthalamic nucleus (STN), globus pallidus interna (GPi), or ventral intermediate (VIM) nucleus of the thalamus reduce off time, dyskinesia, and antiparkinsonian medication usage and improve motor function? 5. Which factors predict improvement after DBS?

Methods: A 10-member committee including movement disorder specialists and general neurologists evaluated the available evidence based on a structured literature review including MEDLINE, EMBASE, and Ovid databases from 1965 through June 2004.

Results, Conclusions, and Recommendations: 1. Entacapone and rasagiline should be offered to reduce off time (Level A). Pergolide, pramipexole, ropinirole, and tolcapone should be considered to reduce off time (Level B). Apomorphine, cabergoline, and selegiline may be considered to reduce off time (Level C). 2. The available evidence does not establish superiority of one medicine over another in reducing off time (Level B). Sustained release carbidopa/levodopa and bromocriptine may be disregarded to reduce off time (Level C). 3. Amantadine may be considered to reduce dyskinesia (Level C). 4. Deep brain stimulation of the STN may be considered to improve motor function and reduce off time, dyskinesia, and medication usage (Level C). There is insufficient evidence to support or refute the efficacy of DBS of the GPi or VIM nucleus of the thalamus in reducing off time, dyskinesia, or medication usage, or to improve motor function. 5. Preoperative response to levodopa predicts better outcome after DBS of the STN (Level B).

Topiramate in essential tremor: a double-blind, placebo-controlled trial

BACKGROUND

Essential tremor is most prevalent and most disabling in older patients. Additional therapies are required for patients with an inadequate response or intolerable side effects. In small trials, topiramate appeared to be beneficial in essential tremor.

METHODS

In this multicenter, double-blind, placebo-controlled, parallel-design trial, patients with moderate to severe essential tremor of the upper limbs were randomized to 24 weeks of treatment with placebo or topiramate (target dose, 400 mg/day) as monotherapy or as an adjunct to one antitremor medication. The primary efficacy variable was the final visit tremor score based on the Fahn-Tolosa-Marin Tremor Rating Scale (TRS).

RESULTS

The intent-to-treat population was 208 patients (topiramate, 108; placebo, 100). The final visit score (last observation carried forward) was lower in the topiramate group than with placebo (p < 0.001). Mean percentage improvement in overall TRS scores was 29% with topiramate at a mean final dose of 292 mg/day and 16% with placebo (p < 0.001). Topiramate was associated with greater improvement in function and disability (p = 0.001). A between-group difference (p < 0.001) was observed at the first on-treatment visit at 4 weeks when the target topiramate dose was 100 mg/day (mean achieved dose, 62 +/- 9 mg/day). The most common treatment-limiting adverse events in topiramate-treated patients were paresthesia (5%), nausea (3%), concentration/attention difficulty (3%), and somnolence (3%). Adverse events were treatment limiting in 31.9% of topiramate patients and 9.5% of placebo patients.

CONCLUSIONS

Topiramate was effective in the treatment of moderate to severe essential tremor. Tremor reduction was accompanied by functional improvements, such as in motor tasks, writing, and speaking.

Modafinil for daytime somnolence in Parkinson's disease: double blind, placebo controlled parallel trial

BACKGROUND

Excessive daytime somnolence (EDS) commonly complicates Parkinson's disease (PD). The aetiology of EDS is probably multifactorial but is probably exacerbated by dopaminergic medications. Modafinil is a wake-promoting agent approved for use in narcolepsy, but it is often used to treat a variety of somnolent conditions.

METHOD

A double blind, placebo controlled parallel design trial was conducted to assess the efficacy of modafinil (200-400 mg/day) for the treatment of EDS in PD. The primary efficacy measure was the Epworth Sleepiness (ES) scale score. Secondary efficacy points included the Unified Parkinson's Disease Rating Scale (UPDRS), the Fatigue Severity Scale, the Hamilton Depression Scale, and the multiple sleep latency test (MSLT).

RESULTS

Of a total of 40 subjects (29 men, mean (SD) age 64.8 (11.3) years), randomised to modafinil or placebo, 37 completed the study. Modafinil failed to significantly improve ES scores compared with placebo (2.7 v 1.5 points improvement, respectively, p = 0.28). MSLT failed to improve with modafinil relative to placebo (-0.16 v -0.70, respectively, p = 0.14). UPDRS, global impressions, Fatigue Severity Scale, and Hamilton Depression Scale scores were unchanged. Adverse events were minimal.

CONCLUSION

Modafinil failed to significantly improve EDS in PD compared with placebo. The drug did not alter motor symptoms in PD and was well tolerated.

Projections of diencephalic dopamine neurons into the spinal cord in mice

The aim of this study is to investigate the pathway of diencephalic dopaminergic (DA) neuronal innervating into the spinal cord in mice, the pathway is postulated relevant to clinical restless legs syndrome (RLS). Tyrosine hydroxylase (TH) immunohistochemistry was used to identify the DA neuron. The fluorescent tracer Fluoro-Gold (FG) was stereotaxically injected into the T10-L5 spinal cord of CBL57 mice (n=20) seven days before the animals were sacrificed. The diencephalic sections were stained with TH antibody and the FG tracer present in the diencephalic DA neurons were examined under fluoresce microscope. The average number of total DA neurons per side in A11, A12, A13 and A14 was 66+/-8, 221+/-12, 350+/-17 and 254+/-21 respectively. After being injected into the spinal cord, FG reached the DA neurons within the A10 and A11 groups, but didn't target to any other DA neuron groups including the A8 and A9 groups in substantia nigra (SN). The diencephalic A11 DA neurons possessed long axons extending over several segments and possibly traversing the entire length of the spinal cord. It is the first time to report A10 and A11 DA neuron projections into the spinal cord in mice.

Practice parameter: therapies for essential tremor: report of the Quality Standards Subcommittee of the American Academy of Neurology

BACKGROUND

Essential tremor (ET) is one of the most common tremor disorders in adults and is characterized by kinetic and postural tremor. To develop this practice parameter, the authors reviewed available evidence regarding initiation of pharmacologic and surgical therapies, duration of their effect, their relative benefits and risks, and the strength of evidence supporting their use.

METHODS

A literature review using MEDLINE, EMBASE, Science Citation Index, and CINAHL was performed to identify clinical trials in patients with ET published between 1966 and August 2004. Articles were classified according to a four-tiered level of evidence scheme and recommendations were based on the level of evidence.

RESULTS AND CONCLUSIONS

Propranolol and primidone reduce limb tremor (Level A). Alprazolam, atenolol, gabapentin (monotherapy), sotalol, and topiramate are probably effective in reducing limb tremor (Level B). Limited studies suggest that propranolol reduces head tremor (Level B). Clonazepam, clozapine, nadolol, and nimodipine possibly reduce limb tremor (Level C). Botulinum toxin A may reduce hand tremor but is associated with dose-dependent hand weakness (Level C). Botulinum toxin A may reduce head tremor (Level C) and voice tremor (Level C), but breathiness, hoarseness, and swallowing difficulties may occur in the treatment of voice tremor. Chronic deep brain stimulation (DBS) (Level C) and thalamotomy (Level C) are highly efficacious in reducing tremor. Each procedure carries a small risk of major complications. Some adverse events from DBS may resolve with time or with adjustment of stimulator settings. There is insufficient evidence regarding the surgical treatment of head and voice tremor and the use of gamma knife thalamotomy (Level U). Additional prospective, double-blind, placebo-controlled trials are needed to better determine the efficacy and side effects of pharmacologic and surgical treatments of ET.

Hearing impairment in essential tremor

OBJECTIVE

To assess hearing in patients with essential tremor (ET) vs patients with Parkinson disease (PD) and normal controls.

METHODS

The authors assessed demographic and clinical information including use of hearing aids in 250 patients with ET, 127 patients with PD, and 127 normal controls. The authors administered the Nursing Home Hearing Handicap Index (NHHI), a validated measure of hearing disability. Regression techniques were used to adjust for factors such as age and sex. The authors assessed a complete audiologic evaluation in a subset of patients with ET.

RESULTS

Patients with ET had worse adjusted NHHI scores when compared to patients with PD (p < 0.001), controls (p < 0.001), and both (p < 0.001). A higher percentage of patients with ET also used hearing aids (p < 0.0001). In the ET group, hearing loss was associated with tremor severity (p = 0.02) and tended to be associated with older age (p = 0.06), male sex (p = 0.06), and the absence of dystonia (p = 0.18). Audiology testing was consistent with high-frequency sensorineural hearing loss. Central processing was not disproportionally greater than peripheral loss.

CONCLUSION

Patients with ET have increased hearing disability compared to patients with PD and normal controls, which correlates with tremor severity.

Vagus nerve stimulation for essential tremor

Objective: To assess the safety and efficacy of vagus nerve stimulation (VNS) for essential tremor (ET).

Methods: This was a pilot open-treatment trial at three centers, with masked videotape tremor assessments. Inclusion required a severity score of 3 or 4 on the Tremor Rating Scale (TRS) in one or both hands. At baseline, tremor was assessed with TRS and Unified Tremor Rating Assessment (UTRA), accelerometry, and a videotape protocol. The VNS device was implanted with leads placed around the left cervical vagus nerve. Stimulation was adjusted over 4 weeks before the repeat tremor assessments. Two raters masked to the study visit scored the videotapes.

Results: Nine subjects participated, with a mean age of 65 years and a mean age at onset of tremor of 24. Investigators rated hand tremor as mildly improved (TRS 2.3 ± 0.7 during VNS vs 3.0 ± 0.4 during baseline, p = 0.06). Accelerometry-measured total power improved 50.2 ± 31.8% (p < 0.01). Videotape tremor scores were highly correlated between the masked raters and revealed no changes in tremor scores with treatment. VNS was well tolerated, with the most common adverse events being stimulation related.

Conclusions: VNS was judged by investigators to mildly improve upper extremity tremor. This finding was not confirmed in videotape scoring by masked raters. VNS is not likely to have a clinically meaningful effect on ET.

Neuropathological examination suggests impaired brain iron acquisition in restless legs syndrome

OBJECTIVE

To assess neuropathology in individuals with restless legs syndrome (RLS).

METHODS

A standard neuropathologic evaluation was performed on seven brains from individuals who had been diagnosed with RLS. The substantia nigra was examined in greater detail for iron staining and with immunohistochemistry for tyrosine hydroxylase and proteins involved in iron management. Five age-matched individuals with no neurologic history served as controls.

RESULTS

There were no histopathologic abnormalities unique to the RLS brains. Tyrosine hydroxylase staining in the major dopaminergic regions appeared normal in the RLS brains. Iron staining and H-ferritin staining was markedly decreased in the RLS substantia nigra. Although H-ferritin was minimally detected in the RLS brain, L-ferritin staining was strong. However, the cells staining for L-ferritin in RLS brains were morphologically distinct from those in the control brains. Transferrin receptor staining on neuromelanin-containing cells was decreased in the RLS brains compared to normal, whereas transferrin staining in these cells was increased.

CONCLUSIONS

RLS may not be rooted in pathologies associated with traditional neurodegenerative processes but may be a functional disorder resulting from impaired iron acquisition by the neuromelanin cells in RLS. The underlying mechanism may be a defect in regulation of the transferrin receptors.

Genetic polymorphisms of the N-acetyltransferase genes and risk of Parkinson's disease

Recently, the authors demonstrated linkage in idiopathic PD to a region on chromosome 8p that contains the N-acetyltransferase genes, NAT1 and NAT2. The authors examined NAT1 and NAT2 for association with PD using family-based association methods and single nucleotide polymorphisms (SNPs). The authors did not find evidence for association with increased risk for PD between any individual NAT1 or NAT2 SNP or acetylation haplotype (N = 397 families, 1,580 individuals).

Complete genomic screen in Parkinson disease: evidence for multiple genes

CONTEXT

The relative contribution of genes vs environment in idiopathic Parkinson disease (PD) is controversial. Although genetic studies have identified 2 genes in which mutations cause rare single-gene variants of PD and observational studies have suggested a genetic component, twin studies have suggested that little genetic contribution exists in the common forms of PD.

OBJECTIVE

To identify genetic risk factors for idiopathic PD.

DESIGN, SETTING, AND PARTICIPANTS

Genetic linkage study conducted 1995-2000 in which a complete genomic screen (n = 344 markers) was performed in 174 families with multiple individuals diagnosed as having idiopathic PD, identified through probands in 13 clinic populations in the continental United States and Australia. A total of 870 family members were studied: 378 diagnosed as having PD, 379 unaffected by PD, and 113 with unclear status.

MAIN OUTCOME MEASURES

Logarithm of odds (lod) scores generated from parametric and nonparametric genetic linkage analysis.

RESULTS

Two-point parametric maximum parametric lod score (MLOD) and multipoint nonparametric lod score (LOD) linkage analysis detected significant evidence for linkage to 5 distinct chromosomal regions: chromosome 6 in the parkin gene (MLOD = 5.07; LOD = 5.47) in families with at least 1 individual with PD onset at younger than 40 years, chromosomes 17q (MLOD = 2.28; LOD = 2.62), 8p (MLOD = 2.01; LOD = 2.22), and 5q (MLOD = 2.39; LOD = 1.50) overall and in families with late-onset PD, and chromosome 9q (MLOD = 1.52; LOD = 2.59) in families with both levodopa-responsive and levodopa-nonresponsive patients.

CONCLUSIONS

Our data suggest that the parkin gene is important in early-onset PD and that multiple genetic factors may be important in the development of idiopathic late-onset PD.

Association of single-nucleotide polymorphisms of the tau gene with late-onset Parkinson disease

CONTEXT

The human tau gene, which promotes assembly of neuronal microtubules, has been associated with several rare neurologic diseases that clinically include parkinsonian features. We recently observed linkage in idiopathic Parkinson disease (PD) to a region on chromosome 17q21 that contains the tau gene. These factors make tau a good candidate for investigation as a susceptibility gene for idiopathic PD, the most common form of the disease.

OBJECTIVE

To investigate whether the tau gene is involved in idiopathic PD.

DESIGN, SETTING, AND PARTICIPANTS

Among a sample of 1056 individuals from 235 families selected from 13 clinical centers in the United States and Australia and from a family ascertainment core center, we tested 5 single-nucleotide polymorphisms (SNPs) within the tau gene for association with PD, using family-based tests of association. Both affected (n = 426) and unaffected (n = 579) family members were included; 51 individuals had unclear PD status. Analyses were conducted to test individual SNPs and SNP haplotypes within the tau gene.

MAIN OUTCOME MEASURE

Family-based tests of association, calculated using asymptotic distributions.

RESULTS

Analysis of association between the SNPs and PD yielded significant evidence of association for 3 of the 5 SNPs tested: SNP 3, P =.03; SNP 9i, P =.04; and SNP 11, P =.04. The 2 other SNPs did not show evidence of significant association (SNP 9ii, P =.11, and SNP 9iii, P =.87). Strong evidence of association was found with haplotype analysis, with a positive association with one haplotype (P =.009) and a negative association with another haplotype (P =.007). Substantial linkage disequilibrium (P<.001) was detected between 4 of the 5 SNPs (SNPs 3, 9i, 9ii, and 11).

CONCLUSIONS

This integrated approach of genetic linkage and positional association analyses implicates tau as a susceptibility gene for idiopathic PD.

Daytime sleepiness and other sleep disorders in Parkinson's disease

BACKGROUND

PD is associated with a variety of sleep problems. The dopamine agonists (DA) pramipexole and ropinirole were recently implicated in causing "sleep attacks" and motor vehicle accidents.

METHODS

In order to determine the overall rate of subjective sleep problems in PD and to determine if any factors, including specific medications, correlate with sleep pathology, the authors surveyed consecutive patients with PD seen over a 3-month period in a Movement Disorders Clinic. The authors collected demographic and medication data, and the patients completed the Epworth Sleepiness Scale (ESS), questions assessing the presence of restless legs syndrome (RLS), a modified National Sleep Foundation sleep survey, and specific questions regarding falling asleep while driving.

RESULTS

A total of 320 patients completed the questionnaire. The authors eliminated 17, six for incomplete data and 11 for having a primary diagnosis other than PD. The mean age of the remaining 303 patients was 67.1 +/- 10.7 years, and the mean duration of PD was 9.1 +/- 5.7 years. The ESS scores averaged 11.1 +/- 5.9, and in 50.2% of patients the score was abnormally high (>10). Stepwise regression analysis found that sleepiness correlated with longer duration of PD (p < 0.001), more advanced PD (p < 0.004), male sex (p < 0.001), and the use of any DA (p < 0.003). The soporific effects of the three most common DA (pramipexole, ropinirole, and pergolide) were similar. Falling asleep while driving was reported by 63/279 (22.6%) of current drivers and correlated with higher ESS scores (p < 0.05). Other sleep disorders, including RLS, were also frequently reported.

CONCLUSION

Daytime sleepiness is common in PD and correlates with more advanced and longer duration of PD, and male sex. The DA were also independently associated with daytime sleepiness, but in this group, no single DA was more culpable than the others.

Switching from pergolide to pramipexole in patients with Parkinson's disease

OBJECTIVE/BACKGROUND

To compare the safety and efficacy of pramipexole and pergolide in the treatment of mild to moderate Parkinson's disease (PD). In contrast to pergolide, a D1 and D2 dopamine agonist, pramipexole is a nonergoline dopamine agonist with D2 and preferential D3 dopamine receptor activity. This selective activity may result in clinically different effects. No prospective head-to-head comparison studies of pergolide and pramipexole have been reported.

METHODS

Patients with PD who were maintained on an optimal dose of pergolide were converted to pramipexole, typically over a one-month period. Clinical assessments were performed just prior to conversion and after an optimal dose of pramipexole was achieved.

RESULTS

Twenty-five patients were converted from pergolide to pramipexole during the period of July, 1997 to January, 1999. Three patients were lost to follow-up, and one patient died. Of the remaining 21 patients there were 11 men and 10 women, mean age was 67.3 years +/- 10.0 (range 51-84). Mean duration of symptoms prior to conversion was 12.5 years +/- 3.4 (range 5-19). All patients (except one) were on concomitant carbidopa/ levodopa and experienced motor fluctuations. After a mean follow-up of 5.9 +/- 2.9 months on pramipexole, the mean levodopa daily dose was reduced from 618.7mg to 581.2mg (16.5% reduction, p = 0.61). The mean daily doses of pergolide and pramipexole (in milligrams per day) were 2.1 +/- 1.5 (0.15-6) and 3.2 +/- 1.1 (0.75-6) respectively. Thirteen patients (62%) reported overall improvement (subjective global response) on pramipexole as compared to pergolide, 5 (24%) were unchanged and 3 (14%) reported worsening. Eighteen of the 21 patients (86%) remained on pramipexole after the study period. Although there was a slight trend toward improved scores on pramipexole, the difference was not statistically significant.

CONCLUSION

This open label study failed to provide evidence of superior efficacy of either dopamine agonist. It is possible, however, that while somepatients may benefit more from either pergolide or pramipexole, other patients may obtain additional benefit from other DA agonists or combination therapy. Future randomized, controlled, double-blinded therapeutic trials are needed to determine which, if any, dopamine agonist is superior in the treatment of PD.

Motor restlessness

Motor restlessness, characterised by an irresistible urge to move about, can be a manifestation of many underlying disorders. Unfortunately, it is often poorly recognised and underdiagnosed in clinical practice, possibly because patients do not seek medical attention, or their complaints were thought to be secondary to anxiety. While the two major conditions to consider are restless legs syndrome and neuroleptic-induced akathisia, there are many other differential diagnoses. We provide a concise review of the clinical features and diagnostic pitfalls of these conditions. A proper detailed clinical history and examination can often help clinch the diagnosis, as most of these conditions have their unique clinical features.

Concepts and methods in chronic thalamic stimulation for treatment of tremor: technique and application

OBJECTIVE

To rationalize the technique and reduce the costs associated with chronic deep brain stimulation of the thalamus for treatment of refractory tremor.

METHODS

The efficacy and safety of a modification in surgical techniques was prospectively assessed in 94 patients with tremor. Bilateral electrodes were implanted in 29 patients, and 65 patients received unilateral implants. Forty-five patients had Parkinson's disease tremor, 42 patients had essential tremor, and 7 patients had kinetic tremors of different causes. In all instances, intraoperative stimulations to analyze the thresholds of intrinsic and extrinsic responses were performed directly with the implanted leads. The electrodes were repositioned until satisfactory results were achieved. The pulse generators were implanted directly after the first step in the same operative session. Patients were not subjected to interoperative test stimulation trials.

RESULTS

Postoperative improvement of tremor at a mean follow-up of 11.9 months was rated as excellent in 47 patients (50%), marked in 37 patients (39%), moderate in 8 patients (9%), and minor in 2 patients (2%). There was no persistent morbidity related to surgery. In patients with Parkinson's disease, the symptomatic improvement of tremor was rated as excellent in 51% of patients, marked in 36%, moderate in 11%, and minor in 2%. In patients with essential tremor, symptomatic outcome was classified as excellent in 57% of patients, marked in 36%, moderate in 5%, and minor in 2%. Six of the seven patients with kinetic tremor achieved marked symptomatic improvement, and one patient experienced moderate improvement. Forty patients experienced stimulation-related side effects. Side effects were mild in general, and they were reversible with a change in electrical parameters. They occurred more frequently in patients who had bilateral stimulation.

CONCLUSION

Excellent to marked improvement of tremor is achieved in the majority of patients with physiological target determination via implanted leads in thalamic deep brain stimulation. Interoperative test stimulation trials are unnecessary. Modifications in technique may help to reduce the costs of the related hospital stay.

Restless legs syndrome in monozygotic twins: clinical correlates

To better understand genetic characteristics of restless legs syndrome (RLS) and identify nongenetic factors that may influence phenotype, the authors studied 12 identical twins in which at least one member expressed RLS. Ten of the 12 twin pairs were concordant for RLS symptoms. Despite the high concordance rate, the disease severity, age at onset, and symptom descriptions often varied between twins. Birth order, birth weight, and serum ferritin levels did not predict RLS severity or age at onset.

Long-term efficacy of posteroventral pallidotomy in the treatment of Parkinson's disease

The authors describe results of unilateral posteroventral pallidotomy (PVP) in 89 patients with PD. At 3 months after surgery, 81.9% of the patients reported marked or moderate improvement in their parkinsonian symptoms. Postoperative Unified PD Rating Scale "off" state mean total motor score improved by 35.5% and the mean activities of daily living score by 33.7% (p <0.001). Improvements in parkinsonian symptoms were maintained in both"off" and "on" states in 62 patients at 12 months after PVP and in 41 patients who were followed for 18 months or longer (mean 26.6 months).

Weight gain following unilateral pallidotomy in Parkinson's disease

OBJECTIVE

To determine the clinical correlates and infer pathogenesis of weight gain following pallidotomy in patients with Parkinson's disease (PD).

BACKGROUND

Surgical ablation of the globus pallidus internus (GPi) improves levodopa induced dyskinesias, moderately improves most other "cardinal" manifestations of PD, and has been noted to result in increased weight.

METHODS

We incorporated Unified Parkinson's Disease Rating Scales (UPDRS) subscales, the Beck depression inventory and feeding questionnaire data into a linear regression model in order to determine which post-surgical change(s) may lead to weight gain over the first year following pallidotomy, n = 60.

RESULTS

The mean weight gain 1 year after pallidotomy was 4.0 +/- 4.1 kg. Improvement in "off" motor scores (P < 0.005), especially gait subscores (P<0.0001), and to a lesser extent improvement in "on" motor scores (P<0.05) predicted weight gain. Changes in dyskinesia ratings, mood, food intake, dysphagia, levodopa dose, weight loss in the year prior to pallidotomy, age, and duration of PD did not correlate with subsequent weight gain.

CONCLUSION

The high correlation between post-pallidotomy weight gain and "off" motor scores, suggests that this phenomenon is related to some change in underlying homeostasis associated with changes in the cardinal manifestations of PD itself, rather than secondary changes resultant from the surgery.

Clinical correlates of 6-hydroxydopamine injections into A11 dopaminergic neurons in rats: a possible model for restless legs syndrome

Pursuant to the clinical suspicion that restless legs syndrome (RLS) may involve dopaminergic diencephalic spinal neurons (A11), we performed stereotaxic bilateral 6-hydroxydopamine (6-OHDA) lesions into the A11 nucleus to observe for any behavioral correlates similar to this clinical condition. Pathologic examination demonstrated a 54% reduction in A11 tyrosine hydroxylase staining cells in rats injected with 6-OHDA versus sham treatment. Multiple blindly rated 90-120-minute video epochs demonstrated an increased average number of standing episodes (14.4+/-11.7 versus 7.3+/-5.5 episodes/epoch) and increased total standing time (38.9+/-20.5 versus 25.3+/-12.2 minutes/epoch) but similar total sleep time in four lesioned rats when compared with two sham rats. Treatment of the lesioned rats with intramuscular pramipexole subsequently resulted in fewer standing episodes (4.4+/-3.3 versus 14.4+/-11.7 episodes/epoch) and less total standing time (20.9+/-12.3 versus 38.9+/-20.5 minutes/epoch) when compared with untreated lesioned rats. Despite a large number of observations, the small number of lesioned animals precluded formal statistical analysis. These behaviors are consistent, although not specific, with what would be expected in an animal model of RLS.

Clinical correlates of 6-hydroxydopamine injections into A11 dopaminergic neurons in rats: a possible model for restless legs syndrome

Pursuant to the clinical suspicion that restless legs syndrome (RLS) may involve dopaminergic diencephalic spinal neurons (A11), we performed stereotaxic bilateral 6-hydroxydopamine (6-OHDA) lesions into the A11 nucleus to observe for any behavioral correlates similar to this clinical condition. Pathologic examination demonstrated a 54% reduction in A11 tyrosine hydroxylase staining cells in rats injected with 6-OHDA versus sham treatment. Multiple blindly rated 90-120-minute video epochs demonstrated an increased average number of standing episodes (14.4+/-11.7 versus 7.3+/-5.5 episodes/epoch) and increased total standing time (38.9+/-20.5 versus 25.3+/-12.2 minutes/epoch) but similar total sleep time in four lesioned rats when compared with two sham rats. Treatment of the lesioned rats with intramuscular pramipexole subsequently resulted in fewer standing episodes (4.4+/-3.3 versus 14.4+/-11.7 episodes/epoch) and less total standing time (20.9+/-12.3 versus 38.9+/-20.5 minutes/epoch) when compared with untreated lesioned rats. Despite a large number of observations, the small number of lesioned animals precluded formal statistical analysis. These behaviors are consistent, although not specific, with what would be expected in an animal model of RLS.

Tetrabenazine treatment for tardive dyskinesia: assessment by randomized videotape protocol

OBJECTIVE

Tetrabenazine, a monoamine depleter and dopamine receptor blocker, is used to treat several hyperkinetic movement disorders. The authors studied the use of tetrabenazine for tardive dyskinesia.

METHOD

Twenty patients with tardive dyskinesia (mean duration = 43.7 months) were videotaped before and after tetrabenazine treatment. Randomized videotapes were scored with the motor subset of the modified Abnormal Involuntary Movement Scale (AIMS) by raters blind to pre- or posttreatment status.

RESULTS

One patient did not tolerate tetrabenazine owing to sedation. The remaining 19 were rated after a mean of 20.3 weeks at a mean tetrabenazine dose of 57.9 mg/day. There were significant improvements in mean scores on both the patient AIMS self-rating and the AIMS motor subset evaluated by the blind videotape raters. All 19 patients continued to take tetrabenazine after the study.

CONCLUSIONS

Tetrabenazine was well tolerated and resulted in significant improvements in AIMS scores for patients with refractory tardive dyskinesia.

Pallidotomy for generalized dystonia

We systematically evaluated the efficacy of both unilateral and bilateral stereotactic pallidotomy in eight patients with generalized dystonia. Six patients had a marked improvement in dystonic movements and motor function; the other two patients also benefited from the procedure but to a lesser extent. The severity of dystonia was assessed before and after surgery by the Burke-Marsden-Fahn Dystonia Scale (BMFDS), the Unified Dystonia Rating Scale (UDRS), and the Activity of Daily Living Scale (ADL). The BMFDS scores decreased by 59.0%, UDRS by 62.5%, and ADL by 47.8% postoperatively. Adverse events were limited to a transient weakness in one patient. We conclude that pallidotomy is a safe and effective treatment in medically refractory cases of generalized dystonia.

Assessment of motor function after stereotactic pallidotomy

Despite a paucity of controlled data, stereotactic pallidotomy is increasingly used for the treatment of advanced Parkinson's disease (PD). To study the efficacy of the procedure on the cardinal PD features of rigidity, tremor, bradykinesia, and postural instability, we blindly rated randomized videos of 34 patients recorded in the "off' state immediately before and 3 months after unilateral stereotactic lesioning of the globus pallidus internus. Total "off' time Unified Parkinson's Disease Rating Scale motor scores improved 13.6% from 28.9 +/- 7.5 to 25.0 +/- 7.0 (p < 0.001). Particularly robust improvement was seen in contralateral tremor, gait, and arising from a chair (p < 0.001). Significant improvement was also seen in ipsilateral tremor, contralateral and some ipsilateral dexterity measures, and body bradykinesia. Most other features tended toward improvement but did not reach statistical significance. We conclude that pallidotomy is a safe and effective treatment of parkinsonian symptoms, many of which improve bilaterally.

Dandy-Walker syndrome presenting as opisthotonus: proposed pathophysiology

A patient with radiographically confirmed Dandy-Walker syndrome who presented with opisthotonus, a rarely reported clinical manifestation, is reported. From four separate pharmacologic trials (baclofen, diazepam, levodopa/carbidopa, and trihexyphenidyl), combination baclofen and diazepam therapy was determined to be most efficacious. Opisthotonus and extensor posturing remain only rudimentarily understood. We review the subject and propose a specific mechanism relating our patient's anatomic and physiologic conditions.