Robert L. Rodnitzky

Effects of tocopherol and deprenyl on the progression of disability in early Parkinson's disease

BACKGROUND AND METHODS In 1987 we began a multicenter controlled clinical trial of deprenyl (a monoamine oxidase inhibitor) and tocopherol (a component of vitamin E that traps free radicals) in the treatment of early Parkinsons disease. We randomly assigned 800 patients to one of four treatments: placebo, active tocopherol and deprenyl placebo, active deprenyl and tocopherol placebo, or both active drugs. The primary end point was the onset of disability prompting the clinical decision to begin administering levodopa. An interim analysis showed that deprenyl was beneficial (N Engl J Med 1989;321:1364-71). We report the results of tocopherol treatment after a mean (+/- SD) follow-up of 14 +/- 6 months, as well as the follow-up results for deprenyl. RESULTS There was no beneficial effect of tocopherol or any interaction between tocopherol and deprenyl. The beneficial effects of deprenyl, which occurred largely during the first 12 months of treatment, remained strong and significantly delayed the onset of disability requiring levodopa therapy (hazard ratio, 0.50; 95 percent confidence interval, 0.41 to 0.62; P < 0.001). The difference in the estimated median time to the end point was about nine months. The ratings for Parkinsons disease improved during the first three months of deprenyl treatment; the motor performance of deprenyl-treated patients worsened after the treatments were withdrawn. CONCLUSIONS Deprenyl (10 mg per day) but not tocopherol (2000 IU per day) delays the onset of disability associated with early, otherwise untreated Parkinsons disease. The action of deprenyl that accounts for its beneficial effects remains unclear.

Safety and efficacy of NeuroBloc (botulinum toxin type B) in type A–responsive cervical dystonia

OBJECTIVE To determine the safety and efficacy of botulinum toxin type B (BoNT/B) in patients with cervical dystonia (CD). BACKGROUND BoNT/B is a form of chemodenervation therapy for the treatment of patients with CD. METHODS The authors performed a 16-week, randomized, multicenter, double-blind, placebo-controlled trial of BoNT/B in patients with CD who continue to respond to botulinum toxin type A. Placebo, or 5,000 U or 10,000 U of BoNT/B was administered in two to four muscles involved clinically in CD. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at week 4 was the primary efficacy measure. Clinical assessments and adverse events were recorded for treatment day 1 and at weeks 2, 4, 8, 12, and 16. RESULTS A total of 109 patients were enrolled randomly across all three treatment groups. The mean improvement in the TWSTRS-Total scores in each group at week 4 was 4.3 (placebo), 9.3 (5,000 U), and 11.7 (10,000 U). For the prospectively defined primary contrast (10,000 U versus placebo), highly significant differences were noted for the primary (TWSTRS-Total, baseline to week 4, p = 0.0004) and supportive secondary (Patient Global Assessment, baseline to week 4, p = 0.0001) outcome measures. Improvement in pain, disability, and severity of CD occurred for patients who were treated with BoNT/B when compared with placebo-treated patients. Overall, improvements associated with BoNT/B treatment were greatest for patients who received the 10,000-U dose. The duration of treatment effect for BoNT/B was 12 to 16 weeks for both doses. CONCLUSION Botulinum toxin type B (NeuroBloc) is safe and efficacious at 5,000 U and 10,000 U for the management of patients with cervical dystonia.

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.

Visual dysfunction in Parkinson disease without dementia

Objective: To determine the profiles of visual dysfunction and their relationship to motor and cognitive dysfunction and to disability in mild to moderate Parkinson disease (PD) without dementia. Methods: Seventy-six independently living participants with mild to moderate PD and 161 neurologically normal older adults were studied using a comprehensive battery to assess visual acuity, contrast sensitivity (CS), visual speed of processing and attention, spatial and motion perception, visual and verbal memory, visuoconstructional abilities, executive functions, depression, and motor function. Results: Participants with PD scored significantly worse on all tests of vision and cognition compared with normal elderly persons. Reduced CS contributed to deficits on tests of spatial and motion perception and attention in participants with PD. Impairments in visual attention and spatial perception predicted worse cognitive function. Worse performances on tests of visual speed of processing and attention, spatial and motion perception, visual construction, and executive functions correlated with measures of postural instability and gait difficulty (in the Motor section of the Unified Parkinsons Disease Rating Scale). Impairments in motor function, visual memory, mood, and executive functions predicted worse disability as measured by Schwab–England Activities of Daily Living Scale. Conclusions: Patients with mild to moderate Parkinson disease showed impaired visual perception and cognition compared with elderly control subjects. Visual dysfunction contributes to parkinsonian disability through its influences on cognition and locomotion.

Heterozygosity for a mutation in the parkin gene leads to later onset Parkinson disease

Background: The vast majority of the parkin mutations previously identified have been found in individuals with juvenile or early onset PD. Previous screening of later onset PD cohorts has not identified substantial numbers of parkin mutations. Methods: Families with at least two siblings with PD were ascertained to identify genes contributing to PD susceptibility. Screening of the parkin gene, by both quantitative PCR and exon sequencing, was performed in those families with either early onset PD (age onset ≤50 years) or positive lod score with a marker in intron 7 of the parkin gene. Results: A total of 25 different mutations in the parkin gene were identified in 103 individuals from 47 families. Mutations were found in both parkin alleles in 41 of the individuals, whereas a single mutation in only one of the two parkin alleles was observed in 62 individuals. Thirty-five of the subjects (34%) with a parkin mutation had an age at onset of 60 years or above with 30 of these 35 (86%) having a detectable mutation on only one parkin allele. Few significant clinical differences were observed among the individuals with two, one, or no mutated copies of the parkin gene. Conclusion: Mutations in the parkin gene occur among individuals with PD with an older age at onset (≥60 years) who have a positive family history of the disease. In addition, the clinical findings of parkin-positive individuals are remarkably similar to those without mutations.

Efficacy and safety of botulinum type A toxin (Dysport) in cervical dystonia: Results of the first US randomized, double-blind, placebo-controlled study

Botulinum toxin type A (Dysport) has been shown in European studies to be a safe and effective treatment for cervical dystonia. This multicenter, double‐blind, randomized, controlled trial assessed the safety and efficacy of Dysport in cervical dystonia patients in the United States. Eighty patients were randomly assigned to receive one treatment with Dysport (500 units) or placebo. Participants were followed up for 4 to 20 weeks, until they needed further treatment. They were assessed at baseline and weeks 2, 4, 8, 12, 16, and 20 after treatment. Dysport was significantly more efficacious than placebo at weeks 4, 8, and 12 as assessed by the Toronto Western Spasmodic Torticollis Rating Scale (10‐point vs. 3.8‐point reduction in total score, respectively, at week 4; P ≤ 0.013). Of participants in the Dysport group, 38% showed positive treatment response, compared to 16% in the placebo group (95% confidence interval, 0.02–0.41). The median duration of response to Dysport was 18.5 weeks. Side effects were generally similar in the two treatment groups; only blurred vision and weakness occurred significantly more often with Dysport. No participants in the Dysport group converted from negative to positive antibodies after treatment. These results confirm previous reports that Dysport (500 units) is safe, effective, and well‐tolerated in patients with cervical dystonia.

Significant Linkage of Parkinson Disease to Chromosome 2q36-37

Parkinson disease (PD) is the second most common neurodegenerative disorder, surpassed in frequency only by Alzheimer disease. Elsewhere we have reported linkage to chromosome 2q in a sample of sibling pairs with PD. We have now expanded our sample to include 150 families meeting our strictest diagnostic definition of verified PD. To further delineate the chromosome 2q linkage, we have performed analyses using only those pedigrees with the strongest family history of PD. Linkage analyses in this subset of 65 pedigrees generated a LOD score of 5.1, which was obtained using an autosomal dominant model of disease transmission. This result strongly suggests that variation in a gene on chromosome 2q36-37 contributes to PD susceptibility.

Impaired Visual Search in Drivers with Parkinson's Disease

To assess the ability for visual search and recognition of roadside targets and safety errors during a landmark and traffic sign identification task in drivers with Parkinsons disease (PD).

Electrophysiologic analysis of aberrant regeneration after facial nerve paralysis

The blink reflex, ordinarily elicited only in the orbicularis oculi and not in other facial muscles, can be used to detect synkinetic movements objectively. In 26 of 29 patients tested at least 4 months after facial nerve degeneration, an aberrant blink reflex was recorded in the orbicularis oris on the affected side. Of the remaining three, one had injury to only a peripheral branch of the facial nerve and experienced a return of function with no evidence of synkinesis; in the other two, the affected side of the face was totally paralyzed in the absence of facial nerve regeneration. Synkinetic movements ultimately will occur in nearly all cases following facial nerve degeneration provided that the facial nerve regenerates from a proximal site.

Driving with distraction in Parkinson disease

Objective: To assess the effects of auditory–verbal distraction on driving performance in Parkinson disease (PD). Methods: We tested licensed, currently active drivers with mild-to-moderate PD (n = 71) and elderly controls with no neurologic disease (n = 147) on a battery of cognitive, visual, and motor tests. While they drove on a four-lane interstate freeway in an instrumented vehicle, we determined at-fault safety errors and vehicle control measures during a distracter task (Paced Auditory Serial Addition Task [PASAT]) and on an uneventful baseline segment. Results: Compared with controls, drivers with PD committed more errors during both baseline and distraction, and drove slower with higher speed variability during distraction. Although the average effect of distraction on driving performance compared with baseline was not different between the groups, the drivers with PD showed a more heterogeneous response to distraction (p < 0.001): the error count increased in 28.2% of drivers with PD (vs 15.8% in controls), decreased in 16.9% (vs 3.4%), and remained stable in 54.9% (vs 80.8%). The odds of increase in safety errors due to distraction was higher in the PD group even after adjusting for baseline errors, level of engagement in PASAT, sex, and education (odds ratio [95% CI] = 2.62 [1.19 to 5.74], p = 0.016). Decreased performance on tests of cognitive flexibility, verbal memory, postural control, and increased daytime sleepiness predicted worsening of driving performance due to distraction within the PD group. Conclusion: The quantitative effect of an auditory–verbal distracter task on driving performance was not significantly different between Parkinson disease (PD) and control groups. However, a significantly larger subset of drivers with PD had worsening of their driving safety errors during distraction. Measures of cognition, motor function, and sleepiness predicted effects of distraction on driving performance within the PD group.