John N. Caviness

Multi-organ distribution of phosphorylated α-synuclein histopathology in subjects with Lewy body disorders

A sensitive immunohistochemical method for phosphorylated α-synuclein was used to stain sets of sections of spinal cord and tissue from 41 different sites in the bodies of 92 subjects, including 23 normal elderly, 7 with incidental Lewy body disease (ILBD), 17 with Parkinson’s disease (PD), 9 with dementia with Lewy bodies (DLB), 19 with Alzheimer’s disease with Lewy bodies (ADLB) and 17 with Alzheimer’s disease with no Lewy bodies (ADNLB). The relative densities and frequencies of occurrence of phosphorylated α-synuclein histopathology (PASH) were tabulated and correlated with diagnostic category. The greatest densities and frequencies of PASH occurred in the spinal cord, followed by the paraspinal sympathetic ganglia, the vagus nerve, the gastrointestinal tract and endocrine organs. The frequency of PASH within other organs and tissue types was much lower. Spinal cord and peripheral PASH was most common in subjects with PD and DLB, where it appears likely that it is universally widespread. Subjects with ILBD had lesser densities of PASH within all regions, but had frequent involvement of the spinal cord and paraspinal sympathetic ganglia, with less-frequent involvement of end-organs. Subjects with ADLB had infrequent involvement of the spinal cord and paraspinal sympathetic ganglia with rare involvement of end-organs. Within the gastrointestinal tract, there was a rostrocaudal gradient of decreasing PASH frequency and density, with the lower esophagus and submandibular gland having the greatest involvement and the colon and rectum the lowest.

Defining mild cognitive impairment in Parkinson's disease

Our purpose was to characterize a state of mild cognitive impairment (MCI) in Parkinsons disease (PD) (PD‐MCI) that would be analogous to the MCI that is posited as a precursor of Alzheimers disease (AD). We categorized 86 PD subjects in a brain bank population as either cognitively normal (PD‐CogNL), PD‐MCI using criteria that included a 1.5 standard deviation or greater deficit upon neuropsychological testing consistently across at least one cognitive domain without dementia, and PD dementia (PD‐D) using DSM‐IV criteria. Twenty‐one percent of our PD sample met criteria for PD‐MCI, 62% were PD‐CogNL, and 17% had PD‐D. The mean duration of PD and MMSE scores of the PD‐MCI group were intermediate and significantly different from both PD‐CogNL and PD‐D. The cognitive domain most frequently abnormal in PD‐MCI was frontal/executive dysfunction followed by amnestic deficit. Single domain PD‐MCI was more common than PD‐MCI involving multiple domains. We conclude that a stage of clinical cognitive impairment in PD exists between PD‐CogNL and PD‐D, and it may be defined by applying criteria similar to the MCI that is posited as a precursor of AD. Defining PD‐MCI offers an opportunity for further study of cognitive impairment in PD and targets for earlier therapeutic intervention.

Unified Staging System for Lewy Body Disorders: Correlation with Nigrostriatal Degeneration, Cognitive Impairment and Motor Dysfunction

The two current major staging systems in use for Lewy body disorders fail to classify up to 50% of subjects. Both systems do not allow for large numbers of subjects who have Lewy-type α-synucleinopathy (LTS) confined to the olfactory bulb or who pass through a limbic-predominant pathway that at least initially bypasses the brainstem. The results of the current study, based on examination of a standard set of ten brain regions from 417 subjects stained immunohistochemically for α-synuclein, suggest a new staging system that, in this study, allows for the classification of all subjects with Lewy body disorders. The autopsied subjects included elderly subjects with Parkinson’s disease, dementia with Lewy bodies, incidental Lewy body disease and Alzheimer’s disease with Lewy bodies, as well as comparison groups without Lewy bodies. All subjects were classifiable into one of the following stages: I. Olfactory Bulb Only; IIa Brainstem Predominant; IIb Limbic Predominant; III Brainstem and Limbic; IV Neocortical. Progression of subjects through these stages was accompanied by a generally stepwise worsening in terms of striatal tyrosine hydroxylase concentration, substantia nigra pigmented neuron loss score, Mini Mental State Examination score and score on the Unified Parkinson’s Disease Rating Scale Part 3. Additionally, there were significant correlations between these measures and LTS density scores. It is suggested that the proposed staging system would improve on its predecessors by allowing classification of a much greater proportion of cases.

Randomized trial of modafinil for treating subjective daytime sleepiness in patients with Parkinson's disease

We assessed the safety and efficacy of modafinil for the treatment of excessive daytime sleepiness in patients with Parkinsons disease (PD). This was a single‐site, randomized, double‐blind, placebo‐controlled crossover study of 21 PD patients having an Epworth Sleepiness Scale (ESS) score ≥10. They received either placebo or modafinil 200 mg/day for 3 weeks, followed by a washout week, then the alternate treatment for 3 weeks. The ESS data demonstrated a carryover effect, so the changes from baseline ESS scores were compared between the two treatments for period 1 only. The ESS scores for the placebo group went from 16.0 ± 4.2 (mean ± SD) to 17.0 ± 5.1 and for the modafinil group went from 17.8 ± 4.2 to 14.4 ± 5.7 (P = 0.039). There was no significant carryover effect for any other measure. The patient Clinical Global Impression of Change (+3 to −3) improved by 0.75 on modafinil compared with 0.15 for placebo (P = 0.07). A total of 7 of 20 (35%) of the patients reported some improvement on modafinil but not placebo. There was no significant improvement or worsening of the UPDRS subscores I–III, Timed Tap test, or time on. Vital signs, electrocardiograms, and lab tests were unchanged. Modafinil was very well tolerated. Our data demonstrate that, in a small sample size, administration of 200 mg/day of modafinil was associated with few side effects and was modestly effective for the treatment of excessive daytime sleepiness in patients with PD.

Myoclonus: current concepts and recent advances

Myoclonus presents as a sudden brief jerk caused by involuntary muscle activity. An organisational framework is crucial for determining the medical significance of the myoclonus as well as for its treatment. Clinical presentations of myoclonus are divided into physiological, essential, epileptic, and symptomatic. Most causes of myoclonus are symptomatic and include posthypoxia, toxic-metabolic disorders, reactions to drugs, storage disease, and neurodegenerative disorders. The assessment of myoclonus includes an initial screening for those causes that are common or easily corrected. If needed, further testing may include clinical neurophysiological techniques, enzyme activities, tissue biopsy, and genetic testing. The motor cortex is the most commonly shown myoclonus source, but origins from subcortical areas, brainstem, spinal, and peripheral nervous system also occur. If treatment of the underlying disorder is not possible, treatment of symptoms is worthwhile, although limited by side-effects and a lack of controlled evidence.

Pathologic findings in prospectively ascertained essential tremor subjects

Objective: To assess pathologic changes in prospectively characterized subjects with essential tremor (ET). Methods: Subjects enrolled in the Sun Health Research Institute Brain and Body Donation Program were examined annually by a movement disorders neurologist, and semiannually by a behavioral neurologist and neuropsychologist. Twenty-four subjects without a prior diagnosis of dementia or other major movement disorder met clinical criteria for ET and came to autopsy. Subjects with mild cognitive impairment (n = 3) were included. These subjects were compared with 21 controls. Brains were examined postmortem according to standardized protocols for assessment of age-related changes and specific pathologic conditions (e.g., Parkinson disease, Alzheimer disease). Results: Subjects had a mean age of 86.2 years and a mean duration of tremor of 11.1 years. Seven subjects had evidence for cerebellar pathology (Purkinje cell loss, cerebellar cortical sclerosis, and proliferation of Bergmann glia). Pigmented neurons were qualitatively depleted in the locus ceruleus in eight subjects and in the substantia nigra in five subjects. Of these, three had Lewy bodies, one subject had brainstem predominant disease, and two had limbic stage. Three subjects had a nonspecific cerebral tauopathy and another met pathologic criteria for progressive supranuclear palsy. However, when compared with controls, only changes in the locus ceruleus and gliosis of the cerebellum remained significant findings. Conclusions: This study supports previous findings of heterogenous pathology in essential tremor (ET). There is an increased frequency of cerebellar gliosis and locus ceruleus depletion. We did not find an increased incidence of Lewy bodies in subjects with ET. GLOSSARY: ET = essential tremor; LB = Lewy body; MCI = mild cognitive impairment; NA = not available; PD = Parkinson disease; PSP = progressive supranuclear palsy; SHRI = Sun Health Research Institute; SN = substantia nigra; WMR = white matter rarefaction.

A randomized, double masked, controlled trial of botulinum toxin type A in essential hand tremor

Objective: To evaluate the safety and efficacy of botulinum toxin type A injection in essential tremor of the hand. Background: Botulinum toxin type A is an effective treatment for dystonia, spasticity, and other movement disorders and has been found to be useful in open-label studies and one double-masked study of essential hand tremor. Methods: One hundred thirty-three patients with essential tremor were randomized to low-dose (50 U) or high-dose (100 U) botulinum toxin type A (Botox) or vehicle placebo treatment. Injections were made into the wrist flexors and extensors. Patients were followed for 16 weeks. The effect of treatment was assessed by clinical rating scales, measures of motor tasks and functional disability, and global assessment of treatment. Hand strength was evaluated by clinical rating and by a dynamometer. Results: Both doses of botulinum toxin type A significantly reduced postural tremor on the clinical rating scales after 4 to 16 weeks. However, kinetic tremor was significantly reduced only at the 6-week examination. Measures of motor tasks and functional disability were not consistently improved with botulinum toxin type A treatment. Grip strength was reduced for the low- and high-dose botulinum toxin type A groups as compared with the placebo group. Adverse reactions consisted mainly of dose-dependent hand weakness. Conclusion: Botulinum toxin type A injections for essential tremor of the hands resulted in significant improvement of postural, but not kinetic, hand tremors and resulted in limited functional efficacy. Hand weakness is a dose-dependent significant side effect of treatment at the doses used in this study.

The Montreal Cognitive Assessment and the Mini-Mental State Examination as Screening Instruments for Cognitive Impairment: Item Analyses and Threshold Scores

Aims: To perform an item analysis of the Montreal Cognitive Assessment (MoCA) versus the Mini-Mental State Examination (MMSE) in the prediction of cognitive impairment, and to examine the characteristics of different MoCA threshold scores. Methods: 135 subjects enrolled in a longitudinal clinicopathologic study were administered the MoCA by a single physician and the MMSE by a trained research assistant. Subjects were classified as cognitively impaired or cognitively normal based on independent neuropsychological testing. Results: 89 subjects were found to be cognitively normal, and 46 cognitively impaired (20 with dementia, 26 with mild cognitive impairment). The MoCA was superior in both sensitivity and specificity to the MMSE, although not all MoCA tasks were of equal predictive value. A MoCA threshold score of 26 had a sensitivity of 98% and a specificity of 52% in this population. In a population with a 20% prevalence of cognitive impairment, a threshold of 24 was optimal (negative predictive value 96%, positive predictive value 47%). Conclusion: This analysis suggests the potential for creating an abbreviated MoCA. For screening in primary care, the MoCA threshold of 26 appears optimal. For testing in a memory disorders clinic, a lower threshold has better predictive value.

Higher sedentary energy expenditure in patients with Huntington's disease

Weight loss is common among patients with Huntingtons disease (HD), although the mechanisms contributing to this phenomenon are not known. We measured 24‐hour sedentary energy expenditure (24‐hour EE) and sleeping metabolic rate (SMR) in a human respiratory chamber in 17 patients with mild to moderate HD and 17 control subjects matched for age, sex, and body mass index. Total energy expenditure was measured during 7 days in free‐living conditions, using the doubly labeled water technique. Body weight, fat mass, and fat‐free mass (measured by dual‐energy x‐ray absorptiometry) were similar in patients with HD and control subjects. Twenty‐four‐hour EE was 14% higher in HD patients than controls in absolute terms (2,038 ± 98 vs 1,784 ± 68 kcal/24 hours) and after adjustment for age, sex, fat mass, and fat‐free mass (1,998 ± 45 vs 1,824 ± 45 kcal/24 hours). In contrast, SMR and total energy expenditure were similar in patients and controls both in absolute terms (1,314 ± 38 vs 1,316 ± 42 and 2,402 ± 102 vs 2,373 ± 98 kcal/24 hours, respectively) and after adjustment. Spontaneous physical activity measured by radar in the chamber and the ratio of 24‐hour EE to SMR were significantly higher in HD patients than controls (11.4 ± 1.4 vs 6.1 ± 0.6% and 1.54 ± 0.05 vs 1.36 ± 0.03, respectively). In the group as a whole, 24‐hour EE/SMR correlated with spontaneous physical activity. Among HD patients, both 24‐hour EE/SMR and spontaneous physical activity correlated with the severity of chorea, but SMR and total energy expenditure did not. There were no differences in reported energy intake during 7 days in patients with HD compared with controls. The results of this study indicate that sedentary energy expenditure is higher in patients with HD than in controls in proportion to the severity of the movement disorder. Total free‐living energy expenditure is not higher, however, because patients with HD appear to engage in less voluntary physical activity. Ann Neurol 2000; 47:64–70

Gambling and increased sexual desire with dopaminergic medications in restless legs syndrome

Objectives: Do patients with restless legs syndrome (RLS) report gambling or other abnormal behaviors as previously reported in Parkinson disease. Methods: This survey study was sent to 261 idiopathic RLS patients, and it included the Gambling Symptoms Assessment Scale, Altman Self-Rating Mania Scale, and questions pertaining to sexual activity and novelty-seeking behaviors. Results: Ninety-nine patients responded to the survey, and 77 were actively taking 1 or more dopaminergic medications. Of the 70 respondents who answered the gambling questions, 5 (7%) noted a change in gambling, with 4 (6%; 95% confidence interval, 2%-14%) stating that increased urges and time spent gambling occurred specifically after the use of dopaminergic medications (2 on pramipexole, 1 on ropinirole, and 1 on levodopa and pramipexole). Increased sexual desire was reported by 4 (5%) of the 77 respondents, 3 (4%; 95% confidence interval, 1%-11%) reported that this occurred specifically after the use of dopaminergic medications (1 on pramipexole, 1 on ropinirole, and 1 on levodopa). One patient reported both an increase in gambling and sexual habits. Conclusions: This exploratory survey study revealed the development of gambling and/or increased sexuality in patients with RLS. These data raise the possibility that, as in Parkinson disease, RLS patients should be cautioned about potential behaviors that may occur with the use of dopaminergic medications. Further prospective studies are needed to assess the relationship between these medications and compulsive behaviors associated with the treatment of RLS.