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Biomedical subjects

E D Louis

Publications and source records attributed to E D Louis.

At least 19 recordsLinked to original sources
PubMed2005

Blood harmane concentrations and dietary protein consumption in essential tremor.

BACKGROUND: Beta-carboline alkaloids (e.g., harmane) are highly tremorogenic chemicals. Animal protein (meat) is the major dietary source of these alkaloids. The authors previously demonstrated that blood harmane concentrations were elevated in patients with essential tremor (ET) vs controls. Whether this difference is due to greater animal protein consumption by patients or their failure to metabolize harmane is unknown. OBJECTIVE: The aim of this study was to determine whether patients with ET and controls differ with regard to 1) daily animal protein consumption and 2) the correlation between animal protein consumption and blood harmane concentration. METHODS: Data on current diet were collected with a semiquantitative food frequency questionnaire and daily calories and consumption of animal protein and other food types was calculated. Blood harmane concentrations were log-transformed (logHA). RESULTS: The mean logHA was higher in 106 patients than 161 controls (0.61 +/- 0.67 vs 0.43 +/- 0.72 g(-10)/mL, p = 0.035). Patients and controls consumed similar amounts of animal protein (50.2 +/- 19.6 vs 49.4 +/- 19.1 g/day, p = 0.74) and other food types (animal fat, carbohydrates, vegetable fat) and had similar caloric intakes. In controls, logHA was correlated with daily consumption of animal protein (r = 0.24, p = 0.003); in patients, there was no such correlation (r = -0.003, p = 0.98). CONCLUSIONS: The similarity between patients and controls in daily animal protein consumption and the absence of the normal correlation between daily animal protein consumption and logHA in patients suggests that another factor (e.g., a metabolic defect) may be increasing blood harmane concentration in patients.

Aged↗
PubMed2005

Practice parameter: therapies for essential tremor [RETIRED]: 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.

Adrenergic beta-Antagonists↗
PubMed2005

Association between mild parkinsonian signs and mild cognitive impairment in a community.

BACKGROUND: Mild parkinsonian signs (MPS) are associated with prevalent and incident dementia but it is not known whether they are associated with mild cognitive impairment (MCI). OBJECTIVE: To determine whether MPS and specific MPS (changes in axial function, rigidity, tremor) are associated with MCI in nondemented community-dwelling older people in northern Manhattan, NY. METHODS: Participants underwent neurologic assessment, including a modified motor portion of the Unified Parkinson Disease Rating Scale. MCI was diagnosed in nondemented participants who had cognitive impairment based on neuropsychological testing and no functional impairment. Participants with MCI were classified as having MCI with memory impairment (MCI+M) vs MCI without memory impairment (MCI-M). RESULTS: MCI was present in 608 (27.3%) of 2,230 participants, including 255 participants with MCI+M and 353 with MCI-M; 1,622 participants did not have MCI. MPS were present in 369 (16.5%) of 2,230 participants. In a univariate logistic regression model, odds of MCI+M (vs no MCI) were 51% higher in participants with MPS compared to those with no MPS (OR = 1.51, 95% CI = 1.09 to 2.09, p = 0.01). Multivariate models yielded similar results (OR = 1.45, 95% CI = 1.03 to 2.05, p = 0.03). Rigidity was present in a higher proportion of participants with MCI+M compared to participants without MCI. CONCLUSIONS: Mild parkinsonian signs, especially rigidity, are associated with amnestic mild cognitive impairment. Mild parkinsonian signs and mild cognitive impairment may share similar pathogeneses. Whether this involves Alzheimer-type pathology, Lewy bodies, or vascular changes in the basal ganglia or basal ganglia circuitry deserves further investigation in postmortem studies.

Age Factors↗
PubMed2004

Essential tremor: occupational exposures to manganese and organic solvents.

Occupational exposures to manganese and organic solvents cause parkinsonism as well as prominent action tremor, resembling essential tremor (ET), yet their association with ET has not been studied. These chemicals cause cerebellar pathology. Cerebellar changes have been linked with ET. Using lifetime occupational histories, the authors demonstrated that occupational exposures were similar in cases and controls, which does not support an etiologic link between occupational exposures to these chemicals and ET.

Aged↗
PubMed2004

Incidence of Parkinson disease and parkinsonism in three elderly populations of central Spain.

BACKGROUND: A two-phase investigation method (screening followed by detailed examination) is the most accurate epidemiologic approach to estimate the epidemiology of Parkinson disease (PD) and secondary parkinsonism. The scarcity of statistics on the incidence of PD and other types of parkinsonism using this methodology led the authors to estimate them in three elderly populations. METHODS: A Spanish elderly parkinsonism-free cohort was followed for an average of 3 years. At the end of the follow-up, the cohort survivors were contacted by way of screening and clinical examination. RESULTS: The cohort consisted of 5,160 subjects (ages 65 to 85 and over): Eight hundred twenty-eight died before the examination, 3,685 completed the screening procedure, and 647 could not be screened because they refused (108) or were unreachable (539). Sixty-eight incident cases of parkinsonism were found: 30 PD (44.1%), 22 drug-induced parkinsonism (32.3%), 8 parkinsonism with associated features (11.7%), and 3 vascular parkinsonism (4.4%). The remaining five cases (7.3%) were classified as unspecified parkinsonism. Average annual incidence rate (per 100,000 person-years) in the population aged 65 to 85 and over years, adjusted to the standard European population, was 409.9 (95% CI 299.0 to 520.8) for parkinsonism and 186.8 (95% CI 110.4 to 263.2) for PD. Incidence rates of parkinsonism increased with advancing age. For PD, incidence rates increased with age in men but decreased beyond the age of 79 in women. Age-adjusted relative risk in men compared with women was 1.56 (95% CI 0.97 to 2.51) for parkinsonism and 2.55 (95% CI 1.21 to 5.37) for PD. Sixteen (53.3%) patients with PD were detected through the screening and had not been diagnosed previously. CONCLUSIONS: Incidence estimates of PD based on two-phase investigation methodology are higher than those based on other approaches. Men had a risk of developing PD that was twice that of women. A large proportion of PD patients may never seek neurologic attention.

Aged↗
PubMed2004

Neurosyphilis masquerading as corticobasal degeneration.

We report on a patient with a syndrome resembling corticobasal ganglionic degeneration (CBD), including slight cognitive impairment, asymmetric akinesia, rigidity with myoclonus, and arm levitation, which can be one of the features of alien limb phenomenon; however, further diagnostic testing was consistent with neurosyphilis. Syphilis, "the great imitator," may also masquerade as CBD. Because neurosyphilis is treatable, it should be considered in the workup of patients with cognitive impairment and motor signs of CBD.

Atrophy↗
PubMed2004

Personality in essential tremor: further evidence of non-motor manifestations of the disease.

OBJECTIVE: To ascertain whether patients with essential tremor have distinct definable personality traits. METHODS: A case-control study of patients with essential tremor was carried out to look for differences in personality characteristics. The controls were derived from the same source population. Using the tridimensional personality questionnaire (TPQ), personality traits were assessed in three dimensions: harm avoidance (HA), novelty seeking (NS), and reward dependence (RD). Additional analyses were conducted to address the possibility of selection bias among the patients with essential tremor. RESULTS: There were 55 patients and 61 controls. There was a difference between patients and controls in HA subscale scores (p = 0.005) but not in NS or RD scores. The difference remained significant in analyses that adjusted for age, sex, race, and education (p = 0.005). HA subscale scores did not correlate with subjective or objective measures of disability or with indices of severity of tremor. CONCLUSIONS: Patients with essential tremor scored higher on the harm avoidance subscale scores than control subjects. HA subscale scores did not correlate with the severity of tremor or with subjective and objective scales of disability, suggesting that the personality profile observed was not entirely related to functional disability caused by the tremor. Longitudinal studies of personality in essential tremor are needed to characterise the stability and evolution of these personality traits within the natural history of the disease process.

Aged↗
PubMed2003

Prevalence of essential tremor: door-to-door neurologic exams in Mersin Province, Turkey.

Estimates of the prevalence of essential tremor (ET) are probably low because screening questionnaires have been used. The authors estimated the prevalence of ET in Mersin Province, Turkey, in 2,253 individuals aged >or=40 years, all of whom were examined by study neurologists. There were 89 ET cases (prevalence = 4.0%, 95% CI = 3.2 to 4.8%). The prevalence of ET may be higher than previously estimated. This is important when defining the extent of the health care problem.

Adult↗
PubMed2003

Objective assessments of longitudinal outcome in Gilles de la Tourette's syndrome.

OBJECTIVE: To define the long-term outcome in Gilles de la Tourette syndrome (GTS) using objective rating measures. BACKGROUND: Previous historical studies suggest spontaneous improvement of tic symptoms after adolescence, but objective longitudinal data are limited. METHODS: The authors reviewed all videotapes in their database (1978 through 1991) of children with GTS (ages 8 to 14) who were seen in their tertiary care movement disorder center and underwent a standardized 5-minute filming protocol (n = 56). Through multiple contact methods, they successfully located 36 of these patients, who are now adults (age >20 years), and recruited 31 (28 men and 3 women) to volunteer for a second videotape and in-person assessment. A blinded rater evaluated the 62 tapes and rated five tic domains: body areas involved, motor and phonic tic frequency, and motor and phonic tic severity. Using standardized GTS videotape rating scale and Wilcoxon signed-rank tests with Bonferroni correction for multiple comparisons, the authors compared the two videotapes for each tic domain as well as the composite tic disability score. RESULTS: Ninety percent of adult patients still had tics. Adult patients who considered themselves tic-free were often inaccurate in their self-assessment: 50% had objective evidence of tics. Mean objective tic disability diminished in comparison to childhood (mean composite tic disability score childhood 9.58 vs adulthood 7.52, p = 0.014). All domains improved by adulthood, and significant improvements occurred in motor tic severity (p = 0.008). The improvements in tic disability did not relate to medication use, as only 13% of adults received medications for tics, compared with 81% of children. CONCLUSIONS: In GTS syndrome, tics objectively improve over time but most adults have persistent tics.

Adolescent↗
PubMed2003

Risk of action tremor in relatives of tremor-dominant and postural instability gait disorder PD.

BACKGROUND: Action tremor may be more prevalent in relatives of patients with Parkinson's disease (PD) than in relatives of control subjects. This tremor could represent mild PD or essential tremor. An estimate of the risk of this condition in families of patients with PD is important when studying the genetics of PD. OBJECTIVE: S: To determine the risk of action tremor in first-degree relatives of probands with tremor-dominant PD (TD-PD) and postural instability gait disorder PD (PIGD-PD) compared with first-degree relatives of control probands. METHODS: PD and control probands participated in a familial aggregation study of PD. The presence of action tremor in their relatives was ascertained from reports of one or more informants. Relatives who met diagnostic criteria for PD were excluded. Cox proportional hazards models adjusting for gender, education, race, and vital status (dead vs alive) of the relatives were used to assess the relative risk (RR) of action tremor in first-degree relatives of PD probands vs first-degree relatives of control probands. RESULTS: There were 487 PD probands, 409 control probands, and 5,563 relatives. The risk of action tremor was higher in the relatives of TD-PD probands than in the relatives of control probands (RR = 2.14; 95% CI = 1.53 to 2.98) but not in the relatives of PIGD-PD probands compared with the relatives of control probands (RR = 1.81; 95% CI = 0.66 to 5.02). CONCLUSION: The risk of action tremor was increased in the relatives of PD probands, particularly when they had TD-PD. Whether the tremor in these relatives represents essential tremor or an isolated manifestation of PD requires further investigation.

Comorbidity↗
PubMed2003

Accuracy of family history data on Parkinson's disease.

BACKGROUND: Genetic studies of PD frequently rely on family history interviews (FHI), yet the accuracy of data obtained in this way is unclear. OBJECTIVE: To assess the interinformant reliability and validity of family history information on PD in first-degree relatives of PD cases and controls. METHODS: A structured FHI was administered to nondemented PD cases and controls and to a second informant (self-report, sibling or child of the subject) for each relative. Interinformant agreement was assessed on four algorithm-derived diagnostic categories of PD: definite, definite or probable, definite, probable or possible ("conservative diagnosis"); or definite, probable, possible, or uncertain ("liberal diagnosis"). The sensitivity and specificity of each diagnostic category were assessed, using as the gold standard diagnoses based on either in-person examination or medical record review. RESULTS: Five hundred thirty-six families containing 2,225 first-degree relatives were included in the interinformant reliability study. Agreement between informants was excellent for definite or probable PD for all three pairwise comparisons: proband vs self-report (kappa = 0.92), proband vs sibling of subject (kappa = 0.80), and proband vs child of subject (kappa = 0.87). Agreement was also good to excellent for the conservative diagnosis (kappa = 0.66, 0.49, and 0.79). In the validity analysis (141 individuals in 96 families), the conservative diagnosis provided the best combination of sensitivity (95.5%) and specificity (96.2%) for the proband's family history report. No difference was apparent across categories defined by case or control status, relationship to the proband, or gender or age at onset of the proband. However, specificity was lower for deceased relatives than for living relatives. CONCLUSION: The FHI can be used to obtain reliable and valid family history information on PD in first-degree relatives when a conservative diagnostic algorithm is applied.

Algorithms↗
PubMed2003

The impact of comorbid disease and injuries on resource use and expenditures in parkinsonism.

BACKGROUND: Persons with parkinsonism have high rates of both associated and unrelated prevalent comorbid conditions. A better understanding of patterns of care and expenditures may aid in designing programs to enhance functioning, lengthen independent living, and manage costs. METHODS: The authors linked national survey data of 24,831 elderly to nearly 1.9 million Medicare claims. Persons with parkinsonism (n = 791) were identified from survey or Medicare encounters for paralysis agitans. Comorbid disease risk was measured using age-adjusted OR with 95% CI. Comorbidity cost ratios (ratio of average per person per year charges for parkinsonism alone vs with comorbid conditions) were developed to describe incremental costs of comorbidities. RESULTS: Patients with parkinsonism were older (78.5 +/- 7.6 vs 75.1 +/- 8.3 years, p < 0.0001) and had more injuries resulting in broken bones (35.6% vs 19.5%, p < 0.0001), including broken hips (15.9% vs 5.8%, p < 0.0001), during the 5-year study. Broken hips were more prevalent among men (OR 3.4, 95% CI 2.5 to 4.8) and women (OR 2.5, 95% CI 2.1 to 3.1) with than without parkinsonism. Among those with parkinsonism, comorbidity cost ratios demonstrated two- to threefold higher charges for dementia, broken bones, broken hip, and diabetes. CONCLUSIONS: Comorbidity associated with parkinsonism is an under-recognized contribution to higher resource use and expenditures. Further study of injuries, dementia, and diabetes is required to assess whether public health interventions could reduce excess morbidity and expenditures associated with parkinsonism.

Aged↗
PubMed2002

Elevation of blood beta-carboline alkaloids in essential tremor.

BACKGROUND: beta-Carboline alkaloids are normal body constituents but are also potent tremor-producing chemicals that are naturally present in the food chain. OBJECTIVE: To explore the hypothesis that high concentrations of beta-carboline alkaloids are associated with essential tremor (ET). METHODS: One hundred cases and 100 controls were frequency matched on age, sex, and ethnicity. Blood concentrations of harmane and harmine were quantified by high-performance liquid chromatography, blinded to clinical information. RESULTS: The mean log blood concentration of harmane was higher in cases than controls (0.72 +/- 0.53 vs 0.51 +/- 0.64 g(-10)/mL; p = 0.01). A nonparametric test on nontransformed data (median harmane = 5.21 g(-10)/mL in cases and 2.28 g(-10)/mL in controls) confirmed this difference (p = 0.005). The mean log blood concentration of harmine was 0.20 +/- 0.48 g(-10)/mL in cases and 0.10 +/- 0.65 g (-10)/mL in controls (p = 0.20). Log harmane concentrations were stratified based on the median value; 62% of cases vs 39% of controls had a high log harmane concentration (p = 0.001). Mean log harmane concentration was similar in the cases with (0.74 +/- 0.58 g(-10)/mL) and without (0.71 +/- 0.50 g(-10)/mL) an affected relative (p = 0.83). CONCLUSIONS: Blood concentrations of harmane were measured in ET cases compared with controls. Concentrations were elevated in cases with and without a family history of ET.

Aged↗
PubMed2002

The association of incident dementia with mortality in PD.

OBJECTIVE: To evaluate the association of incident dementia with mortality in a cohort of patients with idiopathic PD who were nondemented at baseline evaluation, controlling for extrapyramidal sign (EPS) severity at each study visit. BACKGROUND: The development of dementia has been associated with reduced survival in PD. Because EPS severity is associated with both dementia and mortality in PD, the association of dementia with mortality may be confounded by disease severity. METHODS: A cohort of patients with PD was followed annually with neurologic and neuropsychological evaluations. The association of incident dementia and the total Unified PD Rating Scale (UPDRS) motor score with mortality in PD was examined using Cox proportional hazards models with time-dependent covariates. All analyses were adjusted for age at baseline, sex, years of education, ethnicity, and duration of PD. RESULTS: Of 180 PD patients, 41 (22.8%) died during a mean follow-up period of 3.9 +/- 2.2 years. Among those who died during the study period, 48.8% (20 of 41) became demented during follow-up, as compared to 23.0% (32 of 139) of those who remained alive. Both incident dementia (RR: 2.2, 95% CI: 1.1 to 4.5, p = 0.04) and the total UPDRS motor score at each study visit (RR: 1.04, 95% CI: 1.02 to 1.07, p = 0.001) were associated with mortality in PD when included in the same Cox model. CONCLUSIONS: Incident dementia has an independent effect on mortality when controlling for EPS severity. The development of dementia is associated with a twofold increased mortality risk in PD.

Aged↗
PubMed2001

Toxicokinetics of tremorogenic natural products, harmane and harmine, in male Sprague-Dawley rats.

Tremorogenic beta-carboline alkaloids are present in foodstuffs and beverages. Acute exposure to beta-carboline derivatives causes severe tremor; however, the disposition of these dietary contaminants remains unclear. This study was performed to evaluate toxicokinetics of harmane and harmine, two major beta-carboline alkaloids, in rats. Blood concentrations of both toxicants were quantified by high-performance liquid chromatography (HPLC). Following an intravenous injection (0.5 mg/kg), the concentration-time profiles of harmane or harmine fit well with a two-compartment model. While both compounds had comparable elimination t 1/2beta (24 and 26 min for harmane and harmine, respectively), the systemic clearance (CLs) for harmine (103.2 ml/kg/ml) was two times greater than that for harmane (52.2 ml/kg/ml). Accordingly, the area under the blood concentration-time curve (AUC) in harmane-treated rats was 2.7-fold greater than that in harmine-treated rats. Harmine appeared to distribute to tissues better than harmane, with a larger volume of distribution (V,d) (3.9 and 1.6 L/kg for harmine and harmane, respectively). After an oral dose (20 mg/kg), the absolute bioavailability (F) was 19% for harmane and 3% for harmine. Harmane was absorbed more slowly (lower Ka), yet more completely (higher Cmax' AUC, and F) than harmine. An oral administration of harmane resulted in blood harmine whose formation accounted for 13% of the ingested harmane, indicating a biotransformation of harmane to harmine. These results suggest that harmane is absorbed into the systemic circulation more completely than harmine. Upon entering the body, harmane can be metabolized to form harmine; the latter may better distribute to the tissue compartment.

Administration, Oral↗
PubMed2001

A pilot tolerability and efficacy study of levetiracetam in patients with chronic myoclonus.

Levetiracetam was recently approved as adjunctive therapy for partial onset seizures. The authors conducted an open-label trial of levetiracetam in eight patients with chronic myoclonus. Patients were assessed by using the Unified Myoclonus Rating Scale. Levetiracetam was well tolerated. Three of five patients with cortical myoclonus experienced reductions in their myoclonus scores, providing support for a larger, placebo-controlled trial in cortical myoclonus.

Adult↗