Biomedical subjects

Elan D Louis

Publications and source records attributed to Elan D Louis.

82 records · Page 5Linked to original sources

PubMed2002

Body mass index in essential tremor.

BACKGROUND: The pathogenesis of essential tremor (ET) is unknown, but it could be neurodegenerative. Weight loss has been observed in patients with neurodegenerative diseases. OBJECTIVES: To compare body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) in ET cases and controls and to determine whether BMI is correlated with tremor severity and duration. METHODS: Patients with ET were ascertained from the Neurological Institute of New York, New York, NY. Control subjects were recruited from 2 studies at the same institution. Height and weight were measured and BMI was calculated. Dietary data were collected using a Willett Semi-Quantitative Food-Frequency Questionnaire. Tremor severity was assessed using a clinical scale and the Klove Matthews Motor Steadiness Battery. RESULTS: The 78 cases and 242 controls were of similar age. Mean (SD) BMI in cases vs controls was 26.5 (5.0) vs 28.2 (4.8) (P =.008). This difference remained significant in an unconditional linear regression analysis that adjusted for age, sex, ethnicity, and years of education (P =.02). Mean daily caloric intake was similar in cases and controls. In cases, BMI was negatively correlated with both measures of tremor severity (r = -0.22; P =.05 and r = -0.24; P =.03) and with tremor duration (r = -0.22; P =.05). CONCLUSIONS: The BMI was lower in ET cases than in controls, and lower BMI was associated with disease of greater severity and longer duration. Caloric intake did not differ between groups, suggesting that lower BMI is not due to a reduction in calories. Lower BMI may be due to increased energy expenditure in ET.

Aged↗

PubMed2002

Vaccines to treat encephalitis lethargica: human experiments at the Neurological Institute of New York, 1929-1940.

BACKGROUND: Encephalitis lethargica, first observed in 1915, became a pandemic. Because of its presumed infectious basis, there were early attempts to treat it with vaccines. The history of the use of these vaccines has not been analyzed. OBJECTIVE: To document the use of vaccines to treat patients with encephalitis lethargica, and, more specifically, the 1000 patients whose treatments took place with the support of the William J. Matheson Commission at the Neurological Institute of New York, NY (1929-1940). MATERIALS AND METHODS: Archival materials were analyzed, including the files of the Matheson Commission and the medical records of patients evaluated at the Neurological Institute of New York. RESULTS: Two primary vaccines were used to combat encephalitis lethargica. The Rosenow vaccine was based on clinical and experimental evidence suggesting that the causative agent was Streptococcus viridans. The Levaditi C (later Gay F) vaccine was based on evidence that herpes simplex virus was the cause. During a therapeutic study conducted from 1929 through 1940, 1000 patients received treatment. Assessing therapeutic efficacy was problematic, but the Gay vaccine was considered more effective. CONCLUSIONS: Because of its presumed infectious basis, several vaccines were used to treat encephalitis lethargica, with the study at the Neurological Institute constituting the largest organized therapeutic attempt. Many of today's standard clinical trial methods were not practiced, which made it difficult to determine efficacy.

Academies and Institutes↗

PubMed2002

Combined effect of age and severity on the risk of dementia in Parkinson's disease.

Age and severity of extrapyramidal signs have been consistently associated with incident dementia in Parkinson's disease. We evaluated the separate and combined effects of age and severity of extrapyramidal signs on the risk of incident dementia in Parkinson's disease in the setting of a population-based prospective cohort study. Age and the total Unified Parkinson's Disease Rating Scale motor score at baseline evaluation were dichotomized at the median. Four groups of Parkinson's disease patients were defined: younger age/low severity (reference), younger age/high severity, older age/low severity, and older age/high severity. Risk ratios for incident dementia were calculated with Cox proportional hazards models controlling for gender, education, ethnicity, and duration of Parkinson's disease. Of 180 patients, 52 (28.9%) became demented during a mean follow-up period of 3.6 +/- 2.2 years. The median age at baseline of the Parkinson's disease patients was 71.8 years (range, 38.5-95.9 years), and the median total Unified Parkinson's Disease Rating Scale motor score was 24 (range, 2-65). The group with older age/high severity had a significantly increased risk of incident dementia (relative risk, 9.7; 95% confidence interval, 3.9-24.4) compared with the group with younger age/low severity (reference), whereas the groups with older age/low severity (relative risk, 1.6; 95% confidence interval, 0.5-4.8) and younger age/high severity (relative risk, 1.2; 95% confidence interval, 0.5-3.2) did not. These findings suggest that the increased risk of incident dementia in Parkinson's disease associated with age and severity of extrapyramidal signs is related primarily to their combined effect rather than separate effects.

Adult↗

PubMed2002

Is essential tremor predominantly a kinetic or a postural tremor? A clinical and electrophysiological study.

Both postural and kinetic tremors may occur in essential tremor (ET), however the relative contribution of each is not clear. ET has been variably defined with respect to kinetic and postural tremors. To examine the relative severity of postural and kinetic tremors in ET, 50 ET cases from a clinic and 55 from a community underwent a videotaped tremor examination. Kinetic and postural tremors were rated using a validated clinical rating scale (score range, 0-3). Thirty-one cases also underwent accelerometry to precisely quantify tremor amplitude. In clinic cases, the mean postural tremor rating was 1.25 (S.D., 0.89). The mean kinetic tremor rating was 52% higher (1.90; S.D., 0.57; P < 0.001). The community cases had similar characteristics. Sixty percent of the 105 cases had postural tremor ratings scoring 0 or 1 (no tremor or low amplitude, intermittent tremor). In clinic cases, the mean amplitude of postural tremor during tremor analysis was 0.51 mm (S.D., 0.66 mm), and the mean amplitude of kinetic tremor was 2.91 mm (S.D., 2.11 mm; P < 0.01). Similar values were obtained for community cases. These quantitative data suggest that kinetic tremor is more severe than postural tremor in ET. The majority of cases had mild or absent postural tremor. Despite this, ET is defined only as a postural tremor in many studies. Our data argue for a more consistent inclusion of kinetic tremor in diagnostic criteria for ET.

Aged↗

PubMed2002

Survey of essential tremor patients on their knowledge about the genetics of the disease.

A group of essential tremor (ET) patients were surveyed on their knowledge of the genetics of ET in order to provide important information to clinicians who care for and educate patients about this disease. ET patients were ascertained from neurologists at Columbia-Presbyterian Medical Center. A 5- to 10-minute survey was administered to assess knowledge of the genetics of ET. Fifty ET patients had been living with their disease for a mean of 24.2 years. Approximately half (n = 27) reported a family history of ET. When asked, "What causes ET," 12 (24%) replied that it was "hereditary." Even among the 27 who reported a family history, only 25.9% replied that it was "hereditary." A minority of patients (12 [24%]) thought that it was "very likely" that other members of their family would develop the disease some day. Three patients were aware that genetic linkage had been established. Our findings suggest that the majority of patients with ET are not well informed about the genetic basis for the disease. Because of recent advances in genetic research, physicians may need to incorporate more genetic information and education into their practice, including information on risk to other family members and genetic testing. It is hoped that these survey results could be used to improve patient education and to provide clinicians with further insight into patients' perspectives.

Adult↗

PubMed2002

Do risk factors for Alzheimer's disease predict dementia in Parkinson's disease? An exploratory study.

The extent to which concomitant Alzheimer's disease (AD) is etiologically related to the development of dementia in Parkinson's disease (PD) remains controversial. We explored the association of four risk factors associated with AD, including head injury, smoking, hypertension, and diabetes mellitus, with incident dementia in PD. A cohort of 180 nondemented PD patients from the Washington Heights community in northern Manhattan, New York, completed a risk factor questionnaire at baseline and was followed annually with neurological and neuropsychological evaluations. The association of baseline variables with incident dementia was analyzed by using Cox proportional hazards models. All analyses controlled for age at baseline, gender, years of education, duration of PD, and total Unified Parkinson's Disease Rating Scale (UPDRS) motor score at baseline. Of 180 patients (mean age, 71.0 +/- 10.3 years), 52 (29%) became demented during a mean follow-up period of 3.6 +/- 2.2 years. Head injury risk ratio ([RR] 0.9; 95% confidence interval [CI], 0.4-2.2; P = 0.9), hypertension (RR, 0.7; 95% CI, 0.4-1.4, P = 0.3), and diabetes mellitus (RR, 0.8; 95% CI, 0.3-2.3; P = 0.7) were not significantly associated with incident dementia in the Cox models. Patients who reported having ever smoked were at increased risk for the development of dementia compared with nonsmokers (RR, 2.0; 95% CI, 1.0-3.9; P = 0.05). Current smoking was significantly associated with incident dementia (RR, 4.5; 95% CI, 1.2-16.4; P = 0.02), whereas past smoking approached significance (RR, 1.9; 95% CI, 0.9-3.7; P = 0.07). Although an inverse association between smoking and PD has been reported in several studies, our study showed a positive association between smoking and dementia in the setting of PD. The association of smoking with incident dementia in PD deserves further study.

Aged↗

PubMed2002

Levetiracetam in the treatment of paroxysmal kinesiogenic choreoathetosis.

Anticonvulsants are frequently used in the treatment of paroxysmal kinesiogenic choreoathetosis (PKC). Although they are often extremely effective in eliminating paroxysmal movements, short- and long-term side-effects may limit their use in young patients. Levetiracetam (Keppra), a novel antiepileptic drug approved for the treatment of partial seizures is well tolerated in patients with epilepsy. We report on the use of levetiracetam in the treatment of PKC. Levetiracetam was effective in eliminating paroxysmal events and should be considered as an alternative to standard antiepileptic medications in this disorder.

Adult↗

PubMed2002

Diagnosing Parkinson's disease using videotaped neurological examinations: validity and factors that contribute to incorrect diagnoses.

Field work is commonly required in movement disorders research. Sending neurologists into the field can be logistically challenging and costly. Alternatively, neurological examinations may be videotaped and reviewed later. There is little knowledge of the validity of the videotaped neurological examination in the diagnosis of Parkinson's disease (PD). We examined the validity of the videotaped Unified Parkinson's Disease Rating Scale (UPDRS) motor examination in the diagnosis of PD, and sought to determine which factors are associated with incorrect diagnoses. PD patients and controls were enrolled in a familial aggregation study between August of 1998 and June of 2000, and as part of that study each was examined by a physician who performed an in-person UPDRS motor examination. Each also underwent a second, videotaped UPDRS motor examination. Based on the review of this videotape, a neurologist, who was blinded to the previous clinical diagnosis, assigned a diagnosis of PD or normal. A total of 211 of 231 PD patients (sensitivity = 91.3%), and 170 of 172 controls (specificity = 98.8%) were correctly identified based on the videotape. True positives had a higher mean rest tremor score (1.7 vs. 0.3; P < 0.001), action tremor score (0.9 vs. 0.3; P < 0.001), bradykinesia score (11.2 vs. 7.4; P = 0.02), and disease of longer mean duration (8.9 vs. 5.8 years; P = 0.001) than false negatives. False negatives did not differ from true positives in terms of age, total dose of levodopa, Hoehn and Yahr score, or rigidity, gait and posture, or facial masking scores (each assessed during the in-person examination). The videotaped UPDRS motor examination is a useful means of diagnosing PD and provides an alternative approach for the diagnosis of PD in field studies. A limitation is that patients with milder PD of shorter duration may not be recognized as PD.

Adult↗

PubMed2002

Memory and executive function impairment predict dementia in Parkinson's disease.

We analyzed the association of neuropsychological test impairment at baseline with the development of dementia in idiopathic Parkinson's disease (PD) patients. A cohort of nondemented PD patients from northern Manhattan, NY was followed annually with neurological and neuropsychological evaluations. The neuropsychological battery included tests of verbal and nonverbal memory, orientation, visuospatial ability, language, and abstract reasoning. The association of baseline neuropsychological tests scores with incident dementia was analyzed using Cox proportional hazards models. The analysis controlled for age, gender, education, duration of PD, and the total Unified Parkinson's Disease Rating Scale motor score at baseline. Forty-five out of 164 patients (27%) became demented during a mean follow-up of 3.7 +/- 2.3 years. Four neuropsychological test scores were significantly associated with incident dementia in the Cox model: total immediate recall (RR: 0.92, 95% CI: 0.87-0.97, P = 0.001) and delayed recall (RR: 0.73, 95% CI: 0.59-0.91, P = 0.005) of the Selective Reminding Test (SRT), letter fluency (RR: 0.87, 95% CI: 0.77-0.99, P = 0.03), and Identities and Oddities of the Mattis Dementia Rating Scale (RR: 0.85, 95% CI: 0.73-0.98, P = 0.03). When the analysis was performed excluding patients with a clinical dementia rating of 0.5 (questionable dementia) at baseline evaluation, total immediate recall and delayed recall were still predictive of dementia in PD. Our results indicate that impairment in verbal memory and executive function are associated with the development of dementia in patients with PD.

Aged↗

PubMed2002

Erb and Westphal: simultaneous discovery of the deep tendon reflexes.

Although the deep tendon reflexes (DTRs) were first introduced simultaneously into the medical literature by Erb and Westphal (1875), there is some evidence that the knee jerk response was well known to laymen prior to that time. Erb wrote that while he was not calling attention to anything new, he realized the utility of the phenomenon in diagnosing certain disease states. Erb viewed the phenomenon more clearly as a true reflex arc, whereas Westphal interpreted it as a local muscle phenomenon. By 1885, the maneuver was used in Europe and across the Atlantic in America. By then, the DTRs had become one of the cardinal features of the neurological examination.

History, 19th Century↗