Determinants of tapping speed in normal control subjects and subjects with Parkinson's disease: differing effects of brief and continued practice.

BACKGROUND: Alternate tapping speed is widely used as a measure of bradykinesia in Parkinson's disease (PD). Tapping speed in normal control subjects and factors that might influence tapping speed have not been systematically examined. OBJECTIVE: To examine the effects of age, hand dominance, and gender on tapping speed in normal control subjects and to compare the effects of practice on tapping speed in normal and PD control subjects. METHODS: Tapping speed for three sequential trials in the dominant and nondominant hand was examined in 100 normal control subjects and 60 subjects with PD. The effect of hourly practice over 26 hours (19 trials) was investigated in 14 normal and 24 PD subjects. RESULTS: The speed with which normal subjects alternately tapped two counters was negatively correlated with age, was greater in the dominant hand, was not related to gender, and improved with short-term practice (three trials) and with continued practice over 26 hours. Parkinsonian subjects, in general, tapped more slowly than normal control subjects and more slowly in the more affected arm. Parkinsonian subjects benefited from short-term practice as much as normal control subjects but, unlike normal control subjects, did not improve with continued practice over 26 hours. CONCLUSIONS: Alternate tapping speed is influenced by age, hand dominance, Parkinson's disease, and practice. Subjects with PD do not benefit as much from continued practice as do normal subjects, suggesting some limitation or impairment of procedural (motor) learning in PD.

Prospective blinded study of the relationship between plasma homocysteine and progression of symptomatic peripheral arterial disease.

PURPOSE: An elevated plasma homocysteine level is an established risk factor for atherosclerotic coronary heart disease (CHD), cerebrovascular disease (CVD), and lower extremity occlusive disease (LED). An elevated plasma homocysteine level can be reduced by therapy with folate and vitamins B6 and B12. An accurate evaluation of the role of vitamin therapy requires knowledge of the influence of plasma homocysteine levels on the progression of CHD, CVD, and LED. METHODS: The Homocysteine and Progression of Atherosclerosis Study is a blinded prospective study of the influence of homocysteine and of other atherosclerotic risk factors on the progression of disease in patients with symptomatic CVD, LED, or both. This study is set in a university hospital vascular surgery clinic and the General Clinical Research Center. Consecutive patients with stable symptomatic CVD or LED underwent baseline clinical, laboratory, and vascular laboratory testing for homocysteine and other risk factors and were examined every 6 months. The primary endpoints were ankle brachial pressure index, duplex scan-determined carotid stenosis, and death. The secondary endpoints were the clinical progressions of CHD, LED, and CVD. The hypothesis that was tested was whether the progression of symptomatic CVD or LED was more frequent or more rapid in patients with elevated plasma homocysteine levels. plasma homocysteine levels. RESULTS: After a mean follow-up period of 37 months (range, 1 to 78 months) for deaths from all causes (>14 micromol/L; elevated, 18.6%; normal, 9.4%; P = .022), deaths from cardiovascular disease (elevated, 12.5%; normal, 6.3%; P = .05) and the clinical progression of CHD (highest 20% of homocysteine levels, 80%; lowest 20% of homocysteine levels, 39%; P = .007) were significantly more frequent or more rapid by life-table analysis when the homocysteine levels were elevated. Multivariate Cox proportional hazards regression model showed a significant independent and increasing relationship between the plasma homocysteine levels and the time to death (relative risk for highest one third of homocysteine values, 1.6; 95% confidence interval [CI], 1.04 to 2.56; P = 029; and relative risk for highest one fifth of homocysteine values, 3.13; 95% CI, 1.69 to 6.64; P = .0001). After an adjustment for age, smoking, hypertension, diabetes, cholesterol, and the vascular laboratory progression of CVD or LED, each 1.0 micromol/L increase in the plasma homocysteine levels resulted in a 3.6% increase (95% CI, 0.0% to 6.6%; P = .06) in the risk of death (all causes) at 3 years and a 5.6% increase (95% CI, 2.2% to 8.5%; P = .003) in the risk of death from cardiovascular disease. CONCLUSION: We conclude that elevated plasma homocysteine levels are associated significantly with death, with death from cardiovascular disease, and with the progression of CHD in patients with symptomatic CVD or LED. These results strongly mandate clinical trials of homocysteine-lowering vitamin therapy in such patients.

Manufacturers' distribution of drug samples to a family medicine clinic.

The distribution of drug product samples by pharmaceutical companies to a family medicine clinic was studied. Data on all deliveries of drug samples to the clinic site of a university-affiliated family medicine residency program from November 1992 through December 1993 were collected. In addition, the 11 faculty family physicians were surveyed about their experiences with the deliveries of samples. Forty-three manufacturers delivered samples of 331 drugs during the 14-month study period. There were 366 visits by the drug company representatives, who made 1117 separate deliveries. The total value of the samples, based on the average whole-sale price, was $240,782. Twenty-nine percent of the drugs were nonformulary, and only 49% were stocked by the pharmacy. The physicians surveyed indicated that they were either usually or always asked to sign for samples they did not in fact request, that they usually did not know what was recorded on the receipts for samples that they signed, and that they seldom verified what was actually delivered. Pharmaceutical manufactures delivered large quantities of drug samples during the study period, and many of the drugs were nonformulary or not stocked by the pharmacy. The physicians indicated that they were not well informed about delivered samples for which they signed receipts.