Background:Withania somnifera is an herbal medicine that has been known to possess memory-enhancing properties. The current study involved an assessment of cognitive and psychomotor effects of Withania somnifera extract in healthy human participants.Materials and Methods:In this prospective, double-blind, multi-dose, placebo-controlled, crossover study, 20 healthy male participants were randomized to receive 250 mg two capsules twice daily of an encapsulated dried aqueous extract of roots and leaves of Withania somnifera or a matching placebo for a period of 14 days. Cognitive and psychomotor performance was assessed pre-dose (day 1) and at 3 hrs post-dose on day 15 using a battery of computerized psychometric tests. After a washout period of 14 days, the subjects crossed-over to receive the other treatment for a further period of 14 days as per prior randomization schedule. Same battery of test procedures were performed to assess cognitive and psychomotor performance.Results:Significant improvements were observed in reaction times with simple reaction, choice discrimination, digit symbol substitution, digit vigilance, and card sorting tests with Withania somnifera extract compared to placebo. However, no effect can be seen with the finger tapping test.Conclusion:These results suggest that Withania somnifera extract can improve cognitive and psychomotor performance and may, therefore, be a valuable adjunct in the treatment of diseases associated with cognitive impairment.
Background:The Stroop paradigm evaluates susceptibility to interference and is sensitive to dysfunction in frontal lobes and drug effects. The aim of the present study was to establish a simple and reliable computerized version of Stroop color-word test, which can be used for screening of various psychotropic drugs.Materials and Methods:The standardized method was followed in all cases, by recording the reaction time (RT) in msec in 24 healthy participants using computerized version of Stroop color-word test. Reproducibility of the test procedure was evaluated by recording the RTs by a single experimenter on two sessions (interday reproducibility). Validity of the model was further tested by evaluating the psychotropic effect of Zolpidem 5 mg, Caffeine 500 mg, or Placebo on 24 healthy subjects in a randomized, double blind three-way crossover design.Results:The method was found to produce low variability with coefficient of variation less than 10%. Interday reproducibility was very good as shown by Bland-Altman plot with most of the values within ±2SD. There was a significant increase in RTs in Stroop performance with Zolpidem at 1 hr and 2 hrs; in contrast, caffeine significantly decreased RTs in Stroop performance at 1 hr only compared to placebo.Conclusion:The Stroop color-word recording and analysis system is simple, sensitive to centrally acting drug effects, and has potential for future experimental psychomotor assessment studies.
Background:Acute and chronic stress is a risk factor for the development and progression of coronary artery disease. Increased arterial stiffness is an independent marker for cardiovascular disease. Cold pressor test (CPT) is known to be associated with substantial activation of the autonomic nervous system.Objective:The aim of this study was to evaluate the effect of Phyllanthus emblica extract on cold pressor stress test induced changes on cardiovascular parameters and aortic wave reflections in healthy human subjects.Materials and Methods:This was a double-blind, placebo-controlled, crossover study. Participants were randomized to receive either two capsules of P. emblica extract 250 mg (containing aqueous extract of P. emblica, highly standardized by high-performance liquid chromatography to contain low molecular weight hydrolysable tannins emblicanin-A, emblicanin-B, pedunculagin and punigluconin) or two capsules of placebo twice daily for 14 days. Pharmacodynamic parameters such as heart rate, augmentation pressure, augmentation index (AIx), subendocardial viability ratio (SEVR), radial and aortic blood pressure (BP) were recorded before and after CPT at baseline and end of treatment. After washout period of 14 days, subjects crossed over to the other treatment and the same test procedure was repeated again. Safety assessments were done at baseline and at the end of treatment.Results:A total of 12volunteers completed the study. Compared with baseline and placebo, P. emblica extract produced a significant decrease of mean percent change in the indices of arterial stiffness (AIx, radial and aortic BP) and increase in SEVR, an index of myocardial perfusion with CPT. Both treatments were well-tolerated and no serious adverse events were reported.Conclusion:Proprietary P. emblica extract, showed a significant decrease in cold pressor stress test induced changes on aortic wave reflections.
Objective:To evaluate the effects of centrally active drugs using a new indigenously developed automated psychometric test system and compare the results with that obtained using pencil- and paper-based techniques.Materials and Methods:The tests were standardized in 24 healthy participants. Reproducibility of the test procedure was evaluated by performing the tests by a single experimenter on two occasions (interday reproducibility). To evaluate the sensitivity of the tests, the effects of zolpidem (5 mg) and caffeine (500 mg) versus placebo were studied in 24 healthy participants in a randomized, double-blind three-way crossover design.Results:Psychometric tests were performed at baseline and at 1, 2, and 3 h after administration of study medication. The effects of zolpidem and caffeine on the psychomotor performance were most pronounced 1 h after administration. At this time, a significant impairment of performance in the simple reaction test (SRT), choice discrimination test (CDT), digit symbol substitution test (DSST), digit vigilance test (DVT), and card sorting test (CST) was observed with zolpidem. In contrast, caffeine showed a significant improvement in performance in CDT and DVT only.Conclusion:The results suggest that the tests of the computerized system are more sensitive and reliable then the pencil and paper tests in detecting the effects of central acting agents and are suitable for use in clinical areas to conduct studies with patients.
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