Validation of PC 1000 Hz Reaction Timer with Biopac® MP 36 for Recording Simple Reaction Time

Background: In neuropsychological assessment, the time taken by a subject or patient to respond tostimulus provides valuable information about processing in central and peripheral nervous system. Reactiontime is a simple and inexpensive method commonly used in cognitive and sport physiology to assess thesensory-motor performance of an individual.Objective: To compare and validate the baseline values of simple reaction time obtained using the PC 1000Hz reaction timer with Biopac® MP 36.Materials and Methods: 50 healthy subjects (32 males and 18 females) with age of 22.78±3.90 yrs andBMI of 24.820±3.59 kg/m2 participated. Visual (VRT) and auditory (ART) reaction time were estimated usingPC 1000 Hz reaction timer and Biopac® MP 36 separately for minimum of three trials each.Results: There was no significant difference found in ART and VRT values of the subjects estimated by PC1000 Hz and Biopac® MP 36. A strong significant (P<0.01) correlation was found in ART (r=0.92) and VRT(r=0.94) in between the devices. Bland Altman plot also showed that variations for VRT and ART were withinthe acceptable range.Conclusion: The present validation study recommend that the assessment of simple reaction time forauditory and visual stimulus by PC 1000 Hz reaction timer is reliable one and compared with other techniquesit has more advantages such as portable in nature and simplicity to use either in laboratory or in fieldoriented study for the evaluation of psychomotor and cognitive function.

Cardiovascular autonomic responses to whole body isotonic exercise in normotensive healthy young adult males with parental history of hypertension.

The objective of this study was to assess blood pressure and autonomic activity during rest and recovery in young adult normotensives offsprings of hypertensives. A total of 49 healthy normotensive males with BMI of 18.5–24.9 kg/m2 chosen for the study and classified into two groups based on their parental history of hypertension underwent a sub maximal cycle ergometry exercise test. ECG and heart rate were recorded at baseline, during the exercise test and during recovery period of ten minutes while blood pressure was recorded at baseline and during recovery. Spectral analysis of HRV was performed. The basal systolic blood pressure and the recovery systolic blood pressures at the 1st and 3rd minute of recovery after exercise test were significantly higher in the study group than the control group. The basal LFnu and LF/HF ratio were significantly higher while the basal HFnu was significantly lower in the study group than the control group. A difference in basal systolic blood pressure, a higher LFnu and a lower HFnu found in offspring of hypertensive parents may be an early marker of cardiovascular change in subjects with a genetic predisposition to hypertension.

Serum nitrate levels as an index of endothelial function in pre-eclamsia and normal pregnancy.

The study was conducted in St. John's Medical College Hospital and Department of Physiology, with the aim of studying the serum nitrate levels in pre-eclampsia and normal pregnancy. The total number of subjects studied in various groups were 159, control (n = 55), first trimester (n = 13), second trimester normal (n = 42), second trimester pre-eclampsia/PET (n = 5), third trimester normal (n = 32), third trimester pre-eclampsia/PET (n = 12). The serum nitrate was measured by one step enzymatic assay using Nitrate reductase from Aspergillus species. The nitrate levels in the third trimester pre-eclamptic group was found to be significant lower (P = 0.02), as compared to normal subjects, however the renal functions were normal in all the subjects.

The development and validation of a digital peak respiratory pressure monitor and its characteristics in healthy human subjects.

A digital peak respiratory pressure (DPRP) monitor for determining maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) was developed using a pressure transducer and an analog to digital converter. It was calibrated using a mercury manometer. Human studies were conducted in healthy young adults in order to determine within-subject and inter-individual variability, as well as diurnal variations and gender differences in maximal respiratory pressures. The calibration studies for the instrument indicated that the instrument recorded accurate pressures, with little temporal drift. Within-subject variability was generally low while inter-individual variability was higher and significant. Gender differences were similar to those recorded in literature for other racial groups. The DPRP monitor described is inexpensive, accurate and portable, making it ideal for use at the patient's bedside.

The perceptions of first-year medical students on animal and human experiments in physiology.

This study was conducted to ascertain the attitudes of first year medical students to human and animal experimentation, while undergoing a course in Muscle and Nerve experimental Physiology. At the time of administration of the questionnaire, students had been exposed to both human as well as animal experiments. Approximately 81% of the students preferred human experiments (P < 0.05). This preference, however, was related more to the issue of enjoyability rather than the extent to which the experiment contributed to overall understanding and learning. 55% of students identified ethical issues related to laboratory experimentation. Gender and academic performance were not determinants of student's attitude to animal and human experimentation, although ethical insight was. The results suggest that while students recognize the importance and value of animal experiments, they would prefer the introduction of a larger number of human experiments.