Effect of body mass index on physical self concept, cognition & academic performance of first year medical students.

Background & objectives: The relationship between obesity and self perception, particularly in children and young adults has important implications for physical and psychosocial health and well-being. A better understanding of this relationship could help target psychology services and public health strategies more effectively. The aim of the present study was to assess the effect of body mass index (BMI) on physical self concept and cognition of the first year medical undergraduate students in a medical college in north India. The relationship between physical self concept and academic performance and presence of any gender differences were also examined. Methods: The study was carried out on 18-21 yr old first year M.B.B.S. students of Maulana Azad Medical College, New Delhi, India. Physical self concept was assessed using short version of Physical Self Description Questionnaire (PSDQ-S) which is a psychometrically strong instrument for measuring multiple dimensions of physical self-concept. Cognition was assessed by P300 evoked potentials and academic performance was evaluated on the basis of marks obtained in anatomy, physiology and biochemistry subjects. Results: There was no association between BMI and physical self-concept or between BMI and cognition. Gender differences on physical self-concept were also insignificant. No correlation was seen between physical self-concept and academic performance. Interpretation & conclusion: The present results suggest that negative consequences of high body mass index on physical self-concept and cognition are not seen in young adults. It may be that academic achievement nullifies the effect on physical self-concept and the effect on cognition accumulates as the age progresses, therefore, appears later in life.

A study of autonomic nervous system status in children of asthmatic parents.

Asthmatic patients are known to have autonomic abnormalities. This study evaluated the status of autonomic nervous system in children of asthmatic parents for any occurrences of autonomic abnormalities that are known to occur in asthma. In this study autonomic function tests were conducted in children (5 to 10 years of age) divided into two groups: Group A had children from non-asthmatic parents as Control Group and Group B had children from asthmatic parents as Test Group. Both the groups had healthy children showing no clinical signs and symptoms of asthma, allergy or any illness known to affect autonomic nervous system. In response to various parasympathetic function tests (S/L ratio, 30:15 ratio, valsalva ratio and tachycardia ratio) and sympathetic function tests (handgrip test and cold pressor test) done, the two groups did not show any statistically significant dissimilarity for any of the parameters. The results of our study showed that there were no autonomic abnormalities found in the children of asthmatic parents. Thus this study indicates that the autonomic defects seen in asthmatics could be secondary to asthma and not because of autonomic aberrations inheritance in asthmatics as shown by earlier few studies supporting the possible role of inherited automatic reactivity in the pathogenesis and progression of asthma.

Effect of Partial Sleep Deprivation on Auditory Event Related Potential and Reaction Time in Medical Students.

The aim of the present study was to evaluate the effects of partial sleep deprivation on the cognitive status and alertness of medical students using auditory event related potential (ERP) and auditory reaction time (RT) using sleep questionnaire, Stanford Sleepiness Scale (SSS), auditory ERP (P300) and RT. Sleep time was significantly shorter in the test condition as compared to the baseline values (p<0.001). Significantly higher values on the SSS (p<0.05) were found after sleep restriction. The P300 latency and amplitude significantly decreased (p<0.01 and p<0.001 respectively) when the test values were compared to the baseline. RT also showed a significant decrease (p<0.001) in the test condition as compared to the baseline values. However, no significant correlation could be ascertained between SSS and P300 amplitude and latency as well as RT. This study demonstrates that partial sleep deprivation produces variable effects on the cognitive status of medical students as reflected by the decrease in P300 amplitude and latency. Alertness of medical students seemed to show an improvement as reflected by the decrease in RT.

Sensory nerve conduction velocity is greater in left handed persons.

Dependence of nerve conduction velocity on factors like age, sex and temperature is well known. Effect of handedness on nerve conduction velocity has not been studied adequately. In this study correlation between handedness and motor as well as sensory conduction velocity of right as well as left median nerve was studied in 84 medical students in the age group between 17-21 years out of which 72 were right handed and 12 were left handed. In addition auditory and visual reaction times were also studied. Sensory conduction velocity in both right and left median nerve was significantly higher in left handers as compared with right handers whereas, the motor conduction velocity in right handers and left handers was not different. The auditory and visual reaction times were also not different in these groups. Because of greater sensory conduction velocity in left handers there is a requirement of different set of normal reference values for left handers in clinical diagnosis.

Effect of ramipril therapy on cognitive functions in cases of mild to moderate essential hypertension.

Several studies have questioned the effect of hypertension on cognitive functions. Event related potentials (P300) have been used as a reliable and reproducible indicator of cognitive functions. In this non-randomized, open label study we investigated cognitive functions using event related potentials in newly diagnosed mild to moderate essential hypertensive patients and whether or not there was any effect of antihypertensive treatment with angiotensin converting enzyme inhibitor ramipril on the event related potentials. We selected twenty male patients of newly diagnosed mild to moderate essential hypertension by using ambulatory blood pressure monitoring who were previously untreated and compared their event related potentials with 10 normotensive controls. At the beginning of the study, the hypertensive group showed increased P300 and N2 wave latency as compared to the normotensive control subjects. After three months of Ramipril therapy at a dose of 5mg per day, there was a significant decrease in all the ambulatory blood pressure parameters and the mean P300 latency from the pretreatment values. But no significant change in the N2 latency was observed. Thus, treatment with Ramipril 5 mg daily for a period of three months can reverse some aspects of cognitive dysfunction associated with hypertension.

Spinal motoneuron excitability in iron deficiency anaemia.

Decreased tissue oxygenation resulting from iron deficiency anaemia produces generalized weakness and fatigue. The precise physiological mechanism underlying this weakness is unknown and studies in this regard have been scarce. One possible underlying mechanism has been suggested to be reduction of spinal motoneuron excitability. F waves are low amplitude motor responses to nerve stimulation, produced by antidromic activation of the peripheral motor fibers, resulting in recurrent discharge of motoneurons. F waves have been established as an efficient tool to assess spinal motoneuron excitability. 15 patients of iron deficiency anaemia using inclusion criteria of hemoglobin level < 9 g/dL and serum ferritin < 15 microg/L were studied. 8 controls with hemoglobin levels > 12 g/ dL were also included. Bilateral median and common peroneal F wave studies were performed. F wave mean latency, chronodispersion, persistence and mean amplitude were studied. They were within the normal range and no significant differences between the patients and the controls were found. We conclude that spinal motoneuron excitability is not reduced in iron deficiency anaemia. A decreased tissue oxygenation leading to a change in the brain neurotransmitters may have a role to play.

Effect of sodium citrate ingestion on oxygen debt & exercise endurance during supramaximal exercise.

BACKGROUND & OBJECTIVES: Administration of alkalinizing agents has been shown to improve performance in high intensity exercise. The present investigation was undertaken to determine whether sodium citrate ingestion enhances supramaximal endurance performance on a cycle ergometer and to assess its effect on oxygen debt incurred for the same supramaximal energy output. METHODS: Ten untrained, healthy, males performed acute intense bicycle ergometry exercise in two sessions viz., without (control) and with sodium citrate ingestion (experimental) in a dose of 0.5 g/kg body weight. Pre-exercise O2 consumption, pulse rate (PR) and respiratory rate (RR)/minute were recorded before both sessions. Exhaustion time (ET) was noted and work done calculated in the control session. Post-exercise PR and RR/min were also recorded in both sessions of study. Venous blood samples were drawn post-exercise and analysed for pH and lactate. O2 debt incurred was calculated in both sessions. RESULTS: Work output in supramaximal exercise averaged 69.40 +/- 15.31 Watts in the control session. None of the subjects in the experimental session complained of fatigue even when the exhaustion time noted in the control session was reached. Post-exercise tachycardia and tachypnoea were both significantly less (P<0.05 and P<0.001 respectively) in subjects after the experimental session as compared to the control. O2 debt incurred and lowering of blood pH were also significantly less (P<0.001) in the post-citrate phase. However, serum lactate increased significantly (P<0.05) in subjects after the experimental session. INTERPRETATION & CONCLUSION: Ingestion of sodium citrate prior to supramaximal exercise resulted in a reduction in post exercise O2 debt incurred. Blood pH was almost normal despite a higher serum lactate concentration. This probably led to an enhancement in exercise performance.