ABSTRACT
Background: P300 is an auditory evoked potential, called Endogenous Potential because it reflects the functional use which the individual makes of the auditory stimulus, being highly dependent on cognitive skills; among them we list 'attention' and 'auditory discrimination'. During the month of Ramadan, practising Muslims abstain from eating and drinking from sunrise to sunset. We aimed to investigate the effect of Ramadan fasting on the P300, a neurophysiological index of cognitive function. Material and Methods: 16 healthy male students [age ranging between 19 and 21 years] participated in this study. P300 was recorded with the auditory "oddball" two-tone discrimination task in Ramadan fasting and 1 month later during non-fasting period. The data from the central [Cz], frontal [Fz], parietal [Pz] and occipital [Oz] electrodes were analyzed. To determine if there is any correlation between blood glucose level changes and P300, glucose levels in both conditions also measured. Results and Discussion: The P300 latencies at Cz and Pz were prolonged in the fasting condition compared to non-fasting condition. The P300 amplitude at Oz was lower in the fasting condition compared to non-fasting condition. There was a strong correlation between mean glucose level and mean P300 latency at Oz of groups. Conclusion: The prolongation of P300 latencies and reduction of P300 amplitudes in some brain region provides the electrophysiological evidence for the presence of regional cognitive dysfunction in fasting condition and different components of the cognitive performance may be affected in these conditions.