Introduction: Sleep spindles are short burst-like waveform of signals generated in the electroencephalogram (EEG) recorded during sleep, and these are the electrical representation of an oscillatory neuronal activity of thalamic neurons. Some studies have linked different sleep spindle parameters with intelligence quotient (IQ). But there is a lack of uniformity in different studies, as spindle parameters may be positively associated with cognition variables in one study, but those same parameters might be negatively associated or even unrelated in other studies. The present study was conducted to further throw light on the correlation of sleep spindle activity with IQ. Objective: To find the association between different sleep spindle parameters and IQ. Method: The sleep spindle data of 50 healthy young medical students aged between 18 and 23 years were taken from previously conducted sleep studies (polysomnography), which were available in the sleep lab in the department of physiology (King George\'s Medical University). The participating students underwent a Wechsler IQ test. The result of the test was correlated with sleep spindle parameters available with us to see any correlation. Results and conclusion: Sleep spindle frequency was negatively correlated with the IQ, and the number of spindles in deep sleep (N3) was positively associated with the IQ of an individual.
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