The evaluation of effects of chronic smoking on cognitive functions

Cigarette may have negative effects due to its ingredients, namely due to many oxidant agents. Nicotine may have an effect on physiologic, biochemical and behavioural functions directly and indirectly in the central nervous system. It has been assumed that nicotine may have some effects on cognitive functions in healthy smokers. In this study, we aimed to assess the negative or positive effects of smoking on cognitive functions in healthy smokers by P300 and continuous performance tests (CPT).Enrolled subjects and controls' evoked potentials (P300) were obtained by using the standard oddball paradigm in the EMG Laboratory with a Dantec Keypoint modelled 8 channel EMG/evoked Potential Device. Ag/AgCl disc electrodes were used and active electrode was placed to Cz, while reference electrode was placed to electrode to earlobe when the person was in lying position.All enrolled cases completed continuous performance test on computer screen that is one of the neuropsychological tests.Mean P300 latency was observed to be significantly prolonged in smokers than controls. This prolongation was correlated with smoking duration, and it was especially remarkable in more than 10 years smokersThere was not a significant difference between controls and smokers less than 10 years by means of P300 amplitud. However P300 amplitude was observed to be decreased significantly in smokers more than 10 years. When CPT was evaluated; there was not a significant difference between controls and smokers.P300 test may be used as an adjunctive test but CPT test is not useful for assessing the effects of smoking on cognitive functions.Key words: P300, Nicotine, Smoking, CPT, Cognition