Singh Muskan, Kaur Manjinder, Khamesra Renu, Arora Umang, Boonlia Nimit
Physiology, Geetanjali Medical College and Hospital, Udaipur, IND.
Neurology, Geetanjali Medical College and Hospital, Udaipur, IND.
Cureus. 2024 Aug 30;16(8):e68228. doi: 10.7759/cureus.68228. eCollection 2024 Aug.
Purpose of study The goal of this research was to find the correlation of nicotine dependence and duration of smoking with the status of central neuronal processing in chronic smokers. Our primary objective was to record brainstem auditory evoked responses (BAERs) in chronic smokers and further find their correlation to the Heaviness of Smoking Index (HSI) scores and years of non-abstained smoking of the subjects. We postulated that smoking leads to myelination abnormalities which in turn causes decreased impulse conduction velocity. Methods After obtaining informed consent, we conducted BAER on 60 male smokers who were further classified into groups based on their HSI scores (low, moderate, and high nicotine dependency) and 20 age-matched, non-smoking males. The obtained data was examined using the two-way ANOVA test and the Kruskal-Wallis test. Pearson's coefficient of correlation and the median (as a measure of central tendency) were calculated. Results We observed a non-significant negative correlation between wave I BAER latency and the degree of nicotine dependence. Wave II showed minimal correlation, whereas a positive correlation was seen in waves III, IV, and V. Interpeak latencies (IPL) I-III and III-V showed a non-significant positive correlation with the HSI score, whereas IPL I-V showed a significant positive correlation with the same. When correlated with the duration of smoking (years), the latencies (msec) of BAER waves I-V showed a pattern of progressively decreasing negative correlation, out of which waves I, II, and III were significantly affected. The IPL (msec) of waves I-III was non-significantly, yet positively, correlated, while the IPL of waves I-V and III-V showed a significant positive correlation to the duration of smoking. Conclusions The degree of nicotine dependence and duration of tobacco smoking progressively affected the latencies of BAER waves at the pontomedullary level of the brainstem. This indicates slower central neuronal processing at this level and an increased central transmission time, the extent of which is directly dependent on the extent of tobacco smoking. This is attributed to the myelination defects caused by direct and indirect effects of the toxic metabolites of tobacco smoke, chronic hypoxia, hypercapnia, and respiratory acidosis.
研究目的 本研究的目的是找出慢性吸烟者中尼古丁依赖程度和吸烟时长与中枢神经元处理状态之间的相关性。我们的主要目标是记录慢性吸烟者的脑干听觉诱发电位（BAERs），并进一步找出其与受试者吸烟严重程度指数（HSI）得分及吸烟年限之间的相关性。我们推测吸烟会导致髓鞘形成异常，进而导致冲动传导速度降低。方法 在获得知情同意后，我们对60名男性吸烟者进行了BAER检测，并根据他们的HSI得分（低、中、高尼古丁依赖）将其进一步分组，同时选取了20名年龄匹配的非吸烟男性。使用双向方差分析测试和Kruskal-Wallis测试对获得的数据进行检验。计算了Pearson相关系数和中位数（作为集中趋势的度量）。结果 我们观察到I波BAER潜伏期与尼古丁依赖程度之间存在不显著的负相关。II波显示出最小的相关性，而III、IV和V波呈现正相关。峰间潜伏期（IPL）I-III和III-V与HSI得分呈现不显著的正相关，而IPL I-V与HSI得分呈现显著正相关。当与吸烟时长（年）相关时，BAER波I-V的潜伏期（毫秒）呈现出逐渐降低的负相关模式，其中I、II和III波受到显著影响。I-III波的IPL（毫秒）呈现不显著但为正的相关性，而I-V波和III-V波的IPL与吸烟时长呈现显著正相关。结论 尼古丁依赖程度和吸烟时长逐渐影响脑干脑桥延髓水平BAER波的潜伏期。这表明该水平的中枢神经元处理速度减慢，中枢传导时间增加，其程度直接取决于吸烟程度。这归因于烟草烟雾的有毒代谢产物、慢性缺氧、高碳酸血症和呼吸性酸中毒的直接和间接影响所导致的髓鞘形成缺陷。
