Bess Fred H, Gustafson Samantha J, Corbett Blythe A, Lambert E Warren, Camarata Stephen M, Hornsby Benjamin W Y
1Department of Hearing & Speech Sciences, Vanderbilt Bill Wilkerson Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; 2Department of Psychiatry, Vanderbilt University School of Medicine & Vanderbilt Kennedy Center, Nashville, Tennessee, USA; and 3Vanderbilt Kennedy Center for Research on Human Development and University Center of Excellence on Developmental Disabilities, Nashville, Tennessee, USA.
Ear Hear. 2016 May-Jun;37(3):334-44. doi: 10.1097/AUD.0000000000000256.
It has long been speculated that effortful listening places children with hearing loss at risk for fatigue. School-age children with hearing loss experiencing cumulative stress and listening fatigue on a daily basis might undergo dysregulation of hypothalamic-pituitary-adrenal (HPA) axis activity resulting in elevated or flattened cortisol profiles. The purpose of this study was to examine whether school-age children with hearing loss show different diurnal salivary cortisol patterns than children with normal hearing.
Participants included 32 children with mild to moderate hearing loss (14 males; 18 females) and 28 children with normal hearing (19 males; 9 females) ranging in age from 6 to 12 years. Saliva samples were obtained six times per day on two separate school days. Cortisol levels were measured by mass spectrometric detection after liquid-liquid extraction. Salivary cortisol levels between children with hearing loss and children with no hearing loss over the course of the day were examined with hierarchical linear modeling using mixed model statistical analysis. Between-group comparisons were also computed for the area under the curve, an analytical approach for calculating overall cortisol secretion throughout the day.
Significant differences in the cortisol awakening response (CAR) were observed between children with hearing loss and children with normal hearing; however, no differences were observed between the two groups subsequent to the cortisol awakening response (60-min postawakening, 10:00 A.M., 2:00 P.M., and 8:00 P.M.). Compared with children with normal hearing, children with hearing loss displayed elevated cortisol levels at awakening and a reduced growth in cortisol secretion from awakening to 30-min postawakening. No significant differences in overall cortisol secretion throughout the day were found between groups (area under the curve). Finally, cortisol levels increased with increasing age for children with hearing loss but not for children with normal hearing.
Results of this preliminary study indicate a possible dysregulation in HPA axis activity in children with hearing loss characterized by elevated salivary cortisol levels at awakening and a diminished increase in cortisol from awakening to 30-min postawakening. The pattern of elevated cortisol levels at awakening is consistent with some studies on adults with burnout, a condition characterized by fatigue, loss of energy, and poor coping skills. These findings support the idea that children with hearing loss may experience increased vigilance and need to mobilize energy promptly in preparation for the new day.
长期以来，人们一直推测，费力聆听会使听力损失儿童面临疲劳风险。患有听力损失的学龄儿童每天经历累积压力和聆听疲劳，可能会导致下丘脑 - 垂体 - 肾上腺（HPA）轴活动失调，从而导致皮质醇水平升高或变平。本研究的目的是检验患有听力损失的学龄儿童与听力正常的儿童相比，是否表现出不同的昼夜唾液皮质醇模式。
参与者包括32名轻度至中度听力损失儿童（14名男性；18名女性）和28名听力正常儿童（19名男性；9名女性），年龄在6至12岁之间。在两个不同的上学日，每天采集六次唾液样本。通过液 - 液萃取后采用质谱检测法测量皮质醇水平。使用混合模型统计分析的分层线性模型检验了听力损失儿童和无听力损失儿童在一天中的唾液皮质醇水平。还计算了曲线下面积的组间比较，这是一种计算全天皮质醇总分泌量的分析方法。
在听力损失儿童和听力正常儿童之间观察到皮质醇觉醒反应（CAR）存在显著差异；然而，在皮质醇觉醒反应之后（觉醒后60分钟、上午10:00、下午2:00和晚上8:00），两组之间未观察到差异。与听力正常的儿童相比，听力损失儿童在觉醒时皮质醇水平升高，并且从觉醒到觉醒后30分钟皮质醇分泌的增长减少。两组之间全天皮质醇总分泌量（曲线下面积）未发现显著差异。最后，听力损失儿童的皮质醇水平随年龄增长而增加，而听力正常儿童则不然。
这项初步研究的结果表明，听力损失儿童的HPA轴活动可能存在失调，其特征是觉醒时唾液皮质醇水平升高，且从觉醒到觉醒后30分钟皮质醇增加量减少。觉醒时皮质醇水平升高的模式与一些关于倦怠成年人的研究一致，倦怠是一种以疲劳、精力丧失和应对技能差为特征的状况。这些发现支持了这样一种观点，即听力损失儿童可能会提高警惕，并且需要迅速调动能量为新的一天做好准备。
