Hair-cortisol and hair-BDNF as biomarkers of tinnitus loudness and distress in chronic tinnitus

• Published in: Scientific reports 2022-02, Vol.12 (1), p.1934-1934, Article 1934
• Main Authors: Basso, Laura, Boecking, Benjamin, Neff, Patrick, Brueggemann, Petra, Peters, Eva M. J., Mazurek, Birgit
• Format: Article
• Language: English
• Subjects: 631/477; 692/163; 692/308; 692/53; 692/699; Adult; Aged; Aged, 80 and over; Audiometry, Pure-Tone; Biomarkers; Biomarkers - analysis; Brain-derived neurotrophic factor; Brain-Derived Neurotrophic Factor - analysis; Chronic Disease; Cortisol; Data collection; Female; Frequency; Hair; Hair - metabolism; Health Status; Hearing; Hearing aids; Hormones; Humanities and Social Sciences; Humans; Hydrocortisone - analysis; Hypothalamic-pituitary-adrenal axis; Hypothalamo-Hypophyseal System - metabolism; Hypothalamo-Hypophyseal System - physiopathology; Hypothalamus; Loudness Perception; Male; Mental Health; Middle Aged; multidisciplinary; Neuroplasticity; Pituitary; Predictive Value of Tests; Psychometrics; Quality of Life; Sampling; Science; Science (multidisciplinary); Shift work; Smoking; Tinnitus; Tinnitus - diagnosis; Tinnitus - metabolism; Tinnitus - physiopathology; Tinnitus - psychology; Young Adult
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-04811-0

The role of stress and its neuroendocrine mediators in tinnitus is unclear. In this study, we measure cortisol as an indicator of hypothalamus–pituitary–adrenal (HPA) axis alterations and brain-derived neurotrophic factor (BDNF) as a marker of adaptive neuroplasticity in hair of chronic tinnitus patients to investigate relationships with tinnitus-related and psychological factors. Cross-sectional data from chronic tinnitus inpatients were analyzed. Data collection included hair sampling, pure tone audiometry, tinnitus pitch and loudness matching, and psychometric questionnaires. Elastic net regressions with n-fold cross-validation were performed for cortisol (N = 91) and BDNF (N = 87). For hair-cortisol (R 2  = 0.10), the strongest effects were sampling in autumn and body-mass index (BMI) (positive), followed by tinnitus loudness (positive) and smoking (negative). For hair-BDNF (R 2  = 0.28), the strongest effects were hearing aid use, shift work (positive), and tinnitus loudness (negative), followed by smoking, tinnitus-related distress (Tinnitus Questionnaire), number of experienced traumatic events (negative), and physical health-related quality of life (Short Form-12 Health Survey) (positive). These findings suggest that in chronic tinnitus patients, higher perceived tinnitus loudness is associated with higher hair-cortisol and lower hair-BDNF, and higher tinnitus-related distress with lower hair-BDNF. Regarding hair-BDNF, traumatic experiences appear to have additional stress-related effects, whereas hearing aid use and high physical health-related quality of life appear beneficial. Implications include the potential use of hair-cortisol and hair-BDNF as biomarkers of tinnitus loudness or distress and the need for intensive future research into chronic stress-related HPA axis and neuroplasticity alterations in chronic tinnitus.