Neuroanatomical alterations in middle frontal gyrus and the precuneus related to tinnitus and tinnitus distress

Abstract

Tinnitus is the phantom perception of sound when there is no external auditory input. This sound is mostly perceived as a ringing, whistling or buzzing in the ear. There is evidence of neural changes in both central auditory regions as well as other brain areas like the prefrontal cortex and the limbic system. However, brain morphological studies assessing gray matter volume and cortical thickness have shown inconsistent results. We here investigated neuroanatomical alterations in tinnitus related to the tinnitus perception along with tinnitus distress and cognitive abilities. Twenty tinnitus patients and 20 control participants matched in age, sex and hearing loss participated in the study. They underwent magnetic resonance imaging and audiometric as well as cognitive assessments. Our results demonstrate increased gray matter volume in the middle frontal gyrus and frontal pole in tinnitus compared to control participants. Moreover, we found increased cortical thickness in the precuneus associated with tinnitus distress as well as an interaction between group and cognitive assessment scores in cortical thickness of the middle frontal gyrus, indicating higher cortical thickness with better scores in controls and lower scores in tinnitus patients. These findings indicate that increased tinnitus awareness and annoyance is reflected in increased brain structural changes in the precuneus, frontal pole and middle frontal gyrus that may also have implications on general cognitive abilities.