Abnormal neural activities of directional brain networks in patients with long-term bilateral hearing loss

// Long-Chun Xu 2, * , Gang Zhang 3, * , Yue Zou 3, * , Min-Feng Zhang 2 , Dong-Sheng Zhang 1 , Hua Ma 4 , Wen-Bo Zhao 3 and Guang-Yu Zhang 1 1 Department of Radiology, Taishan Medical University, Taian 271016, Shandong Province, China 2 Department of Radiology, Affiliated Hospital of Taishan Medical University, Taian 271000, Shandong Province, China 3 Department of Otorhinolaryngology and Head-Neck Surgery, Affiliated Hospital of Taishan Medical University, Taian 271000, Shandong Province, China 4 Department of Medical Information Engineering, Taishan Medical University, Taian 271016, Shandong Province, China * These authors have contributed equally to this work Correspondence to: Guang-Yu Zhang, email: gyuzhn@163.com Keywords: multivariate regression model, causal connectivity, the virtual brain, bilateral hearing loss, cognitive decline Received: April 11, 2017      Accepted: July 19, 2017      Published: August 19, 2017 ABSTRACT The objective of the study is to provide some implications for rehabilitation of hearing impairment by investigating changes of neural activities of directional brain networks in patients with long-term bilateral hearing loss. Firstly, we implemented neuropsychological tests of 21 subjects (11 patients with long-term bilateral hearing loss, and 10 subjects with normal hearing), and these tests revealed significant differences between the deaf group and the controls. Then we constructed the individual specific virtual brain based on functional magnetic resonance data of participants by utilizing effective connectivity and multivariate regression methods. We exerted the stimulating signal to the primary auditory cortices of the virtual brain and observed the brain region activations. We found that patients with long-term bilateral hearing loss presented weaker brain region activations in the auditory and language networks, but enhanced neural activities in the default mode network as compared with normally hearing subjects. Especially, the right cerebral hemisphere presented more changes than the left. Additionally, weaker neural activities in the primary auditor cortices were also strongly associated with poorer cognitive performance. Finally, causal analysis revealed several interactional circuits among activated brain regions, and these interregional causal interactions implied that abnormal neural activities of the directional brain networks in the deaf patients impacted cognitive function.