title: A causal relationship between hearing loss and cognitive impairment.
abstract: CONCLUSIONS
  Moderate hearing loss in young mice caused decreases in cognition associated with spatial working and recognition memories in 6 months. These results provide evidence for a causal relationship between hearing loss and cognitive impairment.
  
  
  OBJECTIVE
  Hypothesized mechanisms to connect sensory and cognitive functions include the sensory-deprivation, information-degradation, and common-cause hypotheses. This study intended to investigate the effect of hearing loss on cognitive function, as estimated by radial arm maze (RAM) and novel object recognition (NOR) tasks in mice through age- and hearing-matched longitudinal work during a 6-month period.
  
  
  METHODS
  Twenty-four male C57BL/6 mice aged 1 month with normal ABR thresholds were used. Twelve mice in the hearing loss (HL) group were exposed to white noise at 110 dB SPL for 60 min every day for 20 days. At post-noise 6 months, all mice underwent RAM and one-trial NOR test. RAM performance measures and NOR discrimination index were compared between two groups.
  
  
  RESULTS
  At 6 months after noise exposure, all mice in the experimental group had moderate hearing loss. Most of the RAM performances improved gradually within each group across five trials, probably due to learning effect. The HL group showed lower performance scores than the control group in several trial points in the RAM task. The contact time with the novel object was shorter in the HL group than in the control group.
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: Huerxidan
authors.initials: H
authors.lastname: Sikandaner
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: Dong-Kee
authors.initials: DK
authors.lastname: Kim
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Yeo
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: Shi Nae
authors.initials: SN
authors.lastname: Park
mesh_terms: D000818:Animals; D003071:Cognition; D060825:Cognitive Dysfunction / Q000209:etiology*; D034381:Hearing Loss / Q000150:complications / Q000523:psychology*; D008297:Male; D018782:Maze Learning; D008810:Mice, Inbred C57BL
keywords: Cognition; dementia; hearing loss; novel object recognition; radial arm maze; reference memory; working memory