Structural signs of progression of a sensorineural hearing loss after a closed head injury: A CT and MRI study

Abstract

Objective: Progression of a sensorineural hearing loss (SNHL) is not an uncommon sequel after closed head injury (CHI). The mechanisms behind this progression are, however, unclear. The study objective was to search for specific radiological signs of inner ear pathology, such as fibrosis or sclerosis associated with progression of a trauma related SNHL. Could specific types of fractures and/or brain contusions be associated with progression? Methods: Eighteen subjects with a history of CHI, skull fracture and/or brain contusion, four to fifteen years prior to the present investigation were studied. All subjects had an initial trauma related SNHL. Thirteen subjects had a varying degree of SNHL progression. All subjects underwent otomicroscopy, standard audiological evaluation, CT and MRI. Results: No cochlear changes were demonstrated on MRI or CT in any of the 13 subjects with a trauma related SNHL progression, even in cases with extensive progression. However, in one subject with post-traumatic unilateral deafness an inner ear alteration was demonstrated on MRI. Conclusions: The observed progression of SNHL is probably due to processes at cellular level, not detectable using current radiological methodology. Furthermore, no specific type of fracture or localization of brain contusion seen on neuroimaging was found to indicate an increased risk for SNHL progression.

Key words::

• SNHL
• brain contusion
• fracture
• skull base

Acknowledgements

We express thanks to Erik Borg, Inga-Stina Olsson, Agneta Palmkvist-Söderberg, Carina Wikström and Lars Skoglund for skilful assistance. This investigation was supported by the Swedish Medical Research Council, Örebro University, Örebro University Hospital and Lindesberg County Hospital.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.