Background: Advanced magnetic resonance imaging (MRI) technique called diffusion tensor imaging (DTI) can assess tissue microstructure. It's challenging to identify sensorineural hearing loss (SNHL) cause suing CT or MRI without significant gross disruption.
Objectives: to assess microstructural integrity of auditory neural pathway SNHL patients with or without tinnitus by DTI.
Patients and methods: This prospective, case-control study included 55 subjects in three groups: 30 healthy volunteers in control group (GI), 12 patients in bilateral SNHL without tinnitus group (GII), and 13 patients in bilateral SNHL with tinnitus group (GIII) were MRI-assessed using 1.5 Tesla GE machine. Ordinary one-way ANOVA test was used to compare groups with normal distributions, Kroskal Wallis test: compares groups with abnormally distributed data; post-hoc test: determines significance between pairs.
Results: ANOVA test revealed statistically significant difference at Lateral lemniscus(LL), Inferior colliculus(IC), medial geniculate body (MGB), auditory radiation(AR), Superior temporal gyrus(STG), Hippocampus, amygdala, Superior longitudinal fasciculus(SLF), genu and splenium of corpus callosum (CC) with P value ≤0.05. Post-hoc test: group II had lower FA comparing to group I at LL, MGB, IC, AR, STG, genu and splenium of CC. In group III the forementioned regions were affected besides hippocampus and amygdala. Group III had statistically significant lower FA values compared to group II at LL, IC, MGB, hippocampus, amygdala, SLF, genu and splenium of CC.
Conclusion: Using DTI to assess microstructural integrity of auditory pathway, SNHL is associated with white matter microstructure affection as proved by the current study, and presence of tinnitus is associated with limbic system affection.