Persistent cortical deafness: A voxel-based morphometry and tractography study

Objective: In cortical deafness, no auditory signals can be perceived by the cortex despite normal peripheral hearing. Cortical deafness rarely persists, but generally evolves into other cortical auditory syndromes. In this report, we describe a patient showing a stable and persisting pattern of cortical deafness 16 months after two major ischemic strokes. Methods: Voxel based morphometric evidence from high resolution three-dimensional MRI and data from tractography are reported for the first time, to our knowledge, in this syndrome in addition to behavioral and electrophysiological findings. Results: The most remarkable findings came from the tractography data, where an asymmetric pattern was found showing severe damage of connections within the anterior right hemisphere, in regions subserving self-awareness. Frontal asymmetry, although detectable by the morphometric analysis, was less informative than that detected in the tractography data. Conclusion: The evidence from this case study suggests that damage to the neural systems involved in awareness may play an important role in the emergence of cortical deafness and its persistence.