Bilateral hypogeusia caused by a small lesion in the lower midbrain tegmentum
- 1Center for Neurological Diseases, Aizawa Hospital, Matsumoto, Japan
- 2Department of Neurology, Aizawa Hospital, Matsumoto, Japan
- 3Department of Oral and Maxillofacial Surgery, Matsumoto Dental University, Shiojiri, Japan
- Correspondence to Dr Takao Hashimoto,
We report a case with multiple sclerosis which showed bilateral hypogeusia due to a small lesion in the lower midbrain tegmentum. Sweet taste was diminished only on the contralateral side in the territory of the chorda tympani, and salty, sour and bitter tastes were diminished bilaterally. All taste modalities were preserved in the territory of the greater petrosal nerve. The findings in our patient and in the literature suggest that the second gustatory fibres ipsilaterally ascend from the nucleus of the solitary tract to the midbrain and partially cross at the inferior border of the midbrain. The features of hypogeusia in our case suggest segregated channels in the gustatory pathway conveying taste perception of distinct taste modalities and from distinct innervation territories.