[Otoneurological manifestations in Fhar's disease. A case report]

Fhar's disease is a rare idiopathic CNS pathology characterized by widespread calcifications of the basal ganglia, cerebellar nuclei and endocranial vessels. The origin of this disease is unknown and a lack of thyroid and parathyroid pathologies is the main statement. From the clinical point of view, extrapyramidal manifestations are common while vertigo and equilibrium disorders are rare. In the present case vertigo and disequilibrium were the main symptoms. Fhar's disease was diagnosed by CT and MRI showing calcification of the basal ganglia without any metabolism disorders or thyroid and parathyroid pathology. A battery of neurotological tests showed alterations of VOR and ocular movement. In particular the saccades movements showed significant hypometria while the smooth-pursuit showed gain diminution and corrective saccades. These anomalies imply dysfunction of sub-cortical centers regulating and modulating ocular movement. VOR alterations included both qualitative anomalies of nystagmus (i.e. dysrhythmia, square waves) and quantitative alterations (i.e. bilateral deficit response to caloric and rotatory stimuli). These alterations could be due to the impairment of cerebellum-vestibular and vestibular-thalamic pathways. Acoustic evoked potentials (ABR, MLR) ruled out central acoustic pathway dysfunction.