Browsing by Autor "Takao Imai"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item type: Item ,
    A Case of Vertebrobasilar Insufficiency with Spontaneous Downbeat Nystagmus
    (Japan Society for Equilibrium Research, 2025) Kenji Yoshida; Takao Imai; Tadao Okayasu; Tadashi Kitahara
    We report a case of a 79-year-old man who presented with positional vertigo and spontaneous downbeat nystagmus and was diagnosed as having vertebrobasilar insufficiency. Magnetic resonance angiography (MRA) and ultrasonographic evaluation of the vertebral artery revealed hypoplasia of the left vertebral artery. Caloric testing did not reveal canal paresis, but visual suppression was weakened, suggesting the presence of cerebellar and brainstem dysfunction. The video head impulse test revealed increased vestibulo-ocular reflex (VOR) gain in the anterior canal and decreased VOR gain in the left posterior canal, which was thought to be due to disinhibition of the VOR of the anterior canal due to damage to the floccules, and impairment of the VOR of the posterior canal due to damage to the pons. This led to hyperfunctioning of the anterior canal, with formation of an upward slow phase followed by a downward fast phase, resulting in the appearance of spontaneous downbeat nystagmus. The downbeat nystagmus was observed in the right lateral decubitus position in the absence of cervical twisting, but disappeared during the supine roll test in the right-head-down position with cervical twisting. This disappearance was due to a decrease in blood flow in the left vertebral artery caused by rightward twisting of the neck, which led to dysfunction of the midbrain-pontine junction and disappearance of hyperfunctioning of the VOR of the anterior canal.
  • Thumbnail Image
    Item type: Item ,
    New Trends in Emergency Care for Peripheral Vestibular Disorders
    (Japan Society for Equilibrium Research, 2025) Takao Imai
    Patients who experience a severe attack of dizziness and/or vertigo (D/V) at home often use information from the Government Public Relations Online to decide whether to call an ambulance or not. Therefore, we often see patients with D/V in the emergency room. Between April 17, 2022, and May 24, 2024, 39 patients visited the emergency department of our hospital complaining of D/V and were admitted to our center. Among them, 7 patients were examined by the author first, and all had abnormal neuro-otological findings such as nystagmus. Of the remaining 32 patients, 13 had neurological abnormalities at the time of examination by the author, but the medical records of 7 of these patients stated that there were no neurological abnormalities at the time of their first visit. Of the remaining 19 of the 32 patients, the medical records of 5 patients at the time of their first visit stated that they had abnormal nystagmus. From the above, when the author first examined the patients, neurological abnormalities were found in all cases, but when someone other than the author first examined the patients, 66% (21/32) of the cases were judged as having no neurological abnormalities.