Vertebrobasilar insufficiency (VBI) is a brief episode of reversible neurological deficits caused by transient ischemia of the brainstem due to impairment of the vertebrobasilar arterial system.

The most common causes of VBI are atherosclerosis, which can block the posterior circulation supplying the brainstem, embolism arising from the heart and proximal vertebral and basilar arteries due to arrhythmias, as well as by hemodynamic disorder associated with changes of the blood pressure.

Patients with VBI frequently present with vertigo and disequilibrium as the primary symptoms, associated with neurologic symptoms and signs, including double vision, loss of vision, gait ataxia, face and limb numbness, weakness, dysarthria and oropharyngeal dysfunction. Posterior circulation strokes are often characterized by fluctuating symptoms and signs, depending on the area of the brain that is ischemic.

It is crucial to examine the pathological condition of the vessels in the vertebrobasilar system to evaluate the blood flow hemodynamics and vascular morphology in patients presenting with episodes of VBI by ultrasonography, magnetic resonance angiography, and CT angiography. VBI is usually treated with drugs that improve the cerebrovascular circulation and metabolism, antiplatelet agents, etc.

VBI should be considered in the differential diagnosis in patients presenting with recurrent vertigo, and early diagnosis is important. Patients with VBI might require careful follow-up and treatment for preventing the progression of vertigo and other neurological deficits in the vertebrobasilar arterial region. Further discussions are needed to consolidate the diagnostic criteria, as well as the concept and pathogenesis of VBI associated with vertigo in the future.

Upbeat nystagmus is a sign of a central nervous system disorder. Herein, we report a patient with positional upbeat nystagmus in the straight supine position with no evident abnormal central nervous system findings.

A 58-year-old woman visited our clinic complaining of feeling dizzy and a sense of fullness in the right ear since the day before. Initially, the supine head roll test revealed upbeat nystagmus for 50 s with latency of 3 s in the straight supine position. In the prone seated position, oblique nystagmus toward the down and right side was observed for 55 s with a latency of 17 s. No nystagmus was observed in the other head positions in either the supine head roll test or the Dix–Hallpike test. The pure tone audiogram showed low frequency sensorineural hearing loss in the right ear. Neurological examination, brain magnetic resonance imaging and magnetic resonance angiography revealed no abnormal findings. The patient was treated with oral isosorbide and betahistine. Within 5 days of the start of this treatment, the nystagmus, vertigo, as well as the low-frequency sensorineural hearing loss resolved completely.

We speculated that the positional upbeat nystagmus and low frequency sensorineural hearing loss in this patient were not caused by central nervous system disorder, but by some peripheral lesions, and that the pathophysiological basis of the nystagmus was canalolithiasis of the bilateral posterior semicircular canals.

Benign paroxysmal positional vertigo (BPPV) is a typical vertigo disease, and BPPV developing during the course of diseases causing peripheral vertigo, including Meniere’s disease, is also known. Between June 2017 and March 2021, 29 (23%) of 124 patients who visited the Department of Otolaryngology, Osaka Metropolitan University Hospital, who were diagnosed as cases of definite Meniere’s disease exhibited complicating BPPV and their data were analyzed retrospectively. Out of the 29 cases, 23 (79%) had lateral semicircular canal BPPV, 4 (14%) had posterior semicircular canal-type BPPV, 1 had lateral semicircular canal-type BPPV (cupulolithiasis) + posterior semicircular canal-type BPPV, and 1 had lateral semicircular canal BPPV (canalolithiasis) + posterior semicircular canal-type BPPV. Of the 25 cases, 16 had cupulolithiasis and 9 had semicircular canalolithiasis. The side affected by Meniere’s disease and BPPV was the same in 14 of the 29 cases (48%), while opposite sides were affected by the two conditions in the remaining 11 cases (38%). No strong association was found between the severity of Meniere’s disease or hearing loss and the development of BPPV. In regard to the timing of onset of the BPPV, in more than a half of the cases, the BPPV developed within 1 month of the diagnosis of Meniere’s disease. We consider that it would be useful to identify predictors of the development of complicating BPPV in patients diagnosed as having Ménière’s disease.

A 37-year-old woman with hereditary Parkinson’s disease (PARK2: exon 3/7 hetero-duplication & exon 3/5 hetero-deletion) visited our neuro-otology unit for evaluation of postural instability; she had no history of dizziness or vertigo. Neurological examination revealed no other significant abnormalities than the cardinal signs of Parkinsonism: mild rigidity, resting tremor and dystonia. Brain MRI revealed mild atrophy of the cerebellar dorsal vermis and hemisphere. The ENG showed square wave jerks (SWJ) during forward gaze in the dark. The visually guided saccades were hypometric in both the horizontal and vertical directions. Both horizontal and vertical smooth pursuits were slightly disturbed and required corrective anticipated saccades to follow the sinusoidal target. Horizontal OKN could be induced, but the slow phase velocity and frequency were relatively reduced. These findings were slightly different from those in sporadic Parkinson’s disease, although there were also some similarities. Considered with the MRI findings, the above ENG findings suggest dysfunction of not only the basal ganglia, but also of the cerebellum, especially the vestibular cerebellum, including the dorsal vermis, fastigial nucleus, flocculus, and ventral paraflocculus. In conclusion, it is necessary to consider dysfunction of the cerebellum, as also that of the basal ganglia, as the cause of the abnormal eye movements in this case.

Understanding cortical activity associated with vestibular input is of great importance in the diagnosis and treatment of vertigo. Previous studies on the vestibular cortex in humans have mainly used fMRI and PET, but due to the characteristics of these measuring equipments, it has been difficult to measure the cortical responses to physiological vestibular stimuli, such as rotational acceleration or deceleration to the head. Therefore, we used a portable near-infrared spectroscopy system to measure the cortical blood flow responses to rotational acceleration or deceleration stimuli in 18 right-handed normal subjects while the subjects sat on a rotational chair. The temporoparietal junction (TPJ) of both sides, which is considered as the core region of the so-called “multiple vestibular cortices,” was selected as the region of interest for the measurement. All subjects accelerated and decelerated at 3°/sec in either direction, and then performed the same acceleration and deceleration in the opposite direction a total of four times. The NIRS-SPM software was used to verify whether the concentration of oxyhemoglobin was significantly increased under the four conditions of rightward rotational acceleration, rightward deceleration, leftward acceleration, and leftward deceleration in the subjects. The results showed that there was predominant activation within the TPJ under all four conditions, that the direction of nystagmus coincided with the laterality of the activated TPJ under all the conditions, and that the pattern of TPJ activation differed depending on whether the left or right semicircular canal was stimulated.

Chat GPT (Generative Pre-trained Transformer) is a generative artificial intelligence (generative AI) application released by OpenAI in November 2022. It can provide answers in a conversational format, and by specifying the desired response format, one can adjust the output content (such as the word count and expression style). Chat GPT is expected to be used for various applications, such as text summarization, translation, scenario creation, programming, etc. In this study, we presented questions on the vertigo domain from the Otorhinolaryngology Head and Neck Surgery specialist examinations to Chat GPT to evaluate its potential in clinical diagnosis. We presented 51 questions related to vertigo and balance medicine (excluding questions with images) selected from the Otorhinolaryngology specialty certificate examinations held from 2013 (25th) to 2022 (34th) to GPT-3.5 and GPT-4 and evaluated their accuracy rates. The accuracy rates of GPT-3.5 and GPT-4 were 21.6% and 49.0%, respectively. Although the accuracy increased with the version upgrade, Chat GPT is not a specialized AI application for medical use; it is a general-purpose AI. Given the accuracy rates in this study and the possibility of inaccurate answers, it is currently considered uncertain for use for clinical diagnosis in the real world. However, it is expected to be useful for applications such as summarizing patient histories and literature searches to improve the efficiency of medical tasks, and with improvements of the accuracy through version updates, there is potential for application of ChatGPT in the field of medicine in the future.