Ocular flutter and opsoclonus are intermittent bursts of involuntary conjugate eye oscillations, in the horizontal and multidirectional planes, respectively, without intersaccadic intervals. Patients with ocular flutter/opsoclonus often present with oscillopsia and vertigo, sometimes with cerebellar ataxia and myoclonus. Ocular flutter/opsoclonus can be caused by various diseases, such as postinfectious encephalitis, paraneoplastic syndrome, and drug toxicity. Treatment of the causative disease is the primary goal of treatment, but in cases where they occur as a part of paraneoplastic syndrome, the prognosis for neurologic findings may be poor, regardless of the treatment status of the tumor. Ocular flutter/opsoclonus may originate from a loss of omnipause neuronal inhibition on burst neurons within the brainstem burst generator. In recent years, attention has been focused on a hyperexcitable or disinhibited state of the brainstem burst neuronal membrane.

　 Square wave jerks (SWJks) are abnormal eye movements that consist of unilateral saccades and intersaccadic intervals followed by a return to the original eye position. SWJks are also seen in normal subjects and are thought to be of little pathological significance in and of themselves per se. However, high-amplitude SWJks (Macro square wave jerks) may indicate central lesions, such as neurodegenerative diseases. They are thought to be caused by abnormalities in the ocular microsaccades mechanism.

　 Periodic alternating nystagmus (PAN) is a nystagmus in which the direction of the nystagmus alternates periodically at intervals of about two minutes. There are two types: congenital and acquired. Causes of acquired PAN include paraneoplastic syndrome and cerebellar degenerative diseases.PAN is thought to be caused by disruption of the inhibitory control from the cerebellum to the vestibular nucleus concerned with neural velocity storage mechanisms.

　 Vertigo or dizziness is infrequent in pediatric patients. In this study, we retrospectively investigated the prevalence and etiology of vertigo in children. The subjects were 127 patients who were less than 16 years old (at the first visit) and visited the university hospital of Kyoto Prefectural University of Medicine between January 2008 and March 2022, with the chief complaint of vertigo or dizziness. The patients consisted of 53 boys and 74 girls, with a mean age of 11.2 years. The predominant diagnoses were orthopedic dysfunction (OD; 34 patients, 26.7%); psychogenic vertigo (16 patients, 12.6%); vestibular migraine of childhood (VMC; 16 patients, 12.6%); recurrent vertigo of childhood (8 patients, 6.3%); Meniere's disease (5 patients, 3.9%); delayed endolymphatic hydrops (5 patients, 3.9%), hypotension due to underlying conditions (5 patients, 3.9%), and others.

　 The percentage of patients with OD was the highest at 39.7% in junior and senior high school students. The percentage of patients with psychogenic vertigo was the highest at 16.2% in late elementary grades. The percentage of patients with VMC was almost the same in students from elementary school to high school. The percentages of patients with inner ear anomalies and hypotension due to underlying conditions were high in early elementary students.

　 Triggers were observed in 63 patients: psychogenic stress, sleep deprivation, chronic fatigue, excessive gaming, menstruation, pain due to other diseases, water deficiency, and adverse weather. The most frequent cause was bullying in the patients with psychogenic stress. Extracurricular activities were the main cause in both patients with sleep deprivation and those with chronic fatigue.

　 We conducted this study in a total of 442 patients who had visited the first author's clinic between February 1, 2011, and June 30, 2018, were diagnosed as having and been treated for benign paroxysmal positional vertigo (BPPV), and had remained free of relapse for more than one month, in order to examine the recurrence rate/pattern of BPPV. Until May 1, 2020, 266 cases were directly examined for recurrence/non-recurrence of BPPV upon their revisit to the clinic (exam group). The remaining 176 patients did not revisit our clinic after the initial treatment and answered our questionnaire concerning the recurrence of BPPV by mail (questionnaire group). Of all the 442 cases of BPPV, the BPPV originated from the lateral canal (LC-BPPV) in 41.6% of cases and from the posterior canal (PC-BPPV) in 57.9% of cases (P<0.001). Recurrence of BPPV was observed in 209 out of the 266 cases in the exam group, and 54 out of the 176 cases in the questionnaire group. The non-recurrence rate was 73.0% at 12 months, 50.0% at 31.4 months, and 26.3% at 60 months. The average interval to recurrence, overall, was 35.4 months. In patients with PC-BPPV, the rate of relapse on the left side was significantly higher than the rate of relapse on the right side (58.2% vs. 41.2%) (P<0.001). The relapse rate of PC-BPPV was significantly higher than that of LC-BPPV (65.2% vs. 51.1%) (P=0.0016). The relapse rate in cases of PC-BPPV in whom the relapse occurred in the PC was significantly higher than that in cases of LC-BPPV in whom the relapse occurred in the LC (56.5% vs. 39.8%) (P=0.0041). There was no significant difference in the relapse rates between the female and male participants.

　 Sleep disorder is a significant comorbidity in patients with dizziness and negatively impacts the patients' quality of life. Dizziness is reported as a risk factor for insomnia. The purpose of this study was to clarify the relationships among self-perceived dizziness handicap, postural balance, and sleep duration in outpatients with dizziness visiting otolaryngology clinics. Toward this end, we reviewed the medical charts of 59 outpatients with dizziness at our otolaryngology clinic and statistically analyzed the data. The results of logistic regression analysis adjusted for sex, age, and medication use (benzodiazepines) revealed that higher total scores (per 10-point increment) on the Dizziness Handicap Inventory (DHI) were significantly associated with sleep durations of 8 hours or longer (1.6 [1.2-2.2], odds ratio [95% confidence interval]). No association was observed between postural balance (velocity of the path length with the eyes closed on posturography) and the sleep duration (0.63 [0.3-1.1]). Receiver Operating Characteristic curve analysis identified a DHI total score of 52 as the optimal cutoff point to identify patients with a predicted sleep duration of ≥ 8 hrs, with a sensitivity of 58% and specificity of 83% (0.72 [0.57-0.87], Area Under the Curve [95% confidence interval]). Both our data and previous reports suggest that higher self-perceived dizziness handicap is associated with a decreased duration of deep sleep as well as a longer duration of sleep as a result of poor sleep quality.

　 Persistent Postural-Perceptual Dizziness (PPPD) is often secondary to vestibular disorders such as Benign Paroxysmal Positional Vertigo (BPPV) and Meniere's disease. However, PPPD secondary to vestibular disorders is often not correctly diagnosed.

　 The Niigata PPPD Questionnaire (NPQ) was created for to screen for PPPD, but its usefulness for evaluating the symptoms of PPPD has not yet been clearly elucidated.

　 A 49-year-old man with paroxysmal vertigo had been treated medically for 20 years as a case of Meniere's disease. He had had persistent dizziness 3 years before even in the intermittent periods [not sure what this means?] and he took long? leave of absence from his job one year prior to his first visit to us. As his score on the NPQ was 43 (cutoff score, 27), we suspected of PPPD secondary to Meniere's disease. Because the scores on the Hospital Anxiety and Depression Scale (HADS) were high, he was prescribed serotonin and noradrenaline reuptake inhibitors (SNRIs). In response to this treatment, his symptoms improved and his score on the NPQ dropped to 20. However, 3 months after he returned to work, the paroxysmal vertigo episodes reappeared. As the score on the NPQ remained as low as 26, we considered that the PPPD was well controlled and the paroxysmal vertigo represented flare-up of only Meniere's disease. Subsequently, the Meniere's attacks improved with lifestyle guidance alone.

　 In summary, we report a case of PPPD secondary to Meniere's disease in which the vertigo episodes were diagnosed as a manifestation of Meniere's disease for a long period of time, despite the presence of typical symptoms of PPPD. NPQ was useful for diagnosing PPPD and evaluating the cause of the vertigo in this patient, which remained stable even in the presence of frequent attacks of Meniere's disease.

　 Vertigo patients with persistent direction-fixed nystagmus in the absence of hearing impairment are often diagnosed as cases of vestibular neuritis. In reality, however, cerebrovascular disorders account for 2.8% to 7% of cases of vertigo, and the possibility of central vertigo should always be kept in mind. In this report, we describe three cases with a final diagnosis of central vertigo in which the initially suspected diagnosis was vestibular neuritis. Case 1 was a case of Wallenberg syndrome due to dorsolateral infarction of the right medulla oblongata. Case 2 was a case of multiple cerebral infarction (medulla oblongata and cerebellum) also manifesting various other symptoms, including ataxia of the trunk, diplopia, right bias, numbness of the hands, and speech disorder. Case 3 was a case of MLF syndrome with ocular adduction disorder and rotatory nystagmus; the infarct site was at the level of the midbrain to pons on the affected side. All three patients had dizziness with constant directional nystagmus, which was diagnosed as being derived from vestibular neuritis at the time of the initial examination. Especially in cases with suspected brainstem or cerebellar symptoms, such as sensory disturbances, eye movement disorder, and trunk ataxia, it is important to make every effort to rule out central vertigo.

　 We report a case of intralabyrinthine schwannoma with endolymphatic hydrops. A 60-year-old man presented with sudden onset of right-sided hearing loss, aural fullness, tinnitus, and dizziness. His pure-tone audiograms showed mild-to-moderate sensorineural hearing loss, particularly at low frequencies, which, however, spread across all frequencies after a few days. The distortion-product otoacoustic emission (DPOAE) level of the right ear had decreased below the noise level. Equilibrium function tests showed slight leftward spontaneous nystagmus and semicircular canal paralysis in the right ear. The hearing level then gradually recovered once and then began to fluctuate. Gadolinium-enhanced T1-weighted imaging revealed an intralabyrinthine schwannoma, corresponding to “Intravestibular type” of the Modified Kennedy classification system. Four-hour delayed gadolinium-enhanced 3D-FLAIR MR images showed strong enhancement in the right cochlea and lateral semicircular canal, and HYDROPS images revealed endolymphatic hydrops at the apical and middle turns in the cochlea. Follow-up MRI showed persistent strong enhancement in the right cochlea and revealed that the cochlear endolymphatic hydrops had developed to the basal rotation too over a one-year period. Alterations in the blood-labyrinth barrier permeability and endolymphatic hydrops due to obstruction of the endolymphatic cavity were assumed as being involved in the pathogenesis of the cochlear symptoms in this case.

　 Dizziness and imbalance are the most common complaints in older people, and are a growing public health concern. Although the causes of dizziness in older people are multifactorial, peripheral vestibular dysfunction is one of the most frequent causes. Every factor associated with the maintenance of postural stability deteriorates with aging. Age-related deterioration of peripheral vestibular function has been demonstrated through quantitative measurements in the vide head impulse test and evaluation of the vestibulo-collic reflex by testing of vestibular evoked myogenic potentials. Age-related decline of vestibular function has been shown to be correlated with the age-related decrease in the number of vestibular hair cells and neurons. Other factors associated with postural stability, such as somatosensation, visual acuity, cerebellar function, and muscle strength also decline with age. In examining older patients with dizziness or imbalance, it is important to assess each factor associated with postural stability. To improve postural stability, it is recommended that strategies be devised to improve the impaired functions based on the results of the above assessments.

　 Benign paroxysmal positional vertigo (BPPV) is the most commonly encountered peripheral vestibular disorder in clinical practice. The prevalence rate of BPPV has been reported to be higher in older adults than in younger individuals. Although there is evidence for the effectiveness of the canalith repositioning procedure (CRP) for posterior canal BPPV, the success rate of this procedure has been reported to be significantly lower in older patients as compared with younger patients. Since BPPV often improves spontaneously, it is not necessary to perform the CRP in older patients with cervical or lumbar disorders. BPPV should be differentiated from other diseases, including central positional vertigo and vertebrobasilar insufficiency associated with the complaint of cervical vertigo.

　 Meniere's disease is more common in individuals aged 30-50 years and stress has been strongly suggested as being involved in its pathogenesis. The age of onset has been increasing gradually, with a trend towards increased incidence in older adults. Stressors and concerns unique to older adults, such as family caregiving for older adults, anxiety about health loss, and loneliness due to increases in sole–person households have been considered as possible causes. In 2020, the guideline for the treatment of Meniere's disease were revised to add positive pressure therapy for intractable Meniere's disease. Positive pressure therapy is non–invasive and easy to perform in older patients.

　 Recently, we have developed a wearable device, the Tilt Perception Adjustment Device (TPAD), that transmits vibratory input containing head–tilt information to the mandible to substitute for defective vestibular information in patients with unilateral and bilateral vestibulopathy. We assessed patients using the Dizziness Handicap Inventory (DHI) and performed gait analysis in older patients with unilateral and bilateral vestibulopathy. Three months after sensory substitution therapy using TPAD, the DHI and gait parameters in the patients with unilateral vestibulopathy improved on condition that the patients did even when the patients were not wearing the TPAD. In the patients with bilateral vestibulopathy, on the other hand, the gait parameters improved only on condition that, but only when they wore the TPAD. TPAD had potential applications as a wearable device, improving posture control in patients with unilateral and bilateral vestibulopathy.