Spinocerebellar degeneration (SCD) is a group of neurodegenerative disorders characterized by progressive cerebellar ataxia with or without symptoms/signs of pyramidal, extrapyramidal, or peripheral nerve involvement. Patients frequently exhibit unsteadiness of gait associated with nystagmus, which could also be observed in patients with peripheral vestibular impairment. Thus, some of these patients often initially seek consultation with an otolaryngologist. To distinguish SCD from other peripheral vestibular disorders, it is necessary for otolaryngologists to understand the characteristics of SCD.

　 Brainstem and cerebellar lesions affect physiological eye movements, so that the patients often present with various eye movement abnormalities. Slow saccades, saccade dysmetria, down-beat nystagmus, and impairment of smooth pursuit are some of the typically observed abnormalities. Reduced bilateral VOR has been observed in MJD/SCA3 patients, especially developed more those with a disease duration of longer than six years. SCA6 patients, considered as showing pure cerebellar ataxia, show dissociation between control of gaze tracking during smooth pursuit and VOR cancellation. This result indicates that the cerebellar Purkinje cells are not involved in the non-pursuit VOR cancellation system. Therefore, it is important for otorhinolaryngologists to be alert to typical eye movement impairments.

　 A 50-year-old woman visited a neighborhood hospital with a one-year history of paroxysmal dizziness and right-sided hearing loss recurring at least once a month and lasting for approximately 5 hours each time. Recently, the frequency of dizziness had increased to once a week, with the symptom lasting for approximately 7 hours each time. The patient experienced seizures, and had lost 5 kg of body weight. She was treated for right-sided Meniere's disease at another hospital, but as there was no improvement, she was referred to our department.

　 At the first consultation, she had only mild hearing loss in the right ear. However, a pure-tone audiogram recorded during an episode of dizziness showed low-tone sensorineural hearing loss on the right side. Contrast-enhanced MRI of the inner ear revealed vestibular endolymphatic hydrops on the right side. No difference in the cVEMP was observed between the right and left ears. Based on the findings, the patient was diagnosed as having right-sided Meniere's disease with vestibular migraine (vestibular migraine-overlapping syndrome, VMOS). While two courses of intraventricular dexamethasone administration failed to have any therapeutic effect, intraventricular gentamycin administration clearly suppressed the dizziness. however, the patient continued to suffer from migraine and dizziness more than 10 times a month. Finally, subcutaneous administration of a human anti-CGRP receptor monoclonal antibody (erenumab) reduced the frequency of headache and dizziness.

　 Patients with VMOS present with intractable dizziness. Anti-CGRP receptor monoclonal antibody could be effective for treating VMOS. Continuity of treatment and concomitant treatments should be further discussed with headache specialists.

　 Vestibular migraine (VM) is a disorder characterized by recurrent headaches and vertigo. Meniere's disease (MD) is also characterized by similar symptoms, and it is often difficult to differentiate between the two conditions. Therefore, we focused on differences in the temperament and mood of these patients, including their emotional intelligence and anxiety levels. Emotional intelligence is the ability to respond to self, interpersonal situations, and situations surrounding the self, and can be evaluated using the Emotional Intelligence Quotient Scale (EQS). In this study, we conducted a comparative assessment to explore the differences in the scores on the EQS between patients with VM and patients with MD complaining of dizziness. The subjects were 63 patients with VM and 129 patients with MD. Finally, 32 patients each with VM and MD matched for age and sex were included in the evaluation. Our results showed that patients with VM had lower scores on self-response, interpersonal response, and situational response than the patients with MD with particularly low scores on the subfactors of `self-motivation,' `self-control,' and `leadership'. No significant difference in the State-Trait Anxiety Inventory (STAI) was observed between the two patient groups, although the values were slightly higher in the patients with VM than in those with MD. No significant difference in the DHI or VAS was observed either. The patients with VM showed similar characteristics of previously reported migraine. We were prompted to conduct this comparative study, as there are no comparative assessments by the EQS, until date, of patients with VM, patients with MD, and healthy subjects.

　 Periodic alternating nystagmus (PAN) is defined as abnormal horizontal eye movements in periodically alternating directions, and the condition could be both congenital and acquired. Acquired PAN refers to a spontaneous horizontal nystagmus, present in central gaze, reversing in direction periodically. Acquired PAN has been reported to occur in association with a number of conditions, many of which involve the cerebellum.

　 Paraneoplastic neurological syndrome (PNS) is a rare syndrome representing the remote effects of a cancer, that is often associated with the presence of specific serum antibodies. PNS can affect the central, peripheral, and autonomic nervous systems at various levels. Clinically, it is characterized by subacute progression of neurological dysfunction and substantial refractoriness to therapies.

　 We report a case of PNS that presented with dizziness and light headedness. A woman in her 60s visited our otolaryngology department complaining of dizziness and light-headedness. At the first visit, she showed PAN in the front view in the sitting position and in the positional nystagmus test. She was hospitalized for gait disturbance.

　 A central lesion was suspected and MRI was performed, but there were no abnormalities. PNS was also suspected and whole-body CT was performed, which revealed no abnormalities. Under the suspicion of autoimmune cerebellar ataxia and acute cerebellitis, we started the patient on steroid pulse therapy. Although the PAN persisted, her dizziness improved, and she became able to walk and was discharged from the hospital. Three months after discharge from the hospital, she visited another hospital complaining of breathlessness on exertion, and a chest CT revealed an abnormal opacity with atelectasis in the right middle lobe of the lung. Detailed clinical examination and transbronchial lung biopsy at the respiratory department led to a diagnosis of small cell lung cancer, and the PAN was thought to be caused by paraneoplastic syndrome.

　 Vestibulo-ocular reflex (VOR), one of brainstem reflexes that maintains balance, is controlled by the cerebellum. This cerebellar control system of VOR is further coordinated by the cerebrum (e.g., visual suppression of VOR). Therefore, in central lesions, dysregulated, abnormally increased VOR gain may be the underlying pathology of chronic dizziness, unlike in peripheral vestibulopathy, which always involves decreased VOR gain.

　 The characteristics of VOR dysregulation are quite different between brainstem-cerebellar lesions and cerebral lesions. Abnormally increased VOR gain is the major mechanism underlying the chronic dizziness in patients with brainstem-cerebellar lesions, whereas decreased visual suppression rate of VOR is the major mechanism underlying the chronic dizziness in patients with cerebral lesions. Of course, there could be coexisting peripheral vestibulopathy (decreased VOR gain), so that it is necessary to consider all pathologies causing increased VOR gain, decreased visual suppression rate of VOR, and decreased VOR gain to identify the precise mechanism of dizziness, especially in eldery people.