A Case of Acute Vestibular Neuritis with Periodic Alternating Nystagmus / 대한이비인후과학회지

Detection of nystagmus is an important diagnostic clue in patients with acute vertigo. Patients with peripheral disorders exhibit nystagmus with a constant direction whereas those with central disorders exhibit nystagmus with changes in direction with or without gaze fixation. Periodic alternating nystagmus (PAN) is a horizontal or horizontal-rotary jerk-type nystagmus that reverses its direction with time. PAN is typically observed in patients with central disorders, such as cerebellar or pontomedullary lesions, but it is also observed in patients with peripheral disorders, albeit rarely. Here we report a rare case of a 58-year-old patient with vertigo with PAN, which was initially suspected as a central disorder, but eventually diagnosed as a peripheral vestibular disorder. We investigated the characteristics and mechanisms of peripheral PAN in this case. The absence of central disorder symptoms, visual suppression of PAN, normal oculomotor findings, and transient persistence are important diagnostic clues for differentiating peripheral from central PAN.

A Case of Patient with Meniere's Disease Who Presented Periodic Alternating Nystagmus / 대한평형의학회지

Periodic alternating nystagmus (PAN) is a spontaneous horizontal jerky nystagmus that reverses its direction periodically with a quiescent interval. PAN has been reported in acquired and congenital forms. The main lesion site of the acquired form of PAN has been attributed to the caudal brainstem or cerebellum. Herein we report a 63-year-old male patient with Meniere's disease, who presented PAN during a vertigo attack. The patient demonstrated no abnormality on neurologic evaluation and brain imaging, which is different feature compared to the central or congenital form of PAN. It should be kept in mind that peripheral vestibular disorders such as Meniere's disease can produce PAN.

Periodic Alternating Nystagmus in Patients with Cerebellar Abscess / 대한평형의학회지

Periodic alternating nystagmus (PAN) is characterized by a periodical reversal in the direction of the nystagmus. Acquired PAN is caused by lesions of the inferior cerebellar vermis, causing disinhibition of the velocity storage mechanism, which is mediated by the vestibular nuclei. An eighty-year-old woman with abscess in midline cerebellum experienced dizziness and imbalance. We observed short period PAN with 7-8 seconds.

A Case of Isolated Cerebellar Nodulus Infarction with Periodic Alternating Nystagmus and Unilateral Vestibulopathy

We report a patient with an isolated cerebellar nodulus infarction who presented with periodic alternating nystagmus (PAN), perverted head-shaking nystagmus (pHSN), and loss of tilt suppression of the vestibulo-ocular reflex (VOR). Several days after the initial symptoms resolved, the patient also presented with purely vestibular syndrome with vertigo, spontaneous horizontal nystagmus without the usual signs of cerebellar dysfunction. The chain of those symptoms were ascribed to ischemia of the cerebellar nodulus.

Diagnosis and Management of Congenital Periodic Alternating Nystagmus

PURPOSE: To investigate clinical findings, diagnostic criteria and management for patients with congenital periodic alternating nystagmus (PAN). METHODS: A retrospective analysis of clinical findings and electrooculography (EOG) of patients with congenital PAN was performed. Thirteen patients diagnosed with congenital PAN from March 1992 to December 2002 were included. RESULTS: Of 13 patients, the median age at initial visit was 7 years old (range: 1 to 30 years). Eight patients had abnormal head posture. The mean value for the period of alteration was 265.7 seconds. Six patients who received either the modified Kestenbaum-Anderson procedure or four rectus muscle recession showed a significant decrease in amplitude and/or frequency of nystagmus, and showed statistically significant improvement in visual acuity in LogMAR after the procedures by 0.33+/-0.09 in right eye, 0.34+/-0.11 in the left eye, compared with preoperative acuities of 0.43+/-0.19 and 0.38+/-0.09 respectively. CONCLUSIONS: Congenital PAN requires the evaluation of nystagmus along with a thorough evaluation of eye movement and EOG. Close follow is necessary to evaluate the pattern of nystagmus. Also, either modified Kestenbaum-Anderson procedure or four rectus muscle recession could be effective, depending on the presence of abnormal head posture.

Periodic Alternating Nystagmus from Focal Cerebellar Lesion

Periodic alternating nystagmus (PAN) is characterized by a periodical reversal in the direction of the nystagmus. PAN has rarely been reported in discrete cerebellar lesions. We report a patient with PAN from a focal cerebellar lesion, which developed after removal of an ependymoma in the fourth ventricle. The nystagmus decreased upon tilting the head in the direction of the nystagmus. The positional modulation of the nystagmus supports that PAN occurs from an abnormal velocity storage mechanism.

Acquired Periodic Alternating Nystagmus

Periodic alternating nystagmus is a rare form of horizontal jerk nystagmus characterized by a periodical reversal in the direction of nystagmus. It implies a cerebellar disorder or lesions involving the vestibulocerebellar connections. We report a patient with an acquired form of periodic alternating nystagmus associated with meningoencephalitis. Its waveform characteristics were demonstrated by a video-nystagmogram. The brainstem lesions in our patient were thought to be responsible for her nystagmus.

Two Cases of Acute Cerebellitis

Acute cerebellitis occurrs in the absence of cerebral hemispheric involvement and is exceptionally rare. It is charac-terized by an acute onset of cerebellar dysfunction following a respiratory, gastrointesitnal infection or skin rash. However, almost all patients show good prognosis. We experienced two cases of acute cerebellitis in young adults. One patient was admitted due to gait ataxia and dysarthria. The immunological laboratory findings revealed an acute Ebstein Barr virus infection and an electronystagmogram showed a periodic alternating nystagmus. The other patient was admitted due to severe gait ataxia, with no identification of any organism. CSF examinations revealed elevated protein and brain magnetic resonance images showed cerebellar foliae enhancement bilaterally. Both patients recovered without any disabilities.

Periodic Alternating Nystagmus Associated with Chiari-1 Malformation and Syringomyelia

Periodic alternating nystagmus(PAN) is a form of spontaneous nystagmus with a specific pattern. It may be of congenital origin in many cases, and may be related to vestibulo-cerebellar system disease. It usually causes not only many ophthalmic problems such as decreased vision but also neurologic symptoms such as ataxic gait. So, ophthalmologist must perform both ophthalmic and neurologic examinations. Nystagmus can be treated with muscle relaxant. We report our experience about 30-year-old woman who complained of involuntary ocular movement and ataxic gait, and were diagnosed as PAN associated with Chiari-1 malformation and syringomyelia through electronystagmography and brain MRF.

Periodic Alternating Nystagmus

Periodic alternating nystagmus is a horizontal jerk nystagmus that periodically changes in amplitude and directions every 3 or 4 minutes. Usually the eyes beat in one direction for approximately 90 seconds and then go into a null phase for 10 to 20 seconds before beginning to move in the opposite direction and continued about 90 seconds. The exact mechanism is unknown but the rhythmic alteration of the null zone of horizontal jerk nystagmus is taken as a possible mechanism. These patients periodically show alternating head turning. The authors report 6 cases of congenital periodic alternating nystagmus which show horizontal jerk nystagmus of rhythmic direction change and confirmed by electro-oculogram.