Paroxysmal alternating skew deviation and nystagmus after partial destruction of the uvula

A patient with suspected brain stem glioma involving the area of the left vestibular nuclei and cerebellar peduncle, developed paroxysmal alternating skew deviation and direction changing nystagmus after biopsy of the inferior cerebellar vermis resulting in destruction of the uvula. Between attacks she had right over left skew deviation with asymptomatic right beating horizontal nystagmus. Slow phases of the resting nystagmus showed increasing velocity, similar to congenital nystagmus. At intervals of 40-50 seconds, paroxysmal reversal of her skew deviation occurred, accompanied by violent left beating horizontal torsional nystagmus lasting 10-12 seconds and causing severe oscillopsia. It is proposed that this complex paroxysmal eye movement disorder results from (1) a lesion in the left vestibular nuclei causing right over left skew and right beating resting nystagmus and (2) a disruption of cerebellar inhibition of vestibular nuclei, causing alternating activity in the vestibular system with intermittent reversal of the skew deviation and paroxysmal nystagmus towards the side of the lesion.     

Alternating skew on lateral gaze (bilateral abducting hypertropia)

We report thirty-three patients with alternating skew deviation on lateral gaze. The right eye was hypertropic in right gaze, and the left eye was hypertropic in left gaze. Most patients had associated downbeat nystagmus and ataxia and were diagnosed as having lesions of the cerebellar pathways or the cervicomedullary junction. This contrasts with a previous report in which alternating skew was seen mainly in lesions of the midbrain pretectum.     

Surgical management of skew deviation.

There are no published data on the outcomes of realignment surgery for skew deviation. A retrospective chart review disclosed 10 patients who had undergone surgical correction of skew deviation by three surgeons at a single institution between 1991 and 2002. Nine of 10 patients had satisfactory relief of diplopia with an acceptable field of single binocular vision. Vertical rectus recession or resection was the most common procedure. Four patients required more than one procedure. For nonalternating hypertropias, resection of the inferior rectus muscle or recession of the superior rectus muscle of the hypertropic eye was successful. For alternating hypertropia, resection of both inferior rectus muscles was successful. Oblique muscle surgery was not associated with good outcomes.     

Upbeat nystagmus in a patient with a small medullary infarct.

A 43 year old man presented with decreased sensitivity in the left side of the face and both upper limbs, and with upbeat nystagmus and skew deviation. MRI demonstrated a well defined lesion compatible with an infarct in the left side of the medulla, caudal and ventral to the vestibular nuclei, possibly involving the most caudal of the perihypoglossal nuclei, the nucleus intercalatus. Ocular motor studies, using an infrared system, showed that the nystagmus slow phase decayed exponentially, suggesting a failure of integration for vertical eye movements. Vertical integration might, therefore, be performed partly in the nucleus intercalatus.     

Syringobulbia as a cause of laryngeal stridor in childhood.

A 10-year, 11-month-old boy who had had chronic stridor since birth died suddenly following the development of slowly progressive symptoms of respiratory obstruction due to vocal cord paralysis. Autopsy showed extensive bilateral syringobulbia, with the greatest involvement in the nuclei ambigui. Other brain-stem tracts and nuclei were only partially affected. These findings support the theory of the early developmental origin of syringobulbia.     

Fast eye movement initiation of ocular torsion in mesodiencephalic lesions

Three patients with episodic ocular torsion and skew deviation due to mesodiencephalic lesions were studied by using binocular three-dimensional scleral search coils. The conjugate ocular torsion (upper pole of each eye rotating toward the side of the brainstem lesion) was initiated by a torsional fast eye movement. During prolonged episodes, torsional nystagmus was also present. Cessation of the ocular torsion and skew deviation occurred by slow eye movements with exponentially decreasing velocities in 2 patients, and by multiple fast torsional movements in 1 patient. In 1 patient, the abnormal eye movements were temporally linked to dystonic movements in the limbs on the side opposite the brainstem lesion. The occurrence of skew deviation with conjugate ocular torsion in brainstem lesions has been attributed to functional asymmetry in vestibular pathways responsible for the slow-phase compensatory eye movement response to roll. In comparison, the findings in our patients show that in mesodiencephalic lesions conjugate ocular torsion with skew deviation may be generated by torsional fast eye movements, indicating activation of the burst cells of the rostral interstitial nucleus of the medial longitudinal fasciculus.     

Electrical activity in the red nuclei of rats and the effects of hemicerebellectomy at young ages

Extracellular activity in the red nuclei in different behavioural states was investigated in control adult rats and in adults rats who had previously undergone a cerebellar hemispherectomy on their 2nd, 5th, 10th or 20th day. In addition to visual analysis, spectra and coherence functions were computed from the signals during quiescence and movements. Preceding and during movements a particular pattern, characterized by a regular rhythm between 7.5 and 8.0 Hz occurs. Inter-rubral coherences are high at the specific pattern frequency. In rats with a cerebellar hemispherectomy - irrespective of the age at lesioning - power spectra from both red nuclei differ markedly from each other during quiescence. When movements occur, rats operated at the 20th day show a pattern in both red nuclei similar to that found in control rats. However, in rats lesioned at the 5th or 10th day the specific pattern frequency is much lower while in rats operated at the 2nd day no specific patterning of red nuclei activity is evident.     

Alternating skew deviation: 47 patients

Of 408 patients with ocular skew deviation, 47 (12%) had hypertropia that alternated on gaze to either side. Pretectal lesions were responsible for 29 cases, and lower brainstem signs were seen in 5; the site of posterior fossa involvement was uncertain in 13. Acute hydrocephalus, tumors, strokes, and MS were the most frequent causes, followed by spinocerebellar degeneration and tentorial herniation. The mechanism of alternating skew is unknown, but probably involves pathways from both utricles to the vertical-rotatory ocular motor neurons.     

Strabismus and Micro-Opsoclonus in Machado-Joseph Disease

We describe novel deficits of gaze holding and ocular alignment in patients with spinocerebellar ataxia type 3, also known as Machado-Joseph disease (MJD). Twelve MJD patients were studied. Clinical assessments and quantitative ocular alignment measures were performed. Eye movements were quantitatively assessed with corneal curvature tracker and video-oculography. Strabismus was seen in ten MJD patients. Four patients had mild to moderate intermittent exotropia, three had esotropia, one had skew deviation, one had hypotropia, and one patient had moderate exophoria. Three strabismic patients had V-pattern. Near point of convergence was normal in two out of three patients with exotropia. Gaze holding deficits were also common. Eight patients had gaze-evoked nystagmus, and five had micro-opsoclonus. Other ocular motor deficits included saccadic dysmetria in eight patients, whereas all had saccadic interruption of smooth pursuit. Strabismus and micro-opsoclonus are common in MJD. Coexisting ophthalmoplegia or vergence abnormalities in our patients with exotropia that comprised 50 % of the cohort could not explain the type of strabismus in our patients. Therefore, it is possible that involvement of the brainstem, the deep cerebellar nuclei, and the superior cerebellar peduncle are the physiological basis for exotropia in these patients. Micro-opsoclonus was also common in MJD. Brainstem and deep cerebellar nuclei lesion also explains micro-opsoclonus, whereas brainstem deficits can describe slow saccades seen in our patients with MJD.     

Geotropic ocular deviation with skew and absence of saccade in Creutzfelt-Jakob disease.

Three patients with Creutzfelt-Jakob disease (CJD) showed characteristic ocular manifestations. The head was turned left or right with the eyes deviated downward and skewed. When the head was turned to one side, the eyes very slowly deviated to that side. In addition, spontaneous ocular movements were very slow with no saccadic component early in the apathetic stage. Caloric stimulation produced tonic deviation to the appropriate side without nystagmus. At autopsy one patient showed lesions compatible with the panencephalopathic type of CJD. Although bilateral pretectal areas had marked gliosis, other nuclei and structures associated with oculomotor system in the brainstem, including the oculomotor, trochlear, abducens, vestibular and perihypoglossal nuclei, medial longitudinal fasciculus and para-median pontine reticular formation were preserved. These patients had a supranuclear disorder, probably caused by combined disruption of the direct and indirect frontal eye field to the brainstem pathways plus impairment of the superior colliculus-mediated saccade pathways.     

Longitudinal cognitive and motor changes among presymptomatic Huntington disease gene carriers.

OBJECTIVE: To determine whether longitudinal changes in cognitive and motor function can be detected among clinically presymptomatic individuals carrying the Huntington disease (HD) allele. DESIGN: A longitudinal, case-control, double-blind study comparing presymptomatic gene carriers and non-gene carriers at risk for HD examined an average of 3.7 years apart. SETTING: The Department of Medical and Molecular Genetics at a general clinic research center in Indianapolis, Ind. PARTICIPANTS: A sample of 43 at-risk individuals consisting of presymptomatic gene carriers (n = 12) and non-gene carriers (n = 31). MEASURES: Huntington disease gene status was determined by molecular testing of the HD gene. Subscales from the Wechsler Adult Intelligence Scale-Revised and a quantified neurologic rating scale were administered. RESULTS: Scores on the digit symbol subscale of the Wechsler Adult Intelligence Scale-Revised (P<.05) and 2 neurologic variables-optokinetic nystagmus (P<.01) and rapid alternating movements (P<.005)-declined more rapidly among presymptomatic gene carriers than among non-gene carriers. At follow-up examination, compared with nongene carriers, presymptomatic gene carriers had significantly lower scores on the digit symbol subscale (P = .02) and for 4 neurologic variables-rapid alternating movements (P<.005), optokinetic nystagmus (P<.001), overall ocular movements (P<.02), and chorea of the trunk (P<.02). CONCLUSIONS: Psychomotor speed, optokinetic nystagmus, and rapid alternating movements demonstrated significant decline early in the pathological process of HD. These results suggest that subtle worsening of psychomotor, oculomotor, and motor functions occurs before the onset of signs sufficient to make a clinical diagnosis in individuals who have inherited the HD allele.     

Acquired pendular nystagmus: its characteristics, localising value and pathophysiology

Investigations were made of 16 patients with acquired pendular nystagmus and a further 32 cases reported in the literature were reviewed. Amongst our own patients two thirds had multiple sclerosis, almost one third a cerebrovascular accident or angioma and two had optic atrophy with squint. The nystagmus took forms which could be monocular or binocular, conjugate or disconjugate and could involve movements about single or multiple axes. Spectral analysis was used to characterise the amplitude and frequency of the movements and to estimate the degree of relationship (coherence) between movements of the two eyes or between movements of one eye about several axes. The oscillations ranged in frequency from 2·5 Hz to 6 Hz, with typical amplitudes between 3° and 5°. In a given patient all oscillations, regardless of plane, were highly synchronised. Somatic tremors of the upper limb, face and palate associated with the nystagmus were often at similar frequencies to the eye movement. The other ocular signs common to all our patients were the presence of squint with failure of convergence. Most patients also had skew deviation or internuclear ophthalmoplegia or both. The major oculomotor systems, that is, saccades, pursuit, optokinetic and vestibulo-ocular reflexes could be intact. It is inferred that the mechanism responsible for the pendular nystagmus lies at a level which is close to the oculomotor nuclei so that it can have monocular effects but is not part of the primary motor pathways. It is possible that this mechanism normally subserves maintenance of conjugate movement and posture of the eyes. The periodicity of the nystagmus is likely to arise from instability in a certain type(s) of neurone, for the associated somatic tremors have similar characteristics and yet involve very different neuronal muscular circuitry. Prognosis for cessation of the nystagmus is poor. In five patients with multiple sclerosis it was suppressed by intravenous hyoscine with, however, unacceptable subsequent side effects.     

Alternating oblique deviation of the gaze. 3 cases

Three cases of alternating skew deviation of gaze are reported. In two patients, it was associated with oculomotor disorders suggestive of a medial mesencephalic lesion. CT scan showed 3rd ventricule abnormalities accounting for the mesencephalic involvement. The third patient had a tuberculous meningo-encephalitis with basal symptoms. The pathophysiological mechanisms of the vertical interocular divergence is discussed. It was probably related to a bilateral disorder of the superior recti and an overaction of the inferior obliques. It suggested a medial supranuclear dysfunction.     

Abnormal eye movements in Creutzfeldt–Jakob disease

We report 3 patients with autopsy-proven Creutzfeldt–Jakob disease who, early in their course, developed abnormal eye movements that included periodic alternating nystagmus and slow vertical saccades. These findings suggested involvement of the cerebellar nodulus and uvula, and the brainstem reticular formation, respectively. Cerebellar ataxia was also an early manifestation and, in 1 patient, a frontal lobe brain biopsy was normal at a time when ocular motor and cerebellar signs were conspicuous. As the disease progressed, all saccades and quick phases of nystagmus were lost, but periodic alternating gaze deviation persisted. At autopsy, 2 of the 3 patients had pronounced involvement of the cerebellum, especially of the midline structures. Creutzfeldt-Jakob disease should be considered in patients with subacute progressive neurological disease when cognitive changes are overshadowed by ocular motor findings or ataxia.     

Mirror movements and involuntary homolateral limb synkinesis in a patient with probable Creutzfeldt–Jakob disease

We report a 63-year-old man, who was diagnosed with probable Creutzfeldt–Jakob disease, manifested by rapid progressive cognitive decline, gait disturbance, right focal hand dystonia, myoclonus, mirror movements, and involuntary homolateral limb synkinesis during alternating limb movements. Although the exact pathophysiology for contralateral and homolateral limb synkinesis is not known, dysfunction of the secondary motor areas and dorsal premotor cortex by spongiform degeneration of gray matter may cause these abnormalities.     

ASSESSMENT OF NEUROLOGICAL "SOFT SIGNS" IN ADOLESCENTS: RELIABILITY STUDIES

The validity and reliability of a scoring system for 'neurological soft signs' in teenagers was assessed. Six scales were adapted and fitted into the framework of a conventional neurological examination. The following emerged: each of the three multi-item scales had high internal consistency; inter-rater agreement on mirror movements of 'live' subjects was satisfactory; ratings of videotapes agreed among examiners for mirror movements and dysdiadochokinesis but not for choreiform movements; data-based cut-off scores defining present vs. absent were congruent with the ratings of outside neurologists; and each examiner was consistent in rating mirror movements and rapid alternating movements from videotapes over several months.     

Movement cueing and motor execution in patients with dystonia: a kinematic study.

To investigate whether the type of movement cueing influences motor performance in patients with dystonia, we studied externally triggered (ET) and self-initiated (SI) sequential rapid arm movements in patients with generalized or focal dystonia and healthy control subjects. The ET task required subjects to initiate movements in response to consecutive visual cues; the SI task allowed them to start at will. To determine whether patients found sequential motor tasks more difficult than single tasks, we also analyzed single ET movements. Control subjects performed the SI task significantly faster than the ET task. Their single ET movements and first ET sequential submovements had similar speeds. Patients with generalized dystonia were slow in performing the single movement, the ET and the SI sequential tasks, and they executed the SI sequence more slowly than the ET. They made long pauses between SI sequential submovements, had longer reaction times during the ET sequences, and performed the first ET submovement more slowly than the single ET movement. Patients with focal dystonia had normal reaction times but they performed single and sequential tasks slowly, made long pauses during SI tasks, and also executed the first ET submovement more slowly than the single ET movement. Our findings indicate that patients with dystonia have a general impairment of sequential movements. The more marked slowness in executing SI than ET movements observed in patients with generalized dystonia shows that dystonia impairs internal cueing more than external cueing mechanisms. Overall, these findings imply abnormal activation of primary and nonprimary motor areas during movement in dystonia. The greater impairment of SI tasks as well as the delayed motor responses during ET task suggest predominant underactivity of the supplementary motor area.     

Cerebellar mediation of the complexity of bimanual compared to unimanual movements.

OBJECTIVE: To study rapidly alternating movements under fMRI in order to identify the brain regions that mediate increased complexity in bimanual vs unimanual movements and to verify the localization of a clinical test of limb ataxia (diadochokinesis). METHODS: Unimanual and bimanual movements, that is, palm(s) pronated then supinated, served as stimulation in a block design fMRI investigation at 1.5 T. Analyses compared bimanual movements and rest for each hand separately and the unimanual conditions combined. A pronation/supination task was chosen as it provides the same objective motor output during unimanual and bimanual formats. The increased coordination demand of the bimanual format (phase/antiphase movements) was expected to result in distinct activation in supplementary motor, primary motor, prefrontal, and cerebellar regions. RESULTS: The bimanual task uniquely elicited responses in specific anterior medial and posterior (vermal) cerebellar regions. CONCLUSIONS: The study corroborated clinical use of diadochokinesis tasks to test for aspects of cerebellar integrity. The data do not support the literature emphasizing basal ganglia mediation of this type of coordinated movement. Cerebellar medial and vermal regions (in connection with central nuclei) are proposed as the locus within the cerebellum for mediating complexity, that is, the effective integration of separate limb movements that proceed in an asynchronous but systematic fashion.     

Vergence deficits in pontine lesions

Eye movements were recorded with the search coil system in two patients to determine whether lesions of the pontine nuclei selectively impair vergence to ramp targets (slow vergence) or step targets (fast vergence). Whereas conjugate saccades were not different from healthy control subjects, conjugate smooth pursuit eye movements had a reduced gain in horizontal and vertical directions. Slow convergence and divergence were impaired, whereas fast vergence did not differ from that of control subjects. Pontine nuclei appear to be involved in the slow vergence control.     

A case report of pure micrographia progressing over 5 years--an early sign of "pure akinesia"?]

We report a 68-year-old man who have had only slowly progressive micrographia in both hands over the past 5 years without rigidity, tremor, bradykinesia, and festination or freezing in walking. The fine finger movements were normal. PET studies suggested the diagnosis of progressive supranuclear palsy or pure akinesia. Administration of L-DOPA and L-threo-DOPS did not improve his micrographia. Festination and freezing in writing may contribute to the genesis of micrographia in this case. We postulate that "pure micrographia" is an early atypical sign of pure akinesia.