Oculomotor Findings Research Articles

神経耳科学的所見が診断の手がかりとなった小脳梗塞症例

A 53-year-old woman with cerebellar infaction who complained of dizziness as an isolated symptom was presented. She had a normal brain CT scan and no neurological abnormalities at the onset, and she was initially diagnosed as having peripheral vestibular disorder. However, her oculomotor findings obtained 1 week after the onset revealed an impaired pursuit eye movement, lower gain on optokinetic nystagmus, and a failure of visual suppression on a caloric nystagmus test. From the neurootological findings, we suspected that she had a cerebellar lesion and an MRI revealed increased signal intensity in the cerebellar hemisphere. Consequently, the patient was diagnosed as having cerebellar infarction.Symptoms of cerebellar infarcts are frequently similar to those of peripheral vestibular disease, and such patients may be overlooked if neurootological tests are not performed. In particular, oculomotor tests in patients with vertigo/dizziness are very useful to differentiate central nervous system disorders from peripheral vestibular disorders.

Oculomotor phenotypes in autosomal dominant ataxias.

To quantify the oculomotor features of the common spinocerebellar ataxia (SCA) syndromes. University ataxia clinic. Twenty probands with documented SCA mutations. Electro-oculographic recordings of saccadic, smooth pursuit, optokinetic, vestibular, and visual-vestibular eye movements. Distinct phenotype and genotype patterns were identified with modest overlap between patterns. Slowing of saccade peak velocities occurred only in SCA1 and SCA2, being present in 100% of patients with SCA2. Impaired vestibulo-ocular reflex gain occurred with SCA3 only. Patients with SCA6 had prominent deficits in smooth tracking but normal saccade velocities and vestibuloocular reflex gain. The oculomotor findings are consistent with pure cerebellar involvement in SCA6, pontine involvement in SCA1 and SCA2, and vestibular nerve or nuclei involvement in SCA3. These phenotypes can be useful for clinical diagnosis and for investigating the mechanism of system specificity with the SCA syndromes.

Ocular Neuromyotonia in a Case of Paget??s Disease of Bone

The authors report a case of Pager's disease of bone and ocular neuromyotonia (ONM) in a 72-year-old woman. As far as we are aware, this association has never been previously described. The patient had an acquired left third cranial nerve palsy with oculomotor synkinesis and a left sixth cranial nerve palsy, Subjectively, she complained of recurring episodes of transient horizontal and vertical diplopia, lasting for about 30-40 sec and accompanied with discomfort in the left eye (LE), During those episodes, which occurred spontaneously or after sustained eccentric gaze, the LE became more esotropic with increasing restriction of abduction or hypotropic with increasing restriction of elevation. Electromyography (EMG) of the left medial rectus detected repetitive bursts of motor unit potentials with aspect of 'multiplets'. The oculomotor findings and the neurophysiological data evoked the diagnosis of ocular neuromyotonia which was subsequently confirmed by the effective response to carbamazepine. The patient had no history of radiation therapy, a frequent association of ONM. Cerebral and orbital CT scan showed a severe remodelling of the base of the skull, We suggest that cranial nerve palsies as clinically present in this patient, even if not neuroradiologically demonstrable, may result from bone thickening, especially the sphenoid and petrous bones, It is well-established that bone remodelling in Pager's disease may induce a local vascular 'steal phenomenon' which is known to cause neurological symptoms. Both mechanisms may be responsible for ONM.

平衡機能検査で異常所見に乏しかった大きな小脳橋角部腫よう症例

Most large cerebello-pontine angle (CPA) tumors usually cause typical abnormal oculomotor findings on vestibular and oculomotor examinations, reflecting brainstem and cerebellar lesions. However, we encountered four patients with large CPA tumor without the typical abnormal neurotological findings and these cases are described in this report. Case 1 : A 63-year-old female. Chief compliment (CC) was double vision. Audiovestibular examinations showed normal findings except for slight nystagmus on ENG. MRI revealed a 4.8 × 4.7 cm lesion of the right CPA. The histopathological diagnosis was CPA meningioma.Case 2 : A 58-year-old female. CC was a tinnitus. Pure tone audiometry indicated right-sided sensorineural hearing loss (SNHL). Results of vestibular examination were normal. MRI revealed a 4.0 × 3.5 cm lesion from the clivus to the CPA that was diagnosed radiologically as a meningioma. Case 3 : A 50-year-old female. CC were tinnitus and head heaviness. Audiovestibular examinations were all unremarkable. MRI revealed a 3.0 × 2.7 cm lesion of the right CPA that was diagnosed as an epidermoid cyst. Case 4 : A 48-year-old female. CC were hearing loss and tinnitus. Audiometric studies indicated right-sided moderate-to-profound SNHL. There were no responses on ABR. Vestibular examinations were unremarkable. MRI revealed a 4.2 × 4.0 cm left-sided CPA mass that was diagnosed at surgery as an acoustic neuroma with cystic changes. Previous study showed that when the CPA tumor is larger than 3 cm, ETT and OKP demonstrate abnormal findings in 70 to 78% of patients, respectively. However, in our cases, despite pronounced compressions of the brainstem and cerebellum by large CPA tumors, vestibular examinations did not reveal any significant findings. These atypical findings might have resulted from the histological characteristics and slow growth of the CPA tomor, in addition to factors related to central vestibular compensation and indivisual differences in susceptibility to the lesions.

Clinical and genetic analysis of three German kindreds with autosomal dominant cerebellar ataxia type I linked to the SCA2 locus.

The detailed clinical, electrophysiological and imaging data of three German autosomal dominant cerebellar ataxia (ADCA) families are reported. Linkage to SCA2 was established using microsatellite markers D12S105, D12S1339(1328), D12S1304(1329) yielding a lod score exceeding +3.0 for the combined data. Analysis of the pedigree data provided evidence of anticipation as observed in other neurodegenerative disorders due to polyglutamine expansion encoded by a CAG repeat. This hypothesis was confirmed by the detection of the SCA2-specific pathological protein using the 1C2 monoclonal antibody which selectively recognizes large polyglutamine expansions and the characterization of a CAG expansion in the patients. Clinically, the families were characterized by progressive ataxia of stance, gait and limbs. Saccade velocity was markedly reduced in SCA2. Further oculomotor findings were gaze palsy, impaired smooth pursuit and reduced optokinetic reflex. Dementia and pyramidal tract signs were rather rare, while peripheral involvement (reduced or absent ankle reflexes, fasciculation-like movements, amyotrophy) was a prominent feature. Electrophysiological investigations provided evidence of sensory neuropathy of the axonal type and degeneration of the posterior columns. Imaging studies demonstrated severe shrinkage of brain-stem structures even in early stages of the disease.

Ocular neuromyotonia in a case of Paget's disease of bone

The authors report a case of Paget's disease of bone and ocular neuromyotonia (ONM) in a 72-year-old woman. As far as we are aware, this association has never been previously described. The patient had an acquired left third cranial nerve palsy with oculomotor synkinesis and a left sixth cranial nerve palsy. Subjectively, she complained of recurring episodes of transient horizontal and vertical diplopia, lasting for about 30-40 sec and accompanied with discomfort in the left eye (LE). During those episodes, which occurred spontaneously or after sustained eccentric gaze, the LE became more esotropic with increasing restriction of abduction or hypotropic with increasing restriction of elevation. Electromyography (EMG) of the left medial rectus detected repetitive bursts of motor unit potentials with aspect of 'multiplets'. The oculomotor findings and the neurophysiological data evoked the diagnosis of ocular neuromyotonia which was subsequently confirmed by the effective response to carbamazepine. The patient had no history of radiation therapy, a frequent association of ONM. Cerebral and orbital CT scan showed a severe remodelling of the base of the skull. We suggest that cranial nerve palsies as clinically present in this patient, even if not neuroradiologically demonstrable, may result from bone thickening, especially the sphenoid and petrous bones. It is well-established that bone remodelling in Paget's disease may induce a local vascular 'steal phenomenon' which is known to cause neurological symptoms. Both mechanisms may be responsible for ONM.

Delayed visual maturation in infants: A disorder of figure—Ground separation?

Delayed visual maturation (DVM) is characterised by visual unresponsiveness in early infancy, which subsequently improves spontaneously to normal levels. We studied the optokinetic response and recorded pattern reversal VEPs in six infants with DVM (aged 2–4 months) when they were at the stage of complete visual unresponsiveness. Although no saccades or visual tracking with the eyes or head could be elicited to visual objects, a normal full-field rapid buildup OKN response occurred when viewing biocularly or during monocular stimulation in the temporo-nasal direction of the viewing eye. Almost no monocular OKN could be elicited in the naso-temporal direction, which was significantly poorer than normal age-matched infants. No OKN quick phases were missed, and there were no other signs of “ocular motor apraxia”. VEPS were normal in amplitude and latency for age. It appears, therefore, that infants with DVM are delayed in orienting to local regions of the visual field, but can respond to full-field motion. The presence of normal OKN quickphases and slow-phases suggests normal brain stem function, and the presence of normal pattern VEPs suggests a normal retino-geniculo-striate pathway. These oculomotor and electrophysiological findings suggest delayed development of extrastriate cortical structures, possibly involving either an abnormality in figure-ground segregation or in attentional pathways.

Neuroradiological and Eye Movement Correlates in Children with Intermittent Saccade Failure: "Ocular Motor Apraxia"

Ocular motor apraxia (OMA) is a clinical sign involving the intermittent inability to initiate saccades, and a failure of quick phases during optokinetic nystagmus (OKN) and vestibular nystagmus (VN). Some patients have no other associated abnormalities (idiopathic), whereas others have a variety of neurological conditions. We quantified the severity of the saccade failure and correlated it with neuro-radiological and other oculomotor findings in 62 children (aged 17 days - 14 years). Saccades, smooth pursuit, OKN and VN were recorded using electrooculography and the extent of "locking up" (absent quick phases during OKN and VN) was measured. Saccades were usually hypometric. Pursuit and OKN gains were normal in the majority of the idiopathic cases but were low in those with other neurological conditions. Twenty-four patients had essentially normal scans, whereas 38 had abnormal scans: Delayed myelination, cerebellar abnormalities (particularly involving the vermis), and agenesis of the corpus callosum were the most common findings. A significant positive correlation was present between increasing neuro-radiological deficits and severity of "locking up" during OKN. Principal component analysis showed that brainstem and cerebellar vermis abnormalities were the main factors involved. A pathophysiological basis of OMA is discussed in the light of animal and clinical studies.

Fixation instability and oculomotor abnormalities in Friedreich's ataxia.

Eye movements were studied in 13 patients with Friedreich's ataxia and correlated with MRI findings to investigate whether oculomotor abnormalities can be traced to cerebellar disturbances in this disease. One of the most prominent eye signs was fixation instability (square-wave jerks, SWJ.). Besides SWJ the patients showed various combinations of cerebellar, vestibular and brain-stem oculomotor signs. Our patients did not comprise a homogeneous group with regard to their oculomotor findings. There was no correlation between the severity of any of the so-called cerebellar oculomotor disturbances and the number of SWJ. We tried to correlate the extent of oculomotor disturbances with floccular atrophy and atrophy of the dorsal vermis on MRI in seven of the patients. None of the oculomotor features (including SWJ) correlated with flocculus or dorsal vermis size. Furthermore, floccular and vermal measurements on MRI were normal. Accordingly, we think it unlikely that the oculomotor disturbances, including SWJ, are attributable to cerebellar pathology per se.

Acquired pendular nystagmus: oculomotor and MRI findings.

The clinical, oculomotor and ophthalmological features of 27 patients with pendular nystagmus were studied in whom 22 also had MR imaging of the brainstem. The nystagmus was predominately horizontal in 4 patients, torsional in 5, vertical in 3 and mixed in trajectory in 8. Fifteen patients had conjugate nystagmus. Twelve patients had disconjugate nystagmus. Eight patients had INO. In 16 patients visual acuity was 6/12 or worse. Acuity and the presence of INO were unrelated to the conjugacy of the nystagmus. The MRI cuts at the medullary, pontine and midbrain levels were analysed statistically to determine the areas where there was significant (< 0.05%) overlap between areas of abnormal signal in different patients. Significant target areas for lesions causing the nystagmus were: in the pons the medial vestibular nucleus, central tegmental and paramedian tracts; in the medulla the inferior olivary nucleus, reticular formation, dorsal accessory olivary nucleus, central tegmental tracts and olivo-cerebellar fibres; in the midbrain the red nucleus and central tegmental tracts. Horizontal pendular nystagmus was preferentially associated with pontine lesions and torsional nystagmus with medullary lesions. Patients with conjugate nystagmus had a tendency to have bilateral mirror image MRI lesions (p = 0.028). The prevalence of lesions in our patients raises a possibility that more than one neuronal mechanism must be affected to produce pendular nystagmus. The inferior olive may be responsible for the rhythm of ocular oscillation. The disruption of pathways proximal to the oculomotor nuclei may determine the instability in terms of individual eye movement.

Oculomotor and Vestibular Findings in Developmental Dyslexia

Oculomotor and Vestibular Findings in Developmental Dyslexia

Oculomotor findings in autistic children.

Eleven children with infantile autism or autistic-like conditions were examined with oculomotor tests and with auditory brainstem response audiometry. Measurements of voluntary, horizontal non-predictable saccades showed that the eye motor function was abnormal in six (55 per cent) of the eleven patients. The saccades were hypometric in all six instances and the saccadic velocity was reduced in four instances. The abnormalities observed are consistent with brain dysfunction, in most cases probably indicating pontocerebellar involvement. In five instances ABR was found to be abnormal which indicates brainstem dysfunction. Oculomotor dysfunction and/or ABR abnormality was observed in eight (73 per cent) of the patients studied.

Electro-oculographic routine examination in Parkinson's disease.

The authors studied a group of 36 patients with idiopathic Parkinson's disease by electro-oculographic examination in order to evaluate the most frequent vestibular and oculomotor findings. Vestibular alterations were detected mainly in caloric nystagmus (82.9%). Hyperreflectivity was the most frequent evidence, but it does not necessarily represent the sign of a lesion. The occurrence of spontaneous and evoked nystagmus was not significant. Oculomotor findings were more interesting, as they were altered in two-thirds of the cases. Particularly, saccadic eye movements presented a "multiple step" morphology in 58.3% of the series. This saccadic disarrangement was scarcely found in neurological patients with brainstem and/or cerebellum pathology (7.7%). Moreover, in Parkinson's disease patients no other saccadic alterations typical of brainstem or cerebellum involvement were found. Such observations suggest a possible non-cerebellar origin of "multiple step". Vestibular and oculomotor findings were not significantly correlated with the clinical features of the patients.

Correlates of Brain-Stem Oculomotor Disorders in Multiple Sclerosis

Three patients with focal brain-stem oculomotor disturbances (nuclear sixth nerve syndrome, sixth nerve palsy, bilateral internuclear ophthalmoplegia) as a consequence of multiple sclerosis have been studied with high-volume delayed computed tomography and high-field magnetic resonance imaging. In all of them, high-volume delayed computed tomography was inconclusive in the brain stem, but magnetic resonance imaging showed an area of prolonged T1 and/or T2 in the region appropriate to the oculomotor findings. Magnetic resonance imaging is the imaging technique of choice of small plaques in the brain stem. It can considerably aid clinicotopographic correlation in multiple sclerosis.

Diagnostic considerations in ataxia-telangiectasia.

13 children with ataxia-telangiectasia were followed for 6 years. Unlike previously reported cases, these patients had progressive, debilitating neurological disease and slight pulmonary or infectious symptoms. Immunological dysfunction was variable and endocrinological defects were absent. Oculomotor findings, alpha-fetoprotein levels, and the incidence of chromosomal breakage were the most consistent parameters in the diagnosis of the condition. This disease should be considered in any patient with chronic ataxia, regardless of immunological findings or whether he has a history of infections.

Horizontal nystagmus of rhesus monkeys.

Horizontal optokinetic nystagmus (OKN), caloric nystagmus, and positional alcohol nystagmus (PAN) of the rhesus monkey (Macaca mulatto) were surveyed using electrooculography. OKN of the monkey appears to be similar in most respects to that of man although optokinetic after-nystagmus is more prominent in the monkey. of the parameters of OKN which were measured, slow phase velocity was most closely related to the optokinetic stimulus. Caloric nystagmus is easily induced in the monkey and parameters of caloric nystagmus declined exponentially on repeated testing. The first phase of positional alcohol nystagmus was present in all animals tested and the secondary phase in some. The data indicate that oculomotor findings in the monkey can probably be applied to man with few reservations.