Role of saccadic analysis in the diagnosis of multiple sclerosis in the era of magnetic resonance imaging

Eye movement abnormalities in AQP4-IgG positive neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorder (NMOSD) has been recognized as a disease characterized by severe visual afferent impairment. Abnormal eye movements, as the other important neuro-ophthalmic manifestation of NMOSD, were commonly overlooked. The aim of our study was to describe the ocular motor manifestations of AQP4-IgG positive NMOSD patients, and explore the value of eye movement abnormalities in the evaluation of the disabled disease.

METHODS

Systemic clinical bedside ocular motor examinations and quantitative horizontal saccadic eye movement assessments were performed in 90 patients with AQP4-IgG positive NMOSD. General disability was evaluated by expanded disability status scale (EDSS). Vision-specific functional status was evaluated by the National Eye Institute-Visual Function Questionnaire (NEI-VFQ 25) and the 10-item neuro-ophthalmic supplement. Brain magnetic resonance imaging (MRI) was acquired in all patients.

RESULTS

In clinical examination, eye movement abnormalities were found in 38% of NMOSD patients. Abnormalities in the quantitative saccadic test were found in 67% of NMOSD patients, including 48% of patients with clinically normal eye movements. EDSS scores in patients with clinical eye movement abnormality were significantly higher (P<0.001) than those with a normal examination. The 10-item neuro-ophthalmic supplement score was significantly associated with quantitative saccadic eye movement abnormalities (P=0.031).

CONCLUSIONS

Eye movement abnormalities were common in AQP4-IgG positive NMOSD patients, and were associated with general disability and specific visual handicap. The systemic clinical eye movement examination combined with the quantitative saccade test was easy to perform, and could provide additional useful information in evaluating NMOSD.

Sinais e sintomas associados a alterações otoneurológicas diagnoticadas ao exame vestibular computadorizado em pacientes com esclerose múltipla

OBJETIVO: Descrever os principais sintomas e sinais ao exame vestibular computadorizado em pacientes com diagnóstico de esclerose múltipla. MÉTODO:Foram examinados 30 pacientes com diagnóstico de esclerose múltipla. Analisaram-se os dados relativos à sintomatologia e achados ao exame vestibular computadorizado realizado no ambulatório de otoneurologia da Irmandade Santa Casa de Misericórdia de São Paulo, em 2003. RESULTADOS: Em relação aos sintomas relatados, observamos desequilíbrio (60%), formigamento de extremidades (43,3%), vertigem (40%), cefaléia e ansiedade (36,7%), zumbido (30%), depressão (26,7%). Ao exame vestibular encontramos alterações do nistagmo de posicionamento (6,7%), nistagmo espontâneo de olhos fechados (30%), nistagmo semi-espontâneo (13,3%), rastreio pendular (3,3%) e prova calórica (63,3%). Na conclusão do exame tivemos prevalência de síndrome vestibular periférica irritativa (60%) e síndrome central (13,4%). CONCLUÇÃO: Concluimos que a realização do exame otoneurológico torna-se imprescindível nos pacientes com esclerose múltipla devido a elevada prevalência de alterações à vectonistagmografia computadorizada e elevada prevalência de sintomas otoneurológicos.

Binocular saccadic eye movements in multiple sclerosis

We attempted to increase the sensitivity for detection of abnormal binocular saccadic eye movements, particularly of the internuclear ophthalmoplegia (INO) type associated with multiple sclerosis (MS). Saccades of 10 and 20 degrees were binocularly recorded with scleral sensor coils in 10 normal control subjects and 26 patients with definite or probable MS, seven of whom had a clinically manifest INO in one or both directions. In the cases in which this was accompanied by a dissociated nystagmus of the abducting eye, our recordings showed that such secondary saccades were also expressed, in a strongly reduced form, by the adducting eye. The patients with manifest INO showed lower average peak velocities and peak accelerations, especially for adduction of the eye on the affected side, but the distribution of these parameters overlapped with the normal distribution. A much sharper distinction between normals and patients with INOs was found by considering the ratios between peak accelerations and velocities of saccade pairs (abducting eye/adducting eye). These ratios, which eliminate much intra- and inter-individual variability, had a narrow range in normals, and all values for INOs were outside this range. On this basis, the 19 patients without clinically manifest INO were easily separated into subgroups of 14 patients with completely normal interocular ratios and five patients with elevated peak velocity and acceleration ratios, identified as sub-clinical (uni- or bilateral) INOs. Measurements of vertical saccades and of interocular timing differences provided no useful criteria for disturbances of binocular coordination in MS. We conclude that in particular, the acceleration of the adducting eye is strongly reduced in patients with an INO, and that this reduction is best identified by interocular comparison between binocular pairs of saccades.

Multisystem involvement of the central nervous system in Strümpell's disease. A neurophysiological and neuropsychological study

The multisystem involvement of the central nervous system (CNS) in familial spastic paraplegia (FSP) has not been fully investigated by means of complete neurophysiological and neuropsychological examinations. The classification which distinguishes pure and complicated forms of FSP, is based on clinical features and does not take into account the possibility that clinically silent lesions of the CNS can be identified by means of adequate tests. The study was intended to assess the subclinical and multisystem involvement of the CNS in a group of 11 patients affected by FSP, clinically distinguished in 7 pure forms and 4 complicated forms. Neurophysiological tests included saccadic eye movements analysis, visual and auditory brain stem evoked responses. Neuropsychological examination was devised by means of a special purpose mental deterioration battery. Our results, showing a high incidence of multisystemic subclinical involvement of the CNS, confirm and extend the concept that FSP is a multisystemic degenerative disease of the CNS, and that the existence of "pure" forms should be reconsidered.