Author(s): Servillo G, Renard D, Taieb G, Labauge P, Bastide S, et al
Background/Aims. Ocular motor disorders (OMDs) are a common feature of multiple sclerosis (MS). In clinical practice, if not reported by patients, OMDs are often underdiagnosed and their prevalence is underestimated. Methods. We studied 163 patients (125 women, 76.7%, 38 men, 23.3%; median age 45.0 years; median disease duration 10 years; median EDSS 3.5) with definite MS (, 92%) or clinically isolated syndrome (, 8%) who underwent a thorough clinical examination of eye movements. Data on localization of previous relapses, MS subtype, and MRI findings were collected and analyzed. Results. Overall, 111/163 (68.1%) patients showed at least one abnormality of eye movement. Most frequent OMDs were impaired smooth pursuit (42.3%), saccadic dysmetria (41.7%), unilateral internuclear ophthalmoplegia (14.7%), slowing of saccades (14.7%), skew deviation (13.5%), and gaze evoked nystagmus (13.5%). Patients with OMDs had more severe disability and showed more frequently infratentorial MRI lesions . Localization of previous relapses was not associated with presence of OMDs. Conclusion. OMDs are frequent in patients with stable (no relapses) MS. A precise bedside examination of eye motility can disclose abnormalities that imply the presence of subclinical MS lesions and may have a substantial impact on definition of the diagnosis and on management of MS patients.
1. IntroductionMultiple sclerosis (MS) patients often experience ocular motor disorders (OMDs) during the course or sometimes as an early manifestation of the disease [1]. The most common OMDs are internuclear ophthalmoplegia (INO), disturbances of conjugate gaze, such as saccadic dysmetria and impaired smooth pursuit, gaze-evoked nystagmus, and vestibuloocular reflex (VOR) abnormalities [2–4]. Other unusual, more complex, ocular motor disturbances have also been described [5].
Eye movement accuracy is under control of many integrated components of the central nervous system, especially those located in critical areas of the brainstem and the cerebellum [6]. The widespread extension of MS lesions and the frequent involvement of infratentorial structures explain why OMDs are so common in MS patients.
The importance of an accurate examination of ocular movements is underlined by the potential impact of OMDs on disease progression and the value of OMDs as predictors of disability in MS [7, 8].
From the patient’s point of view, major symptoms of OMDs are blurring of vision, oscillopsia, and diplopia, although less obvious symptoms, such as feeling of unsteadiness, may be the only complaints. Many patients, however, do not report any symptom at all [2, 9].
An accurate clinical bedside ocular motor examination, paying attention particularly to the dynamic characteristics of ocular saccades and VOR, performed by an experienced investigator, can detect the majority of OMDs [3, 4, 10]. Oculographic techniques, such as video oculography [11, 12], and electrooculography (EOG) [13, 14] can increase the precision of clinical detection.
Although MRI often can precisely delineate the lesion responsible of OMDs [15], the relationship between disability and lesion burden and the clinicoanatomical correlation of clinical signs/symptoms and the location of MS lesions are not well established [16]. The sensitivity of MRI in revealing small lesions in the brainstem is limited when the lesion size is below the threshold of detection [17], further emphasizing the importance of careful clinical examination [18].
In clinical practice, if not reported by patient, OMDs are often underestimated [9]. Data on the exact prevalence of OMDs in MS patients are rare, resulting from few small sample size studies reporting prevalence varying from 80% [19] to 32% [13] in clinically definite MS.
In patients in stable phase of disease (no relapses) who do not report symptoms of abnormal eye motor function, the detection of a silent lesion by an accurate bedside neuroophtalmologic examination may influence clinical management and therapeutic decisions, and, in the early phase of disease, contribute to the definition of the diagnosis of MS by means of the detection of a dissemination in space of the lesions [20, 21].
The aim of our study was to assess the prevalence of OMDs in a relatively large sample of patients with stable MS (i.e., in absence of acute relapse) and to look for possible correlations between the presence of OMDs and the disability at the moment of examination, a positive history of brainstem/vestibulocerebellar relapses, and the evidence of MRI lesions in the posterior fossa.
2. Patients and MethodsFrom 1 January to 30 June 2012, 195 consecutive patients with definite MS or clinically isolated syndrome (CIS) [21] were referred to the Neurological Department of Centre Hospitalier Universitaire Caremeau, Nîmes, France. Thirty-two patients were excluded because of an acute ongoing relapse or because of recent onset oscillopsia or diplopia. The remaining 163 patients were enrolled in the study (Table 1) and underwent an accurate clinical examination of eye movements by two experienced, independent investigators (G. Castelnovo and G. Servillo). In case of disagreement, a third investigator (D. Renard) performed an independent examination.
Gender (%)Females 125 (76.7)Males 38 (23.3)AgeMean (SD) 44.9 (12.8) yearsMedian 45.0 yearsEDSSMean (SD) 3.4 (1.8)Median 3.5Disease durationMean (SD) 11.9 (9.5) yearsMedian 10 yearsType of diseaseReferred From: https://www.hindawi.com/journals/msi/2014/732329/abs/
Author(s): Pierrot-Deseilligny C
