Factors Associated With Increased Emergency Department Utilization in Patients With Acute Optic Neuritis.

BACKGROUND: Symptoms of acute vision loss and eye pain may lead patients with optic neuritis to seek care in the emergency department (ED). Given the availability of lower cost alternatives for providing medical care for optic neuritis, this study aimed to identify factors associated with higher ED utilization. METHODS: Subjects with acute optic neuritis were identified through a chart review of adults with International Classification of Diseases-9 (ICD-9) or ICD-10 codes for optic neuritis with corresponding gadolinium contrast enhancement of the optic nerve on MRI in the medical record research repository of a tertiary care institution. Subjects were grouped based on the number of ED visits (0-1 and 2-3) within 2 months of either ICD code or MRI. Demographics, characteristics of disease presentation, type and location of medical care, testing (chest imaging, lumbar puncture, optical coherence tomography, spine MRI, visual field, and laboratory tests), treatment, provider specialty of follow-up visits, and duration of care were extracted from the medical record. RESULTS: Of 30 acute optic neuritis subjects (age 41 ± 16 years, range 18-76, 53% [16/30] female), 19 had 0-1 ED visit and 11 had 2-3 ED visits. Most subjects were Caucasian, non-Hispanic (47%), followed by Asian (23%), Hispanic/Latino (17%), Black (10%), and others (3%). Subjects had an initial clinical encounter primarily in the outpatient setting (63%) as compared with the ED (37%). The median time from symptom onset to initial clinical encounter was 4 days with a range of 0-13. Subjects were mostly insured through a private insurance (60%), followed by Medicare/Medicaid (23%) and uninsured (17%). Fewer ED visits were associated with an initial clinical encounter in an outpatient setting (P = 0.02, chi-square), but not residential distance from the hospital or insurance type. Subjects with a higher number of ED visits were more likely to be of Hispanic/Latino ethnicity (P = 0.047, Fisher exact). There was no significant difference in the ophthalmic, radiologic, or laboratory testing performed in both groups. Both groups presented in a similar time frame with similar symptoms and clinical signs. Treatment was similar in both groups. CONCLUSIONS: Subjects with their first clinical encounter for optic neuritis in the ED had more visits to the ED overall when compared with those first seen in an outpatient setting and thus strategies aimed at facilitating outpatient care may help reduce unnecessary ED visits, although some, such as insurance status, may be difficult to modify. Further study in a larger sample is needed to refine these observations.

Differences in Clinical Features of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Optic Neuritis in White and Asian Race.

PURPOSE: To determine whether clinical features and visual outcomes of myelin oligodendrocyte glycoprotein antibody-associated optic neuritis (MOG-ON) differ between White and Asian subjects. DESIGN: Multicenter retrospective cohort. METHODS: This was a multicenter study of 153 subjects who were White or Asian with a history of adult-onset (age 18 years or older) optic neuritis (ON) and positive MOG-IgG serology by cell-based assay. Subjects were enrolled from 2 unpublished cohorts (January 2017-November 2019) and 9 published cohorts with case-level data available (2012-2018). Subjects with alternative etiologies of demyelinating disease and positive or lack of aquaporin-4-IgG serology result were excluded. The main outcome measurements were clinical features and final visual outcomes. RESULTS: Of the 153 subjects who were White (n = 80) or Asian (n = 73) included in the study, 93 (61%) were women, mean age of onset was 40.8 ± 14.9 years, and median follow-up was 35.2 months (range: 1-432 months); all of these characteristics were similar between White and Asian subjects. White subjects were more likely to have recurrent ON (57 [71%] vs 20 [27%]; P = .001) and extra-optic nerve manifestations (35 [44%] vs 8 [11%]; P = .001). Optic disc swelling, neuroimaging findings, presenting visual acuity (VA), treatment, and final VA did not differ according to subjects' race. Despite the high prevalence of severe visual loss (<20/200) during nadir, most subjects had good recovery of VA (>20/40) at final examination (51/77 [66%] White subjects vs 52/70 [74%] Asian subjects). CONCLUSION: White subjects with MOG-ON were more likely to have recurrent disease and extra-optic nerve manifestations. Visual outcomes were similar between White and Asian subjects.

Association of race/ethnicity with visual outcomes following acute optic neuritis: an analysis of the Optic Neuritis Treatment Trial.

IMPORTANCE Retrospective studies have demonstrated disparate outcomes following acute optic neuritis in individuals of African descent compared with individuals of white race/ethnicity. However, published analyses of the prospectively collected Optic Neuritis Treatment Trial (ONTT) data identified no association between worse visual outcomes and black race/ethnicity. OBJECTIVES To investigate the associations of age, sex, and race/ethnicity with visual outcomes following acute optic neuritis through application of longitudinal data analysis techniques to the ONTT data set. DESIGN Secondary analysis of the ONTT (a prospective randomized controlled trial) data set. Our models included effects of treatment (placebo, oral prednisone, or intravenous methylprednisolone), time, and treatment × time interaction, as well as demographic covariates of age, sex, and race/ethnicity. SETTING AND PARTICIPANTS The ONTT data were collected at multiple centers in the United States. Patients of black (n = 58) and white (n = 388) race/ethnicity with acute optic neuritis who enrolled in the ONTT within 8 days of symptom onset were included in analyses. MAIN OUTCOMES AND MEASURES The contrast sensitivity and visual acuity (logMAR) in the affected eye were modeled using 2-stage mixed-effects regression techniques. All available follow-up data from baseline to 15 to 18 years were included. RESULTS The data identified no relationship of age, sex, or treatment with contrast sensitivity or visual acuity outcomes. Race/ethnicity was significantly related to contrast sensitivity (P < .001) and visual acuity (P < .001) during a 15-year period following acute optic neuritis, with black race/ethnicity being associated with worse scores for both. CONCLUSIONS AND RELEVANCE Race/ethnicity seems to be associated with contrast sensitivity and visual acuity outcomes in affected eyes following acute optic neuritis. To our knowledge, this is the largest cohort of black race/ethnicity with acute optic neuritis to be studied and represents the first evidence from a prospectively collected data set to support a hypothesis of race/ethnicity-dependent visual outcomes of acute optic neuritis.

Acute and subacute inflammation of the optic nerve and its sheath: clinical features in Chinese patients.

OBJECTIVE: Inflammation of the optic nerve (optic neuritis) and its sheath (optic perineuritis) can have similar initial clinical presentations. They are less well-defined in the Chinese than in Caucasians, and the aetiology of optic neuritis may also differ depending on ethnicity. The aim of our study was to document the clinical features of acute/subacute optic neuritis/optic perineuritis in Chinese patients. DESIGN: Retrospective case series. SETTING: Hong Kong Eye Hospital, Hospital Authority. PATIENTS: Records of all patients presenting to the Hong Kong Eye Hospital between 2005 and 2008, with their first episode of optic neuritis/optic perineuritis with onset of symptoms within 30 days, were reviewed. MAIN OUTCOME MEASURES: Disease aetiology, clinical features and outcomes. RESULTS: Twenty-nine patients were included (M:F=13:16), with a mean age of 46 years at presentation. Among these, 25 had optic neuritis and four had optic perineuritis; four presented with bilateral optic neuritis. Among the optic neuritis group, 17 (68%) were idiopathic, seven (28%) were related to multiple sclerosis, and one (4%) had neuromyelitis optica. Poor visual outcome in the optic neuritis group was associated with poor visual acuity at presentation and poor visual acuity at the nadir. CONCLUSION: Optic perineuritis and neuromyelitis optica-related optic neuritis were more commonly encountered in our study of Hong Kong Chinese patients than in Caucasian populations. Even in Chinese patients with 'typical' optic neuritis, neuro-imaging and further investigations may be warranted to exclude optic perineuritis/neuromyelitis optica, since Chinese ethnicity is itself an atypical feature. Where neuro-imaging is not readily available, intravenous methylprednisolone may be considered as initial treatment to cover both optic neuritis/optic perineuritis in patients with severe visual loss.

Clinical characteristics of optic neuritis in Koreans greater than 50 years of age.

PURPOSE: To report clinical characteristics of optic neuritis (ON) in Koreans >50 years of age. METHODS: A retrospective chart review was performed on patients with ON between January 2000 and December 2009. We obtained the best-corrected visual acuity (BCVA), Goldmann perimetry, relative afferent pupillary defect (RAPD), and color function tests as well as brain magnetic resonance imaging (MRI) findings in patients who were in the acute stage of the disorder. RESULTS: Nine eyes in eight patients were included. The mean age of patients at presentation was 60.5 years (range, 53 to 71 years). Six patients were female, and two were male. There was one patient with bilateral ON. The mean BCVA at presentation was 20 / 400 (no light perception-20 / 70). Eight eyes (89%) complained of pain with eye movement. Six eyes (66%) had disc edema. Central scotoma was the most common field defect. All eyes had color abnormalities. Five eyes in four patients showed abnormalities of the involved optic nerves on MRI. The patients were followed for a mean of 11.3 months (range, 2 to 34 months). All of the patients recovered to a BCVA of 20 / 40 or better within 2 months. On the last follow-up, the mean BCVA was 20 / 20 (20 / 40 to 20 / 16). Four eyes showed remnant central scotoma. One eye had remnant RAPD, and two eyes had mild color abnormalities. CONCLUSIONS: Although ON is uncommon in elderly patients, it can develop in patients >50 years of age, and clinical features of optic neuritis in elderly patients are similar to those of younger patients.

Optic neuritis in an ethnically diverse population: higher risk of atypical cases in patients of African or African-Caribbean heritage.

PURPOSE: To investigate the presence of an ethnicity bias within patients presenting with optic neuritis in London. DESIGN: Observational cross-sectional study. METHODS: The ethnicity profile of all patients attending a neuro-ophthalmology clinic in central London with acute optic neuritis over a 16month period (n=86) was studied. A comparison was made with the ethnicity profile of the population of London as well as patients with Multiple Sclerosis-associated optic neuritis (n=41), Neuromyelitis Optica spectrum disorder-associated optic neuritis (n=27) and patients with an atypical corticosteroid-dependent optic neuropathy (21). RESULTS: The ethnicity profile of the patient cohort presenting to our clinic with acute optic neuritis over a 16 month period closely matched the ethnicity profile of London (P=0.08). Within this cohort, patients of African or African-Caribbean heritage were found to be more likely to manifest either a pattern or aetiology of optic neuritis requiring immunosuppressive treatment in comparison with patients of a white Caucasian background (relative risk 3.47; 95% CI=1.092 to 11.007). There was a disproportionately high representation of patients from an African or African-Caribbean background within the Neuromyelitis Optica spectrum-related optic neuritis diagnostic group (P<0.00). CONCLUSIONS: Patients with acute isolated optic neuritis from African or African Caribbean backgrounds are over 3 times more likely than patients of white Caucasian backgrounds to have an 'atypical' pattern of optic neuritis where corticosteroid therapy may be required. Our results suggest that a patient's ethnic background is an important factor to be taken into consideration when deciding on the diagnosis and management of acute isolated optic neuritis.

Clinical Characteristics of Optic Neuritis in Koreans Greater than 50 Years of Age

PURPOSE: To report clinical characteristics of optic neuritis (ON) in Koreans >50 years of age. METHODS: A retrospective chart review was performed on patients with ON between January 2000 and December 2009. We obtained the best-corrected visual acuity (BCVA), Goldmann perimetry, relative afferent pupillary defect (RAPD), and color function tests as well as brain magnetic resonance imaging (MRI) findings in patients who were in the acute stage of the disorder. RESULTS: Nine eyes in eight patients were included. The mean age of patients at presentation was 60.5 years (range, 53 to 71 years). Six patients were female, and two were male. There was one patient with bilateral ON. The mean BCVA at presentation was 20 / 400 (no light perception-20 / 70). Eight eyes (89%) complained of pain with eye movement. Six eyes (66%) had disc edema. Central scotoma was the most common field defect. All eyes had color abnormalities. Five eyes in four patients showed abnormalities of the involved optic nerves on MRI. The patients were followed for a mean of 11.3 months (range, 2 to 34 months). All of the patients recovered to a BCVA of 20 / 40 or better within 2 months. On the last follow-up, the mean BCVA was 20 / 20 (20 / 40 to 20 / 16). Four eyes showed remnant central scotoma. One eye had remnant RAPD, and two eyes had mild color abnormalities. CONCLUSIONS: Although ON is uncommon in elderly patients, it can develop in patients >50 years of age, and clinical features of optic neuritis in elderly patients are similar to those of younger patients.

Magnetic resonance imaging in acute optic neuritis in Singapore.

INTRODUCTION: The Optic Neuritis Treatment Trial (ONTT) has established that the magnetic resonance imaging (MRI) findings at the time of presentation of optic neuritis (ON) is the strongest indicator of the development of multiple sclerosis (MS). Reports from Singapore as well as other Asian countries have indicated that these abnormalities are less frequently encountered compared to that reported by the ONTT. This paper aims to describe systematically the brain MRI as well as the optic nerve abnormalities in patients after an episode of acute optic neuritis. MATERIALS AND METHODS: Patients who presented with acute optic neuritis were retrieved from our prospective optic neuritis study and their MRI scans were reviewed and graded in accordance with the standardised classification employed in the ONTT. RESULTS: Fifteen of 24 patients had MRI brain and optic nerves performed during the acute episode. In the evaluation of brain abnormalities, 40% were classified as grade 0, 20% grade I, 20% grade II, 6.7% grade III and 13.3% grade IV. Optic nerve abnormalities were observed in 80% of cases. At study entry, 10 patients had idiopathic (monosymptomatic) ON, 3 had multiple sclerosis (MS), one each with infective and autoimmune optic neuritis, respectively. The single patient who developed MS at study completion presented with grade II brain abnormalities at the initial MRI. For those with idiopathic ON, our study revealed a higher percentage of grade 0-I brain changes as well as a lower lesion load compared to the ONTT.Lesion Load and grade was also lower in anterior optic neuritis compared with retrobulbar disease. CONCLUSION: Our study revealed a lower percentage of grade II-IV brain MRI abnormalities as well as less lesion load in idiopathic ON compared to the ONTT. This may be related to the lower prevalence of MS in our predominantly Asian population. As diagnostic tests and understanding of neuromyelitis optica or Devic's disease improves, we may see more patients being diagnosed with this condition, which may also explain our findings. Our data also showed that MRI grade and lesion load in cases of anterior ON was lower than for retrobulbar disease. MRI in ON has an essential role in characterising the disease, evaluating for associated brain lesions, and assessing prognosis in retrobulbar disease but may be less useful in anterior disease.

Aquaporin-4 autoimmune syndrome and anti-aquaporin-4 antibody-negative opticospinal multiple sclerosis in Japanese.

BACKGROUND: Antibodies to aquaporin-4 (AQP4) are found in a fraction of Japanese opticospinal multiple sclerosis (OSMS) patients. However, it remains unknown whether anti-AQP4 antibody-positive and negative OSMS patients possess an identical disease. OBJECTIVE: The objective of the current study was to clarify immunological differences between the two groups of patients. METHODS: We studied the serum antibody titers against AQP4 in 191 patients with idiopathic central nervous system demyelinating diseases and clarified their relationships with immunological parameters. RESULTS: Anti-AQP4 antibody positivity rate was higher in patients with OSMS (21/58, 36.2%), idiopathic recurrent myelitis (4/17, 23.5%), and recurrent optic neuritis (7/26, 26.9%), than in conventional MS (CMS) patients (6/90, 6.7%) and patients with other diseases (0/87). Anti-AQP4 antibody titer was significantly higher in patients with SS-A/B antibodies than in those without them. Anti-AQP4 antibody-negative OSMS patients showed significantly higher CD4(+)IFN-gamma(+)IL-4(-)T cell percentages and intracellular IFN-gamma/IL-4 ratios than anti-AQP4 antibody-positive patients, anti-AQP4 antibody-negative CMS patients, and healthy controls, and CD4(+)IFN-gamma(+)IL-4(-)T cell percentages were negatively correlated with anti-AQP4 antibody titers. CONCLUSION: Anti-AQP4 antibody-positive patients are immunologically distinct from anti-AQP4 antibody-negative OSMS patients owing to a Th2 shift in the former group in comparison to a Th1 shift in the latter.

Clinical characteristics of multiple sclerosis and associated optic neuritis in Korean children.

PURPOSE: To study the clinical characteristics of multiple sclerosis and associated optic neuritis in Korean children. METHOD: A retrospective analysis was performed on 10 patients with an onset of multiple sclerosis before age 16. Information on sex, age of onset, clinical course, laboratory findings, and clinical characteristics of optic neuritis was obtained. RESULT: The mean age at presentation was 7.31 +/- 2.99 years, and the mean duration of observation was 36.2 +/- 26.1 months. No female predilection (50%) was observed. The disease presented as relapsing-remitting type multiple sclerosis in all patients and transited to secondary progressive type in two cases (20%). No oligoclonal bands were found in any patient. Optic neuritis occurred in eight patients (80%); five (62.5%) of these had optic neuritis at the first multiple sclerosis attack, with all five manifesting bilateral simultaneous optic neuritis. Visual acuity recovered to > or =20/40 in 8 of 15 eyes (53.3%), but in 2 eyes (13.3%) visual acuity remained at < or =20/200. In the patients with optic neuritis, the patients who showed optic neuritis at initial presentation had a worse visual prognosis (p = 0.030, Mann-Whitney U-test). CONCLUSIONS: In Korean children with multiple sclerosis, age of onset was younger than reported in other countries, and there was no female predominance. The prognosis for good visual acuity was worse in patients who initially presented with optic neuritis.

Western and Asian features of multiple sclerosis in Mexican Mestizos.

OBJECTIVES: The objective of this study was to compare the clinical expression of MS in Mexican Mestizos with that of patients of European or Asian descent; as well as to compare the annual frequency of new cases with that observed in the previous decades. PATIENTS AND METHODS: All patients with diagnosis of definite MS seen at the National Institute of Neurology and Neurosurgery of Mexico from January 1993 to December 2003 were studied (n=312). Sociodemographic and clinical characteristics were compared with reports of patients from either Western or Asian origin; the long-term disability score was analyzed according to gender, age of onset of MS and the initial symptom. RESULTS: The clinical expression of MS in Mexican Mestizos shares some characteristics with both, Asian and Western forms of MS indicating that the genetic composition of Mexican Mestizos participates in the clinical expression of the disease. Also, at the prevalence date, the mean age of patients and the duration of the disease were lower in our patients than in MS patients from endemic countries suggesting a true increasing incidence in recent times, rather than only improved case ascertainment. CONCLUSIONS: Clinical expression of MS in Mexican Mestizos shows the coexistence of some features common in European and in Asian cases.

Visual phenotype of multiple sclerosis in the Afro-Caribbean population and the influence of migration to metropolitan France.

PURPOSE: To describe the visual phenotype of multiple sclerosis (MS) in the Afro-Caribbean population living in Martinique (French West Indies) and to specify the influence of the migration to metropolitan France on ocular impairment. DESIGN: Prospective consecutive observational case series. METHODS: A complete ophthalmologic examination was performed. PARTICIPANTS: A total of 112 patients of Afro-Caribbean origin with MS satisfying McDonald's diagnostic criteria, divided into 53 cases (47.3%), the non-migrant patients (group NM), who had never left the Caribbean basin, and 59 cases (52.7%), the migrant patients (group M), who had lived in metropolitan France for at least 1 year before age 15. RESULTS: MS first manifested as an impairment of the optic nerve in 41 cases (36.6%): 25 cases (47.1%) in group NM and 16 cases (27.1%) in group M. Visual function was recovered in 13/25 cases (52%) in group NM compared to 13/16 cases (81%) in group M. Two-thirds of patients presented with a clinical ocular impairment, which was bilateral in 58.5% of cases in group NM. Fourteen cases (12.5%) met the criteria of neuromyelitis optica, nine cases (17%) in group NM and five cases (8.5%) in group M. In group NM, when the initial visual attack did not regress, the visual Expanded Disability Status Scale (EDSS) score was 5+/-1.5 ; 75% of patients had monocular blindness and 50% binocular. CONCLUSIONS: In the non-migrants (group NM), MS manifested more frequently with an optical neuropathy, the ocular impairment was more severe, and corresponded to neuromyelitis optica in 17% of the cases; a visual presentation and the absence of complete recovery from the first attack represented a factor of poor prognosis. This series is the largest description of the visual phenotype of MS in patients of African origin. The results confirm the preferential impairment of the optic nerve in the black population in the course of the disease. The migration towards an area of high prevalence of MS influences the visual phenotype in terms of a lower incidence and less severe prognosis of ocular impairment.

The presentation, aetiology, management and outcome of optic neuritis in an Asian population.

PURPOSE: To analyse the presentation, aetiology, management and outcome of patients with optic neuritis (ON) in Singapore. METHODS: This was a retrospective study involving consecutive patients with ON presentng at the Singapore National Eye Centre between January 1997 and May 1999. The presenting features, investigatons, treatment and visual outcome after 6 months were studied. RESULTS: A total of 31 patents (39 eyes) presented with ON during this period, 17 of whom had anterior ON. No aetiology was found in 26 patients (83.9%), two patients (6.5%) had multiple sclerosis, one had active syphilis, one had rheumatoid arthritis and another had pan-sinusitis. Seventeen patients (54.8%) were treated with intravenous methyl-prednisolone followed by oral prednisolone. Within the follow-up period 26 of 31 eyes (83.9%) wth idiopathic ON attained visual acuity of 6/12 or better with 12 (38.7%) recovering to 6/6 or better and only one eye ending with less than 6/60 visual acuity. The one patient with syphilis recovered 6/6 visual acuity bilaterally. Both patients with multiple sclerosis also had good visual recovery at 6 months. The visual outcome in those cases of ON associated with rheumatoid arthritis and pan-sinusitis was poor with visual acuity of less than 6/60 at 6 months follow up in each instance. CONCLUSION: The majority of the cases of ON in this study were idiopathic. There was a low association with multiple sclerosis. Most patients had good visual recovery within 6 months.

Optic neuritis in an urban black African community.

PURPOSE: To describe the clinical profile of idiopathic optic neuritis in South African blacks. METHODS: South African black patients with acute isolated idiopathic optic neuritis, treated and followed for at least 3 months at a large medical centre, were studied. Exclusion criteria were other causes of optic neuropathy (such as ischaemic optic neuropathy, toxins or Leber's hereditary optic neuropathy); all causes of optic neuritis (such as HIV, neurosyphilis, sarcoid or connective tissue disease); neurological disease outside of the optic nerves; and any race other than South African black. Patients underwent extensive ophthalmic, neurological, radiological, cerebrospinal fluid and blood assessment. RESULTS: Eighteen eyes of 10 patients were studied. The mean age was 35.7 years and 9 patients were female. Only 2 patients had truly unilateral optic neuritis, the other 8 having either bilaterally simultaneous or consecutive disease. Presenting visual acuity (VA) was less than 6/60 in 17 of 18 eyes, with severe dyschromatopsia in all eyes. Fifteen eyes had optic disc swelling. All patients were treated with corticosteroids. After at least 3 months follow-up only 6 eyes recovered VA of 6/12 or better, with only 3 eyes recovering colour vision of 10/13 or better on Ishihara plate testing. No patient had multiple sclerosis (MS) on presentation, nor developed MS on follow-up. CONCLUSION: Idiopathic optic neuritis in black South Africans differs from that in whites. The higher prevalence of bilateral cases and of optic disc swelling, the weaker association with MS and the extremely poor visual outcome distinguish optic neuritis in black South Africans.

Optic-spinal form of multiple sclerosis and anti-thyroid autoantibodies.

The optic-spinal form of multiple sclerosis (OSMS), characterized by recurrent involvement of optic nerve and spinal cord with rare brain magnetic resonance imaging lesions, is relatively common among Asians. While individual cases of OSMS with anti-thyroid autoantibodies (ATABs) have been reported, the frequency of ATAbs in OSMS and classical multiple sclerosis has not been studied. We studied serum ATAbs and anti-nuclear antibodies (ANA) in 46 Japanese patients with multiple sclerosis: 14 with OSMS, and 32 with non-OSMS. Six patients were positive for ATAbs: five women with OSMS and one man with non-OSMS. The frequency of ATAbs in OSMS (5/14) was significantly higher than that in non-OSMS (1/32; P = 0.007), but the frequency of ANA did not differ between OSMS (3/14) and non-OSMS (6/32; P = 0.99). There may be a pathogenetic link between anti-thyroid autoimmunity and a subgroup of OSMS in Japanese.

[Neuromyelopathy in the population of Noir-marron of Saint-Laurent du Maroni in French Guiana]. / Neuromyélopathies dans la population de Noirs marrons de Saint-Laurent du Maroni en Guyane française.

The neurological observations have been reported at André Bouron Hospital of Saint-Laurent du Maroni and at General Hospital of Cayenne during a period of 5 years. All patients belonged to the "Noir Marron" ethnic group and lived in the area of Saint-Laurent. There were six women and four men, aged 15-35 years. Neurological symptoms were isolated or associated to other organ failure. Neurological manifestations included retrobulbar optic neuropathy, spastic paraparesis, sensitive ataxia and cerebellar ataxia, psychiatric symptoms were observed. Other organs affected were cardiovascular, digestive, cutaneous or endocrinologic (thyroid). Diet consist mainly in cassava. Thiamin deficiency has been observed several times. Improvement of neurological deficits following thiamin administration points towards Thiamin as an etiological factor. Ethnological specificity of Saint-Laurent area may explain that such neurological manifestation have not been observed in the rest of the department.