Faculty Bibliography

Saccadic eye movement abnormalities are among the earliest manifestations of Huntington's disease (HD) but are difficult to quantify at the bedside. Similarly, afferent visual pathway involvement in HD is poorly characterised. The objective was to evaluate afferent and efferent visual function in HD. Participants with manifest HD (n = 19) and healthy controls (n = 20) performed the King-Devick test, a timed test of rapid number naming. Binocular high and low-contrast (2.5% and 1.25%) acuities were measured using low-contrast Sloan letter charts, and pupillometric recordings were made using a handheld NeurOptics PLR-3000 pupillometer. The NEI-VFQ-25 questionnaire with 10-item neuro-ophthalmic supplement were also completed. Unified Huntington's Disease Rating Scale (UHDRS) motor score and other clinical and demographic variables were collected. Comparisons between manifest HD and controls were performed using linear regression adjusted for confounders. Mean King-Devick time scores were 102.9 seconds in patients with manifest HD and 48.2 seconds in controls (p < .01, t-test). In unadjusted analyses, binocular high contrast acuity was seven letters (one Snellen line equivalent) lower in manifest HD than controls (p = .043). This effect was similar for low-contrast acuity, but only low-contrast acuity remained statistically significant after adjusting for covariates. Low-contrast acuity also correlated with UHDRS motor score. There were no differences in pupillary reactivity or self-reported vision-related quality of life. In conclusion, HD is associated with reduced low-contrast acuity and abnormal performance on the King-Devick test of rapid number naming. These tests are easy to administer, providing an objective quantitative measure of visual function which could be incorporated into optimised rating scales.

Vision, which requires extensive neural involvement, is often impaired in Alzheimer's disease (AD). Over the last few decades, accumulating evidence has shown that various visual functions and structures are compromised in Alzheimer's dementia and when measured can detect those with dementia from those with normal aging. These visual changes involve both the afferent and efferent parts of the visual system, which correspond to the sensory and eye movement aspects of vision, respectively. There are fewer, but a growing number of studies, that focus on the detection of predementia stages. Visual biomarkers that detect these stages are paramount in the development of successful disease-modifying therapies by identifying appropriate research participants and in identifying those who would receive future therapies. This review provides a summary and update on common afferent and efferent visual markers of AD with a focus on mild cognitive impairment (MCI) and preclinical disease detection. We further propose future directions in this area. Given the ease of performing visual tests, the accessibility of the eye, and advances in ocular technology, visual measures have the potential to be effective, practical, and non-invasive biomarkers of AD.

BACKGROUND:Optical coherence tomography (OCT) measurements of ganglion cell + inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thicknesses are associated with visual function (VF) and disability in multiple sclerosis (MS). However, the value of measuring Bruch membrane opening-minimum rim width (BMO-MRW) thickness in MS remains unclear. METHODS:Sixty-eight patients with MS and 22 healthy controls (HCs) underwent spectral domain OCT, 100%-contrast visual acuity (VA), 2.5%- and 1.25%-contrast letter acuity (LA), and Expanded Disability Status Scale (EDSS) testing. Mixed-effects linear regression models, accounting for within-subject, intereye correlations, were used to assess relationships. RESULTS:The MS cohort exhibited significantly lower BMO-MRW (P = 0.01), pRNFL at 3.7-, 4.1-, and 4.7-mm diameters surrounding the optic disc (P < 0.001 for all), and GCIPL (P < 0.001) thicknesses than HCs. BMO-MRW thickness was associated with 100%-VA (P < 0.001, R = 0.08), 2.5%-LA (P < 0.001; R = 0.13), and 1.25%-LA (P = 0.002; R = 0.11). All measured pRNFL thicknesses were associated with high- and low-contrast VF (all: P < 0.001). GCIPL thickness was more strongly associated with 100%-VA (P < 0.001; R = 0.23), 2.5%-LA (P < 0.001; R = 0.27), and 1.25%-LA (P < 0.001; R = 0.21) than the other OCT measures assessed. All OCT measures were significantly, but weakly, associated with EDSS scores. CONCLUSIONS:BMO-MRW and pRNFL thicknesses are reduced and associated with VF and disability in MS, but GCIPL thickness is a stronger marker of visual impairment. Our findings corroborate the utility of OCT in providing valuable information regarding the MS disease process.

OBJECTIVE:We report analyses of a pooled database by the Multiple Sclerosis Outcome Assessments Consortium to evaluate 4 proposed components of a multidimensional test battery. METHODS:Standardized data on 12,776 participants, comprising demographics, multiple sclerosis disease characteristics, Expanded Disability Status Scale (EDSS) score, performance measures, and Short Form-36 Physical Component Summary (SF-36 PCS), were pooled from control and treatment arms of 14 clinical trials. Analyses of Timed 25-Foot Walk (T25FW), 9-Hole Peg Test (9HPT), Low Contrast Letter Acuity (LCLA), and Symbol Digit Modalities Test (SDMT) included measurement properties; construct, convergent, and known group validity; and longitudinal performance of the measures individually and when combined into a multidimensional test battery relative to the EDSS and SF-36 to determine sensitivity and clinical meaningfulness. RESULTS:The performance measures had excellent test-retest reliability and showed expected differences between subgroups based on disease duration and EDSS level. Progression rates in detecting time to 3-month confirmed worsening were lower for T25FW and 9HPT compared to EDSS, while progression rates for LCLA and SDMT were similar to EDSS. When the 4 measures were analyzed as a multidimensional measure rather than as individual measures, progression on any one performance measure was more sensitive than the EDSS. Worsening on the performance measures analyzed individually or as a multidimensional test battery was associated with clinically meaningful SF-36 PCS score worsening, supporting clinical meaningfulness of designated performance test score worsening. CONCLUSION/CONCLUSIONS:These results support the use of the 4 proposed performance measures, individually or combined into a multidimensional test battery as study outcome measures.

Introduction: Natalizumab treatment in patients with early relapsing-remitting multiple sclerosis (RRMS) may improve clinical outcomes. STRIVE is a completed, 4-year, multicentre, observational, open-label, single-arm study of anti-JC virus antibody negative patients starting natalizumab < 3 years after RRMS diagnosis.
Objective(s): To examine 4-year, end-of-study no evidence of disease activity (NEDA) status, disability worsening and improvement, and cognitive performance of natalizumab-treated patients with early RRMS.
Method(s): Clinical NEDA, the primary endpoint, was defined as no relapses or Expanded Disability Status Scale (EDSS) worsening (score increase of >=1.5 from a baseline [BL] of 0.0, >=1.0 from a BL of 1.0-5.5, or >=0.5 from a BL >=6.0, confirmed over 24 weeks). MRI NEDA was defined as no gadolinium-enhancing or new/enlarging T2-hyperintense lesions. Overall NEDA encompassed both clinical and MRI NEDA. Annualised relapse rates (ARRs) were analysed with a negative binomial regression model. The Kaplan-Meier method estimated time to 24-week-confirmed EDSS worsening or improvement (score decrease of >=1.0 from a BL >=2.0). The Symbol Digit Modalities Test (SDMT) change from BL to year 4 was analysed via a Wilcoxon signed-rank test.
Result(s): At BL (N=222), patients had active disease, a mean (standard deviation [SD]) of 1.4 (1.2) relapses in the prior year, and a mean (SD) EDSS score of 2.04 (1.13). At study end, 100 of 169 patients (59.2%) achieved cumulative clinical NEDA, and 72 of 143 (50.4%) and 45 of 163 (27.6%) had MRI and overall NEDA, respectively. In year 4, 101 of 134 patients (75.4%) had overall NEDA. ARRs decreased by 90.2%, from 1.43 in the year before natalizumab to 0.14 on natalizumab (P< 0.0001). Cumulative probabilities of EDSS worsening and improvement over 4 years were 19.3% and 43.9%, respectively. At study end, the mean (SD) EDSS score was 1.77 (1.55). From BL to year 4, patients had significant improvement in SDMT score (n=174; mean change from BL: 4.6 [95% confidence interval: 2.9-6.2]; P< 0.0001). Serious adverse events were reported in 25 of 222 patients (11.3%), with no cases of progressive multifocal leukoencephalopathy.
Conclusion(s): Natalizumab treatment over 4 years was associated with NEDA achievement, a 43.9% probability of disability improvement, a 19.3% probability of disability worsening, and significantly improved cognitive performance. These results support natalizumab's long-term effectiveness in early RRMS patients