Oculomotor deficits are common in hereditary cerebellar ataxias (HCAs) and their quantitative assessment offers a sensitive and reliable manner to capture disease-severity and progression. As a group of experts of the Ataxia Global Initiative to support trial readiness, we previously established harmonized methodology for quantitative oculomotor assessments in HCAs. Here, we aimed to identify to most promising oculomotor/vestibular outcomes as endpoints for future trials. Through a systematic MEDLINE search we identified 130 articles reporting oculomotor/vestibular recordings in patients with HCAs. A total of 2,018 subjects were included: 1,776 with genetically-confirmed and 242 with clinically-defined HCAs. Studied diseases included spinocerebellar ataxias (SCA) 1/2/3/6/7/27B, episodic ataxia type 2, Friedreich ataxia, RFC1-related ataxia, fragile X-associated tremor/ataxia syndrome, cerebrotendinous xanthomatosis, ataxia-telangiectasia, ataxia with oculomotor apraxia types 1&2, and Niemann-Pick disease type C. We identified up to four oculomotor/vestibular outcomes per diagnostic entity, based on their ability to robustly discriminate patients from controls, correlate with disease-severity, detect longitudinal change, and represent different disease stages. For each parameter we provide recommendations for recordings. While the implementation of quantitative assessments into clinical trials offers a unique opportunity to track dysfunction of oculomotor/vestibular networks and to assess the impact of interventions, in some HCAs, endpoint qualification of available outcomes requires further validation to characterize their reliability, sensitivity to change, and minimally important change to patients. For all HCAs for which quantitative data are scarce or lacking, there is an urgent need for prospective studies covering a broader range of oculomotor/vestibular domains as approaching new treatments require harmonized and reliable endpoints.

• Klíčová slova
• Eye movement recordings, Hereditary ataxia, Oculomotor, Recommendations, Systematic review, Vestibular,
• Publikační typ
• časopisecké články MeSH

Oculomotor deficits are common in hereditary ataxia, but disproportionally neglected in clinical ataxia scales and as outcome measures for interventional trials. Quantitative assessment of oculomotor function has become increasingly available and thus applicable in multicenter trials and offers the opportunity to capture severity and progression of oculomotor impairment in a sensitive and reliable manner. In this consensus paper of the Ataxia Global Initiative Working Group On Digital Oculomotor Biomarkers, based on a systematic literature review, we propose harmonized methodology and measurement parameters for the quantitative assessment of oculomotor function in natural-history studies and clinical trials in hereditary ataxia. MEDLINE was searched for articles reporting on oculomotor/vestibular properties in ataxia patients and a study-tailored quality-assessment was performed. One-hundred-and-seventeen articles reporting on subjects with genetically confirmed (n=1134) or suspected hereditary ataxia (n=198), and degenerative ataxias with sporadic presentation (n=480) were included and subject to data extraction. Based on robust discrimination from controls, correlation with disease-severity, sensitivity to change, and feasibility in international multicenter settings as prerequisite for clinical trials, we prioritize a core-set of five eye-movement types: (i) pursuit eye movements, (ii) saccadic eye movements, (iii) fixation, (iv) eccentric gaze holding, and (v) rotational vestibulo-ocular reflex. We provide detailed guidelines for their acquisition, and recommendations on the quantitative parameters to extract. Limitations include low study quality, heterogeneity in patient populations, and lack of longitudinal studies. Standardization of quantitative oculomotor assessments will facilitate their implementation, interpretation, and validation in clinical trials, and ultimately advance our understanding of the evolution of oculomotor network dysfunction in hereditary ataxias.

• Klíčová slova
• Eye movement recordings, Hereditary ataxia, Oculomotor, Recommendations, Systematic review, Vestibular,
• MeSH
• biologické markery MeSH
• konsensus * MeSH
• lidé MeSH
• pohyby očí fyziologie   MeSH
• poruchy hybnosti oka diagnóza   patofyziologie   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• systematický přehled MeSH

Characterizing bedside oculomotor deficits is a critical factor in defining the clinical presentation of hereditary ataxias. Quantitative assessments are increasingly available and have significant advantages, including comparability over time, reduced examiner dependency, and sensitivity to subtle changes. To delineate the potential of quantitative oculomotor assessments as digital-motor outcome measures for clinical trials in ataxia, we searched MEDLINE for articles reporting on quantitative eye movement recordings in genetically confirmed or suspected hereditary ataxias, asking which paradigms are most promising for capturing disease progression and treatment response. Eighty-nine manuscripts identified reported on 1541 patients, including spinocerebellar ataxias (SCA2, n = 421), SCA3 (n = 268), SCA6 (n = 117), other SCAs (n = 97), Friedreich ataxia (FRDA, n = 178), Niemann-Pick disease type C (NPC, n = 57), and ataxia-telangiectasia (n = 85) as largest cohorts. Whereas most studies reported discriminatory power of oculomotor assessments in diagnostics, few explored their value for monitoring genotype-specific disease progression (n = 2; SCA2) or treatment response (n = 8; SCA2, FRDA, NPC, ataxia-telangiectasia, episodic-ataxia 4). Oculomotor parameters correlated with disease severity measures including clinical scores (n = 18 studies (SARA: n = 9)), chronological measures (e.g., age, disease duration, time-to-symptom onset; n = 17), genetic stratification (n = 9), and imaging measures of atrophy (n = 5). Recurrent correlations across many ataxias (SCA2/3/17, FRDA, NPC) suggest saccadic eye movements as potentially generic quantitative oculomotor outcome. Recommendation of other paradigms was limited by the scarcity of cross-validating correlations, except saccadic intrusions (FRDA), pursuit eye movements (SCA17), and quantitative head-impulse testing (SCA3/6). This work aids in understanding the current knowledge of quantitative oculomotor parameters in hereditary ataxias, and identifies gaps for validation as potential trial outcome measures in specific ataxia genotypes.

• Klíčová slova
• Eye movement recordings, Hereditary ataxia, Oculomotor, Recommendations, Systematic review, Vestibular,
• MeSH
• ataxie MeSH
• Friedreichova ataxie * MeSH
• genotyp MeSH
• lidé MeSH
• pohyby očí MeSH
• progrese nemoci MeSH
• spinocerebelární degenerace * MeSH
• teleangiektatická ataxie * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: To characterize ocular motor function in patients with Niemann-Pick disease type C (NPC). METHODS: In a multicontinental, cross-sectional study we characterized ocular-motor function in 72 patients from 12 countries by video-oculography. Interlinking with disease severity, we also searched for ocular motor biomarkers. Our study protocol comprised reflexive and self-paced saccades, smooth pursuit, and gaze-holding in horizontal and vertical planes. Data were compared with those of 158 healthy controls (HC). RESULTS: Some 98.2% of patients generated vertical saccades below the 95% CI of the controls' peak velocity. Only 46.9% of patients had smooth pursuit gain lower than that of 95% CI of HC. The involvement in both downward and upward directions was similar (51°/s (68.9, [32.7-69.3]) downward versus 78.8°/s (65.9, [60.8-96.8]) upward). Horizontal saccadic peak velocity and latency, vertical saccadic duration and amplitude, and horizontal position smooth pursuit correlated best to disease severity. Compensating strategies such as blinks to elicit saccades, and head and upper body movements to overcome the gaze palsy, were observed. Vertical reflexive saccades were more impaired and slower than self-paced ones. Gaze-holding was normal. Ocular-motor performance depended on the age of onset and disease duration. CONCLUSIONS: This is the largest cohort of NPC patients investigated for ocular-motor function. Vertical supranuclear saccade palsy is the hallmark of NPC. Vertical upward and downward saccades are equally impaired. Horizontal saccadic peak velocity and latency, vertical saccadic duration and amplitude, and horizontal position smooth pursuit can be used as surrogate parameters for clinical trials. Compensating strategies can contribute to establishing a diagnosis.

• Klíčová slova
• Niemann-Pick type C, biomarkers, ocular motor function, saccades, supranuclear vertical gaze palsy, supranuclear vertical saccade palsy, video-oculography,
• MeSH
• lidé MeSH
• Niemannova-Pickova nemoc typu C * MeSH
• pohyby očí MeSH
• prospektivní studie MeSH
• průřezové studie MeSH
• sakadické oční pohyby MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH