Conference Presentations

Introduction​

Cerebellar dysfunction is the central mechanism in most ataxia and often leads to oculomotor abnormalities including smooth pursuit or saccades impairment and nystagmus. Those symptoms can be highly specific to cerebellar dysfunction, making their analysis a valuable aid in diagnosing cerebellar ataxia syndromes and representing potential diagnostic biomarker. On the other end, those symptoms are difficult to assess clinically, and objective evaluation was mainly confined to research. ​

The objective of the study was to validate diagnostic biomarkers for Ataxia using BulbiCAM® device. ​

Method​

·       Non-randomized, parallel-group study (see Table 1)​

·       16 patients without visual history ​

·       20 age-matched healthy controls (HC) ​

·       BulbiCAM® test battery ​

·       Fixation​

·       Smooth pursuit at 3 frequencies (0.2Hz, 0.5Hz, increasing 0.1- 0.6Hz)​

·       Pro-saccades tests (horizontal and multi-directional)​

·       Each Ataxia patient completed 6 repetitions of the battery and HC 2 repetitions. ​

·       Statistical analyisi:​

·       Validity (Ataxia patients vs. HC discrimination) -> AUC CI≥ 0.5 or p≤0.05​

·       Repeatability intra-subjects -> AI ≥ 0.5 and/or SI ≥0,14 ​

·       Repeatability inter-patients -> ICC (3,1) ≥ 0.5​

AI = Agreement Index, AUC = Area Under the Curve, CI = Confidence Interval​

ICC = Intraclass Correlation Coefficient, SI = Stability Index​

Conclusion​

The 3 frequencies of the smooth pursuit test and several parameters of both prosaccade tests met diagnostic biomarker validation criteria.​

These results are consistent with known impairments in saccades and smooth pursuit in ataxia, which are correlated with disease severity and treatment response. ​

Recognizing patterns of ocular motor impairment is often a key step toward the correct diagnosis of ataxia. Recent advances in video-oculography provides rapid, objective and reliable measurement of oculomotor parameters, supporting potential clinical applications for both diagnosis and patient follow-up.​

Significant findings in a small sample indicate large effect size, highlighting the most relevant biomarkers. ​