Videoocular assessment of eye movement activity in an ataxia-telangiectasia: a case study.

PURPOSE: Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by progressive neurological deficits, including prominent oculomotor dysfunction. We report 5 cases of eye movement assessment in children 9-15 years old with A-T. METHODS: Three different oculomotor tasks (gaze holding, visually guided saccades and visual search) were used, and video-oculography was performed. Additionally, the scale for the assessment and rating of ataxia (SARA) score was used to assess severity of the cerebellar ataxia. RESULTS: Unstable gaze holding, nystagmus and saccadic intrusions were found. In addition to psychophysiological assessment results, we provide quantitative analysis of oculomotor activity, revealing a specific abnormal oculomotor pattern, consisting of (i) marked saccade hypermetria, (ii) unstable gaze holding, and (iii) gaze-evoked nystagmus. CONCLUSION: Our study opens the prospect to evaluate efficacy and safety of alternative methods for supporting the patient and improving his/her life quality.

Oculomotor Impairments in Children After Posterior Fossa Tumors Treatment.

Posterior fossa tumors (PFT) are the most common pediatric brain tumors, and the study of the somatic and cognitive status of PFT survivors still remains a critical problem. Since cerebellar damage can affect eye movement centers located in the vermis and hemispheres, such patients suffer from disturbances in visual perception, visual-spatial functions, reading, etc. Our investigation aimed at describing oculomotor impairments in PFT survivors linked to core oculomotor functions assessed through eye tracking method: gaze holding, reflexive saccades, and organization of voluntary saccades and their dependency on age at tumor diagnosis. Also, we investigated the relationship between oculomotor functions and ataxia measured with International Cooperative Ataxia Rating Scale (ICARS). A total of 110 children (patients and age-matched healthy controls, aged 9-17 years old) participated in the study. We found that the earlier the child had a tumor, the more impaired gaze holding (p = 0.0031) and fewer isometric saccades (p = 0.035) were observed at the time of examination. The above-mentioned functions in healthy controls improved with age. Visual scanning was also impaired compared to controls but was not related to age at diagnosis. A positive correlation between ICARS scores and number of hypermetric saccades (r = 0.309, p = 0.039), but no correlation with the number of hypometric saccades (r = - 0.008, p = 0.956). Furthermore, number of hypometric saccades did not differ between patients and controls (p = 0.238). Thus, primarily hypermetric saccades can be considered a prominent oculomotor symptom of cerebellar tumors. Our study provides basis for new methods of PFT diagnosis and rehabilitation procedure evaluation, both playing essential roles in modern pediatric neurooncology.