Oculomotor abnormalities in children with Niemann-Pick Type C

Research output: Contribution to journalArticle

Authors

  • Anupam Chakrapani
  • Paul Gissen
  • Chris Hendriksz
  • Suresh Vijay

Colleges, School and Institutes

External organisations

  • Salford Royal Hosp NHS Fdn Trust
  • University of Pretoria
  • Birmingham Children's Hospital NHS Foundation Trust
  • Great Ormond Street Hospital for Children, London, UK.
  • Great Ormond Street Hospital for Children, Institute of Child Health, University College London

Abstract

Niemann-Pick type C (NP-C) is a rare recessive disorder associated with progressive supranuclear gaze palsy. Degeneration occurs initially for vertical saccades and later for horizontal saccades. There are studies of oculomotor degeneration in adult NP-C patients [1, 2] but no comparable studies in children. We used high-resolution video-based eye tracking to record monocular vertical and horizontal eye movements in 2 neurological NP-C patients (children with clinically observable oculomotor abnormalities) and 3 pre-neurological NP-C patients (children without clinically observable oculomotor abnormalities). Saccade onset latency, saccade peak velocity and saccade curvature were compared to healthy controls (N=77). NP-C patients had selective impairments of vertical saccade peak velocity and vertical saccade curvature, with slower peak velocities and greater curvature. Changes were more pronounced in neurological than pre-neurological patients, showing that these measures are sensitive to disease progress, but abnormal curvature and slowed downward saccades were present in both groups, showing that eye-tracking can register disease-related changes before these are evident in a clinical exam. Both slowing, curvature and the detailed characteristics of the curvature we observed are predicted by the detailed characteristics of RIMLF population codes. Onset latencies were not different from healthy controls. High-resolution video-based eye tracking is a promising sensitive and objective method to measure NP-C disease severity and neurological onset. It may also help evaluate responses to therapeutic interventions.

Details

Original languageEnglish
Pages (from-to)159-168
JournalMolecular Genetics and Metabolism
Volume123
Issue number2
Early online date16 Nov 2017
Publication statusPublished - Feb 2018

Keywords

  • Niemann-Pick C , supranuclear gaze palsy , eye-tracking , ocular motor , neurodegenerative diseases , diagnosis