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E04 Cortical Thinning Of The Occipital Lobe In Huntington’s Disease And Associations With Cognitive Performance
  1. EB Johnson1,
  2. EM Rees1,
  3. I Labuschagne2,
  4. A Durr3,
  5. BR Leavitt4,
  6. RAC Roos5,
  7. H Johnson6,
  8. NZ Hobbs1,
  9. HE Crawford1,
  10. DR Langbehn7,
  11. JC Stout2,
  12. SJ Tabrizi1,
  13. RI Scahill1
  14. and the TRACK-HD investigators
  1. 1UCL Institute of Neurology, University College London, London, UK
  2. 2School of Psychology and Psychiatry, Monash University, Victoria, Australia
  3. 3Department of Genetics and Cytogenetics, and INSERM UMR S679, APHP Hôpital de la Salpêtrière, Paris, France
  4. 4Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
  5. 5Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands
  6. 6Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA, USA
  7. 7Department of Psychiatry, University of Iowa, Iowa City, Iowa, USA

Abstract

Background Previous Huntington’s disease studies have revealed occipital lobe atrophy and cortical thinning, although it is unclear when this develops and whether it is uniform across the lobe. Visual deficits are not typical of HD symptomatology, however it is possible that more subtle visual functions are impaired and, in turn, influence performance on cognitive tasks with a visual component.

Aims To identify the regional distribution of disease-related occipital cortical thinning and investigate associations with cognitive and motor impairment.

Methods T1-weighted 3T MR scans from controls (n = 107), pre-HD (n = 116) and early HD subjects (n = 90) from the TRACK-HD study were processed using the FreeSurfer software; cuneus, pericalcarine, lingual and lateral occipital regions were outputted. Generalised least squares regression models were fitted to assess between-group differences. Relationships between visual cognitive and motor task performance and cortical occipital thinning in gene-positive participants were assessed using general linear regression models.

Results The occipital cortex was significantly thinner in pre-HD and early HD participants. These between-group differences were heterogeneous across regions, with the lateral occipital region showing the most pronounced effects. Significant associations were found between reduced occipital cortical thickness and poorer performance on a number of cognitive tasks involving a visual component. No association was found with finger tapping.

Conclusions Regionally-specific thinning of the occipital cortex was evident more than a decade before estimated HD symptom onset. Associations were found with cognitive tasks, but not finger tapping, suggesting that occipital thickness plays an important role in cognitive tasks with a visual component. This has implications for the interpretation of impaired cognitive performances in HD, which is typically attributed to frontal and executive circuits, rather than to visual regions.

KeyWords
  • Huntington’s disease
  • cortical thinning
  • occipital lobe
  • cognitive performance

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