Spinal cord atrophy in spinocerebellar ataxia type 3 and 6 : impact on clinical disability

J Neurol. 2008 Aug;255(8):1244-9. doi: 10.1007/s00415-008-0907-6. Epub 2008 Jun 5.


Objective: To quantify spinal cord atrophy and its impact on clinical disability in spinocerebellar ataxia (SCA) type 3 and 6.

Methods: Atrophy of the upper spinal cord was assessed by high resolution T1-weighted MRI of patients with SCA3 (n = 14) and SCA6 (n = 10). Furthermore, two groups of age- and sex-matched healthy control subjects (n = 24,) corresponding to the two SCA groups, were studied. Images were post-processed by a semi-automated volumetry method combining a marker based segmentation and an automatic histogram method facilitating highly reliable quantification and morphometry of the upper cervical cord in vivo.

Results: We found a significant reduction of normalized mean crosssectional area of the spinal cord in SCA3 (p < 0.0005), whereas in SCA6 patients normalized mean crosssectional area was in the normal range (p = 0.379). No correlation was found between spinal cord atrophy and disease duration as well as CAG repeat length in both subtypes. In SCA6 a negative dependency between clinical disability, as expressed by the International Cooperative Ataxia Rating Scale as a well established ataxia score, and the mean cross-sectional area was found (p = 0.02). A similar correlation was observed in SCA3 but did not reach statistical significance.

Conclusion: Our results quantify for the first time in vivo spinal cord atrophy as a non-cerebellar neurodegenerative process in SCA3. Our results suggest MR volumetry of the upper cervical cord as a marker of functional importance in SCA3 and SCA6.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Atrophy / etiology
  • Case-Control Studies
  • Disability Evaluation
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Machado-Joseph Disease / complications*
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Regression Analysis
  • Reproducibility of Results
  • Severity of Illness Index
  • Spinal Cord / pathology*
  • Spinocerebellar Ataxias / complications*
  • Statistics, Nonparametric