THERE IS ACCUMULATING evidence that patients with autism spectrum disorders (ASD) exhibit reduced thalamus volume.1 Non-right-handedness has been suggested as a risk factor for ASD.2 Thus, it may be fruitful to investigate the effect of handedness on thalamus volume in ASD patients.

The present study was approved by the Ethics Committee of the Niigata University School of Medicine. All participants and their parents provided written informed consent. The participants were 32 Japanese male patients between 6 and 20 years of age, who met the DSM-IV criteria for autistic disorder (n = 10), Asperger's disorder (n = 12) or pervasive developmental disorder not otherwise specified (n = 10).1,3 Each participant was assessed using the childhood autistic rating scale – Tokyo version, the Wechsler Intelligence Scale for Children – Third Edition or the Wechsler Adult Intelligence Scale – Revised, and the Edinburgh Handedness Inventory. Details of the procedure for magnetic resonance image acquisition and brain volume measurements have been described elsewhere.1

Right and total thalamus volumes were significantly smaller in non-right-handed patients than in right-handed patients (Table 1). The present results provided preliminary evidence for reduced thalamus volume in non-right-handed male patients with ASD. One might speculate that non-right-handedness confers susceptibility to ASD, perturbing developments of structure and function in the thalamus. Although there were no significant differences in age, IQ, autistic symptoms or intracranial volume between handedness groups, we could not exclude the possible confounding effects of these factors. Further large-scale studies should be carried out to confirm these preliminary findings.

Table 1.  Thalamus volume in patients with autism spectrum disorders
Clinical variableHandednessP*
Right (n = 28)Non-right (n = 4)
  • All variables are presented as median and interquartile range (in parentheses).

  • *

    Mann–Whitney U-test.

  • CARS-TV, Childhood Autistic Rating Scale – Tokyo version.

Age12.0 (9.3, 14.0)8.5 (8.0, 16.5)0.344
Full-scale IQ93.0 (78.3, 102.0)74.5 (56.3, 99.5)0.220
CARS-TV total score30.8 (30.0, 33.4)31.3 (28.8, 36.8)0.775
Intracranial volume1498.6 (1397.7, 1623.5)1367.9 (1299.9, 1514.8)0.111
Right thalamus volume3.3 (2.7, 3.9)2.5 (2.2, 2.9)0.043
Left thalamus volume3.2 (2.8, 3.8)2.6 (2.2, 3.0)0.053
Total thalamus volume6.4 (5.6, 7.8)5.1 (4.4, 5.9)0.046


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  • 1
    Tamura R, Kitamura H, Endo T, Hasegawa N, Someya T. Reduced thalamic volume observed across different subgroups of autism spectrum disorders. Psychiatry Res. 2010; 184: 186188.
  • 2
    Dane S, Balci N. Handedness, eyedness and nasal cycle in children with autism. Int. J. Dev. Neurosci. 2007; 25: 223226.
  • 3
    Endo T, Shioiri T, Kitamura H et al. Altered chemical metabolites in the amygdala-hippocampus region contribute to autistic symptoms of autism spectrum disorders. Biol. Psychiatry 2007; 62: 10301037.