Quantification of cranial surface asymmetry using superquadrics

This work addresses a new method for more rapid and reliable measurement of cranial and cerebral asymmetry, which have been hypothesized to correlate with cerebral lateralization. Cerebral laterality itself has been related to speech aphasia, dyslexia, stuttering, autism, hormone levels during development, and some immune system disorders. This new method for quantifying cranial and cerebral asymmetry fits symmetric superquadric geometric models to three dimensional coordinate measurements from cranial and cerebral surfaces. Asymmetry is then quantified as statistical deviations of the surface data points from their best-fit superquadric models. Three dimensional coordinates of random locations on external surfaces of 20 human skulls were measured experimentally and then modeled using superquadric shapes. Polar contour plots of asymmetry are presented for selected individual skulls and for the group as a whole to demonstrate the efficacy of the method.