Williams syndrome is a genetic disorder which gives rise to an unusual
cognitive profile including severe spatial deficits together with
relatively spared language. The exact nature of the spatial impairment
in WS is not well understood at present, but there are indications that
it has "peaks and valleys". For example, individuals with WS perform
extremely poorly in "construction" tasks such as drawing or block
assembly, with adolescents performing in the 1st percentile. In
contrast, we and others have found sparing in a variety of other spatial
tasks, including object and face identification, as well as perception
of biological motion. This pattern of preserved and impaired performance
is consistent with a specific deficit in dorsal stream processing, a
conclusion supported by recent neuroimaging evidence.