A note on Striemer and Danckert's theory of prism adaptation in unilateral neglect

In the four PA studies on motor function in neglect that Striemer and Danckert cite in support of their argument (Dijkerman et al., 2003; Ferber et al., 2003; Angeli et al., 2004; Serino et al., 2006), movements and visual input were not independently controlled for, and their independent roles (passive or active) in improved motor behavior are therefore unclear. Striemer and Danckert (2010a, p. 311) argue that there is little evidence for any effect of PA on “real-world” function, noting that “previous work has failed to observe significant effects of PA upon serial visual search tasks that measure attention in what could be considered a more ‘real-world’ scenario.” [...]this claim is directly contradicted by a recent study by Vangkilde and Habekost (2010) who tested visual search performance following PA in a complex scene (the “where's Waldo” task) in addition to a task where patients were placed in front of a cupboard containing a number of items and were asked to find particular ones. In other words, PA experiments based on advanced assessment of motor and sensory components and statistical voxel-by-voxel lesion mapping are likely to provide more detailed information about the exact nature of any therapeutic effects of PA therapy on neglect.