Travel Planning Ability in Right Brain-Damaged Patients: Two Case Reports
Planning ability is fundamental for goal-directed spatial navigation. Preliminary findings
from patients and healthy individuals suggest that travel planning (TP)—namely,
navigational planning—can be considered a distinct process from visuospatial planning
(VP) ability. To shed light on this distinction, two right brain-damaged patients without
hemineglect were compared with a control group on two tasks aimed at testing VP
(i.e., Tower of London-16, ToL-16) and TP (i.e., Minefield Task, MFT). The former requires
planning the moves to reach the right configuration of three colored beads on three
pegs, whereas the latter was opportunely developed to assess TP in the navigational
environment when obstacles are present. Specifically, the MFT requires participants to
plan a route on a large carpet avoiding some hidden obstacles previously observed.
Patient 1 showed lesions encompassing the temporoparietal region and the insula; she
performed poorer than the control group on the ToL-16 but showed no deficit on the
MFT. Conversely, Patient 2 showed lesions mainly located in the occipitoparietal network
of spatial navigation; she performed worse than the control group on the MFT but not on
the ToL-16. In both cases performances satisfied the criteria for a classical dissociation,
meeting criteria for a double dissociation. These results support the idea that TP is a
distinct ability and that it is dissociated from VP skills.