Spatial and object-based neglect

The observation that patients with brain damage can selectively ignore or neglect one side of space has long been known and has commonly become termed 'unilateral neglect'. In recent years there has been much interest in the study of neglect and it has been found that individual differences between patients are considerable. This has led to the observation that neglect should not be regarded as a unitary 'syndrome' and that there are actually a number of different forms of neglect, Attempts are now being made to fractionate 'neglect' into different types based on the numerous reported dissociations in the performance of patients. One such distinction is between neglect operating in terms of a spatial frame of reference and neglect operating in terms of an individual object, In this article some of the studies that have supported the distinction of separate spatial and object-based forms of neglect are reviewed. The majority of the evidence supports the distinction of these separate forms of neglect and it is suggested that future studies should be devoted to the assessment of each patient's deficits to ascertain the form of neglect that the patient shows. Furthermore, it is argued that as neglect is not a unitary disorder it is best studied using single case designs and that group studies may well be inappropriate unless the dissociations in each patient's performance are examined in detail.