Impaired distance perception and size constancy following bilateral occipitoparietal damage

Exp Brain Res (2009) 194:381393 DOI 10.1007/s00221-009-1707-7

RESEARCH ARTICLE

Impaired distance perception and size constancy following bilateral occipitoparietal damage

Marian E. Berryhill Robert Fendrich Ingrid R. Olson

Received: 7 August 2008 / Accepted: 10 January 2009 / Published online: 30 January 2009 Springer-Verlag 2009

Abstract Accurate distance perception depends on the processing and integration of a variety of monocular and binocular cues. Dorsal stream lesions can impair this process, but details of this neurocognitive relationship remain unclear. Here, we tested a patient with bilateral occipitoparietal damage and severely impaired stereopsis. We addressed four related questions: (1) Can distance and size perception survive limitations in perceiving monocular and binocular cues?(2) Are egocentric (self-referential) and allocentric (object-referential) distance judgments similarly impaired? (3) Are distance measurements equally impaired in peripersonal and extrapersonal space? (4) Are size judgments possible when distance processing is impaired? The results demonstrate that the patients lesions impaired both her distance and size perception, but not uniformly. Her performance when using an egocentric reference frame was more impaired than her performance when using an allocentric reference frame. Likewise, her distance judgments in peripersonal space were more impaired than those in extrapersonal space. The patient showed partial preservation in size processing of novel objects even when familiar size cues were removed.

Keywords Distance Depth Parietal Stereopsis

Simultanagnosia Balints syndrome

Introduction

A veridical representation of the three-dimensional world requires accurate perception of object distance and object size. Distance perception requires the integration of diverse cues; size perception is determined by size constancy, the scaling of an objects retinal subtense by estimated distance (Emmert 1881). The neural correlates of these processes have long been linked to dorsal stream function. Ninety years ago, Holmes and Horrax reported the case study of a soldier with bilateral parietal lobe lesions who exhibited extensive distance perception deWcits (Holmes and Horrax 1919). This patient could not determine the closer of two objects even though he possessed normal visual acuity. He had also lost stereopsis, a binocular distance cue. Additional reports have linked distance perception deWcits with dorsal stream damage (Critchley 1953; Holmes 1918; Riddoch 1917). Other reports have related dorsal stream damage to deWcits in size constancy (Ferber and Danckert 2006; Rode et al. 2006; Wyke 1960). In such classic neuro-psychological reports lesion...