Long-Term Efficacy of Prism Adaptation on Spatial Neglect: Preliminary Results on Different Spatial Components

Maria Luisa Rusconi,Laura Carelli

doi:10.1100/2012/618528

Abstract

This study describes the long-term effectiveness on spatial neglect recovery of a 2-week treatment based on prism adaptation (PA). Seven right-brain-damaged patients affected by chronic neglect were evaluated before, after two weeks of the PA treatment and at a follow-up (variable between 8 and 30 months after the end of PA). Neglect evaluation was performed by means of BIT (conventional and behavioral), Fluff Test, and Comb and Razor Test. The results highlight an improvement, after the PA training, in both tasks performed using the hand trained in PA treatment and in behavioral tasks not requiring a manual motor response. Such effects extend, even if not significantly, to all BIT subtests. These results support previous findings, showing that PA improves neglect also on imagery tasks with no manual component, and provide further evidence for long-lasting efficacy of PA training. Dissociations have been found with regard to PA efficacy on peripersonal, personal, and representational neglect, visuospatial agraphia and neglect dyslexia. In particular, we found no significant differences between the pre-training and post-training PA session in personal neglect measures, and a poor recovery of neglect dyslexia after PA treatment. The recruitment of a larger sample could help to confirm the effectiveness of the prismatic lenses with regard to the different clinical manifestations of spatial neglect.

Highlights

Unilateral spatial neglect (USN) is a syndrome more frequently observed in patients with right brain damage who often do not report or respond to stimuli presented in the contralesional hemispace despite the absence of elementary sensory or motor deficits [1,2,3]
Our results highlight an improvement, after the prism adaptation (PA) training, in both visuo-spatial/motor tasks, similar to those addressed during the treatment, and behavioral tasks without a manual motor response
An improvement has been observed after PA training in most subtests, and resulted to be long-lasting, according to the follow-up evaluation

Summary

Introduction

Unilateral spatial neglect (USN) is a syndrome more frequently observed in patients with right brain damage who often do not report or respond to stimuli presented in the contralesional hemispace despite the absence of elementary sensory or motor deficits [1,2,3]. Improvements have been observed in paperand-pencil neglect tasks (line cancellation, line bisection, and drawing by copying or by memory) and in visuoverbal tasks (object description, object naming, and word and nonword reading) [22, 26], naming towns from a mental map [26], and awareness of tactile stimulations [27] These findings suggest that the long-lasting effect of prism procedure may be conceived as improving active processes involved in brain plasticity related to multisensory integration and high-level space representation. All these interesting studies have observed a beneficial effect on USN for a period variable between two weeks and six months after the PA. The main aim was to evaluate the efficacy of PA training in a long-term follow-up (variable from 8 to 30 months after the prism application) about the different clinical neglect manifestations, that is, personal/peripersonal/representational neglect, neglect dyslexia, and agraphia by means of a standardized battery (BIT, conventional and behavioral) and specific personal neglect test (Fluff Test [29] and Comb and Razor Test [30])

Method

F 56 8

Results

Discussion