Unilateral Neglect: Clinical and Experimental Studies

Contents

Peter W. Halligan and John C. Marshall

What is neglect?

A brief history of visual neglect

Clinical presentation of visual neglect

Illustrations of visual neglect

Conclusions

Acknowledgements

References

2 The Anatomical Basis of Spatial Hemineglect in Humans

Giuseppe Vallar

Introduction

Anatomical correlates of spatial hemineglect

Functional anatomy of hemineglect

The fractionation of spatial hemineglect: Neural correlates

Neural mechanisms of recovery from hemineglect

Summary

Acknowledgements

References

PART II NEUROPSYCHOLOGICAL PROCESSES UNDERLYING NEGLECT

3 Orientational Bias Model of Unilateral Neglect: Evidence from Attentional Gradients Within Hemispace

Marcel Kinsbourne

Introduction

Lateral interactions between opponent processors

What is an attentional gradient?

Modular or interactive processors for lateral attending?

Hemisphere activation and neglect

Clinical observations

Experimental observations

Conclusion

References

4 Neural Mechanisms of Spatial Neglect

Giacomo Rizzolatti and Anna Berti

Introduction

Attention and neglect

Representation and neglect

Conclusion

Acknowledgements

References

5 The Role of Spontaneous Eye Movements in Orienting Attention and in Unilateral Neglect

Guido Gainotti

Introduction

The sensorimotor theories of neglect

Remission of hemineglect during vestibular stimulation

The influence of attention upon signs of right hemisphere damage usually associated with neglect

Direction of spontaneous or automatic eye movements and spatial orienting of attention

Implications for theories of unilateral neglect

References

6 “What” and “Where” in Visual Attention: Evidence from the Neglect Syndrome

Martha J. Farah, Marcie A. Wallace, and Shaun P. Vecera

Attention and representation

Attention to locations and objects: A brief review of evidence from normal subjects

Attention to locations and objects after unilateral parietal damage

Attention to locations and objects after bilateral parietal damage

Conclusions

Acknowledgements

References

7 Interactive Attentional Systems and Unilateral Visual Neglect

Glyn W. Humphreys and M. Jane Riddoch

Introduction

Representational accounts

Attentional accounts

Relations between the attentional accounts: An interactive attentional network

Separating the accounts

Other phenomena in the neglect syndrome: Unconscious perception

Object- and space-systems: High-level representations and neglect

Representations, attention and brain sites

Varieties of visual neglect

Acknowledgements

References

8 Attentional Search in Unilateral Visual Neglect

Lynn C. Robertson and Mirjam Eglin

Introduction

Attention and visual neglect

Attention, spatial representation and neglect

Neglect and spatial transformations

Conclusion

Acknowledgements

References

9 Spatial Dimensions of Automatic and Voluntary Orienting Components of Attention

Elisabetta Làdavas

Selective attentional deficits for different sectors of space

Horizontal dimension

Vertical dimension

Is the deficit related to automatic or voluntary orienting of attention?

References

10 Shifts and Omissions in Spatial Reference in Unilateral Neglect

Reinhard Werth

Introduction

Visual neglect in children

Visual neglect in adult patients

The explanation of the omission of stimuli in visual neglect

Shifts of visual co-ordinates

Conclusions

References

11 Neglect and Visual Language

Andrew W. Ellis, Andrew W. Young, and Brenda M. Flude

Introduction

Neglect and reading I: Spatial neglect dyslexia

Neglect and reading II: Positional neglect dyslexia

Spelling and writing and unilateral neglect

Neglect and visual language

References

12 The Relationship between Lateralised and Non-lateralised Attentional Deficits in Unilateral Neglect

Ian H. Robertson

Introduction

The paradox of neglect: Remission rates, laterality and chronicity

Evidence for attentional deficits within ipsilesional hemispace in unilateral neglect

Evidence for increased neglect with increased demands upon attention

Evidence for relatively greater difficulty with conjunction versus feature search among neglect subjects

Evidence for influence of degree of arousal upon neglect

Evidence for a right hemisphere specialisation for certain aspects of attention

Posner and Peterson’s model of attention

Overview and hypothesis

Coda

References

PART III REHABILITATION OF UNILATERAL NEGLECT

13 Prospects for the Rehabilitation of Unilateral Neglect

Ian H. Robertson, Peter W. Halligan, and John C. Marshall

Why consider rehabilitation?

The role of theories of neglect in determining the nature of rehabilitation

Effectiveness of rehabilitation 1

Effectiveness of rehabilitation 2: Behavioural training of stimulus-specific responses

Effectiveness of rehabilitation 3: Spatio-motor cueing

Possible future directions in neglect rehabilitation

Overview

References

14 The Behavioural Management of Neglect

Leonard Diller and Ellen Riley

Introduction

Defining and altering visual neglect: A review of early studies (1966–82)

Exploring non-visual correlates of neglect: Studies 1983–87

Unawareness: Current studies (1988-present)

Some future directions in remediation of neglect

Acknowledgements

References

CODA

15 Contemporary Theories of Unilateral Neglect: A Critical Review

John C. Marshall, Peter W. Halligan, and Ian H. Robertson

Introduction

Interpretations of neglect