Taresa Stefurak MSc, MD, FRCPC, Neuropsychiatry Fellow, Rotman Research Institute, Baycrest Centre for Geriatric Care, University Health Network, Department of Neurology, University of Toronto, Toronto, ON.

Introduction
Although Parkinson's disease (PD) is by definition a movement disorder, with a clinical diagnosis made by the presence of two out of three cardinal levodopa-responsive motor signs (tremor, rigidity, bradykinesia), both cognitive and neuropsychiatric symptoms are also important components. The clinical impact of these neurobehavioural symptoms is supported by a study in which the strongest predictor of quality of life perceived by PD patients was the presence of depression.¹ Cognitive impairment as well as postural instability and disability also contributed to poor quality of life. Behavioural disturbances and dementia are the primary reasons for nursing home placement in PD patients.²

Characterizing the nature of these symptoms in PD provides an important model to understand the underlying mechanisms of disease progression and brain function. Although psychosocial aspects may play a role in some of the behavioural and mood disturbances in PD, evidence suggests that the underlying mechanism for these symptoms arises from the biological dysfunction of anatomical and neurochemical substrates that occur in PD.

Gail A. Eskes, PhD
Department of Psychology,
Queen Elizabeth II Health Sciences Centre Assistant Professor,
Psychiatry and Medicine (Neurology),
Adjunct Professor, Psychology,
Dalhousie University, Halifax, NS.

Beverly C. Butler, BSc
Department of Psychology,
Dalhousie University, Halifax, NS.

Introduction
Unilateral neglect is a cognitive and behavioural syndrome after brain damage that can have serious consequences for patient recovery, rehabilitation success and long-term reintegration to independent living. Outcome studies commonly identify neglect and related sequelae as significant predictors of poor outcome in stroke patients in terms of increased need for assistance in self-care activities and decreased quality of life.

Definition and Clinical Presentation
Unilateral neglect is most commonly defined as a failure to orient, report or respond to stimuli located in the space or body contralateral to a brain lesion (often due to stroke or brain injury), despite adequate sensorimotor ability to do so.¹ The neglect syndrome is fundamentally different from, although sometimes confused with, hemianopia, hemisensory loss or hemiplegia.