Cognitive and behavioral assessment in Parkinson’s disease

ABSTRACT

Introduction: Cognitive impairment and behavioral disturbances are common findings in Parkinson’s disease (PD). Despite initially being considered late complications of the disease, it is currently accepted that almost all PD patients will exhibit cognitive and behavioral abnormalities from the early and even the premotor stages of the disease.

Areas covered: The present review focuses on the cognitive profile of PD, the clinical picture of PD-MCI and dementia in PD (PDD) and the recommended methods for cognitive assessment in this population. The authors also describe the more representative neuropsychiatric alterations and provide an overview of the recommended methods of assessment.

Expert opinion: Cognitive and behavioral symptoms are inherent to PD, appear in a vast majority of patients at some point during disease progression and have an enormous impact on health-related quality of life of patients and caregivers. Validated methods of cognitive and behavioral assessment are currently developed and must be used in research and clinical settings.

KEYWORDS:

• Parkinson’s disease
• PD-MCI
• neuropsychiatric symptoms
• cognition
• assessment

Article highlights

• In PD, cognitive impairment may be recognized even in the initial stages of the disease, but traditional instruments of global cognitive assessment may not capture it.

• Early cognitive impairment in PD is prototypically characterized as executive dysfunction. However, some individuals also present posterior-cortical alterations.

• Posterior-cortical changes predicts the progression of cognitive impairment to dementia in PD.

• At the beginning of PD, PD-MCI may affect up to 30% of patients. Dementia will affect up to 80% long-term survivals but will also affect up to 35% of patients during the 5 years of disease duration.

• The MDS provided operative criteria for the diagnosis of PD-MCI and PDD and recommendations on the methods of neuropsychological assessment.

• The PD-CRS is the more reliable instrument for global cognitive assessment in PD.

• Neuropsychiatric symptoms of variable severity will affect a large proportion of PD.

• Disorders of mood and effect, motivation, impulse control and psychotic symptoms are common findings in PD.

• Asking for the presence of neuropsychiatric symptoms and using adequate instruments to rate its severity is essential to avoid the common under-recognition of these symptoms.

Declaration of interest

J Kulisevsky has received honoraria for lecturing or consultation from the Michael J. Fox Foundation, Merck Serono, AbbVie, Boheringer Ingelheim, UCB, Zambon, Italfarmaco, General Electric, Teva, Lundbeck, Bial, Prexton, and Accorda. They have also received public grants from la Marato de Tv3 and Fondo de Investigaciones Sanitarias ISCIII. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or conflict with the subject matter or materials discussed in this manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper was not funded.