title: Anxiety is associated with cognitive impairment in newly-diagnosed Parkinson's disease.
abstract: Anxiety and mild cognitive impairment (MCI) are prevalent non-motor manifestations of Parkinson's disease (PD). While few studies have demonstrated a possible link between cognitive dysfunction and anxiety in PD, to our knowledge, no studies have directly examined the association between them. This study investigated the association between anxiety and cognitive deficits in newly diagnosed PD patients.
  
  
  
  Patients with newly diagnosed PD (N = 185) were recruited from community and outpatient clinics. Anxiety was assessed using the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) clinician rated anxiety item, which has previously been validated against a standardized criteria for the diagnosis of anxiety disorders in PD. Participants scoring ≥2 were classified as anxious. A threshold of 1 SD below normative values (obtained from controls) was used to define cognitive impairment. Impairments in specific cognitive domains were identified as being >1 SD below controls in ≥1 test per domain.
  
  
  
  After controlling for age, education and motor severity, patients with anxiety were three times more likely to have cognitive impairment compared to those without anxiety (OR = 3.0, 95% CI = 1.2-7.3, p < 0.05). Patients with anxiety were more than twice as likely to be classified as having cognitive impairment due to impairment in the memory domain compared with PD without anxiety (OR = 2.3, 95% CI = 1.0-5.1, p < 0.05), whilst no associations were found between anxiety and performance on other cognitive domains.
  
  
  
  This study shows an association between anxiety and cognitive impairment (specifically memory impairment). Examining the neural basis of this association warrants future research in this developing field.
authors.affiliation: The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia; Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, Australia; School of Psychology, The University of Queensland, Brisbane, Australia. Electronic address: n.dissanayaka@uq.edu.au.
authors.forename: Nadeeka N W
authors.initials: NNW
authors.lastname: Dissanayaka
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK.
authors.forename: Rachael A
authors.initials: RA
authors.lastname: Lawson
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Yarnall
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Duncan
authors.affiliation: John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.
authors.forename: David P
authors.initials: DP
authors.lastname: Breen
authors.affiliation: School of Medicine & Menzies Health Institute Queensland, Griffith University, Australia.
authors.forename: Tien K
authors.initials: TK
authors.lastname: Khoo
authors.affiliation: John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Barker
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Burn
mesh_terms: D000368:Aged; D001007:Anxiety / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*
keywords: Anxiety; Cognitive subtypes; Mild cognitive impairment; Parkinson's disease