J Neurol Neurosurg Psychiatry 83:601-606 doi:10.1136/jnnp-2011-301874
  • Movement disorders
  • Research paper

Mild cognitive impairment and cognitive-motor relationships in newly diagnosed drug-naive patients with Parkinson's disease

  1. Ubaldo Bonuccelli1,2
  1. 1Department of Neuroscience, University of Pisa, Pisa, Italy
  2. 2Neurology Unit, USL of Viareggio, Viareggio, Italy
  1. Correspondence to Dr Professor Ubaldo Bonuccelli, Department of Neuroscience, University of Pisa, Pisa I56125, Italy; u.bonuccelli{at}
  1. Contributors All the authors met the criteria for authorship and have approved the contents of the text. 1. Research project: A, conception; B, acquisition of data; C, analysis of data. 2. Manuscript: A, writing of the first draft; B, review and critique of the manuscript. 3. Final approval of the version to be published. MP and DF: 1A, 1B, 1C, 2A, 2B, 3. RC and UB: 1A, 1B, 1C, 2B, 3. CP, FB, VN, GT, CL and PDD: 1A, 1B, 2B, 3.

  • Received 22 November 2011
  • Revised 15 February 2012
  • Accepted 27 February 2012
  • Published Online First 4 April 2012


Background and aims (1) To establish the prevalence of mild cognitive impairment (MCI) in newly diagnosed drug-naive patients with Parkinson's disease adopting recently proposed and more conservative preliminary research criteria. (2) To investigate the relation between cognitive performances, MCI and motor dysfunction.

Methods 132 consecutive newly diagnosed drug-naive PD patients and 100 healthy controls (HCs) underwent a neuropsychological evaluation covering different cognitive domains. Moreover, on the basis of the Unified Parkinson's Disease Rating Scale II/III, different motor scores were calculated and patients were classified in motor subtypes. 11 patients were excluded from the analysis during clinical follow-up which was continued at least 3 years from the diagnosis; therefore, the final sample included 121 patients.

Results MCI prevalence was higher in PD (14.8%) patients than in HCs (7.0%). PD patients reported lower cognitive performances than HCs in several cognitive domains; HCs also outperformed cognitively preserved PD patients in tasks of episodic verbal memory and in a screening task of executive functions. MCI-PD patients presented a more severe bradykinesia score than non-MCI PD patients and patients mainly characterised by tremor had better performances in some cognitive domains, and specific cognitive-motor relationships emerged.

Conclusions Although the adoption of more conservative diagnostic criteria identified a lower MCI prevalence, we found evidence that newly diagnosed drug-naive PD patients present a higher risk of MCI in comparison with HCs. Axial symptoms and bradykinesia represent risk factors for MCI in PD patients and a classification of PD patients that highlights the presence/absence of tremor, as proposed in this study, is probably better tailored for the early stages of PD than classifications proposed for more advanced PD stages.


  • Funding This work was supported by a Tuscany Region grant.

  • Competing interests None.

  • Patient consent A local consent form has been signed by the patients according to our local ethics committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement All authors state that no additional unpublished data are available and/or shared.

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