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Psychosocial therapy for Parkinson's-related dementia: study protocol for the INVEST randomised controlled trial
  1. Sheree A McCormick1,2,
  2. Kathryn R McDonald1,2,
  3. Sabina Vatter1,2,3,
  4. Vasiliki Orgeta4,
  5. Ellen Poliakoff1,2,
  6. Sarah Smith5,
  7. Monty A Silverdale2,6,
  8. Bo Fu4,
  9. Iracema Leroi1,2,3
  1. 1 Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, UK
  2. 2 Manchester Academic Health Science Centre, Manchester, UK
  3. 3 Greater Manchester Mental Health NHS Foundation Trust, Manchester, UK
  4. 4 Division of Psychiatry, University College London, London, UK
  5. 5 Faculty of Health Studies, University of Bradford, Bradford, UK
  6. 6 Greater Manchester Neurosciences Centre, Salford Royal NHS Foundation Trust, Salford, UK
  1. Correspondence to Dr Iracema Leroi; iracema.leroi{at}


Introduction Parkinson's disease (PD) with mild cognitive impairment (MCI-PD) or dementia (PDD) and dementia with Lewy bodies (DLB) are characterised by motor and ‘non-motor’ symptoms which impact on quality of life. Treatment options are generally limited to pharmacological approaches. We developed a psychosocial intervention to improve cognition, quality of life and companion burden for people with MCI-PD, PDD or DLB. Here, we describe the protocol for a single-blind randomised controlled trial to assess feasibility, acceptability and tolerability of the intervention and to evaluate treatment implementation. The interaction among the intervention and selected outcome measures and the efficacy of this intervention in improving cognition for people with MCI-PD, PDD or DLB will also be explored.

Methods and analysis Dyads will be randomised into two treatment arms to receive either ‘treatment as usual’ (TAU) or cognitive stimulation therapy specifically adapted for Parkinson's-related dementias (CST-PD), involving 30 min sessions delivered at home by the study companion three times per week over 10 weeks. A mixed-methods approach will be used to collect data on the operational aspects of the trial and treatment implementation. This will involve diary keeping, telephone follow-ups, dyad checklists and researcher ratings. Analysis will include descriptive statistics summarising recruitment, acceptability and tolerance of the intervention, and treatment implementation. To pilot an outcome measure of efficacy, we will undertake an inferential analysis to test our hypothesis that compared with TAU, CST-PD improves cognition. Qualitative approaches using thematic analysis will also be applied. Our findings will inform a larger definitive trial.

Ethics and dissemination Ethical opinion was granted (REC reference: 15/YH/0531). Findings will be published in peer-reviewed journals and at conferences. We will prepare reports for dissemination by organisations involved with PD and dementia.

Trial registration number ISRCTN (ISRCTN11455062).

  • feasibility and exploratory study
  • pilot trial
  • complex intervention
  • psychosocial therapy
  • quality of life
  • parkinson's disease dementia (PDD)
  • mild cognitive impairment in PD (MCI-PD)
  • dementia with Lewy bodies (DLB)
  • process analysis.

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See:

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  • Contributors IL, SM and KRM are responsible for the overall development of an ethically sound protocol. IL, SM, KRM, SV, VO, EP and SS are involved in the conception and production of the study and the development of the initial protocol. VO provided input on the intervention, while BF provided statistical advice. All authors contributed to the drafting, critical revision and final approval of the document.

  • Funding This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (grant reference number PB-PB-0613-31058).

  • Disclaimer The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

  • Competing interests None declared.

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

  • Correction notice This paper has been amended since it was published Online First. Owing to a scripting error, some of the publisher names in the references were replaced with 'BMJ Publishing Group'. This only affected the full text version, not the PDF. We have since corrected these errors and the correct publishers have been inserted into the references.

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