Folkerts 2018.

Methods	RCT (cross‐over RCT)
Participants	People with Parkinson's disease dementia (PDD) living in long‐term care; diagnosed according to the Movement Disorders Society (MDS) task force Level I guidelines and PDD diagnosed with the MMSE (10 to 25 points). Number randomised (n = 12).
Interventions	Although intervention is described as cognitive stimulation therapy, it was a structured standardised Cognitive Training (CT) programme (NEUROvitalis) adapted to the cognitive and psychomotor profile of participants; performed over 8 weeks, twice weekly for 60 minutes. Control group received usual care (arts, sports, music).
Outcomes	Cognition Consortium to Establish a Registry for Alzheimer's Disease test battery ‐ "CERAD Plus" (plus a word fluency test and the TMT; total score as an index for global cognition (maximum 111 points) Neuropsychiatric symptoms Neuropsychiatric Inventory Depression Geriatric Depression Scale‐Short form (GDS‐15) Cornell Scale for Depression in Dementia Activities of daily living Barthel Index Quality of life EQ‐5D‐5L QUALIDEM
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Participants were randomised by picking a note with the participant's identification code, comprised of 2 random letters and random numbers.
Allocation concealment (selection bias)	Low risk	Mentions that randomisation was done by a member of the staff not involved in the study.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No details provided.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not all assessors were blind.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition and reasons for each group are reported.
Selective reporting (reporting bias)	Low risk	All outcomes reported.
Other bias	Low risk	None identified.