You can use Dementia knowledge assessment scale (DKAS). The DKAS comprises statements about the syndrome that are factually correct or incorrect, which were developed on the basis of a literature review and international Delphi study with dementia experts. Respondents answer on a modified Likert scale with five response options: false, probably false, probably true, true, don’t know. Preliminary PCA identified four hypothesised components/subscales within the measure that have been defined as Causes and Characteristics (dementia pathology and terminal course), Communication and Behaviour (how a person with dementia engages with the world), Care Considerations (dementia symptoms relevant to the provision of care), and Risks and Health Promotion (risk factors and conditions that are associated with or mistaken for dementia)
you can develop a questionnaire on thorrow literature review and validate it. Or you can use a vailidated questionnaire structured one (likert scale) scoring for each response can be done. Knowlevel can be assessed and compared using Mean knowledge scores