HI, thanks for using healthcare magic Dementia can be diagnosed by a GP or a psychiatrist. The blood work and imaging would rule out any structural lesions , electrolyte or biochemical abnormality/deficiency or infection as the cause of her confusion. To find another psychiatrist to determine if there is any evidence of dementia you can either ask her present doctor for someone who can provide a second opinion or use one of the web sites that identify doctors within a particular area. This would include findadoctor, webmd directory, findadoc. I hope this helps