Many dementia patients are not receiving "key" health assessments when they are in hospital, a new report has found.
Tests to see whether patients are suffering from delirium and assessments of their mental state are at an "alarmingly low" level, according to the latest national dementia audit.
Many elderly patients with dementia develop confusion during a stay in hospital but less than half are assessed for delirium - a state of mental confusion that can happen if someone becomes medically unwell.
And only half of the 8,000 dementia patients who took part in the audit had received an assessment of their mental state, the authors said.
"Assessment for delirium and of mental state is alarmingly low," the authors said.
"Delirium is associated with greater risks of longer admission, hospital acquired infections, admission to long term care, and death.
"Failure to assess and plan for mental health needs may also prevent appropriate assessment and care for physical health needs."
Story continues below...
The report identifies "continuing problems" in the quality of care received by people with dementia in hospitals in England and Wales.
Researchers, from the Royal College of Psychiatrists, also found that two in five hospitals do not provide dementia awareness training to new staff.
And 11% of hospitals did not provide such training to nurses.
But the authors noted that since the last audit, conducted in 2011, "several aspects of care have improved", including a decrease in the number of patients given anti-psychotic drugs
Professor Peter Crome, chair of the National Audit of Dementia steering group, said: "It is pleasing that the second national audit has shown improvements in the care of people with dementia including a reduction in psychotropic medication prescribing.
"However, much still needs to be done and there remains a large gap between what hospitals say should happen and what actually does happens.
"Everyone working in the NHS must accept that the care of people with dementia is a core part of its business. Hopefully, with strong leadership at all levels, future audit will show further positive change."
George McNamara, head of policy and public affairs at the Alzheimer's Society, added: "Hospitals are under immense public and political pressure to improve their standards, but given that people with dementia occupy a quarter of hospital beds, it is scandalous that improving dementia care is not a top priority for a number of hospital managers.
"Going into hospital can be a frightening experience for anyone, but is especially daunting and bewildering for people with dementia.
"All too often we hear of instances when carers dare not leave their loved ones' side.
"We know that staff want to improve their knowledge of dementia care, but they need to be offered the right tools, support and training to do so. Without a serious culture change to ensure that new policies are actually being put into everyday practice, care for people with dementia cannot and will not improve."