Alzheimer’s disease progresses slowly and insidiously. The symptoms are usually barely noticeable at first – minor forgetfulness, difficulty concentrating and problems with abstract thought. Later, patients experience more severe symptoms such as loss of memory and reduced language skills. A new study shows that the diagnosis of Alzheimer’s disease is often not accurate. Patients are misdiagnosed with Alzheimer’s more often than one would expect.
Alzheimer’s Disease May Be Over Diagnosed in the Elderly
People with Alzheimer’s disease usually have three characteristic brain lesions: plaques, neurofibrillary tangles and granulovacuolar degeneration. Their brains are also usually smaller than normal due to atrophy or loss of brain volume.
Researchers performed a post-mortem exam of the brains of 426 Japanese-American residents of Hawaii. Almost half of them had been diagnosed with Alzheimer’s disease while still alive. Many did not have enough evidence on autopsy to confirm this diagnosis.
A diagnosis of Alzheimer’s was not confirmed because their brains lacked enough of the characteristic lesions. Many actually had brain abnormalities that suggested other forms of dementia. In fact, half of the people they autopsied didn’t have enough evidence to confirm they had Alzheimer’s disease while they were alive.
Alzheimer’s Dementia Is Not the Only Cause of Memory Problems
Doctors must first exclude other causes of dementia in order to diagnosis Alzheimer’s disease. Alzheimer’s can only be definitively confirmed after death by looking for the characteristic brain changes during an autopsy. CTs and MRIs are helpful diagnostic tools, but they are most useful for excluding other causes of dementia.
Other treatable causes of dementia often go untreated when Alzheimer’s disease is misdiagnosed. B12 deficiency, thyroid disease, and syphilis are treatable causes that mimic Alzheimer’s disease. There are also other untreatable causes of dementia. This is why doctors run so many lab and imaging tests before making the diagnosis. They need to definitively exclude other causes of dementia.
By SBarnes [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
Diagnosis of Alzheimer’s Dementia: The Bottom Line?
Diagnosing Alzheimer’s is tricky and the misdiagnosis rate is high. Make sure anyone you know who is being evaluated gets a thorough work-up since Alzheimer’s disease is not the only cause of dementia.