So many of my patients are convinced they are developing dementia. Almost universally, when I have an appointment with a patient who asked for the consultation, a primary dementia like Alzheimers is already ruled out. If they had primary or pure Alzheimer's disease, they wouldn’t have asked for the consult in the first place since one of the hallmarks of the disease is lack of insight. This is not to say that the patients aren’t suffering from their forgetfulness, and some could say they are suffering more since they are more aware of their deficits. They get frustrated every time they misplace their keys, put the milk in the cabinet, or walk into a room and have no idea why they went there in the first place. The reality is that Alzheimer’s is unlikely because they remember that they forgot. 

The broader concept of Dementia, however, is more complex. While the formal definition of dementia has changed over the years, a few key features have persisted. A dementia must be a change from someone’s baseline abilities. These changes must cause someone to lose their ability to function in day to day life. It must be a problem with at least two areas of brain functioning (language, visuospatial reasoning, memory, executive functioning etc…). These deficits must be irreversible. Generally, the deficits must be progressive though there are a few exceptions to this rule. 

The most common difficulty I have in diagnosing dementia is the question of if the deficits are irreversible. If a patient is having a lot of severe cognitive complaints, but their sleep apnea, depression, hypothyroidism, and diabetes are poorly treated then it is impossible for me to confirm or deny that their symptoms are irreversible. In a few rare cases, I have “cured” patients who had a 5 year diagnosis of Alzheimer’s disease with an antidepressant and increased physical and social activity. 

Delirium is also a stark example. Delirium is when a person develops symptoms that look like dementia or even psychosis due to an active medical issue, or more often a combination of many different medical issues. While developing delirium may be a sign that the brain is degenerating, a sudden loss of functioning will be due to an infection, a worsening cardiovascular disorder, or some other medical event. Until the medical condition is treated, there is no way to know how much a person will recover. Consequently, it is foolish to make the diagnosis of dementia in the hospital. Instead, someone should be treated for their medical conditions and tested for dementia at least 3-6 months later, after recovery has slowed or stopped. At times, there is no underlying dementia at all. I’ve seen patients who were teaching graduate school courses one day, presented to the hospital demented the next, and back to teaching a few days later after treating something as simple as constipation or elevated blood pressure.

Consequently, the term dementia has lost favor in the psychiatric diagnostic manual (the DSM). Instead, the diagnosis is “Major Neurocognitive Disorder”. This has kept most of the criteria including a decline from baseline, the loss of independence, and a significant decline in multiple cognitive domains, but allows for the symptoms to be reversible if the medical contributors are properly treated. However, this shift in tone hasn’t reached most of the medical providers who still see “Major Neurocognitive Disorder” and dementia as synonymous. While many applaud these changes, the DSM has removed very important features of specific degenerative disorders. Originally, the DSM had criteria for Alzheimer’s that included loss of the “cortical brain functions” of aphasia, apraxia, and agnosia to help support the diagnosis. Now, the DSM still talks about Major Neurocognitive Disorder due to Alzheimer’s, but just includes evidence of a genetic cause and/or lack of a “mixed etiology”. If you’re confused by now, don’t worry. So are the psychiatrists.

A true dementia evaluation is often a lengthy process. There are times where it is quick, but the referral is usually for something else besides forgetfulness. I’ve diagnosed variants of Fronto-temporal dementia (called primary progressive aphasia) with patients who were referred for anxiety. I often diagnose parkinson’s dementia or dementia with lewy bodies for patients referred for a gait disturbance. However, these are maybe 2% of the consults I get for cognitive decline. 

Nearly every patient I see for cognitive decline has no single cause for their symptoms, but many smaller contributors. This makes evaluation and treatment very difficult. As a neurologist and neuropsychiatrist, I can identify and treat many contributors, but it would be foolish for me to take charge of their thyroid dysfunction, their nutritional deficiencies, or their cardiovascular disease. Sure, their question is neurological, but their treatment needs to be coordinated centrally by a primary care doctor who considers their medical risk factors, knows which labs to screen for every year, and can start treatment while the patient waits for specialist referrals. 

There are a few caveats to this. If someone progresses from a normal baseline to a dementia within 6 months, they have a different syndrome. This is called a “Rapidly Progressive Dementia”. RPD used to be synonymous with a particular group of diseases called “Prion Diseases” but now we know that RPD can be caused by certain specific medical conditions, autoimmune diseases of the brain, or very specific genetic causes that need to be quickly identified and treated when possible. When I meet someone with a cognitive decline over the past few years, I know it may take a few year to identify the contributors. When I meet someone who develops a dementia within a few months, I either bring them into the clinic immediately or send them to the Emergency Department. 

I’m sorry if reading this post has left you more confused, but the reality is that the diagnosis of dementia is extraordinarily complex. I’ve cured patients who had been previously diagnosed with a dementia, and I’ve diagnosed an end stage dementia in patients referred to me for “anxiety”. While these concepts are rapidly evolving in the literature, patients are left disappointed and confused, unsure where to go for help. There is no immediate fix to this problem, but through clear communication and aggressive management of any identified contributors, there is still hope for many. To learn more, request a consultation today.