Lewy body dementia is one of the most commonly misdiagnosed forms of cognitive decline, yet it accounts for up to 20% of all dementia cases. The condition develops when abnormal protein clumps called Lewy bodies accumulate in brain neurons, affecting memory, movement, and perception in ways that can look like Alzheimer's disease or Parkinson's disease. For years, patients with Lewy body dementia were sent to Alzheimer's clinics searching for answers, only to confuse their doctors with symptoms that didn't fit the typical pattern.

What Makes Lewy Body Dementia So Hard to Spot?

The challenge lies in how Lewy body dementia presents itself. Unlike Alzheimer's disease, which primarily affects short-term memory early on, Lewy body dementia can cause a complex mix of cognitive problems, visual hallucinations, and movement difficulties that vary widely from person to person. Doctors who focus narrowly on one symptom may miss the full picture and reach the wrong diagnosis.

Lewy body dementia exists on a spectrum with Parkinson's disease. Both conditions involve the same abnormal protein, alpha-synuclein, but the location and timing of where these proteins accumulate determine whether someone develops movement problems first (Parkinson's) or thinking and memory problems first (Lewy body dementia). This overlap means that patients can have overlapping symptoms, making diagnosis even trickier.

"Patients that have what we would now describe as dementia with Lewy bodies were going into Alzheimer's clinics looking for answers. Doctors and specialists would be confused by the presentation of their symptoms, since it varied so much from Alzheimer's disease," said Samantha Holden, MD, associate professor of neurology and director of the Lewy Body Dementia Association Research Center of Excellence at CU Anschutz.

Samantha Holden, MD, Associate Professor of Neurology at CU Anschutz

How Are Doctors Improving Diagnosis Now?

The field is moving toward a more comprehensive diagnostic approach that combines multiple tools. Rather than relying on a single test or symptom checklist, neurologists now use a combination of strategies to identify Lewy body dementia accurately.

• Blood Tests: A new blood test called PTau217 has been FDA-approved to screen for amyloid positivity associated with Alzheimer's disease. While this test doesn't directly identify Lewy body dementia, it helps rule out Alzheimer's as the primary cause. Researchers are working toward a blood test for alpha-synuclein, the protein specific to Lewy body disease, similar to what PTau217 does for Alzheimer's.
• Imaging and Fluid Tests: Brain MRIs, PET scans, and spinal fluid tests provide visual and biochemical evidence of what's happening in the brain. These tests help neurologists see patterns consistent with Lewy body disease rather than other forms of dementia.
• Skin Biopsies: Emerging biomarkers now include skin biopsies, which can detect alpha-synuclein deposits outside the brain. This represents a major breakthrough because it allows doctors to identify the protein without invasive procedures.
• Cognitive Testing and Patient History: Structured interviews and cognitive assessments help doctors understand how symptoms are affecting daily life and whether the pattern matches Lewy body dementia. Getting to know patients over time and tracking how their symptoms change builds confidence in the diagnosis.

The key insight is that diagnosis requires detective work. Neurologists must piece together information from multiple sources, not just rely on one test result. This personalized approach takes time but leads to more accurate diagnoses and better treatment plans.

What Treatment Options Are Available?

Once Lewy body dementia is correctly identified, patients gain access to treatments specifically designed for their condition. New drugs and therapeutic approaches are emerging that target the underlying protein problems rather than just managing symptoms. The earlier the diagnosis, the sooner patients can start these disease-modifying treatments, potentially slowing cognitive decline.

Beyond medication, a comprehensive care approach addresses the full range of symptoms. This might include managing movement problems, treating visual hallucinations, and supporting caregivers who often face unique challenges with this form of dementia.

Why Does Accurate Diagnosis Matter for Your Brain Health?

Getting the right diagnosis changes everything. Patients who are told they have Alzheimer's when they actually have Lewy body dementia may receive treatments that don't work for their condition or that could even make symptoms worse. An accurate diagnosis opens the door to targeted treatment, realistic expectations about disease progression, and access to support services tailored to Lewy body dementia.

The broader challenge is access. The United States has only around 500 behavioral neurologists and neuropsychiatrist specialists trained in dementia diagnosis, yet approximately 10 million Americans are living with dementia. This gap means many people never get a definitive diagnosis at all.

"How does this little lump of meat inside your head make you who you are and all the things that you've experienced, learned and been exposed to in your life that have made you this really unique human being? We work with patients to really get to the core of what makes us 'us' and then try to figure out why things are changing and how we best preserve who you are as a person," explained Samantha Holden, MD.

Samantha Holden, MD, Associate Professor of Neurology at CU Anschutz

Steps to Take If You're Concerned About Cognitive Changes

• Seek Professional Evaluation: If you or a loved one notice changes in thinking, memory, movement, or vision, don't assume it's normal aging. Schedule an appointment with a neurologist or cognitive specialist who can perform a thorough evaluation.
• Document Your Symptoms: Keep track of when symptoms started, how they've changed over time, and which activities they affect most. This information helps doctors see the full pattern and distinguish between different types of dementia.
• Ask About Multiple Diagnostic Tests: Request comprehensive testing that includes cognitive assessments, blood tests, imaging, and other biomarkers rather than relying on a single test. A thorough workup increases the chances of an accurate diagnosis.
• Discuss Your Family History: Share information about dementia, Parkinson's disease, or other neurological conditions in your family. Genetic factors can influence dementia risk and help guide diagnostic decisions.

The landscape of dementia diagnosis is changing rapidly. New tests are becoming available, and doctors are learning to recognize Lewy body dementia more reliably. If you've been struggling with cognitive symptoms or received a dementia diagnosis that doesn't seem to fit your experience, it may be worth seeking a second opinion from a specialist trained in Lewy body disease. An accurate diagnosis is the first step toward getting the right treatment and support.