How to diagnose Lewy Body Dementia and its MRI findings

Lewy Body Dementia is a neurological disorder and one of the many causes of memory loss, especially in the elderly. With time, the disease can become very debilitating as it hampers with day to day activity. Patients suffering from Lewy Body Dementia often get hallucinations. A striking feature of this condition is that the cognitive function fluctuates heavily on day to day basis. In this article, we shall unearth the process of how to diagnose Lewy Body Dementia and what the MRI brain of such patients looks like.

Lewy Body Dementia - How to Diagnose?

Like any neurological disorder, the clinical features or history of the condition aids in a great way to diagnose the condition. A Neurologist would suspect and consider Lewy Body Dementia as a differential if some have the following signs and symptoms:

• Tremors of limbs and extremities
• Dementia or Cognitive problems
• Hallucinations, which are predominantly visual
• Delusions of Persecution: Where the person constantly holds the belief that someone is conspiring to harm him or his loved one
• Fluctuating alertness level
• REM Sleep Behavior Disorder – In which the sleeping partner informs of excessive violent movement of the patient while sleeping as if enacting dreams.
• Excessive daytime sleepiness
• Lewy Body Dementia is often accompanied or preceded by certain symptoms like:
• Dizziness while getting up suggestive of orthostatic hypotension
• Frequent Constipation
• Depression and Anxiety

Based on the signs and symptoms, the doctor may order multiple tests to confirm the diagnosis as well as to rule out other commoner causes of dementia like Alzheimer’s disease. However, the most commonly used tests are EEG, which shows slowing of the waves in Lewy Body Dementia, MRI Scan of the brain, Functional Imaging and Dopamine Transporter Imaging.

Lewy Body Dementia on MRI

Representational Image. MRI Brain

Although MRI is a useful tool to diagnose any brain-related pathology, the features however in Lewy Body Dementia are not consistent. However, many findings can point towards the condition, and if present with consistent clinical features, Lewy Body Dementia can be diagnosed. A brain biopsy could be confirmatory, but it is not a preferred test. Some MRI findings of Lewy Body Dementia includes

• Decrease in volume of the brain (cerebral atrophy), especially in the frontal and parahippocampal gyrus of the brain. In contrast, the hippocampus is more involved in Alzheimer’s.
• Absent Swallow Tail Sign

Functional Imaging shows greater involvement of the occipital lobe, which could explain the reason behind visual hallucinations

Dopamine transporter Imaging, which is reduced in Lewy Body Dementia is spared in Alzheimer’s, can aid in differentiating the two.

As you might have noticed, Lewy Body Dementia is a bit hard to diagnose and requires clinical features to be correlated with MRI findings. In case, you or someone you know is having the above symptoms, it's time to consult a Neurologist.

Know anyone diagnosed with Lewy Body Dementia? What did they do to get diagnosed? Share the experience in the comments; we would like to hear the story.