Distinguishing Dementia with Lewy Bodies from Parkinson's Disease Dementia

Clinical Features

Fluctuating cognition with pronounced variations in attention and alertness occurring over minutes, hours, or days is a characteristic of both conditions, according to the American College of Radiology 1
Recurrent, well-formed visual hallucinations are a common symptom in patients with dementia with Lewy bodies or Parkinson's disease dementia, as noted by the American College of Radiology 1
Parkinsonism with bradykinesia, rigidity, tremor, and postural instability is a key feature of both conditions, as reported by the American College of Radiology 1
Autonomic dysfunction, including orthostatic hypotension, urinary incontinence, and constipation, is often present in patients with dementia with Lewy bodies or Parkinson's disease dementia, according to the American College of Radiology 1

I-123 Ioflupane SPECT/CT shows decreased dopamine transporter uptake in both dementia with Lewy bodies and Parkinson's disease dementia, as demonstrated by the Journal of the American College of Radiology 2
FDG-PET/CT demonstrates occipital hypometabolism and the "cingulate island sign" in both conditions, as reported by the Journal of the American College of Radiology 3
MRI shows relative preservation of medial temporal lobe structures compared to Alzheimer's disease in both dementia with Lewy bodies and Parkinson's disease dementia, according to the Journal of the American College of Radiology 3
Amyloid PET/CT has very limited usefulness for diagnosis and cannot distinguish between the conditions, as noted by the Journal of the American College of Radiology 3

Both pharmacologic and nonpharmacologic interventions should be implemented in the management of dementia with Lewy bodies and Parkinson's disease dementia, as recommended by the American College of Radiology 4

The Clinician Assessment of Fluctuation (CAF) 4-item scale, Mayo Fluctuations Scale (19-item), or Dementia Cognitive Fluctuation Scale (17-item) are assessment tools used to evaluate fluctuating cognition in patients with Dementia with Lewy Bodies (DLB), as recommended by the Translational Neurodegeneration guideline society 5

The American College of Radiology recommends establishing a dementia diagnosis first, by identifying cognitive or behavioral symptoms that interfere with daily function, represent decline from previous level, and involve impairment in at least two cognitive domains, before proceeding with the diagnostic algorithm for DLB 6
The American College of Radiology also recommends obtaining structural imaging, such as MRI or CT, to exclude other causes and assess for relative preservation of medial temporal lobe structures compared to Alzheimer's disease, as part of the diagnostic algorithm for DLB 6