Like other dementias, a person doesn’t develop Lewy body dementia (LBD) overnight. Very mild symptoms worsen over time until medical attention is needed. Sometimes several years pass before these earliest signs manifest into a recognizable disorder. Before the symptoms have evolved enough to support a clinical diagnosis, the disorder is considered at the ‘prodromal’ stage. For dementia with Lewy bodies, one of the clinical diagnoses under the LBD umbrella, mild cognitive impairment (MCI) is part of the prodromal stage.
A recent study by Marleen van de Beek and colleagues at Amsterdam University Medical Centers in the Netherlands followed people with MCI over time to track symptom progression. This included 73 people with MCI and 2 or more symptoms of LBD (MCI-LB), or MCI, one symptom of LBD, and a positive biomarker test indicating LBD. Another 124 people had MCI with biomarker tests positive for Alzheimer’s disease (MCI-AD). Participants attended study visits annually and provided blood and spinal fluid samples for analysis.
Several symptoms helped to differentiate the MCI-LB group from the MCI-AD group in the prodromal stage. Nearly 70% of the MCI-LB group had parkinsonism; about half had hallucinations, fluctuations or RBD. The MCI-LB group had more neuropsychiatric symptoms than the MCI-AD group, especially apathy and depression.
There were cognitive differences between the groups both at baseline and over time. Those with MCI-LB performed more poorly on non-memory cognitive tests initially, and then declined faster on tests of attention. In comparison, participants in the MCI-AD group scored lower on memory tests at baseline and declined faster in both memory and the Mini Mental Status Exam (MMSE) over time. Higher caregiver burden was reported by the MCI-LB group and was most likely driven by noncognitive symptoms. MCI-LB patients with attentional problems were at risk for faster progression to the dementia phase.
This study underscores the importance of early diagnosis, as the noncognitive symptoms are treatable. Early diagnosis and comprehensive care have the capacity to reduce caregiver burden even in the prodromal stage of LBD.
Prodromal Dementia With Lewy Bodies: Clinical Characterization and Predictors of Progression van de Beek MSc van Steenoven MSc J. van der Zande MD Barkhof MD, PhD E. Teunissen PhD van der Flier PhD Lemstra MD, PhD Movement Disorders 11 February 2020 https://doi.org/10.1002/mds.27997