To be diagnosed with Lewy body dementia (LBD), a person must first have dementia. Simply put, this means a person has had a decline in their cognitive (thinking) abilities that interferes with their everyday life. However, Lewy body disease is present in the brain long before a person has enough problems with their cognitive abilities to be diagnosed with dementia. A new study identifies symptoms closely associated with LBD before a person has dementia – during the mild cognitive impairment (MCI) stage.
Researchers at Newcastle University in the U.K. studied 36 people with MCI with at least two other diagnostic symptoms of LBD (MCI-LB), 21 people with MCI suggesting Alzheimer’s disease MCI (MCI-AD), 36 people with dementia with Lewy bodies (DLB), 21 people with Alzheimer’s disease (AD). Another group of 20 healthy individuals was studied for comparison.
All participants (along with a relative or caregiver, if available) were interviewed using a questionnaire adapted from the Lewy Body Dementia Association’s Comprehensive LBD Symptoms Checklist. Several additional symptoms linked to LBD were also added, specifically vision-related symptoms and response to dementia medications. One LBD symptom, sexual dysfunction, was often not inquired about to avoid the potential discomfort of any participants whose study partners were not spouses.
Next, the symptoms reported by the MCI-LB and MCI-AD groups were compared. Another comparison was made between the DLB and AD groups. The 10 symptoms significantly more common in MCI-DLB than MCI-AD (and that are linked to DLB, but not AD) were:
- Fluctuating concentration or attention
- Unexplained episodes of confusion
- Misjudging objects (difficulty moving around due to misjudging where objects are)
- Muscle rigidity or stiffness
- Changes in handwriting
- Shuffling walk
- Changes in posture
- Frequent falls
- Drooling
- Weak voice
- Symptoms of REM sleep behavior disorder (physically acting out dreams while asleep)
Co-author Ian McKeith, MD of Newcastle University and the lead author of the newly updated DLB diagnostic criteria stated, “At the time this study launched, the LBDA’s symptom checklist was a newly published, user-friendly tool for both patients, caregivers and clinicians. It covered a wide-range of symptoms, including some that are often over-looked by clinicians or not recognized by patients or caregivers as being related to DLB.” Dr. McKeith continued, “The results of this study suggest the symptoms checklist is a very useful tool that can be helpful in both routine clinical care and clinical research.”
The earliest symptoms reported by participants included loss of smell and symptoms of REM sleep behavior disorder. (NOTE: Loss of smell is common in healthy older adults and people with AD, so it is not specific enough to suggest MCI-LB.) Other symptoms were more likely to occur 1-2 years after cognitive changes began.
Interestingly, participants in the MCI-LB and MCI-AD reported seeing things that were not present. When evaluated by a three-physician diagnostic panel, differences in the nature of the hallucinations were identified. Those with MCI-AD did not report the “well-formed and detailed” visual hallucinations seen in DLB. Instead, they reported misidentifying objects seen in low light or simple hallucinations such as flashes of light. This reinforces the value of assessments by experienced clinicians to explore the nature of any visual symptoms of LBD.
Due to an insufficient number of MCI-AD volunteers taking medications to treat cognitive symptoms, a comparison with the MCI-LB group could not be made. Authors noted that 54% of the 13 MCI-LB volunteers reported significant improvement with these medications, and 15% reported minimal improvement. This echoes other research showing those with LBD typically respond more favorably to dementia medications (specifically cholinesterase inhibitors) than those with AD.
The 10 symptoms more common in MCI-LB than MCI-AD were developed into a scale. When testing the scale in the 5 different groups, a threshold of >2 points resulted in positively identifying 83% of those with MCI-LB. 100% of those who scored 2 or more on the scale were in the MCI-LB group. The 83% sensitivity and 100% specificity is a strong indicator of the scale’s potential use. Specifically, it may offer value in identifying people who are at risk for developing LBD. The scale may also be a useful tool in recruiting and screening volunteers for clinical research. Further work is needed to validate the scale in independent studies.
The study was published in the International Journal of Geriatric Psychiatry and was supported by the National Institute for Health Research.