Dementia
with Lewy bodies (DLB) is the second most common neurodegenerative dementia
after Alzheimer’s disease (AD) in people over 65 years of age. DLB differs from
AD as early cognitive symptoms include deficits in visuospatial and executive
function, rather than memory. DLB is characterized by parkinsonism,
fluctuations in mental status, visual hallucination, and hypersensitivity to
neuroleptics. Therefore, it is difficult to discriminate between DLB and
Parkinson’s disease with dementia (PDD). Both diseases also share a similar
pathologic finding, Lewy bodies. Generally, if cognitive impairments appear
within a year of parkinsonism, DLB is diagnosed, while patients with
parkinsonism for at least a year prior to cognitive impairment are classified
as PDD. Early amyloid deposition in DLB relative to PDD may explain the
difference in the timing of dementia and parkinsonism.

Quality
of life (QoL) is a key outcome measure of health and social service
interventions. Currently, patient-reported outcome measures (PROMs) are
increasingly used in evaluating health and social care. Definitions of
health-related QoL include physical, mental, social and role functioning, and
health perceptions 1. Because aging
is a global issue, it is critical to identify QoL determinants in the elderly
who suffer from chronic disease. A recent study from Southern Taiwan showed
Alzheimer disease-8 (AD-8), a screening tool, had the strongest association
with total QoL score in 115 old age adults suffering from chronic disease. It
is important for geriatric health care providers to realize that cognitive
impairment among old age adults with chronic disease is a critical determining
factor of poor QoL 2.

Assessing
QoL in people with dementia is crucial for evaluating their outcomes; however,
it is challenging to interview patients who have a limited ability to express
themselves and may lack insight. Meanwhile, there are questions concerning the
validity of generic measures of QoL, which are not specific to dementia. Currently,
evaluations of QoL largely focus on general dementia or AD. A systematic review
3 regarding QoL
in dementia strongly suggests that depression is consistently related to
decreased QoL. Surprisingly, there is no convincing evidence indicating that
lower cognitive ability or greater limitations in activity are associated with a
lower QoL.

Evidence
concerning QoL in DLB patients is limited 4. In a
comparison study, QoL was measured using the Alzheimer Disease Related Quality of Life (ADRQL) evaluation , a
proxy-rated, dementia-specific instrument. The authors concluded that DLB
patients have poorer QoL than AD patients 5. Figari et al. compared QoL in 46 AD, 23 DLB,
and 39 Huntington’s disease (HD) patients, all of whom had dementia for at
least two years. Patients with DLB scored significantly lower on the SF-12
Physical and Mental Health Summary than patients with HD and AD. The authors
concluded that, when adjusted for age, cognition, comorbidity, and depression,
patients with DLB had the poorest QoL 6.

There
is only one study whose primary aim was to compare the QoL in patients with DLB
and AD 7. 34 DLB
patients and 34 cognitive-matched AD patients were evaluated using two QoL
instruments: EQ-5D and QoL-AD. The results showed both patient-rated and
proxy-rated QoL was poorer in patients with DLB than those with AD. Due to many
differences in clinical symptoms, it is reasonable to predict differences in
QOL between diseases. Herein, we elaborate on studies related to QoL in DLB
patients.