Evaluating How Red-light Therapy Applied to the Head Affects Symptoms, Daily Life, and Brain Activity in People With Dementia With Lewy Bodies

Overview

Dementia with Lewy bodies (DLB) is a neurodegenerative disease diagnosed primarily based on the presence of cognitive decline, which may include difficulties with memory, attention, and more. Additionally, at least two of the following symptoms are needed for a probable diagnosis of DLB, and at least one for a possible DLB diagnosis (McKeith et al. 2017 and 2020): * Fluctuations in cognition, attention, and/or alertness * Visual hallucinations * Spontaneous parkinsonism * REM sleep behavior disorder Patients with DLB can experience cognitive deficits that can fluctuate and can vary for each patient. These may include deficits in memory, executive functions (planning and organizing), attention, visual processing, and language. This study aims to evaluate the effect of red-light therapy, delivered using a helmet that contains small LED lights, in patients with DLB. Participants' cognitive functions, clinical symptoms, quality of life and functional cerebral connectivity will be evaluated before starting therapy and again after three and six months of twice daily therapy use. As DLB also indirectly affects caregivers, the caregiver's quality of life and burden will also be evaluated before and at three and six months of therapy use by the participant. The study's inclusion period is 24 months and the duration of participation for each patient is 8 months (+/-10 days) maximum.

Dementia with Lewy bodies (DLB) is the second most frequent neurodegenerative disease after Alzheimer's disease and represents 15 to 20% of dementia cases (Ballard et al. 2001; Zaccai et al. 2005; Aarsland et al. 2008). DLB is diagnosed primarily based on the presence of cognitive decline, which is most often perceived as difficulties relating to attention, visuospatial capacities and executive functions like planning, decision making and more. Additionally, at least two of the following core clinical symptoms are needed for a probable diagnosis of DLB, and at least one for a possible DLB diagnosis (McKeith et al. 2017 and 2020): * Fluctuations in cognition, attention, and/or alertness * Visual hallucinations * Spontaneous parkinsonism * REM sleep behavior disorder Suggestive symptoms may support the diagnosis of probable DLB when at least one core clinical symptom is present together with one of the following features, or possible DLB when one or more of the following features are present in the absence of any core clinical feature (McKeith et al. 2017 and 2020): * Severe sensitivity to neuroleptics * Postural instability * Recurrent falls * Syncope or transient episodes of responsiveness * Severe autonomic dysfunction: constipation, urinary incontinence, etc. * Hallucinations in other sensory modalities (ex. auditory) * Delusions * Apathy, anxiety, depression * Reduced dopamine transporter uptake in basal ganglia on DAT scan * Abnormal cardiac I-MIBG scintigraphy (reduced myocardial MIBG uptake) * MRI or CT: relative preservation of medial temporal lobe structures * SPECT or PET: reduced tracer uptake with occipital hypometabolism * EEG: prominent posterior slow wave activity with periodic fluctuations in the pre-alpha/theta range There is currently no treatment for DLB (Mueller et al. 2017). The effectiveness of available symptomatic treatments is also limited and sometimes accompanied by severe side effects (Boot et al. 2013; Boot, 2015). There is therefore an urgent need to develop therapeutic solutions adapted to DLB, aiming at neuroprotection and/or improvement of the quality of life of patients through better management of clinical symptoms. We are particularly interested in non-invasive and non-pharmacological approaches, with the aim of identifying methods without side effects and can easily be used by patients daily. In this context, a new approach is the subject of growing interest within the medical and scientific communities, as well as the general public. Known as photobiomodulation (PBM), this technique involves applying red to infrared light (λ=600-1000nm) on biological tissues. This study aims to evaluate the effect of transcranial PBM in patients with DLB. Participants' cognitive functions, clinical symptoms, quality of life and cerebral connectivity will be evaluated before starting therapy and again after three and six months of twice daily therapy use. As DLB also indirectly affects caregivers, the caregiver's quality of life and burden will also be evaluated before and at three and six months of therapy use by the participant.