Introduction

As the population ages, Dementia has become increasingly prevalent, primarily affecting individuals between the ages of 70 to 85.¹ While Alzheimer’s disease is the most common dementia you have probably heard about, the second most common form is Lewy body dementia (LBD), which accounts for approximately 15-25% of dementia cases.² Although LBD shares many similarities with both Alzheimer’s and Parkinson’s disease, the disease is progressive, and symptoms become severe within years.³

What is lewy body dementia?

Lewy body dementia is a type of synucleinopathy, meaning it is a neurodegenerative disorder relating to the protein alpha-synuclein (aS). This group of disorders includes:⁴

• Parkinson’s disease dementia (PDD)
• Dementia with Lewy bodies (DLB)

The prevalence of dementia with Lewy bodies is not well-established. However, it has been estimated to affect around 1.4 million people in the USA and 100,000 people in the UK. However, it is believed that LBD may be greatly underdiagnosed due to symptom overlap with Alzheimer’s disease, leading to great discrepancies between a number of clinical diagnosis and post mortem findings.¹ LBD is a neurocognitive disorder which consists of cognitive impairments and Parkinsonian symptoms.⁵

Causes of lewy body dementia

LBD is caused by the accumulation of alpha-synuclein protein deposits, which form Lewy bodies within the brain.² These deposits lead to altered functioning of the brain, including:⁶   

• Reduction in the amount of the neurotransmitter acetylcholine, which is vital for learning and memory⁶ 
• Loss of dopaminergic neurons (similar to Parkinson’s disease)²

Symptoms of lewy body dementia

LBD can manifest through either motor manifestations of Parkinson’s disease or other non-motor symptoms such as sensory, behavioural, and REM sleep behaviour.⁴ These symptoms include:²

• Cognitive impairment: visual hallucinations, confusion
• Mood and behaviour: depression, apathy
• Sleep disruption: REM sleep behaviour disorder (RBD)
• Motor symptoms: spontaneous parkinsonism

Cognitive impairment

Cognitive impairment affects the ability of an individual to think, which affects various domains, including memory, language, personality, behavior, abstract thinking, and visuo-spatial skills.^2,6 Unlike Alzheimer’s disease, memory problems may not develop until later in LBD, where Loss of thinking abilities will become problematic in daily life. Individuals may frequently experience poor judgment, difficulty with language and numbers and confusion about time and place.⁶ 

Visual hallucinations

Visual hallucinations are considered a key hallmark of LBD, where they are seen to occur within 80% of patients with LBD.¹ Visual hallucinations are highly problematic in LBD since they can be highly frightening and lead to safety problems when patients perceive non-existent animals or people.² These visual hallucinations are more common in individuals with DLB as opposed to PDD.⁷ Non-visual hallucinations may also occur, such as hearing or smelling things, however, they are much less common than visual hallucinations.⁶  

Sleep disturbances

Sleep disorders are prevalent in individuals with LBD, often resulting from disruption of circadian rhythms due to cognitive impairments. Common sleep disturbances include the following:⁶  

• Excessive daytime sleepiness
• Restless legs syndrome
• Insomnia
• REM sleep behaviour disorder (RBD)

RBD is described as physical activity during dreams due to a lack of muscle atonia, the temporary paralysis of muscles that normally occurs during REM sleep, which is highly common in LBD and is estimated to occur in 76% of patients.¹ These sleep disturbances can lower the quality of an individual’s life and exacerbate cognitive functions.

Periods of confusion

Periods of fluctuating confusion involve rapid and variable changes in cognition, arousal, and attention, which has also been described as the ‘waxing and waning’ of consciousness.⁵ This symptom is a hallmark of the disease, and it is estimated to occur in up to 90% of patients with LBD.⁸ Fluctuating confusion causes individuals to lose track of conversations and carry out tasks, where patients can become non-verbal and unresponsive for brief periods of time.^1,3 These fluctuations can vary greatly in alertness and range from mild deficits to more dramatic changes where consciousness can be so minimised that there is a lack of response to painful stimuli.⁸ One especially common feature is ‘staring spells’ where patients can become fully unresponsive. Following these fluctuations, an individual may feel confused when awoken, which can be even worse in especially stimulating environments.⁸ 

Parkinsonian motor features

Some individuals with LBD may not exhibit any motor symptoms until the disease progresses, however, others may present motor symptoms very early on.⁶ Around 50% of individuals, upon diagnosis, have parkinsonian motor symptoms, which increases up to 75% later in the disease.² These movement problems can cause:⁶ 

• Muscle rigidity 
• Bradykinesia (slow movement) 
• Myoclonus (muscle jerks) 
• Tremors or shaking at rest
• Bad posture
• Poor coordination
• Problems balancing
• Weak voice
• Lack of facial expression

Motor symptoms can increase the risk of falls or cause difficulty swallowing, which can impact daily activities and overall safety.¹

Behavioural and mood symptoms

LBD is often associated with a range of behavioural and mood disturbances

• Depression: a common symptom that is reported to occur in around 40% of patients³ 
• Apathy: involves reduced initiative and motivation, where it is seen in around 54% of PDD patients and 57% of DLB patients⁷ 
• Anxiety: presents as frequent questioning and upon absence of loved ones⁶  
• Paranoia: Individuals may feel distrustful and suspicious of other people⁶  

These symptoms can affect relationships and can implicate the emotional well-being of both patients and caregivers.

Diagnosing lewy body dementia

Diagnosing LBD can be highly challenging due to the overlap of cognitive impairments in Alzheimer’s disease (AD) and motor symptoms in Parkinson’s disease (PD).² Differentiating PDD and DLB is crucial to allow for optimal early treatment, especially since those with DLB and PDD have been suggested to decline much more rapidly than individuals with Alzheimer’s disease.⁷ 

There is a 1-year rule that classifies the disease as PDD if the disease has motor symptoms a year before there is cognitive dysfunction.⁵ 

Managing lewy body dementia

Currently, there are no medications or treatments which can prevent the progression of LBD. However, it is possible to manage the motor and neuropsychiatric features of LBD through a combination of pharmacological and non-pharmacological approaches.⁷

Pharmacological treatments

Managing LBD requires a careful selection of medications due to the complex reactions patients with LBD have, where sedatives and sleep medications can awaken them, therefore, antipsychotic medication tends to be avoided.² If a medication such as Levodopa (which is used to treat loss of dopaminergic neurons in Parkinson’s disease) was used to treat Parkinsonian symptoms, this may incidentally exacerbate cognitive deficits.⁵ 

• Cholinesterase inhibitors: These can be seen to reduce hallucinations, delirium, apathy and somnolence³
• Rivastigmine: reduces symptoms of delusions, hallucinations, anxiety, and apathy and is only cholinesterase inhibitor approved by the FDA^3,7 
• Galantamine: shown to improve cognition, hallucinations, and sleep⁵ 
• Levodopa: treat parkinsonian symptoms to aid in moving around⁵ 
• Clonazepam: can be used in low doses to reduce REM sleep behaviour disorder⁶
• Antidepressants: manage depression⁶ 

Non-pharmacological treatments

In addition to medications, various non-pharmacological strategies can help manage LBD:

• Correct sensory impairment: using glasses and hearing aids 
• Provide education to families about the disease and how to manage symptoms
• Structured environment: Create a consistent and structured environment to reduce confusion and agitation⁵

Summary

Lewy body dementia is a highly complicated neurocognitive disorder that significantly impacts the day-to-day life of the individual through a combination of cognitive, motor, behavioural and sleep-related symptoms. Although there is currently no cure, careful assessment and management of symptoms can be carried out through both pharmacological and nonpharmacological interventions.² Currently, there is ongoing research into novel targets that decrease alpha-synuclein aggregates causing LBD, which holds promise for the future of therapeutic advancements.⁵