Dementia with Lewy bodies (DLB) affects movement primarily by causing symptoms similar to those seen in Parkinson’s disease, due to the presence of abnormal protein deposits called Lewy bodies in the brain. These deposits disrupt normal nerve cell function, especially in areas that control movement, leading to a range of motor difficulties.
The movement problems in DLB often include **slowness of movement (bradykinesia)**, where initiating and performing movements becomes slower and more effortful. Muscle stiffness or rigidity is common, making limbs feel tight and less flexible. People with DLB may develop a **shuffling gait**, where steps become short and dragging rather than smooth and purposeful. Tremors, especially resting tremors (shaking when muscles are relaxed), can also occur but are less consistent than in classic Parkinson’s disease. Balance and coordination problems are frequent, increasing the risk of falls. Postural instability often leads to a stooped or hunched posture, making standing and walking more difficult and unsafe.
Facial expressions can become limited, resulting in a mask-like appearance that reduces nonverbal communication. Fine motor skills, such as writing or buttoning clothes, may deteriorate, and speech can become softer or slurred. Swallowing difficulties may also arise as the disease progresses.
These motor symptoms fluctuate and can vary in severity from day to day or even within the same day, which is a hallmark of DLB. This variability can make movement unpredictable and challenging to manage.
The underlying cause of these movement issues is the accumulation of Lewy bodies in brain regions responsible for motor control, including the basal ganglia and cortical areas. These protein clumps interfere with the brain’s ability to regulate muscle activity and coordination. Additionally, DLB affects the autonomic nervous system, which can contribute to symptoms like dizziness or fainting when standing, further complicating mobility.
Because DLB shares features with Parkinson’s disease, treatments for motor symptoms often include medications like levodopa, which can help improve movement but may have limited effectiveness and cause side effects in DLB patients. Physical therapy and supportive care are important to maintain mobility and reduce fall risk.
In summary, dementia with Lewy bodies impairs movement by causing slowness, stiffness, tremors, balance problems, and postural changes due to abnormal protein deposits disrupting brain areas that control motor function. These symptoms resemble Parkinsonism but are accompanied by cognitive and behavioral changes unique to DLB, making the overall impact on movement complex and variable.
