Parkinsonism is a broad term for neurological disorders causing movement issues similar to Parkinson’s disease (PD), including slowed movements, stiffness, tremor, and balance problems. It can also involve non-movement symptoms like mood changes, sleep disturbances, and issues with automatic bodily functions. While PD is the most common cause, atypical parkinsonism conditions present with similar features but have distinct underlying causes and often different responses to treatment.
Understanding Atypical Parkinsonism
Atypical parkinsonism, also known as Parkinson’s plus syndromes, shares motor symptoms with Parkinson’s Disease but presents with additional features, a different disease progression, and often a limited or absent response to levodopa. These disorders frequently involve broader brain degeneration beyond areas primarily affected in PD. Key differentiating factors include early and prominent balance problems and falls, specific cognitive changes or dementia, and significant autonomic dysfunction.
Atypical parkinsonism tends to progress more rapidly than Parkinson’s Disease. Unlike PD, where symptoms often improve significantly with levodopa, individuals with atypical forms typically experience minimal or no sustained benefit from this medication. These distinctions are important for diagnosis and management, as the approach to care differs substantially from that for Parkinson’s Disease.
Major Forms of Atypical Parkinsonism
Multiple System Atrophy (MSA)
Multiple System Atrophy (MSA) is a rare neurodegenerative disorder causing loss of coordination and balance, or slow, stiff movements. It involves progressive degeneration of neurons in brain regions controlling movement, coordination, and automatic bodily functions. MSA is categorized into two types: MSA-P, where parkinsonian symptoms like stiffness and slow movement are prominent, and MSA-C, where cerebellar dysfunction, such as impaired coordination and unsteady walking (ataxia), predominates.
A hallmark of MSA is significant autonomic nervous system dysfunction, manifesting as orthostatic hypotension (a sudden drop in blood pressure upon standing), urinary incontinence, and constipation. Other symptoms include vocal cord palsy, slurred speech, and REM sleep behavior disorder.
Progressive Supranuclear Palsy (PSP)
Progressive Supranuclear Palsy (PSP) is a rare neurological condition affecting brain areas involved in balance, movement, vision, speech, and swallowing. A prominent early symptom is loss of balance, often causing frequent backward falls. Characteristic eye movement issues, especially difficulty looking up and down, can lead to blurred vision and reading problems.
Individuals with PSP may also experience muscle stiffness, personality and behavioral changes like irritability or apathy, and cognitive changes affecting planning and organization. Speech can become slow, quiet, or slurred, and swallowing difficulties are common as the disease progresses. Tremors are rare in PSP.
Corticobasal Syndrome (CBS)
Corticobasal Syndrome (CBS), also known as Corticobasal Degeneration (CBD), is a rare condition causing progressive problems with movement, speech, memory, and swallowing. A distinguishing feature is its asymmetrical presentation, with symptoms often starting and remaining more pronounced on one side of the body. Motor symptoms include stiffness, slow movements, jerky movements (myoclonus), and “alien limb,” where an affected limb seems to act on its own.
Cognitive and behavioral changes are also part of CBS, including difficulties with language (aphasia), apraxia (difficulty performing learned movements), and problems with memory and executive function. Speech may become slurred or effortful. The condition is associated with abnormal tau protein buildup in brain cells, leading to damage and shrinkage.
Dementia with Lewy Bodies (DLB)
Dementia with Lewy Bodies (DLB) is a type of dementia characterized by a decline in thinking ability, particularly in attention, visual perception, and organizational skills. Unlike some other dementias, memory loss may not be an early or prominent symptom. Core features include fluctuating cognition (alertness and attention levels vary significantly), recurrent visual hallucinations, and rapid eye movement (REM) sleep behavior disorder, where individuals physically act out their dreams.
Parkinsonian motor symptoms, such as slow movement, rigidity, and balance problems, are common in DLB, often appearing within one year of cognitive changes. While motor symptoms can be similar to PD, tremor at rest is less common, and symptoms are often symmetric. The presence of Lewy bodies, abnormal protein deposits (alpha-synuclein), in brain cells is characteristic.
How Diagnosis Occurs
Diagnosing atypical parkinsonism can be challenging due to symptom overlap with Parkinson’s disease and other neurological conditions. Diagnosis relies on a detailed medical history and a comprehensive neurological examination. Movement disorder specialists observe symptoms and their progression, looking for “red flags” that distinguish atypical parkinsonism from PD. These include rapid disease progression, early and frequent falls, prominent autonomic failure, and a poor or absent response to levodopa.
While no single definitive test exists for many atypical parkinsonism conditions, supportive diagnostic tools are utilized. Magnetic Resonance Imaging (MRI) can help rule out other conditions like stroke or tumor, or may show specific atrophy patterns. SPECT scans, such as DaTscan, differentiate neurodegenerative parkinsonism (including PD and atypical forms) from conditions like essential tremor, but cannot distinguish among atypical parkinsonism types or between them and PD. Ongoing observation of symptom evolution is crucial for an accurate diagnosis.
Approaches to Treatment
Currently, no treatments can cure or slow the progression of atypical parkinsonism. Unlike Parkinson’s disease, where levodopa often provides significant and sustained improvement in motor symptoms, individuals with atypical parkinsonism typically experience poor or only temporary responses. Treatment focuses on managing symptoms, improving quality of life, and preventing complications.
A multidisciplinary approach is common, involving therapies tailored to individual needs. Physical therapy helps with movement, balance, and gait difficulties, aiming to maintain independence and prevent falls. Occupational therapy assists with daily activities, while speech therapy addresses communication and swallowing problems. Medications may manage specific symptoms like orthostatic hypotension, spasticity, sleep disturbances, or cognitive issues. Botulinum toxin injections can be used for focal dystonia, and other medications may help with mood changes or cognitive dysfunction.