From the Guidelines
PSP may not present with cognitive impairment in its earliest stages, particularly in the Richardson's syndrome variant where motor symptoms like postural instability, falls, and eye movement abnormalities often precede cognitive decline. According to the study published in the Journal of the American College of Radiology in 2020 1, PSP, also known as Steele-Richardson-Olszewski syndrome, is the most common atypical Parkinsonism with a prevalence of around 5/100,000. Patients classically present in the sixth or seventh decade with a lurching gait and axial dystonia, manifested as unexplained falls.
Some key points to consider when diagnosing PSP include:
- The classic finding of vertical supranuclear gaze palsy is usually only seen later in the course of the disease
- Ocular symptoms, including blurred vision and slow saccades, can be seen early in the disease
- PSP can be subdivided into different variants, including Richardson's syndrome and PSP-parkinsonism, each with distinct clinical features
- Sensitive neuropsychological testing can often detect subtle cognitive changes even when they're not clinically apparent
It's essential to note that as PSP progresses, virtually all patients eventually develop some degree of cognitive impairment, typically involving executive dysfunction, slowed thinking, and personality changes, as mentioned in the study 1. However, in rare cases of PSP-pure akinesia with gait freezing, cognitive function may be relatively preserved for longer periods.
In clinical practice, it's crucial to consider the variability in presentation and progression of PSP, and to use a combination of clinical evaluation, imaging, and neuropsychological testing to diagnose and manage the condition effectively. The study 1 highlights the importance of imaging in the evaluation of patients presenting with Parkinsonian symptoms, and the need for a comprehensive diagnostic approach to accurately diagnose and treat PSP.
From the Research
Presentation of Progressive Supranuclear Palsy (PSP)
- PSP is a neurodegenerative condition that presents with various symptoms, including mobility, balance, speech, swallowing, vision, and cognitive changes 2
- Cognitive impairment is a core feature of PSP, with executive dysfunction being the most severely impaired cognitive domain 3
Cognitive Impairment in PSP
- Cognitive impairment is integral to the syndrome of PSP, with most patients experiencing some form of cognitive decline 4
- A study of 121 autopsy-confirmed PSP patients found that 74% had documented cognitive impairment, with executive functioning being the most severely impaired cognitive domain 3
- Cognitive impairment in PSP is associated with tau burden, with a negative correlation between total tau burden and global cognitive impairment index 3
Subtypes of PSP
- PSP can be classified into different subtypes, including PSP-Richardson syndrome (PSP-RS) and PSP-non-RS 5
- Patients with PSP-RS tend to have more severe cognitive impairment and faster disease progression compared to those with PSP-non-RS 5
- A study of 117 patients with PSP found that 16.2% had normal cognition, 53.0% had mild cognitive impairment, and 30.8% had dementia at baseline 5
Treatment and Management of PSP
- There is currently no cure for PSP, but various treatments and therapies can help manage its symptoms 2
- Physiotherapy rehabilitation programs have been shown to improve balance, gait, and gaze control in patients with PSP 2
- Intrajejunal levodopa infusion therapy has been found to have beneficial effects on motor and nonmotor aspects in patients with the parkinsonian variant of PSP 6