Multiple System Atrophy—Parkinsonism Predominant (MSA-P) and Progressive Supranuclear Palsy—Parkinsonism Predominant (PSP-P) are the clinical manifestations of atypical parkinsonism. Currently, there are no efficient in vivo methods available relating to neuroimaging or biochemical analysis in the examination of these entities. Among the advanced methods available, using positron emission tomography is constrained by high cost and low accessibility. In this study the authors examined patients with two types of atypical parkinsonism—MSA-P and PSP-P, which are difficult to differentiate, especially in the early years of their development. The aim of this study was to assess whether the examination of patients in the period following the early years (3–6-year duration of symptoms) could be enhanced by perfusion single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI) or evaluation of cognitive abilities. Extended examination using MRI and perfusion SPECT showed that the evaluation of the mesencephalon/pons ratio, mesencephalic volume decrease, the Magnetic Resonance Parkinsonism Index (MRPI) and frontal perfusion should be considered more feasible than screening cognitive evaluation in MSA-P and PSP-P with a 3–6-year duration of symptoms.

Differential diagnosis of progressive supranuclear palsy remains difficult, especially when it comes to the parkinsonism predominant type (PSP-P), which has a more favorable clinical course. In this entity, especially during the advanced stages, significant clinical overlaps with other tauopathic parkinsonian syndromes and multiple system atrophy (MSA) can be observed. Among the available additional diagnostic methods in every-day use, magnetic resonance imaging (MRI) focused specifically on the evaluation of the mesencephalon seems to be crucial as it is described as a parameter associated with PSP. There is growing interest in relation to more advanced mesencephalic parameters, such as the magnetic resonance parkinsonism index (MRPI) and MRPI 2.0. Based on the evaluation of 74 patients, we demonstrate that only the mesencephalon/pons ratio and MRPI show a significant difference between PSP-P and MSA-parkinsonian type (MSA-P). Interestingly, this differential feature was not maintained by MRPI 2.0. The mesencephalon to pons ratio (M/P), MRPI and MRPI 2.0 were not found to be feasible for the differentiation of PSP-P from other atypical tauopathic syndromes.

Multiple studies have analyzed the possible correlations between diabetes and Alzheimer’s disease. Less is known about the context of cognitive deterioration among patients with atypical Parkinsonian syndromes and glucose metabolism impairment. The aim of this study was to evaluate the association between the impaired glucose metabolism and cognitive decline among patients with progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). The study included 22 patients with PSP and CBS with disease durations varying from 3 to 6 years. The levels of glycated hemoglobin (HbA1C), fasting blood glucose, fasting C-peptide and the presence of microalbuminuria were evaluated, and oral glucose tolerance tests (OGTT) were performed. Based on the OGTT results, the glycemic variability, mean glycemia, glycemia standard deviation (SD) and coefficient of variation (%CV) were calculated. All patients underwent a three-Tesla brain magnetic resonance (MRI) examination and neuropsychological cognitive assessment with the use of standardized scales: Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). A statistical analysis revealed that poor control of glycemia with high glycemic variability and increased atrophy of the medial temporal lobe among patients with PSP and CBS correlated with worse cognitive performance independent of age or sex, even among patients who did not fulfill the criteria for diabetes. The study results indicate the importance of glucose metabolism control and optimal treatment in the context of cognition maintenance among patients with PSP and CBS. Due to the relatively small number of analyzed patients, the issue requires further assessment. To the best of our knowledge, this is the first study discussing the role of glycemic variability in atypical Parkinsonian syndromes.

Transcranial sonography is one of the methods of examination used in atypical parkinsonian syndromes. The assessment is not indicated in the diagnostic criteria of entities in this group e.g., Progressive Supranuclear Palsy, Corticobasal Degeneration, Multiple System Atrophy and Dementia with Lewy Bodies. Atypical parkinsonisms are a group of diseases affected by diverse pathologies including alpha-synuclein or tau among others. Recently broader attention was brought to less common atypical parkinsonisms as Perry syndrome. Atypical parkinsonisms are related to poor response to levodopa treatment, rapid deterioration and unfavorable prognosis. Additionally, the entities often overlap in terms of clinical manifestation, especially in the early stages. Though atypical parkinsonisms are affected by the lack of possibility of obtaining definite in vivo diagnosis, growing interest is associated to supplementary evaluations including neuroimaging. Among these methods could be mentioned magnetic resonance imaging, positron emission tomography, single photon emission computed tomography and transcranial sonography. Transcranial sonography is associated with high accessibility and low cost. The goal of this paper is to highlight the strengths and weaknesses of transcranial sonography in the examination of atypical parkinsonisms.

Progressive supranuclear palsy syndrome (PSPS) and corticobasal syndrome (CBS) are clinical manifestations of tauopathic Parkinsonian syndromes. Due to their overlapping symptomatology, the differential diagnosis of these entities may be difficult when bounded to clinical assessment. The manifestations are commonly associated with pathological entities—corticobasal degeneration and progressive supranuclear palsy, which are four-repeat tauopathies. In this study, the authors attempted to find whether the asymmetry typically associated with CBS may be feasible in the interpretation of perfusion single-photon computed tomography. The analysis based on the examination of patients with progressive supranuclear palsy—Richardson syndrome (PSP-RS), progressive supranuclear palsy—Parkinsonism predominant (PSP-P), and corticobasal syndrome (CBS) revealed significant asymmetry of perfusion of the amygdala in corticobasal syndrome. The more pronounced abnormalities of perfusion were observed in the left amygdala among patients with more severe Parkinsonian syndromes in CBS on the right. This study shows that the comparison of the perfusion of tauopathic Parkinsonian syndromes should be extended by asymmetry analysis. Interestingly, the differentiating potential of brain perfusion is present in the comparison of CBS and PSP-RS, but not in CBS and PSP-P. This phenomenon could be explained by more distinct asymmetry in the perfusion observed in PSP-P, which diminishes the differentiating potential of this parameter when it comes to the comparison of PSP-P and CBS. To the best of our knowledge, this is the first study evaluating which structures can be interpreted as significantly asymmetrical in the context of perfusion in CBS.

Progressive Supranuclear Palsy (PSP) is an atypical Parkinsonism, pathologically described as a four-repeat tauopathy. The contemporary criteria for diagnosis of PSP indicate akinesia, oculomotor dysfunction, postural instability, and language/cognitive impairment as core symptoms. Among these features, the first two are linked to PSP—Parkinsonism predominant (PSP-P). PSP-P is the second most common subtype of PSP, following PSP—Richardson’s syndrome (PSP-RS), and is associated with a more gradual deterioration, beneficial course, and longer life expectancy after diagnosis. It is also problematic in terms of clinical evaluation, as this entity may overlap with Parkinson’s disease (PD) in early stages and with other atypical Parkinsonisms in more advanced stages. The evolution in understanding PSP and the possible progress in care and therapy of the disease leads to the necessity of finding optimal examination methods with sufficient sensitivity and specificity. In this context, PSP-P seems a crucial point. The goal of this narrative review is to provide an overview of the possibilities provided by Magnetic Resonance Imaging (MRI) assessments in terms of PSP-P and analyze their strengths and weaknesses.