Differentiation of progressive supranuclear palsy: clinical, imaging and laboratory tools

Striatal and thalamic automatic segmentation, morphology, and clinical correlates in Parkinsonism: Parkinson's disease, multiple system atrophy and progressive supranuclear palsy

Parkinson's disease (PD), multisystem atrophy (MSA), and progressive supranuclear palsy (PSP) present similarly with bradykinesia, tremor, rigidity, and cognitive impairments. Neuroimaging studies have found differential changes in the nigrostriatal pathway in these disorders, however whether the volume and shape of specific regions within this pathway can distinguish between atypical Parkinsonian disorders remains to be determined. This paper investigates striatal and thalamic volume and morphology as distinguishing biomarkers, and their relationship to neuropsychiatric symptoms. Automatic segmentation to calculate volume and shape analysis of the caudate nucleus, putamen, and thalamus were performed in 18 PD patients, 12 MSA, 15 PSP, and 20 healthy controls, then correlated with clinical measures. PSP bilateral thalami and right putamen were significantly smaller than controls, but not MSA or PD. The left caudate and putamen significantly correlated with the Neuropsychiatric Inventory total score. Bilateral thalamus, caudate, and left putamen had significantly different morphology between groups, driven by differences between PSP and healthy controls. This study demonstrated that PSP patient striatal and thalamic volume and shape are significantly different when compared with controls. Parkinsonian disorders could not be differentiated on volumetry or morphology, however there are trends for volumetric and morphological changes associated with PD, MSA, and PSP.

Eye tracking identifies biomarkers in α-synucleinopathies versus progressive supranuclear palsy

Objectives

This study (1) describes and compares saccade and pupil abnormalities in patients with manifest alpha-synucleinopathies (αSYN: Parkinson’s disease (PD), Multiple System Atrophy (MSA)) and a tauopathy (progressive supranuclear palsy (PSP)); (2) determines whether patients with rapid-eye-movement sleep behaviour disorder (RBD), a prodromal stage of αSYN, already have abnormal responses that may indicate a risk for developing PD or MSA.

Methods

Ninety (46 RBD, 27 PD, 17 MSA) patients with an αSYN, 10 PSP patients, and 132 healthy age-matched controls (CTRL) were examined with a 10-min video-based eye-tracking task (Free Viewing). Participants were free to look anywhere on the screen while saccade and pupil behaviours were measured.

Results

PD, MSA, and PSP spent more time fixating the centre of the screen than CTRL. All patient groups made fewer macro-saccades (> 2^◦ amplitude) with smaller amplitude than CTRL. Saccade frequency was greater in RBD than in other patients. Following clip change, saccades were temporarily suppressed, then rebounded at a slower pace than CTRL in all patient groups. RBD had distinct, although discrete saccade abnormalities that were more marked in PD, MSA, and even more in PSP. The vertical saccade rate was reduced in all patients and decreased most in PSP. Clip changes produced large increases or decreases in screen luminance requiring pupil constriction or dilation, respectively. PSP elicited smaller pupil constriction/dilation responses than CTRL, while MSA elicited the opposite.

Conclusion

RBD patients already have discrete but less pronounced saccade abnormalities than PD and MSA patients. Vertical gaze palsy and altered pupil control differentiate PSP from αSYN.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11136-5.

Imaging pathological tau in atypical parkinsonisms: A review

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[18F]AV-1451 displays mixed results for specificity to 4R CBD- and PSP-tau.

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[18F]PI-2620 and [18F]PM-PBB3 are the most promising second-generation tau PET tracers.

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Research using second-generation tau PET tracers in CBD and PSP is still limited.

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Finding an imaging diagnostic biomarker requires further work with larger samples.

Atypical parkinsonisms (APs) are a group of diseases linked to tau pathology. These include progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). In the initial stages, these APs may have similar clinical manifestations to Parkinson’s disease (PD) and other parkinsonisms: bradykinesia, postural instability, tremor, and cognitive decline. Because of this, one major hurdle is the accurate early diagnosis of APs. Recent advances in positron emission tomography (PET) radiotracer development have allowed for targeting pathological tau in Alzheimer’s disease (AD). Currently, work is still in progress for identifying a first-in-class radiotracer for imaging tau in APs. In this review, we evaluate the literature on in vitro and in vivo testing of current tau PET radiotracers in APs. The tau PET tracers assessed include both first-generation tracers ([18F]AV-1451, [18F]FDDNP, [18F]THK derivatives, and [11C]PBB3) and second-generation tracers ([18F]PM-PBB3, [18F]PI-2620, [18F]RO-948, [18F]JNJ-067, [18F]MK-6240, and [18F]CBD-2115). Concerns regarding off-target binding to cerebral white matter and the basal ganglia are still prominent with first-generation tracers, but this seems to have been mediated in a handful of second-generation tracers, including [18F]PI-2620 and [18F]PM-PBB3. Additionally, these two tracers and [18F]MK-6240 show promising results for imaging PSP- and CBD-tau. Overall, [18F]AV-1451 is the most widely studied tracer but the mixed results regarding its efficacy for use in imaging AP-tau is a cause for concern moving forward. Instead, future work may benefit from focusing on the second-generation radiotracers which seem to have a higher specificity for AP-tau than those originally developed for imaging AD-tau.

Binding characteristics of [18F]PI-2620 distinguish the clinically predicted tau isoform in different tauopathies by PET

The novel tau-PET tracer [¹⁸F]PI-2620 detects the 3/4-repeat-(R)-tauopathy Alzheimer's disease (AD) and the 4R-tauopathies corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP). We determined whether [¹⁸F]PI-2620 binding characteristics deriving from non-invasive reference tissue modelling differentiate 3/4R- and 4R-tauopathies. Ten patients with a 3/4R tauopathy (AD continuum) and 29 patients with a 4R tauopathy (CBS, PSP) were evaluated. [¹⁸F]PI-2620 PET scans were acquired 0-60 min p.i. and the distribution volume ratio (DVR) was calculated. [¹⁸F]PI-2620-positive clusters (DVR ≥ 2.5 SD vs. 11 healthy controls) were evaluated by non-invasive kinetic modelling. R1 (delivery), k2 & k2a (efflux), DVR, 30-60 min standardized-uptake-value-ratios (SUVR_30-60) and the linear slope of post-perfusion phase SUVR (9-60 min p.i.) were compared between 3/4R- and 4R-tauopathies. Cortical clusters of 4R-tau cases indicated higher delivery (R1_SRTM: 0.92 ± 0.21 vs. 0.83 ± 0.10, p = 0.0007), higher efflux (k2_SRTM: 0.17/min ±0.21/min vs. 0.06/min ± 0.07/min, p < 0.0001), lower DVR (1.1 ± 0.1 vs. 1.4 ± 0.2, p < 0.0001), lower SUVR_30-60 (1.3 ± 0.2 vs. 1.8 ± 0.3, p < 0.0001) and flatter slopes of the post-perfusion phase (slope_9-60: 0.006/min ± 0.007/min vs. 0.016/min ± 0.008/min, p < 0.0001) when compared to 3/4R-tau cases. [¹⁸F]PI-2620 binding characteristics in cortical regions differentiate 3/4R- and 4R-tauopathies. Higher tracer clearance indicates less stable binding in 4R tauopathies when compared to 3/4R-tauopathies.

PTPRC Expression in Blood is Downregulated in Parkinson's and Progressive Supranuclear Palsy Disorders

BACKGROUND

Parkinson's disease (PD) shares pathological and clinical features with progressive supranuclear palsy (PSP) patients making the diagnosis challenging. Distinguishing PD from PSP is crucial given differences in disease course, treatment and clinical management.

OBJECTIVE

Although some progress has been made in the discovery of biomarkers for PD and PSP, there is an urgent need to identify additional biomarkers capable of distinguishing between these diseases.

METHODS

In this study, we tested the phosphatases DUSP8 and PTPRC for their diagnostic potential using quantitative PCR assays, in blood of 138 samples from participants nested in the Parkinson's Disease Biomarkers Program.

RESULTS

Relative abundance of PTPRC mRNA was downregulated in PSP patients compared to PD and healthy controls, whereas there was no significant difference in the expression of DUSP8. Interestingly, PTPRC mRNA correlated with the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) total score and MDS-UPDRS- part III, thus indicating it might be useful as part of a biosignature to stratify patients according to disease severity and progression.

CONCLUSIONS

Collectively, these results suggest that PTPRC expression may be useful for distinguishing PD from PSP patients as part of a biosignature. Evaluation of PTPRC along with additional biomarkers in a larger and well-characterized longitudinal study is warranted.

Cognitive and behavioural dysfunctions in a patient with progressive supranuclear palsy (PSP)

Background

The aim of the case study was to describe the profile of cognitive and emotional functioning of a patient with possible progressive supranuclear palsy (PSP) from a longitudinal perspective.

Participants and procedure

This study involved an 71-year-old male patient diagnosed with PSP, and 9 matched healthy subjects. Neuro-psychological examination of the patient was performed twice with a 6 month interval. A set of neuropsycho-logical tests was used to assess both cognition and behaviour.

Results

Neuropsychological assessment revealed executive dysfunction dominance (planning deficits, reduced cogni-tive flexibility and abstract thinking, impulsiveness), reduced verbal fluency, psychomotor slowness and prob-lems with memory retrieval from the long-term memory storage in contrast to significantly better recognition of the previously learned information. According to emotional functioning, frontal change of personality was ob-served, with apathy, disinhibition, lack of insights, impulsiveness and “utilization behaviours”.

Conclusions

The profile of emotional and cognitive impairments met the criteria for dementia. There was a progression of deficits at visit two in comparison to visit one. The longitudinal perspective allowed the dynamics of emotional, cognitive and behavioural changes to be described over time: from depression related to initially preserved criticism of the illness to apathy and emotional blunting and behavioural frontal syndrome connected with the systematic loss of insight.

Neuroimaging in aging and neurologic diseases

Neuroimaging biomarkers for neurologic diseases are important tools, both for understanding pathology associated with cognitive and clinical symptoms and for differential diagnosis. This chapter explores neuroimaging measures, including structural and functional measures from magnetic resonance imaging (MRI) and molecular measures primarily from positron emission tomography (PET), in healthy aging adults and in a number of neurologic diseases. The spectrum covers neuroimaging measures from normal aging to a variety of dementias: late-onset Alzheimer's disease [AD; including mild cognitive impairment (MCI)], familial and nonfamilial early-onset AD, atypical AD syndromes, posterior cortical atrophy (PCA), logopenic aphasia (lvPPA), cerebral amyloid angiopathy (CAA), vascular dementia (VaD), sporadic and familial behavioral-variant frontotemporal dementia (bvFTD), semantic dementia (SD), progressive nonfluent aphasia (PNFA), frontotemporal dementia with motor neuron disease (FTD-MND), frontotemporal dementia with amyotrophic lateral sclerosis (FTD-ALS), corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), Parkinson's disease (PD) with and without dementia, and multiple systems atrophy (MSA). We also include a discussion of the appropriate use criteria (AUC) for amyloid imaging and conclude with a discussion of differential diagnosis of neurologic dementia disorders in the context of neuroimaging.

Difficulties in the diagnosis of four repeats (4R) tauopathic parkinsonian syndromes

Corticobasal Degeneration Degeneration (CBD) and Progressive Supranuclear Palsy (PSP) are types of four repeats (4R) tauopathies, which are associated to parkinsonian syndromes. The aim of the work is to analyze cases of patients of the Department of Neurology, overlapping of syndromes related to both pathologies and to show that most likely CBS and PSP are not lineary related to their commonly associated syndromes i.e. adequately corticobasal syndromes and progressive supranuclear palsy syndromes. In the context of each patient factors in favor of most likely CBS, PSP or both diseases are discussed and analyzed using contemporary criteria. This work discusses multidimensional aspect of the examination of five patient aged 64 to 83 - 4 females and 1 male with 4R tauopathies and difficulties in distinguishing both diseases. The duration of the disease varied from 1 to 5 years. Each patient after neurological examination was assessed using magnetic resonance imaging (MRI) and psychological test. Examination of all patients was extended using single photon emission computer tomography (SPECT) to reveal the usefulness of this tool in differentiation of diseases was done. The outcome of this examination was verified with prior clinical manifestation of patients and morphological abnormalities in magnetic resonance imaging. Autopsies were not conducted.

Positron emission tomography imaging of tau pathology in progressive supranuclear palsy

Progressive supranuclear palsy is a rare form of atypical Parkinsonism that differs neuropathologically from other parkinsonian disorders. While many parkinsonian disorders such as Parkinson's disease, Lewy body dementia, and multiple system atrophy are classified as synucleinopathies, progressive supranuclear palsy is coined a tauopathy due to the aggregation of pathological tau in the brain. [¹⁸F]AV-1451 (also known as [¹⁸F]-T807) is a positron emission tomography radiotracer that binds to paired helical filaments of tau in Alzheimer's disease. We investigated whether [¹⁸F]AV-1451 could be used as biomarker for the diagnosis and disease progression monitoring in progressive supranuclear palsy. Six progressive supranuclear palsy, six Parkinson's disease, and 10 age-matched healthy controls were recruited. An anatomical MRI and a 90-min PET scan, using [¹⁸F]AV-1451, were acquired from all participants. The standardized uptake value ratio from 60 to 90 min post-injection was calculated in each region of interest, using the cerebellar cortex as a reference region. No significant differences in standardized uptake value ratios were detected in our progressive supranuclear palsy group compared to the two control groups. [¹⁸F]AV-1451 may bind selectivity to the paired helical filaments in Alzheimer's disease, which differ from the straight conformation of tau filaments in progressive supranuclear palsy.

Imaging tau pathology in Parkinsonisms

The recent development of positron emission tomography radiotracers targeting pathological tau in vivo has led to numerous human trials. While investigations have primarily focused on the most common tauopathy, Alzheimer's disease, it is imperative that testing also be performed in parkinsonian tauopathies, such as progressive supranuclear palsy, corticobasal degeneration, and frontotemporal dementia and parkinsonism linked to chromosome 17. Tau aggregates differ in isoforms and conformations across disorders, and as a result one radiotracer may not be appropriate for all tauopathies. In this review, we evaluate the preclinical and clinical reports of current tau radiotracers in parkinsonian disorders. These radiotracers include [18F]FDDNP, [11C]PBB3, [18F]THK-5317, [18F]THK-5351, and [18F]AV-1451 ([18F]T807). There are concerns of off-target binding with [18F]FDDNP and [11C]PBB3, which may increase the signal to noise ratio and thereby decrease the efficacy of these radiotracers. Testing in [18F]THK-5317, [18F]THK-5351, and [18F]AV-1451 has been performed in progressive supranuclear palsy, while [18F]THK-5317 and [18F]AV-1451 have also been tested in corticobasal degeneration patients. [18F]THK-5317 and [18F]THK-5351 have demonstrated binding in brain regions known to be afflicted with pathological tau; however, due to small sample sizes these studies should be replicated before concluding their appropriateness in parkinsonian tauopathies. [18F]AV-1451 has demonstrated mixed results in progressive supranuclear palsy patients and post-mortem analysis shows minimal to no binding to non-Alzheimer's disease tauopathies brain slices.

An autopsy-confirmed case of progressive supranuclear palsy with predominant postural instability

Postural instability and supranuclear gaze palsy represent the key symptoms of Richardson’s syndrome, the most frequent clinical manifestation of progressive supranuclear palsy (PSP). However, a proportion of PSP patients never develops ocular motor symptoms, which prevents clinicians from establishing the diagnosis during lifetime according to current diagnostic criteria. We present one instructive autopsy-confirmed PSP case with prospective video-documented clinical course, showing striking temporal divergence of initially present postural instability and delayed development of ocular motor dysfunction. Brain imaging and autopsy findings were typical of PSP, but the temporal sequence of symptoms was unusual with isolated postural instability predominating the clinical course for many years and slowing of vertical saccades/supranuclear gaze palsy evolving not until the 9^th/11^th year after disease onset. Although other differential diagnoses were unlikely, this patient did not pass the threshold for possible or probable diagnosis of PSP according to current diagnostic criteria until very late in the disease course. This first well documented, autopsy confirmed case of PSP with predominant postural instability further expands the clinical spectrum of PSP and points out the need of new clinical diagnostic criteria with sufficient sensitivity and specificity for an early and reliable diagnosis.

Brain MR Contribution to the Differential Diagnosis of Parkinsonian Syndromes: An Update

Brain magnetic resonance (MR) represents a useful and feasible tool for the differential diagnosis of Parkinson's disease. Conventional MR may reveal secondary forms of parkinsonism and may show peculiar brain alterations of atypical parkinsonian syndromes. Furthermore, advanced MR techniques, such as morphometric-volumetric analyses, diffusion-weighted imaging, diffusion tensor imaging, tractography, proton MR spectroscopy, and iron-content sensitive imaging, have been used to obtain quantitative parameters useful to increase the diagnostic accuracy. Currently, many MR studies have provided both qualitative and quantitative findings, reflecting the underlying neuropathological pattern of the different degenerative parkinsonian syndromes. Although the variability in the methods and results across the studies limits the conclusion about which technique is the best, specific radiologic phenotypes may be identified. Qualitative/quantitative MR changes in the substantia nigra do not discriminate between different parkinsonisms. In the absence of extranigral abnormalities, the diagnosis of PD is more probable, whereas basal ganglia changes (mainly in the putamen) suggest the diagnosis of an atypical parkinsonian syndrome. In this context, changes in pons, middle cerebellar peduncles, and cerebellum suggest the diagnosis of MSA, in midbrain and superior cerebellar peduncles the diagnosis of PSP, and in whole cerebral hemispheres (mainly in frontoparietal cortex with asymmetric distribution) the diagnosis of Corticobasal Syndrome.

MR parkinsonism index predicts vertical supranuclear gaze palsy in patients with PSP-parkinsonism

Objective:

To identify a biomarker for predicting the appearance of vertical supranuclear gaze palsy (VSGP) in patients affected by progressive supranuclear palsy–parkinsonism (PSP-P).

Methods:

Twenty-four patients with PSP-P were enrolled in the current study. Patients were clinically followed up every 6 months until the appearance of VSGP or the end of the follow-up (4 years). Participants underwent MRI at baseline and at the end of follow-up. Magnetic resonance parkinsonism index (MRPI), an imaging measure useful for diagnosing PSP, was calculated.

Results:

Twenty-one patients with PSP-P completed follow-up, and 3 patients dropped out. Eleven of 21 patients with PSP-P developed VSGP after a mean follow-up period of 28.5 months (range 6–48 months), while the remaining 10 patients with PSP-P did not develop VSGP during the 4-year follow-up period. At baseline, patients with PSP-P who later developed VSGP had MRPI values significantly higher than those of patients not developing VSGP without overlapping values between the 2 groups. MRPI showed a higher accuracy (100%) in predicting VSGP than vertical ocular slowness (accuracy 33.3%) or postural instability with or without vertical ocular slowness (accuracy 71.4% and 42.9%, respectively).

Conclusions:

Our study demonstrates that MRPI accurately predicted, on an individual basis, the appearance of VSGP in patients with PSP-P, thus confirming clinical diagnosis in vivo.

Fragile X-associated tremor/ataxia syndrome: phenotypic comparisons with other movement disorders

OBJECTIVE

The purpose of this paper is to review the typical cognitive and motor impairments seen in fragile X-associated tremor/ataxia syndrome (FXTAS), essential tremor (ET), Parkinson disease (PD), spinocerebellar ataxias (SCAs), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP) in order to enhance diagnosis of FXTAS patients.

METHODS

We compared the cognitive and motor phenotypes of FXTAS with each of these other movement disorders. Relevant neuropathological and neuroimaging findings are also reviewed. Finally, we describe the differences in age of onset, disease severity, progression rates, and average lifespan in FXTAS compared to ET, PD, SCAs, MSA, and PSP. We conclude with a flow chart algorithm to guide the clinician in the differential diagnosis of FXTAS.

RESULTS

By comparing the cognitive and motor phenotypes of FXTAS with the phenotypes of ET, PD, SCAs, MSA, and PSP we have clarified potential symptom overlap while elucidating factors that make these disorders unique from one another. In summary, the clinician should consider a FXTAS diagnosis and testing for the Fragile X mental retardation 1 (FMR1) gene premutation if a patient over the age of 50 (1) presents with cerebellar ataxia and/or intention tremor with mild parkinsonism, (2) has the middle cerebellar peduncle (MCP) sign, global cerebellar and cerebral atrophy, and/or subcortical white matter lesions on MRI, or (3) has a family history of fragile X related disorders, intellectual disability, autism, premature ovarian failure and has neurological signs consistent with FXTAS. Peripheral neuropathy, executive function deficits, anxiety, or depression are supportive of the diagnosis.

CONCLUSIONS

Distinct profiles in the cognitive and motor domains between these movement disorders may guide practitioners in the differential diagnosis process and ultimately lead to better medical management of FXTAS patients.

Diagnostic potential of automated subcortical volume segmentation in atypical parkinsonism

OBJECTIVE

To determine whether automated and observer-independent volumetric MRI analysis is able to discriminate among patients with Parkinson disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP) in early to moderately advanced stages of disease.

METHODS

T1-weighted volumetric MRI from patients with clinically probable PD (n = 40), MSA (n = 40), and PSP (n = 30) and a mean disease duration of 2.8 ± 1.7 y were examined using automated volume measures of 22 subcortical regions. The clinical follow-up period was 2.5 ± 1.2 years. The data were split into a training (n = 72) and a test set (n = 38). The training set was used to build a C4.5 decision tree model in order to classify patients as MSA, PSP, or PD. The classification algorithm was examined by the test set using the final clinical diagnosis at last follow-up as diagnostic gold standard.

RESULTS

The midbrain and putaminal volume as well as the cerebellar gray matter compartment were identified as the most significant brain regions to construct a prediction model. The diagnostic accuracy for PD vs MSA or PSP was 97.4%. In contrast, diagnostic accuracy based on validated clinical consensus criteria at the time of MRI acquisition was 62.9%.

CONCLUSIONS

Volume segmentation of subcortical brain areas differentiates PD from MSA and PSP and improves diagnostic accuracy in patients presenting with early to moderately advanced stage parkinsonism.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that automated MRI analysis accurately discriminates among early-stage PD, MSA, and PSP.

Tau imaging in neurodegenerative diseases

Aggregated tau protein is a major neuropathological substrate central to the pathophysiology of neurodegenerative diseases such as Alzheimer's disease (AD), frontotemporal dementia, progressive supranuclear palsy, corticobasal degeneration and chronic traumatic encephalopathy. In AD, it has been shown that the density of hyperphosphorylated tau tangles correlates closely with neuronal dysfunction and cell death, unlike β-amyloid. Until now, diagnostic and pathologic information about tau deposition has only been available from invasive techniques such as brain biopsy or autopsy. The recent development of selective in-vivo tau PET imaging ligands including [(18)F]THK523, [(18)F]THK5117, [(18)F]THK5105 and [(18)F]THK5351, [(18)F]AV1451(T807) and [(11)C]PBB3 has provided information about the role of tau in the early phases of neurodegenerative diseases, and provided support for diagnosis, prognosis, and imaging biomarkers to track disease progression. Moreover, the spatial and longitudinal relationship of tau distribution compared with β - amyloid and other pathologies in these diseases can be mapped. In this review, we discuss the role of aggregated tau in tauopathies, the challenges posed in developing selective tau ligands as biomarkers, the state of development in tau tracers, and the new clinical information that has been uncovered, as well as the opportunities for improving diagnosis and designing clinical trials in the future.

Imaging pathological tau in atypical parkinsonian disorders

PURPOSE OF REVIEW

This review examines the current literature on tau imaging in atypical parkinsonian disorders and other tauopathies.

RECENT FINDINGS

There are a number of tau PET radiotracers that have demonstrated promising preliminary results in atypical parkinsonian disorders, such as progressive supranuclear palsy and corticobasal degeneration. These radiotracers were capable of selectively labeling tau in vitro and in vivo, with high affinity. Other radiotracers tested more extensively in patients with Alzheimer's disease have also been able to successfully image tau deposition.

SUMMARY

The development of tau radioligands for PET has led to the current testing of these tracers in clinical studies, many of which concentrate on patients with Alzheimer's disease. Atypical parkinsonian disorders such as progressive supranuclear palsy and corticobasal degeneration are now being investigated as well. These disorders can be very difficult to diagnose, because of their clinical overlap with other parkinsonian disorders. Imaging tau using PET could serve as a diagnostic biomarker for these tauopathies and provide a means of assessing treatment that targets tau burden.

Brain imaging in the differential diagnosis of young-onset dementias

Young-onset dementia is a broad category of diseases that affect adults before the age of 65, with devastating effects on individuals and families. Neuroimaging plays a clear and ever-expanding role in the workup of these diseases. MRI demonstrates classic patterns of atrophy that help to confirm the clinical diagnosis and may predict the underlying disease. Functional nuclear imaging, such as PET, demonstrates areas of brain dysfunction even in the absence of visible atrophy. These techniques can inform important aspects of the care of young-onset dementia, such as the underlying pathologic condition, treatment, and prognosis.

A guideline for the management of bladder dysfunction in Parkinson's disease and other gait disorders

Parkinson's disease (PD) is a common neurodegenerative disorder, and lower urinary tract (LUT) dysfunction is one of the most common autonomic disorders with an estimated incidence rate of 27-80%. Studies have shown that bladder dysfunction significantly influences quality-of-life (QOL) measures, early institutionalisation, and health economics. We review the pathophysiology of bladder dysfunction in PD, lower urinary tract symptoms (LUTS), objective assessment, and treatment options. In patients with PD, disruption of the dopamine D1-GABAergic direct pathway may lead to LUTS. Overactive bladder (OAB) is the most common LUT symptom in PD patients, and an objective assessment using urodynamics commonly shows detrusor overactivity (DO) in these patients. The post-void residual (PVR) volume is minimal in PD, which differs significantly from multiple system atrophy (MSA) patients who have a more progressive disease that leads to urinary retention. However, subclinical detrusor weakness during voiding may also occur in PD. Regarding bladder management, there are no large, double-blind, prospective studies in this area. It is well recognised that dopaminergic drugs can improve or worsen LUTS in PD patients. Therefore, an add-on therapy with anticholinergics is required. Beta-3 adrenergic agonists are a potential treatment option because there are little to no central cognitive events. Newer interventions, such as deep brain stimulation (DBS), are expected to improve bladder dysfunction in PD. Botulinum toxin injections can be used to treat intractable urinary incontinence in PD. Transurethral resection of the prostate gland (TURP) for comorbid BPH in PD is now recognised to be not contraindicated if MSA is excluded. Collaboration of urologists with neurologists is highly recommended to maximise a patients' bladder-associated QOL. Neurourol. Urodynam. 35:551-563, 2016. © 2015 Wiley Periodicals, Inc.

Behavioral and neurophysiological effects of transdermal rotigotine in atypical parkinsonism

Effective therapies for the so-called atypical parkinsonian syndrome (APS) such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), or corticobasal syndrome (CBS) are not available. Dopamine agonists (DA) are not often used in APS because of inefficacy and in a minority of case, their side effects, like dyskinesias, impairment of extrapyramidal symptoms or the appearance of psychosis, and REM sleep behavioral disorders (RBD). Transdermal rotigotine (RTG) is a non-ergot dopamine agonist indicated for use in early and advanced Parkinson’s disease with a good tolerability and safety. Moreover, its action on a wide range of dopamine receptors, D1, D2, D3, unlike other DA, could make it a good option in APS, where a massive dopamine cell loss is documented. In this pilot, observational open-label study we evaluate the efficacy and tolerability of RTG in patients affected by APS. Thirty-two subjects with diagnosis of APS were treated with transdermal RTG. APS diagnosis was: MSA parkinsonian type (MSA-P), MSA cerebellar type (MSA-C), PSP, and CBS. Patients were evaluated by UPDRS-III, neuropsychiatric inventory, mini mental state examination at baseline, and after 6, 12, and 18 months. The titration schedule was maintained very flexible, searching the major clinical effect and the minor possible adverse events (AEs) at each visit. AEs were recorded. APS patients treated with RTG show an overall decrease of UPDRS-III scores without increasing behavioral disturbances. Only three patients were dropped out of the study. Main AEs were hypotension, nausea, vomiting, drowsiness, and tachycardia. The electroencephalographic recording power spectra analysis shows a decrease of theta and an increase of low alpha power. In conclusion, transdermal RTG seems to be effective and well tolerated in APS patients.

Non-ergot dopamine agonist rotigotine as a promising therapeutic tool in atypical parkinsonism syndromes: a 24 months pilot observational open-label study

Rotigotine (RTG) is a non-ergot dopamine agonist developed as a new transdermal formulation, indicated for use in early and advanced Parkinson's disease (PD). The potential advantages of the RTG patch include immediacy of effect onset, constant drug delivery, better tolerability avoiding drug peaks and easy of use, helping patient's compliance. So, RTG patch appears to be a suitable candidate in the treatment of patients with atypical parkinsonism. The present is an observational study to evaluate the efficacy and tolerability of RTG in patients affected by atypical parkinsonian disorders. 61 subjects with diagnosis of atypical parkinsonian disorders were treated with transdermal RTG. Diagnosis was: Parkinson disease with dementia, multiple system atrophy parkinsonian type, multiple system atrophy cerebellar type, progressive sopranuclear palsy, cortico-basal degeneration, Lewy body dementia and fronto-temporal dementia with parkinsonism. Patients were evaluated by UPDRS-III, NPI, MMSE and adverse events (AEs) were recorded. Patients treated with RTG show an overall decrease of UPDRS III scores without increasing behavioral disturbances. Main adverse events (AE) were hypotension (14 patients), nausea (13), vomiting (5), drowsiness (5), tachycardia (2) dystonia (3 patients, all treated with concomitant l-dopa). On the whole, 16 patients were affected by AE and 7 patients suspended RTG treatment due to AE (vomiting, tachycardia and sleepiness). In our population transdermal RTG seems to be effective and well tolerated. Due to its system of drug delivery, RTG appears to be a suitable therapy in elderly patients as it has a good tolerability profile, improves patient's compliance and helps management of fragile patients.

Rotigotine is safe and efficacious in Atypical Parkinsonism Syndromes induced by both α-synucleinopathy and tauopathy

Transdermal rotigotine (RTG) is a non-ergot dopamine agonist (D3>D2>D1), and is indicated for use in early and advanced Parkinson's disease (PD). RTG patch has many potential advantages due to the immediacy of onset of the therapeutic effect. Of note, intestinal absorption is not necessary and drug delivery is constant, thereby avoiding drug peaks and helping patient compliance. In turn, transdermal RTG seems a suitable candidate in the treatment of atypical Parkinsonian disorders (APS). Fifty-one subjects with a diagnosis of APS were treated with transdermal RTG. The diagnoses were: Parkinson's disease with dementia, multiple system atrophy Parkinsonian type, multiple system atrophy cerebellar type, progressive supranuclear palsy, corticobasal degeneration, Lewy body dementia, and frontotemporal dementia with Parkinsonism. Patients were evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS; part III), Neuropsychiatric Inventory (NPI), and mini-mental state examination (MMSE) and all adverse events (AEs) were recorded. Patients treated with RTG showed an overall decrease of UPDRS III scores without increasing behavioral disturbances. Main AEs were hypotension, nausea, vomiting, drowsiness, tachycardia, and dystonia. On the whole, 15 patients were affected by AEs and seven patients suspended RTG treatment due to AEs. The results show that transdermal RTG is effective with a good tolerability profile. RTG patch could be a good therapeutic tool in patients with APS.

The pimple sign of progressive supranuclear palsy syndrome

BACKGROUND

Some patients with progressive supranuclear palsy syndrome (PSPS) demonstrate a focal area of midbrain hypometabolism on FDG-PET scans which we call the 'pimple sign'. We assessed its association with midbrain atrophy, its reliability and its ability to differentiate PSPS from corticobasal syndrome (CBS) and multiple system atrophy (MSA).

METHODS

We identified 67 patients with PSPS, CBS or MSA who had volumetric MRI as well as FDG-PET imaging. Midbrain volume was measured and expressed as a percentage of total intracranial volume. Two independent, blinded specialists rated the 'pimple sign' on FDG-PET as 'absent', 'possible' or 'definite'. Midbrain volumes were compared across these groups and reliability assessed with the kappa statistic. Sensitivity and specificity were calculated using CBS and MSA patients as controls.

RESULTS

Midbrain volume was decreased in the 'definite' group compared to the 'absent' and 'possible' groups (p = 0.0036). Inter-rater reliability for the pimple sign was high (κ = 0.90). A 'definite pimple sign' had a high specificity (100%) but low sensitivity (29%) for PSPS, whilst the presence of a possible or definite sign had a sensitivity of 79%.

CONCLUSION

The 'pimple sign' of PSPS is associated with midbrain atrophy, and may be helpful in differentiating PSPS from CBS and MSA.