Olfactory function in atypical parkinsonian syndromes

Introduction – Olfaction is markedly impaired in patients with idiopathic Parkinson's disease (IPD). This deficit contrasts with reports of preserved or only mildly reduced olfaction in patients with atypical parkinsonism. However, the sensitivity and specificity of olfactory function testing in the differential diagnosis of parkinsonian syndromes has not been studied. In addition, olfactory function in patients with corticobasal degeneration (CBD) is unknown. Material and methods — Using the University of Pennsylvania Smell Identification Test (UPSIT) with a test score ranging from 0 to 40 we studied olfactory function in patients with IPD as well as other parkinsonian syndromes including CBD and progressive supranuclear palsy (PSP). Results — UPSIT scores in 118 patients with IPD, 29 with MSA, 15 with PSP, and 7 patients with CBD, as well as in 123 healthy control subjects revealed a marked impairment in the IPD group in contrast to mild impairment in MSA patients and normal olfaction in PSP and CBD patients. An UPSIT score of 25/40 was associated with a sensitivity of 77% and a specificity of 85% in differentiating IPD from atypical parkinsonism. Conclusions — These results indicate that olfactory function is differentially impaired or preserved in distinct parkinsonian syndromes and that it might also have some value as a diagnostic pointer. Thus, preserved or mildly impaired olfactory function in a parkinsonian patient is more likely to be related to atypical parkinsonism such as MSA, PSP or CBD, whereas markedly reduced olfaction is more suggestive of IPD.     

Prefrontal cortex dysfunction and depression in atypical parkinsonian syndromes.

Depressive symptoms are common in patients with neurodegenerative disorders. Imaging studies suggest that a disruption of frontal-subcortical pathways may underlie depression associated with basal ganglia disease. This pilot study tested the hypothesis that frontal dysfunction contributes to depression associated with multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Depressed patients with MSA (n = 11), PSP (n = 9), and age-matched controls (n = 25) underwent measures of cerebral glucose metabolism applying positron emission tomography with (18)F-fluorodeoxyglucose. Regional metabolism in the patient groups was compared to the normal subjects using the voxel-based statistical parametric mapping. Depressive symptom severity (Hamilton Depression Rating) and degree of locomotor disability (Hoehn & Yahr) were assessed in the patient groups. The association between prefrontal metabolism and the occurrence of depressive symptoms and the degree of locomotor disability was investigated. When compared to controls, MSA patients revealed significant metabolic decreases in bilateral frontal, parietal, and cerebellar cortex and in the left putamen. In PSP patients, significant hypometabolism was demonstrated in bilateral frontal cortex, right thalamus, and midbrain. Depression severity but not the patients' functional condition was significantly associated with dorsolateral prefrontal glucose metabolism in both patient groups. The findings of this pilot study support the hypothesis that depressive symptoms in MSA and PSP are associated with prefrontal dysfunction.     

Milestones in atypical and secondary Parkinsonisms

During the last decades, atypical parkinsonian disorders such as multiple system atrophy, dementia with Lewy bodies, progressive supranuclear palsy, and corticobasal degeneration along with secondary parkinsonian disorders have been increasingly recognized as important causes of parkinsonism. Although treatment options are largely limited to date, remarkable progress has occurred through advances in the fields of molecular biology and diagnostic neuroimaging, resulting in intense preclinical drug discovery programs. Early‐investigation‐assisted clinical diagnosis has become more crucial than ever because disease‐modifying therapies will hopefully become available within this decade. © 2011 Movement Disorder Society     

Freezing of gait in postmortem-confirmed atypical parkinsonism.

The frequency and pathophysiology of freezing of gait (FoG) in atypical parkinsonism is unknown. We analysed the frequency of FoG in postmortem-confirmed atypical parkinsonian disorders (APD) comprising corticobasal degeneration (CBD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). Sixty-six patients with pathologically confirmed APD (CBD, n = 13; DLB, n = 14; MSA, n = 15; PSP, n = 24) formed the basis for a multicenter clinicopathological study. Clinical features at first and last clinical visit were abstracted from patient records on standardized forms following strict instructions. At the first visit (median 36 months after symptom onset), 24% of APD had FoG (CBD, 8%; DLB, 21%; PSP, 25%; MSA, 40%). Logistic regression analysis showed a significant association of FoG and urinary incontinence (P = 0.04) at first visit. At last visit, 47% of APD had FoG (CBD, 25%; PSP, 53%; DLB, 54%; MSA, 54%). Clinicopathological correlation based on routine postmortem examination failed to identify a consistent neuropathological substrate of FoG. This study demonstrates that (1) FoG is common in APD, and (2) urinary incontinence is significantly associated with FoG in these disorders. Whether FoG and urinary incontinence share similar neuropathological substrates remains to be determined by future studies.     

Atypical parkinsonian syndromes: a general neurologist's perspective

The differential diagnosis of atypical parkinsonian syndromes is challenging. These severe and often rapidly progressive neurodegenerative disorders are clinically heterogeneous and show significant phenotypic overlap. Here, clinical, imaging, neuropathological and genetic features of multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration and frontotemporal lobar degeneration (FTLD) are reviewed. The terms corticobasal degeneration and FTLD refer to pathologically confirmed cases of corticobasal syndrome and frontotemporal dementia (FTD). Frontotemporal lobar degeneration clinically presents as the behavioral variant FTD, semantic variant primary progressive aphasia (PPA), non‐fluent agrammatic variant PPA, logopenic variant PPA and FTD associated with motor neuron disease. While progressive supranuclear palsy and corticobasal syndrome have been called Parkinson‐plus syndromes in the past, they are now classified as FTD‐related disorders, reflecting that they pathologically differ from α‐synucleinopathies like multiple system atrophy and Parkinson disease. The contribution of genetic factors to atypical parkinsonian syndromes is increasingly recognized. Genes involved in the etiology of FTLD include MAPT, GRN and C9orf72. Novel neuroimaging techniques, including tau positron emission tomography imaging, are being investigated. Multimodal magnetic resonance imaging approaches and automated magnetic resonance imaging volume segmentation techniques are being evaluated for optimized differential diagnosis. Current treatment options are symptomatic, and disease modifying therapies are under active investigation.     

The final diagnoses of patients with clinically suspected atypical parkinsonian syndromes

We report on 189 patients who were evaluated for APS. Final diagnoses included 77 cases of PSP, 32 patients with MSA and 11 patients with CBS. 35 patients were diagnosed or confirmed with iPD, while in 26 cases a differentiation between iPD and APS could not be definitely made.     

Verbal adynamia in parkinsonian syndromes: behavioral correlates and neuroanatomical substrate

ABSTRACT

Verbal adynamia (impaired language generation, as during conversation) has not been assessed systematically in parkinsonian disorders. We addressed this in patients with Parkinson’s dementia, progressive supranuclear palsy and corticobasal degeneration. All disease groups showed impaired verbal fluency and sentence generation versus healthy age-matched controls, after adjusting for general linguistic and executive factors. Dopaminergic stimulation in the Parkinson’s group selectively improved verbal generation versus other cognitive functions. Voxel-based morphometry identified left inferior frontal and posterior superior temporal cortical correlates of verbal generation performance. Verbal adynamia warrants further evaluation as an index of language network dysfunction and dopaminergic state in parkinsonian disorders.     

Systematic review of proton magnetic resonance spectroscopy of the striatum in parkinsonian syndromes

It has been suggested that proton magnetic resonance spectroscopy (MRS) of the striatum can differentiate between parkinsonian syndromes. The present study aims to examine this claim by performing a systematic review of the existing literature. A MEDLINE search was performed between 1966 and October 1999, along with searches of conference abstracts and reference lists of papers identified. Eleven groups have used MRS to examine metabolite ratios in the striatum in Parkinsonian syndromes. A number of these have shown reduced N-acetylaspartate/choline (NAA/Cho) and/or N-acetylaspartate/creatine (NAA/Cr) ratios in either idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP) or corticobasal degeneration. However, the heterogeneity in the results precludes the use of any of these findings in differential diagnosis at the present time. The only group to use absolute metabolite concentrations rather than ratios showed that the decreased NAA/Cho ratio in IPD was because of an increase in choline which is of uncertain biological significance. Further large multicentre trials are required using absolute quantitation of tissue metabolite concentrations and a standardized technique. The patients entering such studies must be rigorously assessed to establish the diagnosis of the type of parkinsonism as accurately as possible. Any discriminatory abnormality must be tested in a large prospective study of newly presenting parkinsonian patients with long-term clinical follow up and ultimate pathological confirmation of the diagnosis as far as possible.     

“Atypical” atypical parkinsonism: New genetic conditions presenting with features of progressive supranuclear palsy,corticobasal degeneration,or multiple system atrophy—A diagnostic guide

Recently, a number of genetic parkinsonian conditions have been recognized that share some features with the clinical syndromes of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and multiple system atrophy (MSA), the classic phenotypic templates of atypical parkinsonism. For example, patients with progranulin, dynactin, or ATP13A gene mutations may have vertical supranuclear gaze palsy. This has made differential diagnosis difficult for practitioners. In this review, our goal is to make clinicians aware of these genetic disorders and provide clinical clues and syndromic associations, as well as investigative features, that may help in diagnosing these disorders. The correct identification of these patients has important clinical, therapeutic, and research implications. © 2013 Movement Disorder Society     

Anal sphincter EMG in the diagnosis of parkinsonian syndromes

Winge K, Jennum P, Lokkegaard A, Werdelin L. Anal sphincter EMG in the diagnosis of parkinsonian syndromes.
Acta Neurol Scand: 2010: 121: 198–203.
© 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Background – The role of electromyography (EMG) recorded from the external anal sphincter (EAS) in the diagnosis of atypical parkinsonian syndromes is a matter for continuous debate. Most studies addressing this issue are retrospective. Methods – In this study, we prospectively investigated six patients with Parkinson’s Disease (IPD), 14 patients with multiple system atrophy (MSA) and eight with progressive supranuclear palsy (PSP) using EMG of the EAS, motor‐evoked potential (MEP) to the EAS and EMG of m. gastrocnemius and nerve conduction velocity measured at the sural nerve. Patients were followed up for 2 years to secure correct diagnosis. Results – The mean duration of motor unit potentials (MUPs) recorded from the EAS was significantly longer in patients with MSA and PSP compared with MUPs recorded from patients with PD (P < 0.005 for both). There were no signs of diffuse loss of motor neurons or peripheral neuropathy. MEP revealed signs of supranuclear affection in patients with MSA, whereas in patients with PSP the mechanism is a focal loss of motor neurons in Onuf’s nucleus. Conclusion – Abnormal EMG of the EAS is strongly suggestive of atypical parkinsonism and the pathophysiology may be different in patients with MSA and PSP.     

Botulinum toxin treatment in atypical parkinsonian disorders associated with disabling focal dystonia

We investigated the efficacy of botulinum toxin A (BtxA) therapy in patients with atypical parkinsonian disorders (APD) exhibiting different types of disabling focal dystonia unresponsive to oral drug therapy. Eight patients with functionally disabling focal dystonia out of a series of 60 consecutive patients with APDs regularly treated at our outpatient movement disorders clinic were included. Patients were diagnosed according to established criteria and had disabling limb dystonia (n=4) or craniocervical dystonia (n=4) unresponsive to oral pharmacological treatment. Localization and dose of BtxA injections was determined individually based on clinical examination as well as EMG in patients with limb dystonia. BtxA reduced dystonic symptoms in all patients; only one developed a transient local side-effect. BtxA was particularly effective in the long-term treatment (up to 50 months) of blepharospasm associated with progressive supranuclear palsy (PSP). BtxA also alleviated PSP-associated retrocollis and orofacial dystonia with lower lip retraction associated with PSP and multiple system atrophy. BtxA treatment of limb dystonia in corticobasal degeneration (CBD) temporarily improved hand and arm function in early disease stages while treatment in advanced stages reduced pain, facilitated hygiene and prevented secondary contractures. Limb dystonia was also alleviated by BtxA therapy in one patient with neuronal multisystem degeneration of undetermined cause. The results suggest that BtxA therapy may represent an effective means of alleviating disabling focal dystonia in different APDs. Particularly in early stage APD with disabling limb dystonia local BtxA injections may result in functional improvement. Received: 14 March 2001, Accepted: 25 July 2001     

Glial localization of four‐repeat tau in atypical progressive supranuclear palsy

In the present case, a patient in whom limb apraxia and asymmetrical parkinsonism developed suggesting corticobasal degeneration, is reported. Neuropathologic examination revealed numerous tufted astrocytes in the precentral cortex in addition to the characteristic pathologic findings of PSP. Therefore, on the basis of clinicopathologic features, atypical progressive supranuclear palsy was diagnosed. In addition, the brain tissue of the present patient was investigated with an antibody specific for four‐repeat tau (4R‐tau). In the precentral cortex, numerous tau‐positive tufted astrocytes, pretangles, and threads were positive for 4R‐tau. Using a confocal microscopy we demonstrated that tufted astrocytes positive for 4R‐tau were adjacent to astrocytes positive for GFAP. The present findings suggest that accumulation of four‐repeat tau in astrocytes is a degenerative process rather than a reactive process.     

Routine MRI for the differential diagnosis of Parkinson's disease,MSA, PSP,and CBD

We assessed the usefulness of routine MRI for the differential diagnosis of Parkinson's disease (PD) with "atypical" parkinsonian syndromes in everyday clinical practice. We studied routinely performed MRI in PD (n = 32), multiple system atrophy (MSA, n = 28), progressive supranuclear palsy (PSP, n = 30), and corticobasal degeneration (CBD, n = 26). From a preliminary analysis of 26 items, 4 independent investigators rated 11 easily recognizable MRI pointers organized as a simple scoring system. The frequency, severity and inter-rater agreement were determined. The total severity score was subdivided into "cortical", "putaminal", "midbrain", and "pontocerebellar" scores. The frequency of putaminal involvement (100%) and vermian cerebellar atrophy (45%) was significantly higher in MSA, but that of cortical atrophy (50%), midbrain atrophy and 3(rd) ventricle enlargement (75%) was higher in PSP and CBD. The median total score fairly differentiated "atypical" parkinsonian syndromes from PD (positive predictive value-PPV-90%). However, the median total score was unable to differentiate atypical parkinsonian syndromes each other. The "cortical" score distinguished CBD and PSP from MSA with a fair PPV (>90%). The PPV of the "putaminal" score was high (70%) for the differential diagnosis of MSA with PSP and CBD. The "midbrain" score was significantly higher in PSP and CBD compared to MSA. These results are in accordance with the underlying pathology found in these disorders and demonstrate that a simple MRI scoring procedure may help the neurologist to differentiate primary causes of parkinsonism in everyday practice.     

Abnormal metabolic networks in atypical parkinsonism

Spatial covariance analysis has been used with ¹⁸F‐fluorodeoxyglucose (FDG) PET to detect and quantify specific metabolic patterns associated with Parkinson's disease (PD). However, PD‐related patterns cannot necessarily serve as biomarkers of the processes that underlie the atypical parkinsonian syndromes. In this FDG PET study, we used strictly defined statistical criteria to identify disease‐related metabolic patterns in the imaging data from patients with multiple system atrophy (MSA) and progressive supranuclear palsy (PSP), the two most common of these atypical conditions. We found that MSA and PSP were each associated with a specific, highly stable metabolic brain network (P < 0.0001, bootstrap estimation). The MSA‐related pattern was characterized by decreased metabolism in the putamen and cerebellum. The PSP‐related pattern was characterized by metabolic decreases in the brainstem and medial frontal cortex. For both conditions, pattern expression was significantly elevated in patients relative to age‐matched healthy control subjects (P < 0.001). For each condition, we validated the associated disease‐related metabolic pattern by computing its expression on an individual scan basis in two independent patient cohorts, and in one subsequent healthy volunteer cohort. We found that for both MSA and PSP, prospective assessments of pattern expression accurately discriminated patients from controls (P < 0.001). These findings suggest that the major atypical parkinsonian syndromes are associated with distinct patterns of abnormal regional metabolic activity. These disease‐related networks can potentially be used in conjunction with functional brain imaging as quantifiable biomarkers for the assessment of these pathological conditions. © 2008 Movement Disorder Society     

Differentiation of parkinsonian syndromes according to differences in executive functions

Summary. Groups of patients with Parkinsons disease (PD), striatonigral degeneration-type multiple system atrophy (MSA) or progressive supranuclear palsy (PSP) with motor disability stages II and III according to Hoehn and Yahr, and a healthy control group were compared using neuropsychological tests of executive functions. The results indicate that all three patient groups were impaired in the tests of executive functions. In comparison with healthy subjects, the three patient groups showed impaired performance regarding verbal fluency, problem solving and verbal and figural working memory. Patients with PD differed significantly from healthy subjects in a test of verbal recency, while patients with MSA or PSP were unimpaired. The comparison of patient groups revealed no differences between PD and MSA patients. However, patients with PSP showed greater impairment in both phonemic and semantic fluency than patients with PD or MSA. Using discriminant function analysis, it was found that variables derived from four verbal fluency tasks (simple and alternate semantic and phonemic fluency) discriminated among the three patient groups at a level significantly exceeding chance. Over 90% of patients with PSP were correctly classified. Patients with PD and MSA were correctly classified in over 70% of cases. These results suggest that verbal fluency tasks may be sensitive measures in the differential diagnosis of PD, MSA and PSP.Received November 5, 2002; accepted March 27, 2003 Published online June 30, 2003