The epidemiology of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome)

Four-repeat tauopathies

Tau is a microtubule-associated protein with versatile functions in the dynamic assembly of the neuronal cytoskeleton. Four-repeat (4R-) tauopathies are a group of neurodegenerative diseases defined by cytoplasmic inclusions predominantly composed of tau protein isoforms with four microtubule-binding domains. Progressive supranuclear palsy, corticobasal degeneration, argyrophilic grain disease or glial globular tauopathy belong to the group of 4R-tauopathies. The present review provides an introduction in the current concept of 4R-tauopathies, including an overview of the neuropathological and clinical spectrum of these diseases. It describes the genetic and environmental etiological factors, as well as the contemporary knowledge about the pathophysiological mechanisms, including post-translational modifications, aggregation and fragmentation of tau, as well as the role of protein degradation mechanisms. Furthermore, current theories about disease propagation are discussed, involving different extracellular tau species and their cellular release and uptake mechanisms. Finally, molecular diagnostic tools for 4R-tauopathies, including tau-PET and fluid biomarkers, and investigational therapeutic strategies are presented. In summary, we report on 4R-tauopathies as overarching disease concept based on a shared pathophysiological concept, and highlight the challenges and opportunities on the way towards a causal therapy.

Supranuclear eye movement abnormalities

PURPOSE OF REVIEW

The components of the efferent ocular motor network include supranuclear, nuclear, internuclear, infranuclear, neuromuscular junction, and muscle. Within this schema, clinicians are often least acquainted with the supranuclear components; however, derangement of this system is a common cause of ocular dysmotility and diplopia. This article will provide the neurologist with an overview of the anatomy and clinical aspects of the supranuclear ocular motor control systems.

RECENT FINDINGS

Continued research moves us toward a more complete understanding of the anatomy and physiology of the complex networks providing supranuclear control of eye movements. This background serves as a framework for the application of clinical techniques, such as bedside assessment of the vestibuloocular reflex, localizing limitations of conjugate gaze (eg, midbrain lesions affecting vertical gaze), and derangements of specific classes of eye movements (pursuit and saccadic dissociation in conditions such as Parinaud dorsal midbrain syndrome).

SUMMARY

The efferent neuro-ophthalmic system is a complex series of networks that function to provide accurate control of eye movements, visual stabilization, and ocular alignment. Disturbance within these networks can produce diplopia; impaired control of eye movement, such as gaze palsy; or unwanted eye movements, such as nystagmus.

Brain alterations and mini-mental state examination in patients with progressive supranuclear palsy: voxel-based investigations using f-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging

BACKGROUND/AIMS

The aim of this study was to compare differences in morphological and functional changes in brain regions in individual patients with progressive supranuclear palsy (PSP) and correlate their Mini-Mental State Examination (MMSE) score with anatomy and function using magnetic resonance imaging (MRI) and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET).

METHODS

Sixteen PSP patients and 20 age-matched healthy volunteers underwent FDG-PET and 3-dimensional MRI. Gray matter, white matter and metabolic activity were compared between patients and normal controls. In addition, possible correlations between the MMSE score and brain function/anatomy were examined.

RESULTS

The PSP group had reduced cerebral glucose metabolism, and lower gray and white matter volumes in the frontal lobes and midbrain compared with normal controls. In PSP subjects, the metabolic changes observed in the PET scans were greater than the loss in gray and white matter observed in the MRI scans. The MMSE scores were positively correlated with volume and FDG uptake in the frontal lobe.

CONCLUSION

FDG-PET is a more effective tool in the diagnosis of PSP than MRI. Atrophy and hypometabolism in the frontal lobe are as important as in the basal midbrain for differentiating PSP patients who primarily exhibit cognitive dysfunction from normal controls.

The economic costs of progressive supranuclear palsy and multiple system atrophy in France, Germany and the United Kingdom

Progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are progressive disabling neurological conditions usually fatal within 10 years of onset. Little is known about the economic costs of these conditions. This paper reports service use and costs from France, Germany and the UK and identifies patient characteristics that are associated with cost. 767 patients were recruited, and 760 included in the study, from 44 centres as part of the NNIPPS trial. Service use during the previous six months was measured at entry to the study and costs calculated. Mean six-month costs were calculated for 742 patients. Data on patient sociodemographic and clinical characteristics were recorded and used in regression models to identify predictors of service costs and unpaid care costs (i.e., care from family and friends). The mean six-month service costs of PSP were €24,491 in France, €30,643 in Germany and €25,655 in the UK. The costs for MSA were €28,924, €25,645 and €19,103 respectively. Unpaid care accounted for 68-76%. Formal and unpaid costs were significantly higher the more severe the illness, as indicated by the Parkinson's Plus Symptom scale. There was a significant inverse relationship between service and unpaid care costs.

The potential research impact of patient reported outcomes on osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta (OI) is an inherited connective tissue disorder with many phenotypic presentations ranging from mild to severe. It is often called "brittle bone disease." Treatment consists of physical therapy, surgical interventions, medications and, in some cases, experimental therapies. Because treatment is not standardized and is often experimental, information on the success of different methods is usually not available or well documented.

QUESTIONS/PURPOSES

We therefore asked if social networking can make OI patients' lives better. How would a bone disorder community work? Is it possible for patients to know how well they are doing in comparison to others like them, and if they are getting the most successful treatment for their disease?

METHODS

An evaluation of how PatientsLikeMe®, a personal research and social networking website and database for patients with life changing illnesses, can aid in improving patient outcomes through the anonymous sharing of medical information.

RESULTS

PatientsLikeMe® could help patients answer the question, "Given my condition, what is the best outcome I could hope to achieve, and how do I get there?" Participants could record their real-time day-to-day progress in achieving their treatment goals, such as preventing fractures, and share that with the community to help patients, caregivers, researchers and industry learn more about OI.

CONCLUSIONS

Social networking can change the lives of Osteogenesis Imperfecta patients for the better, and make them a part of the treatment discovery process. Here we present a possible OI online community and demonstrate its potential utility for patients and medical professionals alike.

Riluzole treatment, survival and diagnostic criteria in Parkinson plus disorders: the NNIPPS study

Parkinson plus diseases, comprising mainly progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are rare neurodegenerative conditions. We designed a double-blind randomized placebo-controlled trial of riluzole as a potential disease-modifying agent in Parkinson plus disorders (NNIPPS: Neuroprotection and Natural History in Parkinson Plus Syndromes). We analysed the accuracy of our clinical diagnostic criteria, and studied prognostic factors for survival. Patients with an akinetic-rigid syndrome diagnosed as having PSP or MSA according to modified consensus diagnostic criteria were considered for inclusion. The psychometric validity (convergent and predictive) of the NNIPPS diagnostic criteria were tested prospectively by clinical and pathological assessments. The study was powered to detect a 40% decrease in relative risk of death within PSP or MSA strata. Patients were randomized to riluzole or matched placebo daily and followed up to 36 months. The primary endpoint was survival. Secondary efficacy outcomes were rates of disease progression assessed by functional measures. A total of 767 patients were randomized and 760 qualified for the Intent to Treat (ITT) analysis, stratified at entry as PSP (362 patients) or MSA (398 patients). Median follow-up was 1095 days (range 249–1095). During the study, 342 patients died and 112 brains were examined for pathology. NNIPPS diagnostic criteria showed for both PSP and MSA excellent convergent validity with the investigators’ assessment of diagnostic probability (point-biserial correlation: MSA r_pb = 0.93, P< 0.0001; PSP, r_pb = 0.95, P< 0.0001), and excellent predictive validity against histopathology [sensitivity and specificity (95% CI) for PSP 0.95 (0.88–0.98) and 0.84 (0.77–0.87); and for MSA 0.96 (0.88–0.99) and 0.91 (0.86–0.93)]. There was no evidence of a drug effect on survival in the PSP or MSA strata (3 year Kaplan–Meier estimates PSP-riluzole: 0.51, PSP-placebo: 0.50; MSA-riluzole: 0.53, MSA-placebo: 0.58; P = 0.66 and P = 0.48 by the log-rank test, respectively), or in the population as a whole (P = 0.42, by the stratified-log-rank test). Likewise, rate of progression was similar in both treatment groups. There were no unexpected adverse effects of riluzole, and no significant safety concerns. Riluzole did not have a significant effect on survival or rate of functional deterioration in PSP or MSA, although the study reached over 80% power to detect the hypothesized drug effect within strata. The NNIPPS diagnostic criteria were consistent and valid. They can be used to distinguish between PSP and MSA with high accuracy, and should facilitate research into these conditions relatively early in their evolution.

Current and future treatments in progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is an atypical parkinsonian disorder that, in spite of its growing recognition, is still underdiagnosed. For management, prognosis, and research, an accurate and early diagnosis is essential. PSP is a relentlessly progressive neurodegenerative disorder, clinically characterized by parkinsonism with prominent axial involvement and postural instability, bulbar symptoms, supranuclear ophthalmoplegia, and executive dysfunction. Abnormal neuronal and glial four-repeat tau aggregations affecting the basal ganglia and selective brainstem structures result in dysfunction of the five frontosubcortical circuits and brainstem functions. Primary therapeutic approaches are based on neurotransmitter replacement and palliative strategies. This article reviews the experience and challenges with neurotransmitter replacement and palliative strategies through an extensive literature search of studies published between 1965 and 2005. The role of and limited experience with alternative therapies, such as deep brain stimulation and pallidotomy, are also discussed. Advances in the development of biological therapies for PSP and a better understanding of its etiopathogenesis will likely result from epidemiologic studies and developed four-repeat tau-transgenic animal models. The management of patients with this disorder poses a considerable challenge and includes symptomatic and palliative strategies, as well as education and support, to improve the quality of life for patients and their caregivers.

Diffusion tensor imaging and voxel based morphometry study in early progressive supranuclear palsy

BACKGROUND

A comprehensive characterisation of grey and white matter changes in progressive supranuclear palsy (PSP), the second most common extrapyramidal syndrome after Parkinson disease, is still not available.

OBJECTIVE

To evaluate grey and white matter changes in mild PSP patients by voxel based morphometry (VBM) and diffusion tensor imaging (DTI), respectively.

METHODS

14 mild PSP patients and 14 healthy controls entered the study and underwent a clinical and neuropsychological evaluation according with a standardised assessment. Each subject had a structural magnetic resonance imaging (MRI) study. Processing analysis of MRI data was carried out according to optimised VBM and fractional anisotropy was determined.

RESULTS

Compared with the controls, in PSP patients VBM analysis showed a significant clusters of reduced grey matter in premotor cortex, frontal operculum, anterior insula, hippocampus, and parahippocampal gyrus, bilaterally. With regard to subcortical brain regions, the pulvinar, dorsomedial and anterior nuclei of the thalamus, and superior and inferior culliculum were affected bilaterally. A bilateral decrease in fractional anisotropy in superior longitudinal fasciculus, anterior part of corpus callosum, arcuate fascicolus, posterior thalamic radiations, and internal capsule, probably involving the cortico-bulbar tracts, was present in PSP patients.

CONCLUSIONS

These data provide evidence for both grey and white matter degeneration in PSP from the early disease stage. These structural changes suggest that atrophy of cortical and subcortical structures and neurodegeneration of specific fibre tracts contribute to neurological deficits in PSP.

Population based mortality and quality of death certification in progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome)

OBJECTIVE

To estimate the mortality of progressive supranuclear palsy (PSP) and to assess the quality of death certification in patients with PSP who died in England and Wales.

METHODS

An analysis was conducted of ICD-9 (International Classification of Diseases, version 9) coded deaths obtained through the Office of National Statistics over an eight year period.

RESULTS

The crude annual mortality rate was 1.77 (95% confidence interval, 1.64 to 1.90) cases per million, using the mid-1996 population estimate for England and Wales. Annual mortality increased over time, possibly as a result of increased incidence or increased awareness of the disorder. Forty nine death certificates from deceased patients previously diagnosed clinically showed that the commonest proximate cause of death was pneumonia, occurring in 45% of cases (22/49). The underlying cause of death was cited as pneumonia in 14% of cases (7/49). PSP was mentioned in only 65% of death certificates (32/49). Eight of the 49 cases (16%) underwent necropsy and results were available for five of these cases. PSP was confirmed pathologically in four; the remaining case was diagnosed as Parkinson's disease.

CONCLUSIONS

Further research is needed to establish the reasons for the observed increase in mortality. Determining the population mortality rate for PSP using the ICD-9 coding system is problematic but is likely to improve following the introduction of ICD-10 updated codes and coding rules.

Progressive supranuclear palsy: clinical features, pathophysiology and management

Progressive supranuclear palsy (PSP) is a degenerative condition of unknown aetiology that produces an akinetic-rigid form of parkinsonism characterised by early falls and abnormalities of extraocular movements. Mean age of onset is approximately 63 years, and mean survival from symptom onset is 9 years. Men are much more frequently affected than women. The classic clinical finding is supranuclear ophthalmoplegia, which may not present until late in the illness, if at all. The clinical diagnosis of PSP can be difficult to make, as the sites of pathology are heterogeneous. Structural and functional neuroimaging studies, although not specific for PSP, may be of some assistance in making the diagnosis. The definitive diagnosis of PSP requires the presence of both clinical and neuropathological evidence. Multiple anatomical sites are affected in PSP. The most consistently involved are the subthalamic nucleus, globus pallidus interna and externa, pontine nuclei, periaqueductal grey matter and the substantia nigra. The location of the pathology accounts for the clinical features. The histological hallmark of PSP is the presence of globose neurofibrillary tangles in the affected subcortical nuclei. Neurofibrillary tangles are composed of abnormally phosphorylated tau, a microtubule-associated protein that is involved in maintenance of the cytoskeleton. Abnormalities near or in the gene coding for tau are implicated in the pathogenesis of PSP. The multiple neurotransmitter abnormalities, including those affecting dopamine, acetylcholine, gamma-aminobutyric acid and norepinephrine (noradrenaline) systems and pathways, as well as both pre- and post-synaptic pathology, make pharmacological therapy of PSP a challenge. Although an individual patient may respond to a drug, in general patients with PSP have a minimal response and a short duration of sustained benefit.