A recent surge of nitrous oxide misuse around London which merits a public health warning

BACKGROUND

Use of nitrous oxide (N2O) gas for recreational purposes by young people is increasingly recognized as a public health hazard in the UK.

METHODS

We looked at the hospital records of patients admitted over the last 4 years to a single neurological centre in Essex to determine the demographics, presentation, and management of patients presenting with symptoms of N2O toxicity from its recreational use.

RESULTS

Of the 17 patients (mean age = 22.9 ± 3 years) admitted between September 2018 and October 2022, 70% were admitted between January and October 2022. All patients reported limb paraesthesiae and 16/17 reported (95%) imbalance; 11/17 (65%) showed objective limb weakness. Serum B12 concentration was low in 9/17 (53%). Plasma methylmalonic acid (n = 7) and homocysteine (n = 8) levels were elevated in all patients tested. Spinal cord Magnetic Resonance Imaging (MRI) imaging was abnormal in 10/17 (59%) patients. Nerve conduction studies were abnormal in 10/13 (77%) patients, with evidence of a symmetric, length-dependent, large fibre neuropathy.

CONCLUSIONS

There has been a recent surge of cases with neurological complications of recreational N2O abuse in the UK, with a relatively greater rate in 2022. Greater awareness of this condition amongst clinicians and health regulators is urgently required to prevent harm from N2O misuse in young people.

Chorea-acanthocytosis

A middle-aged Asian man had gait difficulty progressing over several years. His speech had gradually become slurred with involuntary tongue biting. He was the product of a consanguineous marriage with no other relevant family history. MR scan of brain showed bilateral caudate atrophy. Nerve conduction studies showed a predominantly sensory peripheral neuropathy. Serum creatine kinase was slightly elevated but electromyography showed no evidence of myopathy. Three consecutive peripheral blood films were negative for acanthocytes. Whole-genome sequencing confirmed a mutation in VPS13A gene, consistent with autosomal recessive chorea-acanthocytosis.

A Systematic Review of the Spectrum and Prevalence of Non-motor Symptoms in Multiple System Atrophy

BACKGROUND

Patients with Multiple System Atrophy (MSA) frequently report non-motor symptoms, and several research groups have highlighted this.

OBJECTIVE

We systematically searched for and reviewed papers assessing prevalence of non-motor symptoms (NMS) in MSA patients as reported in the scientific literature.

METHODS

We performed a systematic review of studies of subjects with MSA (involving > 10 patients) who were assessed for NMS, published in the English literature in PUBMED and EMBASE databases from 1947-2022.

RESULTS

23 research papers, with data from 2648 clinically diagnosed and 171 pathologically verified cases of MSA were included, along with 238 controls. Mean age for MSA cases was 61.3 (9.2) years, mean disease duration 3.6 (2.7) years. 57.9% were male. Our analysis showed that the prevalence of cognitive issues in MSA varied widely (between 15-100%); dementia per se was uncommon, but assessment in advanced stages of MSA is impacted by unintelligible speech (which may be noted in a quarter of cases). The prevalence of depressive symptoms in MSA was between 44-88%. Sleep disturbances were reported by 17-89%, with REM-sleep behaviour disorder (RBD) rates as high as 75%. Pain was reported by 40-47% of patients: rheumatic or musculoskeletal sources of pain being commonest. Fatigue was reported by 29-60% of patients. Symptoms of autonomic failure in MSA were seen in 34-96.5% patients at baseline.

CONCLUSION

In routine clinical practice, NMS in MSA are under-recognised by clinicians. These impact hugely on patient quality of life and contribute to their overall morbidity. A methodical ascertainment of these complaints will address an unmet need, and lead to a more holistic approach of care for individuals with MSA.

Neurological update: non-motor symptoms in atypical parkinsonian syndromes

Among people with Parkinson's disease (PD), non-motor symptoms (NMS) are a well-recognised cause of significant morbidity and poor quality of life. Yet, it is only more recently that NMS have been recognised to affect the lives of patients with atypical parkinsonian syndromes in a similar fashion. The aim of this article is to highlight and compare the relative prevalence of NMS among patients with atypical parkinsonian syndromes in the published literature, which largely remain underreported and unaddressed in routine clinical practice. All NMS that are recognised to occur in PD are also found to commonly occur in atypical parkinsonian syndromes. In particular, excessive daytime sleepiness is more prevalent among atypical parkinsonian syndromes (94.3%) compared to PD (33.9%) or normal controls (10.5%) (p < 0.001). Urinary dysfunction (not limited to urinary incontinence) is not only found to occur in MSA (79.7%) and PD (79.9%), but has also been reported in nearly half of the patients with PSP (49.3%), DLB (42%) and CBD (53.8%) (p < 0.001). Apathy is significantly more common among the atypical parkinsonian syndromes [PSP (56%), MSA (48%), DLB (44%), CBD (43%)] compared to PD (35%) (p = 0.029). Early recognition and addressing of NMS among atypical parkinsonian syndromes may help improve the holistic patient care provided and may encompass a range of conservative and pharmacotherapeutic treatments to address these symptoms.

Functional Neurologic Disorders, disorders to be managed by neurologists, or are neurologists wandering in a dangerous field with inadequate resources?

In recent years, some neurologists reconsidered their approach to Medically Unexplained Symptoms and proposed Functional Neurologic Disorders (FND) as a new entity, claiming that neurology could offer alternative treatment options to the psychotherapies provided in psychiatry settings. FNDs, for this purpose, should include only the disorders listed as Conversion from the Somatic Symptom and Related Disorders (SSRD) group. The present review analyzes the rationale of this position and challenges the arguments provided for its support. The review also discusses the systematization of these disorders as provided by public health systems. It outlines risks stemming from economic support and public funding uncertainty, given their negligible epidemiological dimensions resulting from the parcellation of SSRD. The review underlines the unresolved issue of Factitious Disorders, which are in the same SSRD category of the international classification but are, nonetheless, overlooked by the theoretical proponents of the FND entity. Comorbidity with other psychiatric disorders is also analyzed. We propose a model that supports the continuum between different SSRD conditions, including Factitious Disorders. The model is based on the emergence of feigned death reflex and deception from frontal lobe dysfunction. Finally, the paper summarizes the wealth of historical psychiatric and psychodynamic approaches and critical reviews. The study also puts in context the categorization and interpretation efforts provided by the most eminent researchers of the past century.

Neurological update: structural and functional imaging in epilepsy surgery

Structural and functional imaging prior to surgery in drug-resistant focal epilepsy, has an important role to play alongside electroencephalography (EEG) techniques, in planning the surgical approach and predicting post-operative outcome. This paper reviews the role of structural and functional imaging of the brain, namely computed tomography (CT), magnetic resonance imaging (MRI), functional MRI (fMRI), single photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging in the preoperative work-up of people with medically refractory epilepsy. In MRI-negative patients, the precise localisation of the epileptogenic zone may be established by demonstrating hypometabolism on PET imaging or hyperperfusion on SPECT imaging in the area surrounding the seizure focus. These imaging modalities are far less invasive than intracranial EEG, which is the gold standard but requires surgical placement of electrodes or recording grids. Even when intracranial EEG is needed, PET or SPECT imaging can assist in the planning of EEG electrode placement, due to its' limited spatial sampling. Multimodal imaging techniques now allow the multidisciplinary epilepsy surgery team to identify and better characterise focal pathology, determine its' relationship to eloquent areas of the brain and the degree of interconnectedness within both physiological and pathological networks, as well as improve planning and surgical outcomes for patients. This paper will update the reader on this whole field and provide them with a practical guide, to aid them in the selection of appropriate investigations, interpretation of the findings and facilitating patient discussions in individuals with drug-resistant focal epilepsy.

Striatal dopamine loss in early Parkinson's disease: systematic review and novel analysis of dopamine transporter imaging

Background

Neuropathological studies, based on small samples, suggest that symptoms of Parkinson's disease (PD) emerge when dopamine/nigrostriatal loss is around 50-80%. Functional neuroimaging can be applied in larger numbers during life, which allows analysis of the extent of dopamine loss more directly.

Objective

To quantify dopamine transporter (DaT) activity by neuroimaging in early PD.

Methods

Systematic review and novel analysis of DaT imaging studies in early PD.

Results

In our systematic review, in 423 unique cases from 27 studies with disease duration of less than 6 years, mean age 58.0 (SD 11.5) years, and mean disease duration 1.8 (SD 1.2) years, striatal loss was 43.5% (95% CI 41.6, 45.4) contralaterally, and 36.0% (95% CI 33.6, 38.3) ipsilaterally. For unilateral PD, in 436 unique cases, mean age 57.5 (SD 10.2) years, and mean disease duration 1.8 (SD 1.4) years, striatal loss was 40.6% (95% CI 38.8, 42.4) contralaterally, and 31.6% (95% CI 29.4, 33.8) ipsilaterally. In our novel analysis of the Parkinson's Progressive Marker Initiative study, 413 cases had 1436 scans performed. For a disease duration of less than 1 year, age was 61.8 (SD 9.8) years, and striatal loss was 51.2% (95% CI 49.1, 53.3) contralaterally and 39.5% (36.9, 42.1) ipsilaterally, giving an overall striatal loss of 45.3% (43.0, 47.6).

Conclusions

Loss of striatal DaT activity in early PD is less at 35-45%, rather than the 50-80% striatal dopamine loss estimated to be present at the time of symptom onset, based on backwards extrapolation from autopsy studies.

Conus medullaris syndrome as a presenting feature of MOG-associated disease

We report a case of conus medullaris syndrome presenting with lower limb and bladder symptoms. MR imaging showed an abnormality in the lowest part of the spinal cord as a first presentation of myelin oligodendrocyte glycoprotein (MOG)-associated disease. While such cord swelling can mimic a tumour, these patients respond well to corticosteroids, with good outcomes. MOG-associated disease is an immune-mediated syndrome distinct from aquaporin 4 antibody positive neuromyelitis optica syndrome and is now considered an independent entity. Although there can be overlapping phenotypes, there are also differences, and MOG-associated disease generally has a much better prognosis compared with aquaporin 4 antibody-positive neuromyelitis optica syndrome.

A Systematic Review of the Spectrum and Prevalence of Non-Motor Symptoms in Adults with Hereditary Cerebellar Ataxias

Background

Cerebellar ataxias comprise a large group of heterogeneous disorders with both motor and non-motor symptoms (NMS).

Objective

We wanted to ascertain the reported prevalence of NMS in different subtypes of hereditary cerebellar ataxias.

Methods

Systematic review of studies of hereditary cerebellar ataxias (involving >5 patients) who were assessed for NMS, published in the English literature in PUBMED and EMBASE databases from 1947 to 2021.

Results

A total of 35 papers, with data from 1311 autosomal dominant spinocerebellar ataxia (SCA), 893 autosomal recessive cerebellar ataxia (ARCA), and 53 X-linked ataxia cases were included with a total of 450 controls. Mean age for SCA cases at diagnosis was 47.6 (SD, 14.9) years, for ARCA cases was 34.6 (SD, 14.7) years and for X-linked ataxia cases was 68.6 (9.1) years. The prevalence of cognitive problems in SCAs was between 23% and 75% (ranging from mild to severe), being least prevalent in SCA6. The prevalence of depression in SCAs was between 13% and 69% and sleep disorders were between 7% and 80%. Pain was reported by 18% to 60% of patients, especially in SCA3, and fatigue by 53% to 70%. The prevalence of reported cognitive dysfunction in ARCA was 12.5% to 100% and depression between 14% and 51%. The prevalence of anxiety in X-linked ataxias (FXTAS) was 17 % and depression 55%.

Conclusions

The presence of NMS in hereditary cerebellar ataxias is common. The prevalence and spectrum of NMS in SCAs, ARCAs, and X-linked ataxias vary. In routine clinical practice, NMS in cerebellar ataxias are under-recognized and certainly under-reported. Therefore, they are unlikely to be addressed adequately. Improved ascertainment of NMS in cerebellar ataxias in clinical practice will enable holistic treatment of these patients.

Genetics of validated Parkinson's disease subtypes in the Oxford Discovery and Tracking Parkinson's cohorts

OBJECTIVES

To explore the genetics of four Parkinson's disease (PD) subtypes that have been previously described in two large cohorts of patients with recently diagnosed PD. These subtypes came from a data-driven cluster analysis of phenotypic variables.

METHODS

We looked at the frequency of genetic mutations in glucocerebrosidase (GBA) and leucine-rich repeat kinase 2 against our subtypes. Then we calculated Genetic Risk Scores (GRS) for PD, multiple system atrophy, progressive supranuclear palsy, Lewy body dementia, and Alzheimer's disease. These GRSs were regressed against the probability of belonging to a subtype in the two independent cohorts and we calculated q-values as an adjustment for multiple testing across four subtypes. We also carried out a Genome-Wide Association Study (GWAS) of belonging to a subtype.

RESULTS

A severe disease subtype had the highest rates of patients carrying GBA mutations while the mild disease subtype had the lowest rates (p=0.009). Using the GRS, we found a severe disease subtype had a reduced genetic risk of PD (p=0.004 and q=0.015). In our GWAS no individual variants met genome wide significance (<5×10e-8) although four variants require further follow-up, meeting a threshold of <1×10e-6.

CONCLUSIONS

We have found that four previously defined PD subtypes have different genetic determinants which will help to inform future studies looking at underlying disease mechanisms and pathogenesis in these different subtypes of disease.

Amyloid-beta-related angiitis: a treatable rapidly progressive dementia

A 73-year-old woman developed cognitive decline over 1 year. MR scan of the brain showed a focal asymmetrical leukoencephalopathy involving the right frontal, temporal, parietal and occipital lobes. Extensive laboratory investigations found no cause but brain biopsy identified amyloid-beta-related angiitis (ABRA), a potentially treatable cause of rapid-onset dementia. We gave intravenous methylprednisolone and then two courses of intravenous cyclophosphamide, after which her cognitive skills gradually but significantly improved over several months.

[Clinical relevance of the new S3 guideline on hepatocellular carcinoma and biliary tract cancer for practitioners]

The update of the S3 German guideline for the management of the hepatocellular carcinoma and biliary tract cancer contains a comprehensive revision of the guideline for hepatocellular carcinoma and establishes a new guideline for biliary tract cancer. In recent years several studies have been conducted to improve diagnostic and therapeutic options for liver cancer. Magnetic resonance imaging (MRI) and biopsy are important for the diagnosis of hepatocellular carcinoma or cholangiocarcinoma. This guideline shows the progress in the treatment options for hepatocellular carcinoma, including advances in liver transplantation, bridging and downstaging. For cholangiocarcinoma there is a focus on interventional treatment and resection. This guideline also emphasizes the need of molecular diagnostics and the resulting treatment options in targeted therapy.

Butane Toxicity: The Curse of Volatile Solvent Abuse

We discuss the presentation and management of a young person who presented to the emergency department with butane toxicity. A delay in recognition of butane toxicity can have fatal consequences. On the contrary, prompt recognition of the clinical scenario by physicians can lead to early commencement of appropriate treatment with a potential for full recovery.

Comparison between four published definitions of hyposmia in Parkinson's disease

OBJECTIVES

Hyposmia is a common feature of Parkinson's disease (PD), yet there is no standard method to define it. A comparison of four published methods was performed to explore and highlight differences.

MATERIALS AND METHODS

Olfactory testing was performed in 2097 cases of early PD in two prospective studies. Olfaction was assessed using various cut-offs, usually corrected by age and/or gender. Control data were simulated based on the age and gender structure of the PD cases and published normal ranges. Association with age, gender, and disease duration was explored by method and study cohort. Prevalence of hyposmia was compared with the age and gender-matched simulated controls. Between method agreement was measured using Cohen's kappa and Gwet's AC1.

RESULTS

Hyposmia was present in between 69.1% and 97.9% of cases in Tracking Parkinson's cases, and between 62.2% and 90.8% of cases in the Parkinson's Progression Marker Initiative, depending on the method. Between-method agreement varied (kappa 0.09-0.80, AC1 0.55-0.86). The absolute difference between PD cases and simulated controls was similar for men and women across methods. Age and male gender were positively associated with hyposmia (p < .001, all methods). Odds of having hyposmia increased with advancing age (OR:1.06, 95% CI:1.03, 1.10, p < .001). Longer disease duration had a negative impact on overall olfactory performance.

CONCLUSIONS

Different definitions of hyposmia give different results using the same dataset. A standardized definition of hyposmia in PD is required, adjusting for age and gender, to account for the background decline in olfactory performance with ageing, especially in men.

Winning hearts and minds: ECG reporting in the first seizure clinic

BACKGROUND AND AIMS

An electrocardiogram (ECG) is a mandatory test for anyone presenting with loss of consciousness. Many referrals to the first seizure clinic (FSC) are caused by syncope. We assessed the sensitivity of neurologists' ECG reporting in detecting rhythm abnormalities including some potentially life-threatening cardiac conditions.

METHODS

We audited patients referred to a FSC in Glasgow over 4 years. All ECGs were interpreted by the attending neurologist as standard practice. Subsequently, two cardiologists reviewed the ECGs independently.

RESULTS

Of 160 consecutive patients, 92 patients (58%) were diagnosed as having seizures, 43 (27%) as syncope, and 25 (16%) were unclassified. Twenty eight ECGs thought to be normal by the neurologist were considered abnormal by the cardiologist, including three with long corrected QT interval. The proportion of abnormal ECGs and disparity in reporting between neurologists and cardiologists persisted independent of the underlying diagnosis.

CONCLUSION

Reporting of ECGs by non-cardiologists may not be adequately sensitive in picking up potentially life threatening cardiac conditions. Cardiologist input into FSCs is recommended to enhance the diagnostic yield.

Genome-Wide Association Studies of Cognitive and Motor Progression in Parkinson's Disease

BACKGROUND

There are currently no treatments that stop or slow the progression of Parkinson's disease (PD). Case-control genome-wide association studies have identified variants associated with disease risk, but not progression. The objective of the current study was to identify genetic variants associated with PD progression.

METHODS

We analyzed 3 large longitudinal cohorts: Tracking Parkinson's, Oxford Discovery, and the Parkinson's Progression Markers Initiative. We included clinical data for 3364 patients with 12,144 observations (mean follow-up 4.2 years). We used a new method in PD, following a similar approach in Huntington's disease, in which we combined multiple assessments using a principal components analysis to derive scores for composite, motor, and cognitive progression. These scores were analyzed in linear regression in genome-wide association studies. We also performed a targeted analysis of the 90 PD risk loci from the latest case-control meta-analysis.

RESULTS

There was no overlap between variants associated with PD risk, from case-control studies, and PD age at onset versus PD progression. The APOE ε4 tagging variant, rs429358, was significantly associated with composite and cognitive progression in PD. Conditional analysis revealed several independent signals in the APOE locus for cognitive progression. No single variants were associated with motor progression. However, in gene-based analysis, ATP8B2, a phospholipid transporter related to vesicle formation, was nominally associated with motor progression (P = 5.3 × 10^-6 ).

CONCLUSIONS

We provide early evidence that this new method in PD improves measurement of symptom progression. We show that the APOE ε4 allele drives progressive cognitive impairment in PD. Replication of this method and results in independent cohorts are needed. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Genetic analysis of Mendelian mutations in a large UK population-based Parkinson's disease study

Our objective was to define the prevalence and clinical features of genetic Parkinson’s disease in a large UK population-based cohort, the largest multicentre prospective clinico-genetic incident study in the world. We collected demographic data, Movement Disorder Society Unified Parkinson’s Disease Rating Scale scores, and Montreal Cognitive Assessment scores. We analysed mutations in PRKN (parkin), PINK1, LRRK2 and SNCA in relation to age at symptom onset, family history and clinical features. Of the 2262 participants recruited to the Tracking Parkinson’s study, 424 had young-onset Parkinson’s disease (age at onset ≤ 50) and 1799 had late onset Parkinson’s disease. A range of methods were used to genotype 2005 patients: 302 young-onset patients were fully genotyped with multiplex ligation-dependent probe amplification and either Sanger and/or exome sequencing; and 1701 late-onset patients were genotyped with the LRRK2 ‘Kompetitive’ allele-specific polymerase chain reaction assay and/or exome sequencing (two patients had missing age at onset). We identified 29 (1.4%) patients carrying pathogenic mutations. Eighteen patients carried the G2019S or R1441C mutations in LRRK2, and one patient carried a heterozygous duplication in SNCA. In PRKN, we identified patients carrying deletions of exons 1, 4 and 5, and P113Xfs, R275W, G430D and R33X. In PINK1, two patients carried deletions in exon 1 and 5, and the W90Xfs point mutation. Eighteen per cent of patients with age at onset ≤30 and 7.4% of patients from large dominant families carried pathogenic Mendelian gene mutations. Of all young-onset patients, 10 (3.3%) carried biallelic mutations in PRKN or PINK1. Across the whole cohort, 18 patients (0.9%) carried pathogenic LRRK2 mutations and one (0.05%) carried an SNCA duplication. There is a significant burden of LRRK2 G2019S in patients with both apparently sporadic and familial disease. In young-onset patients, dominant and recessive mutations were equally common. There were no differences in clinical features between LRRK2 carriers and non-carriers. However, we did find that PRKN and PINK1 mutation carriers have distinctive clinical features compared to young-onset non-carriers, with more postural symptoms at diagnosis and less cognitive impairment, after adjusting for age and disease duration. This supports the idea that there is a distinct clinical profile of PRKN and PINK1-related Parkinson’s disease. We estimate that there are approaching 1000 patients with a known genetic aetiology in the UK Parkinson’s disease population. A small but significant number of patients carry causal variants in LRRK2, SNCA, PRKN and PINK1 that could potentially be targeted by new therapies, such as LRRK2 inhibitors.

Deep Brain Stimulation in Parkinson's Disease

Deep brain stimulation (DBS) has become an established therapeutic tool for treating patients with Parkinson's disease (PD) who have troublesome motor fluctuations and dyskinesias refractory to best medical therapy. In addition to its proven efficacy in patients with late PD, the EARLYSTIM trial not only demonstrated the efficacy of DBS in patients with early motor complications but also showed that it did not lose its therapeutic efficacy as the years passed by. However, like all other therapies for PD, DBS is not offered to patients either as a cure for this disease nor is it expected to stop the progression of the neurodegenerative process underlying PD; these important issues need to be highlighted to patients who are considering this therapy. This article aims to provide an introduction to residents or trainees starting a career in movement disorders of the technical aspects of this therapy and the evidence base for its use. For the latter objective, PUBMED was searched from 1946 to 2017 combining the search terms "deep brain stimulation" and "Parkinson's disease" looking for studies demonstrating the efficacy of this therapy in PD. Inclusion criteria included studies that involved more than 20 patients with a physician confirmed diagnosis of PD and a follow-up of greater than or equal to at least 12 months. The findings from those studies on motor symptoms, medication requirements, quality of life, and independence in activities of daily living in PD patients are summarized and presented in tabulated form in this paper at the end.

The Levodopa Response Varies in Pathologically Confirmed Parkinson's Disease: A Systematic Review

Background

A good response to levodopa is a key feature of Parkinson's disease (PD), and a poor response suggests an alternative diagnosis, but the extent of variation in the levodopa response in definite PD is not well defined.

Literature Review

A systematic review of articles reporting pathologically confirmed PD and levodopa responsiveness from 1971 to 2018 was performed using the medical subheadings "postmortem," "Parkinson's disease," "levodopa," and "l-dopa" in PubMed, Embase, and Latin American and Caribbean Health Sciences Literature (LILACS) databases.

Cases

A total of 12 articles described 445 PD cases: 61.7% male, age at disease onset 64.0 years (SD 9.6), age at death 77.1 years (SD 7.2). Levodopa responsiveness was reported in 399 cases (89.7%) either as a graded or a binary response. In the 280 cases (70.2%) describing a graded response, it was excellent in 37.5%, good in 45.7%, moderate in 12.1%, and poor in 4.6%. In the 119 cases describing a binary response (29.8%), 73.1% were levodopa responsive, and 26.9% were nonresponsive. Comorbid brain pathology was present in 137 of 235 cases assessed, being cerebrovascular in 46.0% and Alzheimer's disease in 37.2% of these, but its contribution to levodopa responsiveness was unclear.

Conclusions

The levodopa motor response varies in definite PD. Explanations other than diagnostic inaccuracy should be explored.

Neuropathology of dementia in patients with Parkinson's disease: a systematic review of autopsy studies

BACKGROUND

Dementia is a common, debilitating feature of late Parkinson's disease (PD). PD dementia (PDD) is associated with α-synuclein propagation, but coexistent Alzheimer's disease (AD) pathology may coexist. Other pathologies (cerebrovascular, transactive response DNA-binding protein 43 (TDP-43)) may also influence cognition. We aimed to describe the neuropathology underlying dementia in PD.

METHODS

Systematic review of autopsy studies published in English involving PD cases with dementia. Comparison groups included PD without dementia, AD, dementia with Lewy bodies (DLB) and healthy controls.

RESULTS

44 reports involving 2002 cases, 57.2% with dementia, met inclusion criteria. While limbic and neocortical α-synuclein pathology had the strongest association with dementia, between a fifth and a third of all PD cases in the largest studies had comorbid AD. In PD cases with dementia, tau pathology was moderate or severe in around a third, and amyloid-β pathology was moderate or severe in over half. Amyloid-β was associated with a more rapid cognitive decline and earlier mortality, and in the striatum, distinguished PDD from DLB. Positive correlations between multiple measures of α-synuclein, tau and amyloid-β were found. Cerebrovascular and TDP-43 pathologies did not generally contribute to dementia in PD. TDP-43 and amyloid angiopathy correlated with coexistent Alzheimer pathology.

CONCLUSIONS

While significant α-synuclein pathology is the main substrate of dementia in PD, coexistent pathologies are common. In particular, tau and amyloid-β pathologies independently contribute to the development and pattern of cognitive decline in PD. Their presence should be assessed in future clinical trials where dementia is a key outcome measure.

TRIAL REGISTRATION NUMBER

CRD42018088691.

Cephalic tetanus presenting with bilateral facial palsy

We discuss the case and differential diagnoses of an elderly man who presented with bilateral facial palsy. He had injured his forehead in the garden during a fall on his face and the open wound was contaminated by soil. He then presented to the emergency department with facial weakness causing difficulty speaking. The penny dropped when he started developing muscle spasms affecting his lower jaw a day after admission. It also became clear that he could not open his mouth wide (lock jaw). The combination of muscle spasms and lock jaw (trismus) made tetanus the most likely possibility, and this was proven when he had samples taken from his wound and analysed under the microscope, which showed Clostridium tetani bacilli. C. tetani spores are widespread in the environment, including in the soil, and can survive hostile conditions for long periods of time. Transmission occurs when spores are introduced into the body, often through contaminated wounds. Tetanus in the United Kingdom is rare, but can prove fatal if there is a delay in recognition and treatment.

Developing and validating Parkinson's disease subtypes and their motor and cognitive progression

OBJECTIVES

To use a data-driven approach to determine the existence and natural history of subtypes of Parkinson's disease (PD) using two large independent cohorts of patients newly diagnosed with this condition.

METHODS

1601 and 944 patients with idiopathic PD, from Tracking Parkinson's and Discovery cohorts, respectively, were evaluated in motor, cognitive and non-motor domains at the baseline assessment. Patients were recently diagnosed at entry (within 3.5 years of diagnosis) and were followed up every 18 months. We used a factor analysis followed by a k-means cluster analysis, while prognosis was measured using random slope and intercept models.

RESULTS

We identified four clusters: (1)  fast motor progression with symmetrical motor disease, poor olfaction, cognition and postural hypotension; (2) mild motor and non-motor disease with intermediate motor progression; (3) severe motor disease, poor psychological well-being and  poor sleep with an intermediate motor progression; (4) slow motor progression with tremor-dominant, unilateral disease. Clusters were moderately to substantially stable across the two cohorts (kappa 0.58). Cluster 1 had the fastest motor progression in Tracking Parkinson's at 3.2 (95% CI 2.8 to 3.6) UPDRS III points per year while cluster 4 had the slowest at 0.6 (0.1-1.1). In Tracking Parkinson's, cluster 2 had the largest response to levodopa 36.3% and cluster 4 the lowest 28.8%.

CONCLUSIONS

We have found four novel clusters that replicated well across two independent early PD cohorts and were associated with levodopa response and motor progression rates. This has potential implications for better understanding disease pathophysiology and the relevance of patient stratification in future clinical trials.

THUR 117 The L-DOPA response in pathologically confirmed parkinson’s disease

Background

l-dopa is the standard treatment for Parkinson’s disease, but the response is variable.

Aim

Systematic review of papers reporting the l-dopa response (motor response and/or complications) in pathologically confirmed Parkinson’s disease.

Results

467 cases of pathologically confirmed Parkinson’s were identified: 60.2% male, age at disease onset 63.3 years (SD 10.3), age at death 76.7 years (SD 7.8). Data on a graded l-dopa response were available in 411 cases (88.0% of 467). The motor response was excellent in 148/411 cases (36.0%), good in 179/411 (43.6%), moderate in 51/411 (12.4%) and poor/absent in 33/411 (8.0%). Data about motor complications were available for 161 patients: 71/161 (44.1%) had motor fluctuations and 89/161 (55.3%) had dyskinesia. Comorbid brain pathology was evaluated in 251/411 cases (61.1%), and was present in 148/251 (59.0%): cerebrovascular in 65/148 (43.9%), Alzheimer’s in 55/148 (37.2%), amyloid angiopathy in 18/148 (12.2%), and diffuse Lewy body disease in 10/148 (6.8%). Data linking the graded l-dopa response to comorbid pathologies were available in only 17 cases, of whom 8/17 (47.1%) had a good/excellent response.

Conclusion

There is variation in the l-dopa response in pathologically confirmed Parkinson’s disease. The limited available information suggests a possible association of motor response to comorbid brain pathology.

AL amyloidosis presenting with limb girdle myopathy

An elderly Caucasian man presented with a 10-month history of proximal myopathy and dysphagia. His serum creatine kinase (CK) was elevated at 877 U/L (normal 40-320) and electromyography confirmed a myopathic process. Blood and urine tests suggested myeloma; bone marrow examination showed 30% plasma cells and stained positive for amyloid. The muscle biopsy was initially reported as normal but in the light of the bone marrow report, the biopsy specimen was stained for amyloid, which was positive. We diagnosed systemic amyloidosis causing a myopathy and have started treatment for myeloma.

Features of GBA-associated Parkinson's disease at presentation in the UK Tracking Parkinson's study

OBJECTIVES

To examine the influence of the glucocerebrosidase (GBA) mutation carrier state on age at onset of Parkinson's disease (PD), the motor phenotype and cognitive function at baseline assessment in a large cohort of UK patients. We also analysed the prevalence of mood and behavioural problems that may confound the assessment of cognitive function.

METHODS

We prospectively recruited patients with PD in the Tracking Parkinson's study. We fully sequenced the GBA gene in all recently diagnosed patients (≤3.5 years). We examined cognitive (Montreal Cognitive Assessment) and motor (Movement Disorder Society Unified Parkinson's Disease Rating Scale part 3) function at a baseline assessment, at an average of 1.3 years after diagnosis. We used logistic regression to determine predictors of PD with mild cognitive impairment and PD with dementia.

RESULTS

We studied 1893 patients with PD: 48 (2.5%) were heterozygous carriers for known Gaucher's disease (GD) causing pathogenic mutations; 117 (6.2%) had non-synonymous variants, previously associated with PD, and 28 (1.5%) patients carried variants of unknown significance in the GBA gene. L444P was the most common pathogenic GBA mutation. Patients with pathogenic GBA mutations were on average 5 years younger at disease onset compared with non-carriers (P=0.02). PD patients with GD-causing mutations did not have an increased family risk of PD. Patients with GBA mutations were more likely to present with the postural instability gait difficulty phenotype compared with non-carriers (P=0.02). Patients carrying pathogenic mutations in GBA had more advanced Hoehn and Yahr stage after adjustment for age and disease duration compared with non-carriers (P=0.005). There were no differences in cognitive function between GBA mutation carriers and non-carriers at this early disease stage.

CONCLUSIONS

Our study confirms the influence of GBA mutations on the age of onset, disease severity and motor phenotype in patients with PD. Cognition did not differ between GBA mutation carriers and non-carriers at baseline, implying that cognitive impairment/dementia, reported in other studies at a later disease stage, is not present in recently diagnosed cases. This offers an important window of opportunity for potential disease-modifying therapy that may protect against the development of dementia in GBA-PD.

CLINICAL TRIAL REGISTRATION

NCT02881099; Results.

Trismus caused by paraneoplastic brainstem encephalitis

We discuss the assessment and differential diagnoses of a middle-aged man who presented with trismus, double vision and behavioural problems. MRI scan of the brain was initially normal, but a month later showed high signal in the hippocampal region on fluid attenuated inversion recovery sequence (FLAIR) imaging. We suspected a paraneoplastic brainstem encephalitis because of his smoking history, rapidly progressive symptoms and abnormal brainstem signs. A positron emission tomography-CT scan identified abnormal subcarinal nodes, shown on biopsy to be metastatic small cell lung cancer. He is currently undergoing treatment with chemotherapy and radiotherapy.

Rare case of atypical parkinsonism: why family history is important

We discuss the clinical presentation and assessment of a middle aged previously fit and well man who presented with two episodes of syncope to the cardiologists followed by the development of a rapidly progressive parkinsonian syndrome a couple of years later, which was not responsive to standard dopaminergic replacement therapies. Magnetic resonance imaging scan of the brain was normal and a DAT SPECT scan showed reduced dopamine uptake in the basal ganglia. On further enquiry, a family history of a similar presentation in his first cousin was elicited and that cousin had tested positive for a mutation in the PRNP gene. Subsequently, he also tested positive for A117V mutation in the PRNP gene, confirming familial Creutzfeld Jakob disease. Familial Creutzfeld Jakob disease presenting with parkinsonism is rare in clinical practice, but it is something that neurologists and geriatricians running movement disorder clinics should be aware of, as this is a rapidly progressive and uniformly fatal condition with inheritance risks to family members.

Variation in Recent Onset Parkinson's Disease: Implications for Prodromal Detection

BACKGROUND

The detection of prodromal Parkinson's disease (PD) is desirable to test drugs with neuroprotective potential, but will be affected by known disease variations.

OBJECTIVE

To assess the prevalence of four key non-motor prodromal PD markers, and evaluate the sensitivity of case detection when non-motor screening tools for prodromal PD are implemented in an early clinical PD cohort.

METHODS

Hyposmia (University of Pennsylvania smell identification test ≤15th centile or Sniffin' Sticks at or ≤10th centile corrected for age and sex), rapid-eye movement sleep behaviour disorder (RBD questionnaire >4), constipation (<1 daily spontaneous bowel motion) and depression (Leeds >6) were recorded in recent onset PD cases, and proposed non-motor screening criteria applied.

RESULTS

In 1,719 PD cases, mean age 68.6 years (SD 8.1), 65.5% male, mean disease duration 1.3 years (SD 0.9), 72.2% were hyposmic, 43.3% had RBD, 22.1% depression, and 21.5% constipation. 11.6% of cases had no key non-motor features, 38.8% one, 32.1% two, 15.5% three, and 2.0% all four. Increasing numbers of non-motor features were associated with younger age (p = 0.019), higher motor scores (p < 0.001), more postural instability gait difficulty (PIGD) (p < 0.001), greater cognitive impairment (p < 0.001) and higher total non-motor burden (p < 0.001). Cases with hyposmia alone were younger (p < 0.001), had less severe cognitive (p = 0.006) and other non-motor features (p < 0.001). All screening criteria selected younger patients (p = 0.001, p < 0.001), three of four greater overall non-motor burden (p = 0.005, p < 0.001), and inclusion of RBD more cognitive impairment (p = 0.003, p = 0.001) and PIGD (p = 0.004, p = 0.001).

CONCLUSIONS

Varying sensitivity levels, and age and phenotype selectivity, are found when different non-motor screening methods to detect prodromal PD are applied to an early clinical PD cohort.

Autonomic Dysfunction in Early Parkinson's Disease: Results from the United Kingdom Tracking Parkinson's Study

BACKGROUND

Autonomic dysfunction is common in the later stages of Parkinson's disease (PD), but less is known about its presence and severity in early disease.

OBJECTIVE

To analyze features of autonomic dysfunction in recent onset PD cases, and their relationship to motor severity, medication use, other nonmotor symptoms (NMS), and quality-of-life scores.

METHODS

Detailed patient-reported symptoms of autonomic dysfunction were assessed in a multicenter cohort study in PD cases that had been diagnosed within the preceding 3.5 years.

RESULTS

There were 1746 patients (1132 males, 65.2%), mean age 67.6 years (SD 9.3), mean disease duration 1.3 years (SD 0.9), mean Movement Disorder Society Unified Parkinson's Disease Rating Scale motor score 22.5 (SD 12.1). Orthostatic symptoms were reported by 39.6%, male erectile dysfunction by 56.1%, and female anorgasmia by 57.4%. Sialorrhea was an issue in 51.4% of patients, constipation in 43.6%, and dysphagia in 20.1%. Autonomic features increased with higher modified Hoehn and Yahr stages (P < 0.001). The severity of autonomic dysfunction was associated with the postural instability gait difficulty motor phenotype [β-coefficient 1.7, 95% confidence interval (CI) 0.7, 2.6, P < 0.001], depression (β-coefficient 4.1, CI 3.0, 5.2, P < 0.001), and excess daytime sleepiness (β-coefficient 3.1, CI 1.9, 4.2, P < 0.001). Dopamine agonists were the only drug class associated with greater autonomic dysfunction (P = 0.019). The severity of autonomic dysfunction strongly correlated with the presence of other NMS (ρ = 0.717, P < 0.001), and with poorer quality-of-life scores (ρ = 0.483, P < 0.001).

CONCLUSIONS

Autonomic dysfunction is common in early PD. Autonomic dysfunction correlates with the presence of other NMS, and with worse quality of life.

Common toxidromes in movement disorder neurology

BACKGROUND

Physicians can come across patients who are exposed to certain prescription drugs or toxins that can result in adverse effects and complications which have high rates of morbidity and mortality.

OBJECTIVE

To summarise the key clinical features and management of the common movement disorder toxidromes relevant to physicians (with an interest in neurology).

METHODS

We searched PUBMED from 1946 to 2016 for papers relating to movement toxidromes and their treatment. The findings from those studies were then summarised and are presented here.

RESULTS

The key features of 6 of the common movement disorder toxidromes and their treatment are tabulated and highlighted. The management of toxidromes with the highest mortality like neuroleptic malignant syndrome and serotonin syndrome are discussed in detail.

CONCLUSION

There are several toxidromes that have the potential to become a serious life-threatening emergency if there is a delay in recognition of key clinical features and instituting the appropriate treatment at the earliest is crucial.

A review of medication adherence in people with epilepsy

People with epilepsy (PWE) have a higher risk of mortality in comparison with the general population. This in part reflects intrinsic factors or associated comorbidities, but poor adherence to anti-epileptic drugs (AED) has also been shown to contribute to increased risk of death and increased utilization of unscheduled care. The aim of this review was to determine the prevalence of non-adherence to AED in PWE, evaluate whether specific clinical and demographic features can allow clinicians to identify those at highest risk and identify the methods and techniques that can be used to improve adherence in clinical settings. We identified relevant studies for the prevalence of medication non-adherence in PWE by searching MEDLINE (1946-7 Dec 2015), EMBASE (1947-7 Dec 2015) and Cochrane Library (1946-7 Dec 2015) as per predefined inclusion and exclusion criteria. We included 17 research studies from our review of the medical literature to determine the prevalence of medication non-adherence in epilepsy. The prevalence of significant medication non-adherence in epilepsy has been reported to vary between 26% and 79%. This variation partly reflects the differences in defining what clinically significant medication adherence is, the methods used to estimate the scale of the problem and the underlying population heterogeneity. A number of clinical and demographic features have been associated with poor adherence allowing clinicians to identify those at greatest risk. Educating patients and their carers about the risks associated with poor adherence, certain behavioural interventions and simplifying their drug regimens have been shown to improve adherence.

Relationship between [123 I]-FP-CIT SPECT and clinical progression in Parkinson's disease

BACKGROUND

The demonstration of presynaptic dopaminergic deficiency on [¹²³ I]-FP-CIT SPECT imaging is a useful ancillary tool in the diagnosis of Parkinson's disease (PD). Whilst there is evidence of a cross-sectional relationship between the degree of dopaminergic deficiency and severity of bradykinesia and rigidity, longitudinal studies are rare. Moreover, the relationship between motor subtypes and their dopaminergic deficient state is not well characterized.

AIM

Our primary aim was to assess the correlations between dopaminergic deficiency on baseline [¹²³ I]-FP-CIT SPECT imaging with the progression of motor severity in patients classified by motor subtype, and the development of motor complications. Our secondary aim was to assess the correlation between UPDRS-III subscores and the time to onset of motor complications.

METHODS

42 PD patients with abnormal baseline [¹²³ I]-FP-CIT SPECT scans and at least 3 years of clinical follow-up were classified by motor subtype: akinetic-rigid, tremor-dominant or mixed. UPDRS-III scores at baseline and at 3-year follow-up, and time to onset of motor complications were recorded.

RESULTS

[¹²³ I]-FP-CIT uptake ratios were inversely correlated with UPDRS-III scores at 3 years only in akinetic-rigid patients (r=-.51, P=.04). Time to onset of motor complications was inversely correlated with UPDRS-III subscores for bradykinesia and rigidity at baseline (r=-.52, P=.02) and at 3 years (r=-.54, P=.01).

CONCLUSION

The degree of dopaminergic deficiency on baseline [¹²³ I]-FP-CIT SPECT inversely correlates with motor severity at 3-year follow-up in akinetic-rigid patients only. Furthermore, UPDRS-III subscores for bradykinesia and rigidity at baseline show an inverse correlation with time to onset of motor complications across all PD subtypes.

Electroencephalographic markers in dementia

Dementia is a global health problem with a huge impact on the lives of those afflicted. There are several distinct diseases that are classified under the umbrella term "dementia" ranging from neurodegenerative disorders such as Alzheimer's disease to chronic infections of the central nervous system such as subacute sclerosing panencephalitis (SSPE), a rare complication of measles virus infection in childhood. Clinical features, neuropsychological profiles and imaging characteristics of the various dementia syndromes can be sufficiently distinct to distinguish them from one another. However, in some cases, the cognitive, psychiatric and behavioural features can sufficiently overlap such that neurophysiologic testing may be of help. While it is recognized the electroencephalogram (EEG) may have a special role to play in the diagnosis of certain dementing illnesses such as SSPE and Creutzfeldt-Jakob disease (CJD) that have characteristic EEG changes, current research focusses on the potential utility of quantitative EEG as one more tool in the armamentarium of clinicians dealing with patients who suffer from a dementing illness. We searched PubMed and the Cochrane Database from 1 January 1946 up to 1 January 2016, combining the search terms "EEG," "electroencephalography," "dementia" and "status epilepticus"; identified papers from these searches were then read in detail and summarized. Here, we discuss both the qualitative and quantitative EEG findings in the various types of dementia.

Hereditary chorea - what else to consider when the Huntington's disease genetics test is negative?

Chorea, cognitive, behavioural and psychiatric disturbance occur in varying combinations in Huntington's disease (HD). This is often easy to recognise particularly in the presence of an autosomal dominant history. Whilst HD may be the most common aetiology of such a presentation, several HD phenocopies should be considered if genetic testing for HD is negative. We searched PubMed and the Cochrane Database from January 1, 1946 up to January 1, 2016, combining the search terms: 'chorea', 'Huntington's disease', 'HDL' and 'phenocopies'. HD phenocopies frequently display additional movement disorders such as myoclonus, dystonia, parkinsonism and tics. Here, we discuss the phenotypes, and investigations of HD-like disorders where the combination of progressive chorea and cognitive impairment is obvious, but HD gene test result is negative. Conditions presenting with sudden onset chorea such as vascular, infectious and autoimmune causes are not the primary focus of our discussion, but we will make a passing reference to these as some of these conditions are potentially treatable. Hereditary forms of chorea are a heterogeneous group of conditions and this number is increasing. While most of these conditions are not curable, molecular genetic testing has enabled many of these disorders to be distinguished from HD. Getting a precise diagnosis may enable patients and their families to better understand the nature of their condition.

Statins are underused in recent-onset Parkinson's disease with increased vascular risk: findings from the UK Tracking Parkinson's and Oxford Parkinson's Disease Centre (OPDC) discovery cohorts

BACKGROUND

Cardiovascular disease (CVD) influences phenotypic variation in Parkinson's disease (PD), and is usually an indication for statin therapy. It is less clear whether cardiovascular risk factors influence PD phenotype, and if statins are prescribed appropriately.

OBJECTIVES

To quantify vascular risk and statin use in recent-onset PD, and examine the relationship between vascular risk, PD severity and phenotype.

METHODS

Cardiovascular risk was quantified using the QRISK2 calculator (high ≥20%, medium ≥10 and <20%, low risk <10%). Motor severity and phenotype were assessed using the Movement Disorder Society Unified PD Rating Scale (UPDRS) and cognition by the Montreal cognitive assessment.

RESULTS

In 2909 individuals with recent-onset PD, the mean age was 67.5 years (SD 9.3), 63.5% were men and the mean disease duration was 1.3 years (SD 0.9). 33.8% of cases had high vascular risk, 28.7% medium risk, and 22.3% low risk, while 15.2% of cases had established CVD. Increasing vascular risk and CVD were associated with older age (p<0.001), worse motor score (p<0.001), more cognitive impairment (p<0.001) and worse motor phenotype (p=0.021). Statins were prescribed in 37.2% with high vascular risk, 15.1% with medium vascular risk and 6.5% with low vascular risk, which compared with statin usage in 75.3% of those with CVD.

CONCLUSIONS

Over 60% of recent-onset PD patients have high or medium cardiovascular risk (meriting statin usage), which is associated with a worse motor and cognitive phenotype. Statins are underused in these patients, compared with those with vascular disease, which is a missed opportunity for preventive treatment.

TRIAL REGISTRATION NUMBER

GN11NE062, NCT02881099.

Vascular disease and vascular risk factors in relation to motor features and cognition in early Parkinson's disease

OBJECTIVE

The purpose of this study was to examine the relationship between vascular disease (and vascular risk factors), cognition and motor phenotype in Parkinson's disease (PD).

METHODS

Recently diagnosed PD cases were enrolled in a multicenter prospective observational longitudinal cohort study. Montreal cognitive assessment (normal >23, mild cognitive impairment 22 to 23 or lower but without functional impairment, and dementia 21 or less with functional impairment) and Movement Disorder Society Unified PD Rating Scale part 3 (UPDRS 3) scores were analyzed in relation to a history of vascular events and risk factors.

RESULTS

In 1759 PD cases, mean age 67.5 (standard deviation 9.3) years, mean disease duration 1.3 (standard deviation 0.9) years, 65.2% were men, 4.7% had a history of prior stroke or transient ischemic attack, and 12.5% had cardiac disease (angina, myocardial infarction, heart failure). In cases without a history of vascular disease, hypertension was recorded in 30.4%, high cholesterol 27.3%, obesity 20.7%, diabetes 7.2%, and cigarette smoking in 4.6%. Patients with prior stroke or transient ischemic attack were more likely to have cognitive impairment (42% vs 25%) and postural instability gait difficulty (53.5% vs 39.5%), but these findings were not significant after adjustment for age, sex, and disease duration (P = .075). The presence of more than 2 vascular risks was associated with worse UPDRS 3 motor scores (beta coefficient 4.05, 95% confidence interval 1.48, 6.61, p = .002) and with cognitive impairment (ordinal odds ratio 2.24, 95% confidence interval 1.34, 3.74, p = .002). In 842 patients (47.8%) with structural brain imaging, white matter leukoaraiosis, but not lacunar or territorial infarction, was associated with impaired cognition (p = .006) and postural instability gait difficulty (p = .010).

CONCLUSION

Vascular comorbidity is significantly associated with cognitive and gait impairment in patients with early PD, which may have prognostic and treatment implications. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Olfaction in Parkin single and compound heterozygotes in a cohort of young onset Parkinson's disease patients

BACKGROUND

Parkin related Parkinson's disease (PD) is differentiated from idiopathic PD by absent or sparse Lewy bodies, and preserved olfaction. The significance of single Parkin mutations in the pathogenesis of PD is debated.

OBJECTIVES

To assess olfaction results according to Parkin mutation status. To compare the prevalence of Parkin single heterozygous mutations in patients diagnosed with PD to the rate in healthy controls in order to establish whether these single mutations could be a risk factor for developing PD.

METHODS

Parkin gene mutation testing was performed in young onset PD (diagnosed <50 years old) to identify three groups: Parkin homozygous or compound heterozygote mutation carriers, Parkin single heterozygote mutation carriers, and non-carriers of Parkin mutations. Olfaction was tested using the 40-item British version of the University of Pennsylvania smell identification test (UPSIT).

RESULTS

Of 344 young onset PD cases tested, 8 (2.3%) were Parkin compound heterozygotes and 13 (3.8%) were Parkin single heterozygotes. Olfaction results were available in 282 cases (eight compound heterozygotes, nine single heterozygotes, and 265 non-carriers). In Parkin compound heterozygotes, the median UPSIT score was 33, interquartile range (IQR) 28.5-36.5, which was significantly better than in single Parkin heterozygotes (median 19, IQR 18-28) and non-carriers (median score 22, IQR 16-28) (ANOVA P < 0.001). These differences persisted after adjusting for age, disease duration, gender, and smoking (P < 0.001). There was no significant difference in UPSIT scores between single heterozygotes and non-carriers (P = 0.90).

CONCLUSIONS

Patients with Parkin compound heterozygous mutations have relatively preserved olfaction compared to Parkin single heterozygotes and non-carriers. The prevalence of Parkin single heterozygosity is similar to the 3.7% rate reported in healthy controls.

Tracking Parkinson's: Study Design and Baseline Patient Data

Background:

There is wide variation in the phenotypic expression of Parkinson’s disease (PD), which is driven by both genetic and epidemiological influences.

Objectives:

To define and explain variation in the clinical phenotype of PD, in relation to genotypic variation.

Methods:

Tracking Parkinson’s is a multicentre prospective longitudinal epidemiologic and biomarker study of PD. Patients attending specialist clinics in the United Kingdom with recent onset (<3.5 years) and young onset (diagnosed <50 years of age) PD were enrolled. Motor, non-motor and quality of life assessments were performed using validated scales. Cases are followed up 6 monthly up to 4.5 years for recent onset PD, and up to 1 year for young onset PD. We present here baseline clinical data from this large and demographically representative cohort.

Results:

2247 PD cases were recruited (1987 recent onset, 260 young onset). Recent onset cases had a mean (standard deviation, SD) age of 67.6 years (9.3) at study entry, 65.7% males, with disease duration 1.3 years (0.9), MDS-UPDRS 3 scores 22.9 (12.3), LEDD 295 mg/day (211) and PDQ-8 score 5.9 (4.8). Young onset cases were 53.5 years old (7.8) at study entry, 66.9% male, with disease duration 10.2 years (6.7), MDS-UPDRS 3 scores 27.4 (15.3), LEDD 926 mg/day (567) and PDQ-8 score 11.6 (6.1).

Conclusions:

We have established a large clinical PD cohort, consisting of young onset and recent onset cases, which is designed to evaluate variation in clinical expression, in relation to genetic influences, and which offers a platform for future imaging and biomarker research.

Equating scores of the University of Pennsylvania Smell Identification Test and Sniffin' Sticks test in patients with Parkinson's disease

Background

Impaired olfaction is an important feature in Parkinson's disease (PD) and other neurological diseases. A variety of smell identification tests exist such as “Sniffin’ Sticks” and the University of Pennsylvania Smell Identification Test (UPSIT). An important part of research is being able to replicate findings or combining studies in a meta-analysis. This is difficult if olfaction has been measured using different metrics. We present conversion methods between the: UPSIT, Sniffin’ 16, and Brief-SIT (B-SIT); and Sniffin’ 12 and Sniffin’ 16 odour identification tests.

Methods

We used two incident cohorts of patients with PD who were tested with either the Sniffin’ 16 (n = 1131) or UPSIT (n = 980) and a validation dataset of 128 individuals who took both tests. We used the equipercentile and Item Response Theory (IRT) methods to equate the olfaction scales.

Results

The equipercentile conversion suggested some bias between UPSIT and Sniffin’ 16 tests across the two groups. The IRT method shows very good characteristics between the true and converted Sniffin’ 16 (delta mean = 0.14, median = 0) based on UPSIT. The equipercentile conversion between the Sniffin’ 12 and 16 item worked well (delta mean = 0.01, median = 0). The UPSIT to B-SIT conversion showed evidence of bias but amongst PD cases worked well (mean delta = −0.08, median = 0).

Conclusion

We have demonstrated that one can convert UPSIT to B-SIT or Sniffin’ 16, and Sniffin’ 12 to 16 scores in a valid way. This can facilitate direct comparison between tests aiding future collaborative analyses and evidence synthesis.

•

Need to harmonise olfaction tests (UPSIT and Sniffin’ Sticks) for meta-analysis.

•

Use of Item Response Theory and equipercentile methods to convert scores.

•

Validation shows high concordance and little bias between true and converted scores.

•

New age and gender corrected centiles for impaired olfaction from Sniffin’ scores.