Psychogenic paroxysmal movement disorders – Clinical features and diagnostic clues

AbstractBackgroundThe diagnosis of psychogenic paroxysmal movement disorders (PPMD) can be challenging, in particular their distinction from the primary paroxysmal dyskinesias (PxD) remains difficult.MethodsHere we present a large series of 26 PPMD cases, describe their characteristics, contrast them with primary PxD and focus on their distinguishing diagnostic features.ResultsMean age at onset was 38.6 years, i.e. much later than primary PxD. Women were predominantly affected (73%). Most subjects (88.4%) had long attacks, and unlike primary PxD there was a very high within-subject variability for attack phenomenology, duration and frequency. Dystonia was the most common single movement disorder presentation, but 69.2% of the patients had mixed or complex PxD. In 50% of PPMD cases attack triggers could be identified but these were unusual for primary PxD. 42.3% of patients employed unusual strategies to alleviate or stop the attacks. Response to typical medication used for primary PxD was poor. Precipitation of the disorder due to physical or emotional life events and stressors were documented in 57.6% and 65.3% of the cases respectively. Additional interictal psychogenic signs were documented in 34.6% and further medically unexplained somatic symptoms were present in 50% of the cases. 19.2% of patients had a comorbid organic movement disorder and 26.9% had pre-existing psychiatric comorbidities.ConclusionAlthough the phenotypic presentation of PPMD can be highly diverse, certain clinical characteristics help in distinguishing this condition from the primary forms of PxD. Recognition is important as multidisciplinary treatment approaches led to significant improvement in most cases

A priori collaboration in population imaging: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement consortium

AbstractIntroductionVirchow-Robin spaces (VRS), or perivascular spaces, are compartments of interstitial fluid enclosing cerebral blood vessels and are potential imaging markers of various underlying brain pathologies. Despite a growing interest in the study of enlarged VRS, the heterogeneity in rating and quantification methods combined with small sample sizes have so far hampered advancement in the field.MethodsThe Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement (UNIVRSE) consortium was established with primary aims to harmonize rating and analysis (www.uconsortium.org). The UNIVRSE consortium brings together 13 (sub)cohorts from five countries, totaling 16,000 subjects and over 25,000 scans. Eight different magnetic resonance imaging protocols were used in the consortium.ResultsVRS rating was harmonized using a validated protocol that was developed by the two founding members, with high reliability independent of scanner type, rater experience, or concomitant brain pathology. Initial analyses revealed risk factors for enlarged VRS including increased age, sex, high blood pressure, brain infarcts, and white matter lesions, but this varied by brain region.DiscussionEarly collaborative efforts between cohort studies with respect to data harmonization and joint analyses can advance the field of population (neuro)imaging. The UNIVRSE consortium will focus efforts on other potential correlates of enlarged VRS, including genetics, cognition, stroke, and dementia

A priori collaboration in population imaging: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement consortium

Introduction: Virchow-Robin spaces (VRS), or perivascular spaces, are compartments of interstitial fluid enclosing cerebral blood vessels and are potential imaging markers of various underlying brain pathologies. Despite a growing interest in the study of enlarged VRS, the heterogeneity in rating and quantification methods combined with small sample sizes have so far hampered advancement in the field. Methods: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement (UNIVRSE) consortium was established with primary aims to harmonize rating and analysis (www.uconsortium.org). The UNIVRSE consortium brings together 13 (sub)cohorts from five countries, totaling 16,000 subjects and over 25,000 scans. Eight different magnetic resonance imaging protocols were used in the consortium. Results: VRS rating was harmonized using a validated protocol that was developed by the two founding members, with high reliability independent of scanner type, rater experience, or concomitant brain pathology. Initial analyses revealed risk factors for enlarged VRS including increased age, sex, high blood pressure, brain infarcts, and white matter lesions, but this varied by brain region. Discussion: Early collaborative efforts between cohort studies with respect to data harmonization and joint analyses can advance the field of population (neuro)imaging. The UNIVRSE consortium will focus efforts on other potential correlates of enlarged VRS, including genetics, cognition, stroke, and dementia

Tremor stability index:a new tool for differential diagnosis in tremor syndromes

Background Misdiagnosis among tremor syndromes is common, and can impact on both clinical care and research. To date no validated neurophysiological technique is available that has proven to have good classification performance, and the diagnostic gold standard is the clinical evaluation made by a movement disorders expert. We present a robust new neurophysiological measure, the Tremor Stability Index, which can discriminate Parkinson’s disease tremor and essential tremor with high diagnostic accuracy. Methods The Tremor Stability Index is derived from kinematic measurements of tremulous activity. It was assessed in a test cohort comprising 16 rest tremor recordings in tremor-dominant Parkinson’s disease and 20 postural tremor recordings in essential tremor, and validated on a second, independent cohort comprising a further 50 tremulous Parkinson’s disease and essential tremor recordings. Clinical diagnosis was used as gold standard. 100 seconds of tremor recording were selected for analysis in each patient. The classification accuracy of the new index was assessed by binary logistic regression, and by receiver operating characteristic (ROC) analysis. The diagnostic performance was examined by calculating the sensitivity, specificity, accuracy, likelihood ratio positive, likelihood ratio negative, area under the ROC curve, and by cross-validation. Results Tremor Stability Index with a cutoff of 1.05 gave good classification performance for Parkinson’s disease tremor and essential tremor, in both test and validation datasets. Tremor Stability Index maximum sensitivity, specificity and accuracy were 95%, 95% and 92%, respectively. ROC analysis showed an AUC of 0.916 (95% C.I. 0.797 – 1.000) for the Test dataset and a value of 0.855 (95% C.I. 0.754 – 0.957) for the Validation dataset. Classification accuracy proved independent of recording device and posture. Conclusion The Tremor Stability Index can aid in the differential diagnosis of the two most common tremor types. It has a high diagnostic accuracy, can be derived from short, cheap, widely available and noninvasive tremor recordings, and is independent of operator or postural context in its interpretation

Levodopa-responsive Holmes' Tremor Caused by a Single Inflammatory Demyelinating Lesion

<p><strong>Background</strong>: Holmes&rsquo; tremor is characterized by a combination of rest, postural, and kinetic tremor that is presumably caused by interruption of cerebello-thalamo-cortical and nigrostriatal pathways. Medical treatment remains unsatisfactory.</p><p><strong> Case Report</strong>: A 16-year-old girl presented with Holmes&rsquo; tremor caused by a transient midbrain abnormality on magnetic resonance imaging (MRI). To explore the discrepancy between persistent tremor and resolved MRI changes, we performed dopamine transporter single-photon emission computed tomography (DaT-SPECT) with a 123I-ioflupane that revealed nearly absent DaT binding in the right striatum. Levodopa dramatically improved the tremor.</p><p><strong> Discussion</strong>: This is only the second report of a transient midbrain MRI abnormality disrupting nigrostriatal pathways. The case highlights the sometimes limited sensitivity of morphologic imaging for identifying the functional consequences of tissue damage and confirms that DaT imaging may serve as a predictor for levodopa responsiveness in Holmes&rsquo; tremor.</p

Acoustic interface for tremor analysis

Presented at the 18th International Conference on Auditory Display (ICAD2012) on June 18-21, 2012 in Atlanta, Georgia.Reprinted by permission of the International Community for Auditory Display, http://www.icad.org.In this paper we introduce new methods for real-time acoustical tremor diagnosis. We outline the problems of tremor diagnosis in the clinical context and discuss how sonification can complement and expand the existing tools neurologists have at their disposal. Based on three preliminary sonification experiments upon recorded tremor movement data, we show how temporal as well as spectral characteristics of a tremor can be made audible in realtime. Our first observations indicate that differences among tremor types can be made recognizable via sonification. Therefore, we suggest that the proposed methods could allow for the formulation of more confident diagnoses. At the end of the paper, we will also shortly outline the central topics of future research

Facial Emotion Recognition in Parkinson's Disease: An fMRI Investigation.

Findings of behavioral studies on facial emotion recognition in Parkinson's disease (PD) are very heterogeneous. Therefore, the present investigation additionally used functional magnetic resonance imaging (fMRI) in order to compare brain activation during emotion perception between PD patients and healthy controls.We included 17 nonmedicated, nondemented PD patients suffering from mild to moderate symptoms and 22 healthy controls. The participants were shown pictures of facial expressions depicting disgust, fear, sadness, and anger and they answered scales for the assessment of affective traits. The patients did not report lowered intensities for the displayed target emotions, and showed a comparable rating accuracy as the control participants. The questionnaire scores did not differ between patients and controls. The fMRI data showed similar activation in both groups except for a generally stronger recruitment of somatosensory regions in the patients.Since somatosensory cortices are involved in the simulation of an observed emotion, which constitutes an important mechanism for emotion recognition, future studies should focus on activation changes within this region during the course of disease

Gait in SWEDDs patients:comparison with Parkinson's disease patients and healthy controls

Patients diagnosed with Parkinson's disease on clinical grounds who subsequently turn out to have normal dopamine transporter imaging have been referred to as SWEDDs (scans without evidence of dopaminergic deficits). Despite having clinical features similar to those of Parkinson's disease, these patients seem to have different pathophysiology, prognosis, and treatment requirements. In this study we determined the similarities and differences in the gaits of SWEDDs and Parkinson's disease patients to investigate whether walking patterns can distinguish these entities. We used 3-D motion capture to analyze the gaits of 11 SWEDDs patients (who had unilateral or asymmetric upper limb tremor with a rest component), 12 tremor-dominant Parkinson's disease patients, and 13 healthy control participants. In common with Parkinson's disease patients, SWEDDs patients had a slow gait mainly because of a small stride length, as well as a reduced arm swing. However, several abnormal features of posture and gait in Parkinson's disease were normal in SWEDDs. Thus, SWEDDs patients had normal trunk and elbow posture, normal stride length variability, and normal bilateral step-phase coordination, all of which were abnormal in Parkinson's disease patients. We also searched for signs of ataxic movements during normal and tandem walking, but found no evidence that ataxic gait was a general feature in SWEDDs. These findings could aid the clinician in identification of potential tremulous SWEDDs cases. (C) 2011 Movement Disorder Societ