Faculty Bibliography

Objective: To develop a clinical score to distinguish between the parkinsonian variant of multiple system atrophy (MSA-P) and Parkinson's disease (PD).
Background(s): The differential diagnosis between MSA-P and PD is often difficult, particularly early in the disease course.
Method(s): We compared patients with probable MSA-P and with PD with a disease duration of <3 years, selected from those who were enrolled in the Natural History Study of the Synucleinopathies, an international prospective observational study. Detailed clinical neurological, and autonomic parameters were assessed at enrollment using UMSARS part I, II and IV; Schrag quality of life (QoL) scale; burden of autonomic dysfunction by COMPASS-31 scale; smell function using the UPSIT; cardiovascular autonomic function using heart rate variability during deep-breathing, analysis of the Valsalva maneuver, orthostatic stress test, plasma catecholamine levels during supine rest and after head-up tilt; and cognitive evaluation using MoCA. Positive and negative likelihood ratios (LR) were obtained for each variable assessed. Multiple iterations of a composite score based on sequential addition of variables with the highest diagnostic accuracy were created by multiplying each variable's LR and applying a logarithmic function.
Result(s): Fifty-eight MSA-P and 53 PD patients had a disease duration of less than 3 years. The vast majority of patients had been diagnosed within the last 12 months (81% MSA-P and 66% PD patients). MSA-P patients were more frequently female (53% vs. 30% p<0.05) and younger at diagnosis (63+/-8 years vs. 71+/-8 years, p<0.001). A 7-item score comprising the bladder weighted subscore of the COMPASS-31, UMSARS's part 1, UPSIT, hyperreflexia, the motor subscore of Schrag's MSA quality of life scale, falls within 3 years of diagnosis, and new or increased snoring resulted in a ROC curve AUC of 0.983, with excellent 93% sensitivity and 98% specificity to distinguish early MSA-P from PD.
Conclusion(s): We propose a scale of 7 clinical items to distinguish early stage MSA-P from PD. It considers urinary function, olfactory function, corticospinal signs, performance of activities of daily living, motor symptoms burden on quality of life, frequent early falls and sleep disordered breathing. We are now prospectively validating the scale to determine its predictive value in our prodromal cohort. (Figure Presented)

Objective: To study the rate of progression of multiple system atrophy (MSA) and assess for a potential ceiling effect of the Unified Multiple System Atrophy Rating Scale (UMSARS).
Background(s): Disease progression of MSA as measured by UMSARS varied significantly in natural history studies. Reported 1-year UMSARS-1 and UMSARS-2 progression rates ranged from 3.9 to 6.5 and 3.5 to 8.2 respectively. We hypothesize that this variability is due, at least in part, to differences in severity at enrollment and a potential ceiling effect in the scale, so that patients in more advanced stages may appear to worsen less, which would have important implications for clinical trial design.
Method(s): We analyzed the rate of change in the UMSARS in a large international cohort of well-characterized patients with a clinical diagnosis of possible or probable MSA enrolled in the Natural History Study of Synucleinopathies. Annualized progression rates were obtained using 2-year follow-up data.
Result(s): Three hundred and forty nine patients (61.4+/-7.9 years old) with MSA were enrolled. Disease duration was 4.5+/-5.1 years. 143 patients completed 1-year evaluations and 61 completed the 2-year evaluation. The 12-month progression rates were 5.4+/-5.1 for the UMSARS-I, 5.9+/-5.3 for the UMSARS-II, and 11.8+/-9.6 for the total score. The 24-month progression rates were 10.8+/-7.3 for the UMSARS-I, 12.2+/-7.9 for the UMSARSII, and 22.6+/-13.7 for the total score. Annualized progression rates were divided according to their baseline UMSARS-I and UMSARS II. There was a significant (p = 0.0153) inverse relationship between rate of progression and UMSARS-I at baseline. A similar, but not significant trend was observed with UMSARS-II at baseline.
Conclusion(s): The rate of progression as measured by UMSARS is influenced by the baseline disease severity. A possible ceiling effect should be considered when planning enrollment, power calculations, and outcome measures in clinical trials

Von Economo neurons (VENs) and fork cells are principally located in the anterior cingulate cortex (ACC) and the frontoinsular cortex (FI). Both of these regions integrate inputs from the autonomic nervous system (ANS) and are involved in decision-making and perception of the emotional states of self and others. Familial dysautonomia (FD) is an orphan disorder characterized by autonomic dysfunction and behavioral abnormalities including repetitive behavior and emotional rigidity, which are also seen in autism spectrum disorder. To understand a possible link between the ANS and the cortical regions implicated in emotion regulation we studied VENs and fork cells in an autonomic disorder. We determined the densities of VENs, fork cells, and pyramidal neurons and the ratio of VENs and fork cells to pyramidal neurons in ACC and FI in 4 FD patient and 6 matched control brains using a stereologic approach. We identified alterations in densities of VENs and pyramidal neurons and their distributions in the ACC and FI in FD brains. These data suggest that alterations in migration and numbers of VENs may be involved in FD pathophysiology thereby supporting the notion of a functional link between VENs, the ANS and the peripheral nervous system in general.

Head and neck tumors can affect afferent baroreceptor neurons and either interrupt or intermittently increase their signaling, causing blood pressure to become erratic. When the afferent fibers of the baroreflex are injured by surgery or radiotherapy or fail to develop as in familial dysautonomia, their sensory information is no longer present to regulate arterial blood pressure, resulting in afferent baroreflex failure. When the baroreflex afferents are abnormally activated, such as by paragangliomas in the neck, presumably by direct compression, they trigger acute hypotension and bradycardia and frequently syncope, by a mechanism similar to the carotid sinus syndrome. We describe our observations in a large series of 23 patients with afferent baroreflex dysfunction and the cardiovascular autonomic features that arise when the sensory baroreceptor neurons are injured or compressed. The management of afferent baroreceptor dysfunction is limited, but pharmacological strategies can mitigate blood pressure swings, improve symptoms, and may reduce hypertensive organ damage. Although rare, the prevalence of afferent baroreflex dysfunction appears to be increasing in middle-aged men due to human papillomavirus related oropharyngeal cancer.

A 10-year-old girl presented with ileus, urinary retention, dry mouth, lack of tears, fixed dilated pupils, and diffuse anhidrosis 7-days after a febrile illness. We hypothesized that her syndrome was due to autoimmunity against muscarinic acetylcholine receptors, blocking their activation. Using an indirect enzyme-linked immunosorbent assay for all five muscarinic receptors (M₁ -M₅ ) we identified in the patient's serum antibodies that selectively bound to M₃ receptors. In-vitro functional studies confirmed that these autoantibodies selectively blocked M₃ receptor activation. Thus, autoantibodies against M₃ acetylcholine receptors can cause acute postganglionic cholinergic dysautonomia. This article is protected by copyright. All rights reserved.