Internal Versus External Frame of Reference in Functional Movement Disorders.

OBJECTIVE: The purpose of this study was to determine whether patients with functional movement disorders (FMDs) differ in their internal versus external locus of control (LOC) and whether LOC in these patients affected disease severity, quality of life, and functional impairment compared with control subjects with degenerative (Parkinson's disease) and nondegenerative (focal dystonia) neurological conditions. METHODS: A total of 156 patients with FMD (N=45), Parkinson's disease (N=64), and focal dystonia (N=47) were recruited between June 2015 and August 2017. The authors administered the general Levenson Multidimensional LOC (LOC-G) and health-specific Multidimensional Health LOC (LOC-H) scales. An internal LOC was represented similarly in both scales: the external LOC included "chance" and "powerful others" in the LOC-G measure and chance, "other people," and "doctors" in the LOC-H measure. Quality of life, functional impairment, and FMD severity were assessed. One-way analysis of variance and adjusted logistic regressions were used, as well as ordinary least-squares between and within groups, respectively. RESULTS: Patients with FMD had lower external chance LOC-G scores compared with patients in the Parkinson's disease group (odds ratio=0.90, p=0.03) and higher internal (odds ratio=1.22, p=0.01) and lower external (odds ratio=0.77, p=0.02) doctors LOC-H scores compared with patients in the focal dystonia group. External powerful others LOC-G score was associated with functional impairment (regression coefficient=-0.04, p=0.02). There were no effects of LOC on quality of life or disease severity. CONCLUSIONS: Patients with FMD exhibited high "within our control" internal general and health-specific frame of reference. LOC had no influence on quality of life or disease severity in this patient population.

Movement Disorders in Prionopathies: A Systematic Review.

Background: Movement disorders are frequent features of prionopathies. However, their prevalence and onset remain poorly described. Methods: We performed a systematic review of case reports and case series of pathologically- and genetically confirmed prionopathies. Timing of symptom and movement disorder onset were documented. Continuous variables were compared between two groups using the Wilcoxon rank sum test and between multiple groups using Kruskal-Wallis test. Categorical variables were compared using Fisher's exact test. Results: A total of 324 cases were included in this analysis. Movement disorders were a common feature at the onset of symptoms in most prionopathies. Gait ataxia was present in more than half of cases in all types of prionopathies. The prevalence of limb ataxia (20%) and myoclonus (24%) was lower in Gerstmann-Sträussler-Scheinker disease compared to other prionopathies (p ≤ 0.004). Myoclonus was common but often a later feature in sporadic Creutzfeldt-Jakob disease (2 months before death). Chorea was uncommon but disproportionately prevalent in variant Creutzfeldt-Jakob disease (30% of cases; p < 0.001). In genetic Creutzfeldt-Jakob disease, E200K PRNP carriers exhibited gait and limb ataxia more often when compared to other mutation carriers. Discussion: Movement disorders are differentially present in the course of the various prionopathies. The movement phenomenology and appearance are associated with the type of prion disease and the PRNP genotype and likely reflect the underlying pattern of neurodegeneration. Reliance on myoclonus as a diagnostic feature of sporadic Creutzfeldt-Jakob disease may delay its recognition given its relatively late appearance in the disease course.

Diagnostic performance of the "Huffing and Puffing" sign in psychogenic (functional) movement disorders.

OBJECTIVE: To determine the diagnostic value of effort-associated behaviors ("huffing and puffing" spectrum) in patients with psychogenic movement disorders. METHODS: Three blinded clinicians rated presence, severity, and duration of effort-associated features during standing and walking tasks on edited videos of 131 patients with psychogenic gait disorders and 37 patients with organic gait disorders. RESULTS: Huffing, grunting, grimacing, and breath holding were the most common effort-associated behaviors in patients with psychogenic gait disorders, with a combined prevalence of 44% and disproportionate to the severity of gait impairment compared to organic gait disorders. The presence of "huffing and puffing"-type behaviors yielded a relatively low sensitivity but high specificity for the diagnosis of psychogenic movement disorders, increasing the odds of diagnosis 13-fold (95%, CI: 4.2-43.8) compared to organic gait disorders. CONCLUSIONS: Demonstration of effort-associated behaviors during standing and walking strongly supports the psychogenic nature of disorders when gait is involved.

Weight loss by calorie restriction versus bariatric surgery differentially regulates the hypothalamo-pituitary-adrenocortical axis in male rats.

Behavioral modifications for the treatment of obesity, including caloric restriction, have notoriously low long-term success rates relative to bariatric weight-loss surgery. The reasons for the difference in sustained weight loss are not clear. One possibility is that caloric restriction alone activates the stress-responsive hypothalamo-pituitary-adrenocortical (HPA) axis, undermining the long-term maintenance of weight loss, and that this is abrogated after bariatric surgery. Accordingly, we compared the HPA response to weight loss in five groups of male rats: (1) high-fat diet-induced obese (DIO) rats treated with Roux-en-Y gastric bypass surgery (RYGB, n = 7), (2) DIO rats treated with vertical sleeve gastrectomy (VSG, n = 11), (3) DIO rats given sham surgery and subsequently restricted to the food intake of the VSG/RYGB groups (Pair-fed, n = 11), (4) ad libitum-fed DIO rats given sham surgery (Obese, n = 11) and (5) ad libitum chow-fed rats given sham surgery (Lean, n = 12). Compared with Lean controls, food-restricted rats exhibited elevated morning (nadir) non-stress plasma corticosterone concentration and increased hypothalamic corticotropin-releasing hormone and vasopressin mRNA expression, indicative of basal HPA activation. This was largely prevented when weight loss was achieved by bariatric surgery. DIO increased HPA activation by acute (novel environment) stress and this was diminished by bariatric surgery-, but not pair-feeding-, induced weight loss. These results indicate that the HPA axis is differentially affected by weight loss from caloric restriction versus bariatric surgery, and this may contribute to the differing long-term effectiveness of these two weight-loss approaches.