Neuropsychological assessment protocol in an ongoing randomized controlled trial on posterior subthalamic area vs. ventral intermediate nucleus deep brain stimulation for essential tremor.

Objective: Patients with essential tremor (ET) may experience cognitive-affective impairment. Deep brain stimulation (DBS) of different targets, such as the ventral intermediate nucleus (VIM) of the thalamus or the posterior subthalamic area (PSA), has been shown to be beneficial for refractory ET. However, there is little evidence regarding the possible neuropsychological effects of PSA-DBS on patients with ET, and there are few studies comparing it with VIM-DBS in this population.In this study, we aim to present the evaluation protocol and neuropsychological battery as used in an ongoing trial of DBS for ET comparing the already mentioned targets. Methods: As part of a randomized, double-blind, crossover clinical trial comparing the effectiveness and safety of PSA-DBS vs. VIM-DBS, 11 patients with refractory ET will undergo a multi-domain neuropsychological battery assessment. This will include a pre-/post-implantation assessment (3 months after the stimulation of each target and 6 months after an open stage of DBS on the most optimal target). Conclusion: Evidence on the neuropsychological effects of DBS in patients with refractory ET is very scarce, particularly in lesser-explored targets such as PSA. This study could contribute significantly in this field, particularly on pre-procedure safety analysis for tailored patient/technique selection, and to complete the safety analysis of the procedure. Moreover, if proven useful, this proposed neuropsychological assessment protocol could be extensible to other surgical therapies for ET.

PET-Amyloid After Inconclusive Cerebrospinal Fluid Biomarkers in Clinical Practice. Is it Necessary to Duplicate Procedures?

INTRODUCTION: In the absence of a gold standard for in vivo Alzheimer disease (AD) diagnosis, AD biomarkers such as cerebrospinal fluid biomarkers (CSF-B) and PET-Amyloid are considered diagnostically useful in clinical practice guidelines and have consensual appropriate use criteria (AUC). However, little evidence has been published on their utilization in the clinical setting or on approaches to mismatched results. The objective of this work was to evaluate the use of AD biomarkers in clinical practice, focusing on the implementation of PET-Amyloid in cases of inconclusive CSF-B. METHODS: This naturalistic, ambispective case series included patients fulfilling AUC for CSF-B and PET-Amyloid whose CSF-B results were non-diagnostic (target population), analyzing the diagnostic certainty, the treatment approach, and the relationship between CSF-B and PET-Amyloid results. RESULTS: Out of 2373 eligible patients, AD biomarkers were studied in 417 (17.6%), most frequently due to cognitive impairment in under 65-year-olds, using CSF-B in 311 patients and PET-Amyloid in 150. CSF-B results were non-diagnostic for 44 patients (52.3% male; aged 60.9±6.6 years), who then underwent PET-Amyloid study, which was positive in 31. A 'k' coefficient of 0.108 was obtained between CSF-B and PET-amyloid (54.5% concordance). In multivariate regression analysis, Aß42 was the only significant predictor (p= 0.018) of a positive PET-Amyloid result. In the target population, PETAmyloid increased diagnostic confidence by 53.7% (p <0.001) and modified the therapeutic approach in 36.4% of cases. CONCLUSION: These findings support the duplication of AD biomarkers and demonstrate that the implementation of PET-Amyloid provides an early and certain diagnosis to guide appropriate treatment.

Evaluación de la equivalencia de tres versiones paralelas del Fototest / Evaluation of the equivalence of three parallel versions of the Phototest

Introducción: el Fototest es un test cognitivo muy breve y aplicable a analfabetos que se ha mostrado válido y coste- efectivo en la detección del deterioro cognitivo y la demencia y en el seguimiento de estos pacientes. Las aplicaciones repetidas de un test cognitivo pueden inducir mejorías en el rendimiento debido al fenómeno «efecto de la práctica »; este efecto puede minimizarse con el uso de formas paralelas. Nuestro objetivo es evaluar la equivalencia de tres versiones paralelas del Fototest. Material y métodos: estudio transversal en una muestra de conveniencia; los sujetos se distribuyeron aleatoriamente en tres grupos a los que se aplicó respectivamente la versión original (Fototest- 1) y dos versiones paralelas (Fototest-2 y Fototest-3) del Fototest, que diferían en los objetos por denominar y recordar. Análisis estadístico: estadística descriptiva univariada y comparación entre grupos con ANOVA o χ2 según tipo de variables. Resultados: 223 sujetos (65,3 % mujeres) con una edad de 58,0 ± 16,8 (media ± DE) años, distribuidos aleatoriamente en tres grupos de 75 (Fototest-1), 76 (Fototest-2) y 72 (Fototest-3) sujetos; estos grupos no diferían entre sí en edad, sexo o nivel educativo. No hay diferencias significativas entre los grupos en las puntuaciones parciales (denominación, fluencia hombres, fluencia mujeres, recuerdo libre y recuerdo facilitado), subtotales (fluencia total, recuerdo total) y total del Fototest (Fototest-1: 37,8 ± 5,6, Fototest-2: 36,8 ± 7,5, Fototest-3: 37,4 ± 5,8; p = 0,66). Discusión: las tres versiones del Fototest son equivalentes e intercambiables, lo que puede facilitar la labor del explorador y contrarrestar el «efecto de la práctica » asociado al uso repetido (AU)

Introduction: The Phototest is a very short cognitive test that is applicable to illiterates and has proven to be valid and cost-effective for the detection of cognitive impairment and dementia and for the follow-up of these patients. Repeated applications of a cognitive test may induce improvements in performance due to «practice effects», which can be minimized by the use of parallel forms. Our objective was to evaluate the equivalence of three parallel versions of the Phototest. Material and Methods: Cross-sectional study of a convenience sample; participants were randomly distributed into three groups for the respective application of the original version of the Phototest (Phototest-1) and two parallel versions (Phototest-2 and Phototest-3), which differ in the objects to be named and recalled. Statistical analysis: univariate descriptive statistics and comparison among groups using ANOVA or the chi-square test according to the type of variable. Results: 223 participants (65.3% females) with a mean±SD of 58.0±16.8 yrs were randomly distributed among three groups of 75 (Phototest-1), 76 (Phototest-2) and 72 (Phototest-3) participants, with no significant inter-group differences in age, sex, or educational level. The groups did not significantly differ in partial Phototest scores (naming, fluency of males, fluency of females, free recall or cued recall), subtotal scores (total fluency, total recall) or total scores (Phototest-1: 37.8±5.6, Fototest-2: 36.8±7.5, Fototest-3: 37.4±5.8; p=0.66). Discussion: The three versions of Phototest are equivalent and interchangeable, which can assist the work of the examiner and counteract the 'practice effects' associated with repeated applications (AU)