Plasma Neurofilament Light Chain and Clinical Diagnosis in Frontotemporal Dementia Syndromes.

BACKGROUND: Frontotemporal dementia (FTD) syndromes, mimics, phenocopy (phFTD), and slowly progressive behavioral variant FTD (bvFTD) can be difficult to distinguish clinically. Biomarkers such as neurofilament light chain (NfL) may be helpful. OBJECTIVE: To study plasma NfL levels in people with FTD syndromes and determine if plasma NfL can distinguish between FTD syndromes and phFTD. METHODS: Plasma NfL levels were estimated using both Simoa® Quanterix HD-X™ and SR-X™ machines grouped via final diagnosis after investigation and review. RESULTS: Fifty participants were studied: bvFTD = 20, semantic variant FTD (svFTD) = 11, non-fluent variant FTD (nfvFTD) = 9, FTD with motor neuron disease (MND) = 4, phFTD = 2, slow progressors = 3, FTD mimic = 1, mean age 67.2 (SD 8.4) years. NfL levels were significantly higher in the FTD group compared to phenocopy group (p = 0.003). Median NfL (IQR) pg/mL was comparable in the FTD syndromes: bvFTD 41.10 (50.72), svFTD 44.38 (16.61), and nfvFTD 42.61 (22.93), highest in FTD with MND 79.67 (45.32) and lowest in both phFTD 13.99 (0.79) and slow progressors 17.97 (3.62). CONCLUSION: Plasma NfL appears to differentiate FTD syndromes and mimics. However, a lower NfL may predict a slower, but not necessarily absence of neurodegeneration, and therefore appears limited in distinguishing slow progressors from FTD phenocopies. Larger numbers of patients from all clinical groups are required to strengthen diagnostic utility.

Psychometric deficits in autoimmune encephalitis: A retrospective study from the Australian Autoimmune Encephalitis Consortium.

BACKGROUND AND PURPOSE: Despite the rapid increase in research examining outcomes in autoimmune encephalitis (AE) patients, there are few cohort studies examining cognitive outcomes in this population. The current study aimed to characterise psychometric outcomes in this population, and explore variables that may predict psychometric outcomes. METHODS: This retrospective observational study collected psychometric data from 59 patients across six secondary and tertiary referral centres in metropolitan hospitals in Victoria, Australia between January 2008 and July 2019. Frequency and pattern analysis were employed to define and characterize psychometric outcomes. Univariable logistic regression was performed to examine predictors of intact and pathological psychometric outcomes. RESULTS: Deficits in psychometric markers of executive dysfunction were the most common finding in this cohort, followed by deficits on tasks sensitive to memory. A total of 54.2% of patients were classified as having psychometric impairments across at least two cognitive domains. Twenty-nine patterns were observed, suggesting outcomes in AE are complex. None of the demographic data, clinical features or auxiliary examination variables were predictors of psychometric outcome. CONCLUSIONS: Cognitive outcomes in AE are complex. Further detailed and standardized cognitive testing, in combination with magnetic resonance imaging volumetrics and serum/cerebrospinal fluid biomarkers, is required to provide rigorous assessments of disease outcomes.

White matter microstructure is associated with language in children born very preterm.

Very preterm birth is associated with altered white matter microstructure and language difficulties, which may compromise communication, social function and academic achievement, but the relationship between these two factors is unclear. The aim of this study was to explore associations between white matter microstructure and language domains of semantics, grammar and phonological awareness at 7-years of age on a whole-brain level and within the arcuate fasciculus, an important language pathway, in very preterm and term-born children. Language was assessed in 145 very preterm-born (<30 weeks' gestation and/or <1250 g birth weight) and 33 term-born children aged 7 years. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), axon orientation dispersion and axon density were estimated from diffusion magnetic resonance images also obtained at 7 years. The correlation between diffusion values and language was assessed using Tract-Based Spatial Statistics (TBSS). The arcuate fasciculus was delineated using constrained spherical deconvolution tractography and diffusion parameters from this tract were related to language measures using linear regression. While there was evidence for widespread associations between white matter microstructure and language, there was little evidence of differences in these associations between very preterm and term-born groups. TBSS analyses revealed that higher FA and lower AD, RD, and MD in major fibre tracts, including those subserving language, were associated with better semantic, grammar and phonological awareness performance. Higher axon density in widespread fibre tracts was also associated with better semantic performance. The tractography analyses of the arcuate fasciculus showed some evidence for associations between white matter microstructure and language outcomes. White matter microstructural organisation in widespread fibre tracts, including language-relevant pathways, was associated with language performance in whole-brain and tract-based analyses. The associations were similar for very preterm and term-born groups, despite very preterm children performing more poorly across language domains.

Impaired language abilities and white matter abnormalities in children born very preterm and/or very low birth weight.

OBJECTIVES: To investigate language abilities in children born very preterm (VPT; <32 weeks' gestational age) or very low birth weight (VLBW; <1500 g) at 7 years of age and compare their performances with children born at term, and to determine whether group differences could be explained by cerebral white matter abnormality on neonatal magnetic resonance imaging. STUDY DESIGN: A cohort of 198 children born <30 weeks' gestational age and/or <1250 g, and 70 term controls were examined. White matter abnormalities were rated quantitatively on brain magnetic resonance imaging at term-equivalent age. Language was assessed at age 7 years using standardized language tests. Differences between groups were tested in the 5 language subdomains of phonological awareness, semantics, grammar, discourse, and pragmatics. A mediation effect was tested between birth group, white matter abnormality, and language subdomains. RESULTS: The VPT/VLBW group performed significantly worse than controls on all language subdomains (all P < .001). White matter abnormality mediated the effect of group differences on phonological awareness, and partly mediated this effect for semantics, grammar, and discourse. White matter abnormality was not significantly associated with pragmatics (P = .13). CONCLUSIONS: Language is an important area of concern in children born VPT/VLBW. Neonatal white matter abnormality is an important predictor of outcome; however, different language abilities are differentially associated with neonatal white matter abnormality.

Assessing executive function in preschoolers.

Executive function develops at an unprecedented rate during the preschool period, yet few clinicians attempt to assess executive processes in young children. The primary objective of this article is to demonstrate that executive function can be assessed in preschoolers, and to highlight the importance of detecting executive dysfunction as early as possible. Following a description of executive function and the underlying neural systems, this article outlines some of the challenges in assessing executive function in young children. The various assessment paradigms used for assessing executive function in preschoolers are presented, and based on studies that have applied these measurement tools normal development of executive domains is described. Finally, the benefits and opportunities for executive function intervention in the preschool period are considered.