P10. ‘Clustered sparse’ fMRI using simultaneous multislice excitation in language mapping

Recovery of orthographic processing after stroke: A longitudinal fMRI study

A model for visual naming based on spatiotemporal dynamics of ECoG high-gamma modulation

Intraoperative mapping of eloquent cortex during left (speech dominant) anterior temporal lobectomy has shown a significant proportion of patients to have sites on the anterior superior temporal gyrus at which visual confrontation naming can be disrupted by electrical stimulation. The purpose of this investigation was to conduct a randomized clinical trial to determine whether sparing versus resection of the superior temporal gyrus affected visual confrontation naming outcome after standard left anterior temporal lobectomy. Also examined was the degree to which inherent patient characteristics were associated with language outcome regardless of surgical technique. Thirty patients with intractable left temporal lobe epilepsy undergoing standard anterior temporal lobectomy were randomized in regard to whether the superior temporal gyrus was resected or spared. Patients were tested preoperatively and 6-8 months postoperatively by using two conventional tests of visual confrontation naming ability. No significant differences were found between the groups in either confrontation naming or surgical outcome. Postoperative decline in nominal speech was most closely associated with later age at onset of epilepsy/absence of hippocampal sclerosis. It appears that specific types of localization-related temporal lobe epilepsy are more closely associated with the risk of adverse language outcome after anterior temporal lobectomy than with the surgical variations investigated in this study.

Accumulating evidence suggests that visual object understanding involves a rapid feedforward sweep, after which subsequent recurrent interactions are necessary. The extent to which recurrence plays a critical role in object processing remains to be determined. Recent studies have demonstrated that recurrent processing is modulated by increasing semantic demands. Differentially from previous studies, we used dynamic causal modeling to model neural activity recorded with magnetoencephalography while 14 healthy humans named two sets of visual objects that differed in the degree of semantic accessing demands, operationalized in terms of the values of basic psycholinguistic variables associated with the presented objects (age of acquisition, frequency, and familiarity). This approach allowed us to estimate the directionality of the causal interactions among brain regions and their associated connectivity strengths. Furthermore, to understand the dynamic nature of connectivity (i.e., the chronnectome; Calhoun et al., 2014) we explored the time-dependent changes of effective connectivity during a period (200-400 ms) where adding semantic-feature information improves modeling and classifying visual objects, at 50 ms increments. First, we observed a graded involvement of backward connections, that became active beyond 200 ms. Second, we found that semantic demands caused a suppressive effect in the backward connection from inferior frontal cortex (IFC) to occipitotemporal cortex over time. These results complement those from previous studies underscoring the role of IFC as a common source of top-down modulation, which drives recurrent interactions with more posterior regions during visual object recognition. Crucially, our study revealed the inhibitory modulation of this interaction in situations that place greater demands on the conceptual system.

Functional Dissociation between Cognitive Estimation and Object Naming in Focal Temporal and Frontal Lobe Epilepsies

Processing of sub-syllabic speech units in the posterior temporal lobe: An fMRI study

When running statistical tests, researchers can commit a Type II error, that is, fail to reject the null hypothesis when it is false. To diminish the probability of committing a Type II error (β), statistical power must be augmented. Typically, this is done by increasing sample size, as more participants provide more power. When the estimated effect size is small, however, the sample size required to achieve sufficient statistical power can be prohibitive. To alleviate this lack of power, a common practice is to measure participants multiple times under the same condition. Here, we show how to estimate statistical power by taking into account the benefit of such replicated measures. To that end, two additional parameters are required: the correlation between the multiple measures within a given condition and the number of times the measure is replicated. An analysis of a sample of 15 studies (total of 298 participants and 38,404 measurements) suggests that in simple cognitive tasks, the correlation between multiple measures is approximately .14. Although multiple measurements increase statistical power, this effect is not linear, but reaches a plateau past 20 to 50 replications (depending on the correlation). Hence, multiple measurements do not replace the added population representativeness provided by additional participants.

Epidemiologists have advocated for reporting confidence intervals and deemphasizing P values to address long-standing concerns about null-hypothesis statistical-significance testing, P hacking, and reproducibility. It is unknown if efforts to reduce reliance on P values have altered the distribution of P values. For 21 332 abstracts published 2000 to 2024 in 4 major epidemiology journals, two-sided P values (N=25 288) were calculated from estimates and confidence intervals scraped using ChatGPT's 4o-mini model. We evaluated trends over time to determine whether the empirical distribution of P values changed. We fitted to expected P-value distributions and simulated these distributions with and without assuming changes in statistical power over time. Average P values decreased from 2000 to 2024; the fraction of P values just below the .05 threshold also decreased. Fits to models indicate that statistical power increased. Increasing power would reduce average P value while also decreasing P values near the .05 threshold-precisely the trends observed in epidemiology journals. Although the frequency of P values near the .05 threshold has declined modestly, this likely reflects increases in statistical power rather than decreases in P hacking.

Cluster randomised crossover designs (CRXOs) are a powerful type of longitudinal cluster randomised trial in which all participating clusters switch between two treatment conditions. "Multiple-period" CRXOs divide the trial duration into a number of periods of equal length and can allow for multiple crossovers between treatment conditions. It can be assumed that increasing the number of crossovers leads to an increase in statistical power. We investigate whether this is true for standard correlation structures, comparing CRXO designs with equal numbers of clusters, participants, and periods but differing in the number of crossovers, considering continuous outcomes. We consider the formula for the variance of the treatment effect estimator for multiple-period CRXOs under exchangeable and block-exchangeable within-cluster correlation structures, assuming equal cluster-period sizes and different patterns of treatment conditions in the treatment sequences varying in the number of crossovers. We also conduct a simulation study to compare the statistical power between multiple-period CRXO designs with different numbers of crossovers that share the same number and duration of periods and the same number of participants in each cluster period. Under exchangeable and block-exchangeable correlation structures and equal cluster-period sizes, the number of crossovers in the treatment sequences does not impact study power, provided the design is balanced in terms of the number of periods and clusters implementing each condition. When an exchangeable or block-exchangeable within-cluster correlation structure and a time-invariant effect of treatment are assumed, power calculations for CRXO designs are invariant to the specific ordering of treatment conditions. In particular, a CRXO design with additional crossovers does not lead to increased statistical power compared to a CRXO design with just one crossover for these within-cluster correlation structures. Further work is required to investigate the utility of multiple crossovers in situations where the treatment effect varies over time.

BackgroundPhelan-McDermid syndrome (PMS), a neurodevelopmental disorder caused by deletion or mutation in the SHANK3 gene, is one of the more common single-locus causes of autism spectrum disorder (ASD). PMS is characterized by global developmental delay, hypotonia, delayed or absent speech, increased risk of seizures, and minor dysmorphic features. Impairments in language and communication are one of the most consistent characteristics of PMS. Although there is considerable overlap in the social communicative deficits associated with PMS and ASD, there is a dearth of data on underlying abnormalities at the level of neural systems in PMS. No controlled neuroimaging studies of PMS have been reported to date. The goal of this study was to examine the neural circuitry supporting the perception of auditory communicative signals in children with PMS as compared to idiopathic ASD (iASD).MethodsEleven children with PMS and nine comparison children with iASD were scanned using functional magnetic resonance imaging (fMRI) under light sedation. The fMRI paradigm was a previously validated passive auditory task, which presented communicative (e.g., speech, sounds of agreement, disgust) and non-communicative vocalizations (e.g., sneezing, coughing, yawning).ResultsPrevious research has shown that the superior temporal gyrus (STG) responds selectively to communicative vocal signals in typically developing children and adults. Here, selective activity for communicative relative to non-communicative vocalizations was detected in the right STG in the PMS group, but not in the iASD group. The PMS group also showed preferential activity for communicative vocalizations in a range of other brain regions associated with social cognition, such as the medial prefrontal cortex (MPFC), insula, and inferior frontal gyrus. Interestingly, better orienting toward social sounds was positively correlated with selective activity in the STG and other “social brain” regions, including the MPFC, in the PMS group. Finally, selective MPFC activity for communicative sounds was associated with receptive language level in the PMS group and expressive language in the iASD group.ConclusionsDespite shared behavioral features, children with PMS differed from children with iASD in their neural response to communicative vocal sounds and showed relative strengths in this area. Furthermore, the relationship between clinical characteristics and neural selectivity also differed between the two groups, suggesting that shared ASD features may partially reflect different neurofunctional abnormalities due to differing etiologies.Electronic supplementary materialThe online version of this article (doi:10.1186/s11689-016-9138-9) contains supplementary material, which is available to authorized users.

The diagnostic value of urinary incontinence in the differential diagnosis of seizures

In this paper, we propose a portmanteau test for whether a graph-structured network dataset without replicates exhibits autocorrelation across units connected by edges. Specifically, the well known Ljung-Box test for serial autocorrelation of time series data is generalized to the network setting using a specially derived central limit theorem for a weakly stationary random field. The asymptotic distribution of the test statistic under the null hypothesis of no autocorrelation is shown to be chi-squared, yielding a simple and easy-to-implement procedure for testing graph-structured autocorrelation, including spatial and spatial-temporal autocorrelation as special cases. Numerical simulations are carried out to demonstrate and confirm the derived asymptotic results. Convergence is found to occur quickly depending on the number of lags included in the test statistic, and a significant increase in statistical power is also observed relative to some recently proposed permutation tests. An example application is presented by fitting spatial autoregressive models to the distribution of COVID-19 cases across counties in New York state.

Trichloroethylene: Johnson et al.’s Response

The aim of the present work was to establish whether or not prescribed medication is a usable risk indicator for work-related ischaemic heart disease (IHD), in Denmark. Weighted Spearman rank correlation coefficients (rho) were used to evaluate the agreement between Standardised Hazard Ratios (SHR) for hospital treatment or death due to IHD and SHR for purchase of prescriptions for medicine that may prevent IHD from (re)occurring, among socio-occupational and economic activities groups in Denmark. The SHR were based on a 10-year prospective follow-up of 2 million people in Danish national registers 1996-2005. We found approximately 7 times more cases of medicine usage (N = 411 651) than we did for hospital treatment or death (N = 55 684). The correlations between the 2 types of SHR were strong (rho = 0.94 for the socio-occupational groups; rho = 0.74 for the economic activities groups). We observed, however, one markedly contradictive result; the industrial group entitled 'general practitioner, dentists etc.' was associated both with significantly high rates of medicine usage (SHR = 1.15, 95% CI: 1.12-1.19) and significantly low rates of hospital treatment or death due to IHD (SHR = 0.80, 95% CI: 0.71-0.91). Apart from a few caveats, the strong correlations obtained in the present study signify that purchase of a prescription for IHD-related medication is a usable risk indicator for IHD in the working population of Denmark. The usage of medicine data in addition to or instead of the use of death or hospital data in epidemiological studies on work-related IHD risk will bring about a tremendous increase in statistical power.

A bilingual pediatric patient who underwent tumor resection was mapped extraoperatively using cortical stimulation to preserve English and Hebrew languages. The authors mapped both languages by using 4 tasks: 1) English visual naming, 2) Hebrew visual naming, 3) read English/respond Hebrew, and 4) Hebrew reading. Essential cortical sites for primary and secondary languages were compared, photographically recorded, and plotted onto a schematic brain of the patient. Three types of sites were found in this patient: 1) multiuse sites (multiple tasks, both languages) in frontal, temporal, and parietal areas; 2) single-task sites (1 task, both languages) in postcentral and parietal areas; and 3) single-use sites (1 task, 1 language) in frontal, temporal, and parietal areas. These results lend support to the concept that bilingual patients can have distinct cortical representations of each language and of different language tasks, in addition to overlapping or shared sites that support both languages and multiple tasks.