刑部 恵介

PURPOSE: Shear wave velocity (Vs) measurements can be unstable in individuals with obesity or with a skin-capsule distance (SCD) of ≥ 20 mm. However, instability of Vs has also been observed in cases where SCD is not markedly increased; therefore, the present study aimed to investigate the factors contributing to reduced VsN (net amount of effective shear wave velocity), an index that reflects the reliability of individual Vs measurements. METHODS: In total, 317 individuals who underwent community-based health screening were included in this study. We investigated the relationship between VsN and physical findings, laboratory data, SCD, and structure of the SCD (single vs. multilayered) to identify factors associated with decreased VsN. RESULTS: Multiple regression analysis revealed that body fat percentage (β = - 0.135, p = 0.011), SCD (β = - 0.347, p < 0.0001), and the structure of the SC region (β = - 0.295, p < 0.0001) were independently associated with decreased VsN. In cases where the SCD exceeded 20 mm, the VsN within the SCD was significantly lower in the multilayer structural type [52 (28-75)] than in the single-layer structural type [95 (77-99)] (p = 0.004). Furthermore, even when the SCD was 20 mm or less, the VsN within the SCD was significantly lower in the multilayer structure type [80 (68-89)] than in the single-layer structure type [99 (92-100)] (p < 0.0001). CONCLUSION: The results show that, in addition to SCD thickness, its internal structure reduces the VsN and contributes to Vs measurement instability.

OBJECTIVE: The accuracy of self-reported seizure-freedom duration are essentially limited. Scalp high-frequency oscillations (HFOs) are more tightly linked to seizures than spikes alone and are a promising new biomarker. The purpose of this study is to determine the relationship between scalp HFO and time since the last reported seizure. METHODS: The study population consisted of 169 pediatric epilepsy patients (91 males; age range, 0-20 years). A holdout method was used to develop and validate a predictive model (multivariate HFO model) to estimate the time since the last reported seizure. RESULTS: The multivariate HFO model was created with four variables: scalp HFO detection rate, developmental delay, epilepsy duration, and the use of antiepileptic drugs. The area under the curve (AUC) of the multivariate HFO model was higher than that for the HFO and spike models in all four discriminations for time since the last reported seizure (≥ 2 years: AUC = 0.95, ≥ 1 year: 0.91, ≥ 2 months: 0.82, and ≥ 2 weeks: 0.76). CONCLUSIONS: The multivariate HFO model showed higher performance in patients with a longer time since the last reported seizure (≥ 1 year). SIGNIFICANCE: This model may help establish a new measure of epilepsy remission.

OBJECTIVE: Epilepsy treatment with anti-seizure medications (ASMs) is based on careful assessment of the balance between the likelihood of further seizures and the risk of side effects of treatment. However, there is currently no established biomarker to ascertain seizure control status with ASMs. High-frequency oscillations (HFOs), transient bursts of EEG activity with frequencies beyond 80 Hz, are a new and promising noninvasive epilepsy biomarker. We compared the risk of scalp HFO appearance between pediatric patients with good and poor seizure control by treatment with ASMs. METHODS: A total of 72 epilepsy patients (aged 0-18 years, 39 males) with good and poor seizure control with ASMs participated in this study. We applied a validated automated detector to determine HFO and spike. We calculated the odds ratios (ORs) for scalp HFO and spike appearance according to seizure control status by multiple logistic regression analysis. RESULTS: Scalp HFO was seen more commonly and with a significantly higher detection rate in patients with poor seizure control as compared with patients with good seizure control for both ripple and fast ripple. These significant associations were found for both focal and generalized epilepsy. The ORs for scalp HFO appearance adjusted for confounding factors were significantly higher in patients with poor seizure control compared to those with good seizure control (ripple: OR [95% CI] = 11.91 [2.21-64.30], p = 0.004; fast ripple: 4.98 [1.03-24.09], p = 0.046). There were no significant associations between spike appearance and seizure control status. SIGNIFICANCE: We found an increased risk of scalp HFO appearance in patients with poor seizure control. The results of this study support that scalp HFO is associated with patients having frequent seizures after treatment in both ripple and fast ripple. PLAIN LANGUAGE SUMMARY: This study analyzed scalp high-frequency oscillations and spikes in pediatric patients with various types of epilepsy who were being treated using ASMs. The results showed that an increased risk of scalp HFO appearance was observed in patients with poor seizure control compared to those with good seizure control. These findings were observed in both the ripple (80-250 Hz) and fast ripple (250-500 Hz) bands. The scalp HFO is associated with patients having frequent seizures after treatment in both ripple and fast ripple.