Despite their common use as eating utensils in East Asia, chopsticks require complex fine motor-skills for adequate operation and are thus most frequently used with the dominant hand; however, the effect of training time on the proficiency of using chopsticks with the non-dominant hand, as well as the brain activity underlying changes in skill, remain unclear. This study characterised the effect of time spent training in chopstick operation with the non-dominant hand on chopstick-use proficiency and the related brain activity to obtain data that may help individuals who are obliged to change handedness due to neurological disease to learn to use their non-dominant hand in performing daily activities. Thirty-two healthy right-handed students were randomly allocated to training (n = 16) or control (n = 16) groups; the former received 6 weeks of training in chopstick use with their non-dominant (left) hand, and the latter received none. After training, significant improvements in the execution speed and smoothness of upper extremity joints were observed in the training group. Moreover, left dorsolateral prefrontal cortex activity significantly decreased, and bilateral premotor cortex activity significantly increased across training. These results indicated that 6 weeks of chopstick training with the non-dominant hand effectively improved chopstick operation.

Previous neuroimaging studies have reported dual-task interference (DTi) and deterioration of task performance in a cognitive-motor dual task (DT) compared to that in a single task (ST). Greater frontoparietal activity is a neural signature of DTi; nonetheless, the underlying mechanism of cortical network in DTi still remains unclear. This study aimed to investigate the regional brain activity and neural network changes during DTi induced by highly demanding cognitive-motor DT. Thirty-four right-handed healthy young adults performed the spiral-drawing task. They underwent a paced auditory serial addition test (PASAT) simultaneously or independently while their cortical activity was measured using functional near-infrared spectroscopy. Motor performance was determined using the balanced integration score (BIS), a balanced index of drawing speed and precision. The cognitive task of the PASAT was administered with two difficulty levels defined by 1 s (PASAT-1 s) and 2 s (PASAT-2 s) intervals, allowing for the serial addition of numbers. Cognitive performance was determined using the percentage of correct responses. These motor and cognitive performances were significantly reduced during DT, which combined a drawing and a cognitive task at either difficulty level, compared to those in the corresponding ST conditions. The DT conditions were also characterized by significantly increased activity in the right dorsolateral prefrontal cortex (DLPFC) compared to that in the ST conditions. Multivariate Granger causality (GC) analysis of cortical activity in the selected frontoparietal regions of interest further revealed selective top-down causal connectivity from the right DLPFC to the right inferior parietal cortex during DTs. Furthermore, changes in the frontoparietal GC connectivity strength between the PASAT-2 s DT and ST conditions significantly correlated negatively with changes in the percentage of correct responses. Therefore, DTi can occur even in cognitively proficient young adults, and the right DLPFC and frontoparietal network being crucial neural mechanisms underlying DTi. These findings provide new insights into DTi and its underlying neural mechanisms and have implications for the clinical utility of cognitive-motor DTs applied to clinical populations with cognitive decline, such as those with psychiatric and brain disorders.

We have studied the steroid sulfatase (STS) gene in three Japanese families with X-linked ichthyosis (XLI), using polymerase chain reaction (PCR). PCR was performed using three sets of intraexonic primers covering exons 1, 5 and 10. In affected individuals from two of the families, DNA was not amplified in any of the three exons, suggesting that XLI in these families was due to the complete deletion of the STS gene. In affected individuals in the remaining family, DNA was amplified in predicted sizes in exons 1 and 5, but not in exon 10, suggesting that XLI in this family was due to partial deletion of the STS gene including exon 10. These results suggested that STS gene deficiency is heterogeneous in Japanese families with XLI. PCR is useful for the rapid diagnosis of XLI, the differentiation of XLI from ichthyosis vulgaris, and genetic counseling of XLI families. The PCR method was not applicable for carrier detection.

Alopecia associated with epidermal growth factor receptor (EGFR) inhibitor therapy is a rare cutaneous side effect with the potential to progress to scarring alopecia. Thus, dermatologists should make an early diagnosis. We present the case of a 57-year-old Japanese female with scarring alopecia associated with gefitinib, which is an EGFR inhibitor, including trichoscopic findings. The patient treated with gefitinib for non-small cell lung cancer experienced skin rash and hair loss of the scalp. The scalp lesions appeared similar to erosive pustular dermatosis of the scalp. Trichoscopic examination showed follicular keratotic plugging, milky red areas, white patches, hair shaft disorder, tapering hair, and absence of follicular opening. Histological examination showed ruptured hair follicles with a perifollicular infiltration of plasma cells, lymphocytes, and histiocytes. Oral minocycline and topical steroid treatment produced no improvement. With a reduction in the gefitinib dosage, alopecia gradually improved, although scarring remained. We consider these trichoscopic findings and suspect that follicular keratotic plugging might be a finding associated with scarring alopecia due to EGFR inhibitor therapy.

Learning point for clinicians. The mRNA-based COVID-19 vaccine causes flare of glomerulonephritis, especially in patients with IgA nephropathy. Clinicians shoul