Feasibility and preliminary effectiveness of a psychosocial support program for adolescent and young adult cancer patients in clinical practice: a retrospective observational study.

PURPOSE: Adolescent and young adult cancer patients (AYAs) often experience profound psychological distress, with various unmet supportive care needs that can be alleviated with appropriate screening and attention by healthcare workers. The Distress Thermometer and Problem List-Japanese version (DTPL-J) is our previously developed screening tool to facilitate individual support of AYAs. This study evaluated the feasibility and preliminary effectiveness of a psychosocial support program based on the DTPL-J for AYAs in clinical practice. METHODS: This multicenter, retrospective, observational study included 19 of 126 wards and 9 of 75 outpatient clinics at 8 institutions in Japan. Over 200 patients were expected to participate during the eligibility period. Patients participated in a support program at least once, and approximately once a month based on the DTPL-J results. The program was evaluated using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) implementation framework. RESULTS: The screening rate of the 361 participants was 90.3%, suggesting high feasibility. Distress Thermometer scores, the number of supportive care needs, and the rates of AYAs with high distress were significantly reduced 1 month after screening (p < 0.05), suggesting the preliminary effectiveness of the program. The program was continued at the 8 institutions as part of routine care after the study. CONCLUSION: Analysis using the RE-AIM suggested the sufficient feasibility and preliminary effectiveness of a psychosocial support program based on the DTPL-J for AYAs. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN CTR) UMIN000042857. Registered 25 December 2020-Retrospectively registered.

Factors associated with employment status among mothers of survivors of childhood cancer: a cross-sectional study.

PURPOSE: To identify the factors associated with employment status among mothers of childhood cancer survivors (CCSs). METHODS: We conducted a questionnaire survey on mothers of survivors of childhood cancer to clarify practical factors such as care demands, psychological factors such as motivation to work, and support. After calculating descriptive statistics for all variables, binary logistic regression analysis was performed. RESULTS: Of 171 mothers, 129 (75.4%) were employed. The most common form of employment was non-regular (n = 83; 48.5%), including part-time, dispatched, and fixed-term workers. At the time of the survey, compared with nonworking mothers, working mothers tended to be more motivated to work and have lower scores for "Long-term Uncertainty" on the Parent Experience of Child Illness Scale. The results of the binary logistic regression analysis indicated that employment was related to higher motivation to work, the continuation of employment during treatment, more outpatient visits, and a higher amount of support. CONCLUSION: As employment of CCSs' mothers is associated with psychological factors such as motivation to work and long-term uncertainty, psychological support for CCSs' mothers might promote employment. In addition, because the continuation of employment during treatment affects the employment of mothers after the end of cancer treatment, a leave system that covers the treatment period for childhood cancer needs to be established.

Fertility preservation in adolescent and young adult cancer patients: From a part of a national survey on oncofertility in Japan.

PURPOSE: This study evaluated the current status of reproductive disorders and provision of information on oncofertility to female adolescent and young adult (AYA) cancer patients in Japan. METHODS: A national survey of AYA cancer survivors was conducted. Children were <15 years old, and AYAs were 15-39 years old. Results from the survivors of other than gynecological disease who underwent chemotherapy were analyzed. RESULTS: Among the survivors, 41.4% were concerned about their reproductive function and infertility, and 36.2% were aware of menstrual cycle abnormalities. Among them, 15.5% (n = 20) of all and 21.2% (n = 17) of the AYA-onset survivors suffered infertility due to chemo- or radiotherapy and gave up childbearing. These rates were significantly higher than those of healthy AYAs. Although 80.8% of AYA-onset survivors answered that they had received information on reproductive function and infertility, only 55.8% had received information on fertility preservation methods. Furthermore, only 22.4% of all and 42.3% of AYA-onset survivors had received pretreatment information on fertility preservation methods. CONCLUSIONS: Not a few AYA cancer survivors reported reproductive dysfunction. These findings indicate that information provided on therapy-related problems before cancer treatment in Japan was insufficient and highlight the need to improve patient decision-making and support systems for fertility preservation.

Problems of reproductive function in survivors of childhood- and adolescent and young adult-onset cancer revealed in a part of a national survey of Japan.

PURPOSE: This study aimed to evaluate the current status of reproductive disorders as long-term complications in adolescent and young adult (AYA) cancer patients by comparing survivors of childhood-onset with those of AYA-onset cancer in Japan. METHODS: We conducted a national survey of AYA cancer survivors and healthy AYAs and analyzed the results from survivors who underwent chemotherapy and reported fertility problems as their current concern. RESULTS: Among all of the childhood-onset survivors, 27 (35.5%; nine males [28.1%] and 18 females [40.9%]) listed reproduction fertility problems as their current concern. Among all AYA-onset survivors, 25 (69.5%; 1/4 males [25.0%] and 24/32 females [75.0%]) listed these problems as a current concern. In contrast, 96.3% (26/27) of all childhood-onset cancer survivors and 68.0% (17/25) of all AYA-onset cancer survivors who received chemotherapy listed these problems as a current concern. CONCLUSIONS: A considerable number of both childhood-onset and AYA-onset cancer survivors, and especially those who had undergone chemotherapy, reported reproductive dysfunction as a delayed complication. It is vitally important to establish a supportive care system both for the patients whose fertility was abolished after the completion of cancer treatment and prophylactically for patients before they begin treatment.

[Perceptions toward Employment and Support Needs in Medical Institutions and Workplace among AYA Cancer Survivors].

We conducted a cross-sectional questionnaire study to explore perceptions of employment, job-related help-seeking behaviors at the time of cancer diagnosis, illness disclosure at the workplace, and support needs for continuous employment among adolescent and young adult cancer survivors. The mean age at the time of cancer diagnosis was 27.8(range, 15-37) years. For survivors in this age category, employment is the foundation for economic development and contributions to society. Approximately half of the participants sought job-related help from medical staff and employment experts. Approximately 90%of the participants disclosed their illness to their workplace, and most were given consideration for their situation. To ensure continuous employment, the participants required environmental improvement at the workplace rather than consultation services at hospitals. This study suggests the need to further investigate when and where certain support is required and to consider ways to improve support at both hospitals and workplaces.

Risk factors for psychological and psychosomatic symptoms among children with malignancies.

AIM: With increasing survival rates in paediatric malignancies, the quality-of-life of children during hospitalisation should be given more attention. We aimed to identify factors associated with psychological and psychosomatic symptoms (PPS) that required medication among children hospitalised for treatment of malignancies. METHODS: We retrospectively analysed data of 190 patients aged 2-18 years old. They were diagnosed with malignant diseases and admitted for treatment at St. Luke's International Hospital between 2003 and 2013. Patients were considered as having PPS if they were prescribed psychotropic agents during hospitalisation. RESULTS: Of the 190 patients, 56 (30%) were prescribed psychotropic agents for PPS. Types of PPS included insomnia in 21 (38%), anxiety in 11 (20%), and others conditions (psychogenetic nausea, agitation, delirium, depression). The most prescribed psychotropic agents were etizolam for 34 cases (61%), followed by diazepam and risperidone. The multivariable analyses confirmed statistically significant independent associations for haematopoietic stem cell transplantation (HSCT) (odds ratio (OR), 5.21; 95% confidence interval (CI), 1.77-15.35), older age (12-18 years vs. 2-5 years, OR, 3.74; 95% CI, 1.04-10.00), and opioid use (OR, 7.15; 95% CI, 2.36-21.69). CONCLUSIONS: Older age at admission, undergoing HSCT, and those given opioids were found to be risk factors for PPS among children with malignancies. Appropriate preventive measures against PPS may be warranted for patients with these risk factors.

Differences in posttraumatic growth and grief reactions among adolescents by relationship with the deceased.

AIM: The aim of this study was to examine three hypotheses: (1) adolescents who had experienced the death of a parent would report higher grief reactions than those who had lost a grandparent; (2) adolescents who experienced the death of a parent would report higher posttraumatic growth than those who had lost a grandparent; and (3) posttraumatic growth and grief reactions are positively associated. BACKGROUND: To date, no study has investigated adolescents' posttraumatic growth by their relationship with the deceased. DESIGN: Cross-sectional web-based survey. METHODS: Participants were adolescents who had experienced the death of a parent or grandparent in the last 5 years. Participants completed the Japanese version of the Posttraumatic Growth Inventory and grief reaction items. We conducted a web-based survey during January 2014. We used Pearson product-moment correlations to examine the association between each Posttraumatic Growth Inventory domain and each grief reaction item. Differences in the relationship with the deceased for each Posttraumatic Growth Inventory and grief reaction item were compared with an independent-sample t-test. RESULTS: Participants (n = 124) reported grief reactions including 'I began to get frustrated at the little things' (43·5%), 'It was difficult to go to school' (41·1%) and 'I was not able to sleep at night' (33·9%). The independent t-test indicated that parentally bereaved adolescents reported higher grief reactions than those who had lost a grandparent. There were no differences in post-traumatic growth by relationship with the deceased. [corrected]. Pearson's bivariate analysis showed an association between grief reactions and posttraumatic growth. CONCLUSION: Parentally bereaved adolescents reported higher grief reactions. [corrected]. Nurses should ensure bereaved adolescents receive appropriate support.

Effect of a group intervention for children and their parents who have cancer.

OBJECTIVE: Although support programs for children whose parents have cancer have been described and evaluated, formal research has not been conducted to document outcomes. We adapted a group intervention called CLIMB®, originally developed in the United States, and implemented it in Tokyo, Japan, for school-aged children and their parents with cancer. The purpose of this exploratory pilot study was to examine the feasibility, acceptability, and impact of the Japanese version of the CLIMB® Program on children's stress and parents' quality of life and psychosocial distress. METHODS: We enrolled children and parents in six waves of replicate sets for the six-week group intervention. A total of 24 parents (23 mothers and 1 father) diagnosed with cancer and 38 school-aged children (27 girls and 11 boys) participated in our study. Intervention fidelity, including parent and child satisfaction with the program, was examined. The impact of the program was analyzed using a quasiexperimental within-subject design comparing pre- and posttest assessments of children and parents in separate analyses. RESULTS: Both children and parents experienced high levels of satisfaction with the program. Children's posttraumatic stress symptoms related to a parent's illness decreased after the intervention as measured by the Posttraumatic Stress Disorder-Reaction Index. No difference was found in children's psychosocial stress. The Functional Assessment of Chronic Illness Therapy scores indicated that parents' quality of life improved after the intervention in all domains except for physical well-being. However, no differences were found in parents' psychological distress and posttraumatic stress symptoms. SIGNIFICANCE OF RESULTS: Our results suggest that the group intervention using the CLIMB® Program relieved children's posttraumatic stress symptoms and improved parents' quality of life. The intervention proved the feasibility of delivering the program using manuals and training. Further research is needed to provide more substantiation for the benefits of the program.

Factors associated with the specific worries of childhood cancer survivors: Cross-sectional survey in Japan.

BACKGROUND: Previous research has shown that adult childhood cancer survivors (CCS) have many worries. We re-analyzed the employment data in order to identify these worries and their associated factors. METHODS: The participants were selected from the membership directory of Heart Link mutual-aid health insurance, and recruited by the CCS Network. We conducted a cross-sectional survey (a self-rated questionnaire on employment) via post or email with a link to an Internet website. We investigated the association between CCS factors and the specific worries. The adjusted odds ratios (OR) for the associated factors with a specific worry were estimated on logistic regression analysis. RESULTS: A total of 240 questionnaires were collected by November 2012. One questionnaire was excluded because the answers were not provided by the CCS him/herself. The most common worries were health-related problems (50%) and employment issues (40%), which were followed by his/her personality and life (23%) and self-appearance (20%). Fifty (21%) out of 239 CCS answered no specific worry. The common consistent factor associated with worries was the presence of late effects. Of note was that the CCS worries were not associated with age at diagnosis or follow up, gender, educational achievement or marriage. The worry about employment issues was associated with economic status, disability qualification, and employment status. CONCLUSIONS: The CCS worries were strongly affected by the presence of late effects. No significant association was noted between CCS worries and gender, age at diagnosis or follow up, or educational achievements. Economic status and disability qualification were associated with some worries.

Psychosocial difficulties in adolescent and young adult survivors of childhood cancer.

BACKGROUND: With a large number of children surviving cancer worldwide, numerous investigations have assessed psychological and social adjustment among childhood cancer survivors. According to these studies, it is unclear whether childhood cancer survivors successfully adjust to daily life after being discharged from hospital, especially for adolescent and young adult survivors who have unique needs and concerns. The primary aim of this study was to identify the factors underlying psychosocial difficulties faced by adolescent and young adult survivors in their day-to-day lives after being discharged from hospital. METHODS: Semi-structured interviews were conducted. Twenty-five childhood cancer survivors were recruited from two regional cancer institutions in Japan. Content analysis was applied to the responses. RESULTS: Nineteen attributes were extracted and classified into four categories as follows: physical difficulties, interpersonal difficulties, behavioral difficulties, and uncertainty about the future. The attributes indicated by >50% of the participants were "I am worried about not feeling well," "I have difficulty continuing treatment in daily life," "I have difficulty moving my body," "I have to be absent from school or work because of illness," and "I am left behind academically." CONCLUSIONS: This study identified important factors of psychosocial day-to-day difficulties. Clinically, these results suggest that it is important to watch for these signs and to provide early support to survivors so that their daily life and development are not hindered by the treatment and its side-effects, and to offer long-term support focusing on individual patient characteristics such as sex, age, and cancer history.

Recent employment trend of childhood cancer survivors in Japan: a cross-sectional survey.

BACKGROUND: Previous research has shown that some adult childhood cancer survivors (CCSs) have experienced employment difficulties. However, the actual employment status of CCSs in Japan has not been studied. PARTICIPANTS AND METHODS: The participants were selected from the membership directory of Heart Link mutual-aid health insurance and recruited by the Childhood Cancer Patients' Network. We conducted a cross-sectional survey (a self-rated questionnaire on employment) via postal mail or an email communication with a link to an Internet website. We explored the association between the characteristics of CCSs who require disability qualification and having experienced unemployment. The adjusted odds ratios (ORs) for the factors with an outcome of interest were estimated with logistic regression analysis. RESULTS: In total, 44 CCSs indicated that they had a disability qualification. The significant independent factors related to needing a disability qualification were late effects [OR 12.3; 95 % confidence interval (CI) 3.37-45.2], brain tumors (OR 9.55; 95 % CI 1.90-48.0), and being a high school graduate (OR 9.86; CI 2.67-36.4). The unemployment rate was 15.9 % among CCSs, excluding homemakers and students. Approximately 70 % of unemployed CCSs had some late effects; independent factors related to unemployment were late effects (OR 6.22; 95 % CI 1.80-21.40), dropping out of school (OR 8.46; 95 % CI 1.66-43.10), and brain tumors (OR 2.73; 95 % CI 0.83-8.96). Most unemployed CCSs were likely to seek work, despite their health problems. CONCLUSIONS: The unemployment rate is not high in Japan, but some CCSs need extended disability qualification. The independent factors related to unemployment were late effects and dropping out of school.

Significance of active screening for detection of health problems in childhood cancer survivors.

Background: Childhood cancer survivors (CCSs) have a lifelong increased risk of chronic health problems, most of which are associated with the curative therapies. Recent studies have suggested that prospective active screening using comprehensive assessments for CCSs is superior in identifying undiagnosed chronic health problems. Methods: To assess the significance of active screening using comprehensive medical examinations for detecting chronic health problems in multiple organ systems in CCSs, we retrospectively compared the frequency and severity of health problems between two different cohorts of CCSs in a single institution: 110 CCSs who visited the outpatient clinic for regular follow-ups between December 2010 and December 2015 (regular follow-up group) vs. 58 CCSs who underwent comprehensive medical examinations between February 2016 and September 2019 (active screening group). CCSs were defined as patients aged ≥ 18 years who had been diagnosed as having childhood cancer ≥ 10 years before and had survived without cancer for ≥ 5 years. Results: Patient characteristics were similar between the two groups except for primary diagnosis (more brain tumors and embryonal tumors in the active screening group) and treatment history (more alkylating agents used and surgical interventions performed in the active screening group). The prevalence and the median number of health problems were significantly higher in the active screening group than in the regular follow-up group: 93% vs. 67% and 1.0 [0.0-8.0] vs. 2.0 [0.0-7.0] respectively. In term of organ-specific health problems, pulmonary dysfunction, neurocognitive impairment, ocular abnormalities, and dental abnormalities were identified more in the active screening group, partly because these problems had not been assessed in the regular follow-up group. Nevertheless, the prevalence of grade 3-5 health problems was similar between the two groups, except for pulmonary dysfunction. Conclusion: Active screening using comprehensive medical examinations was effective for identifying health problems in CCSs. Although the prevalence of severe problems identified by both approaches was similar, comprehensive medical examinations could detect overlooked problems such as severe pulmonary dysfunction, dental maldevelopment, and borderline intellectual functioning, which might have an impact on quality of life in CCSs.

Factors related to employment in childhood cancer survivors in Japan: A preliminary study.

Purpose: Previous research has revealed vocational and academic difficulties in childhood cancer survivors, and explored impact of survivors' medical history and physical function on vocational and academic status. However, we often encounter survivors with similar diagnoses and late effects but different academic or employment statuses. This raises the question of what affects academic attainment and employment other than treatment or late effects. This study aimed to explore factors associated with childhood cancer survivors' employment status and academic achievement. Methods: Comprehensive health check-up and questionnaire survey were conducted for 69 survivors who were over the age of 18 and participated in St. Luke's Lifetime cohort study. We obtained survivors' biological function using comprehensive health check-up, neurocognitive states, quality of life, transition readiness, and family function. We conducted univariate analysis (Mann-Whitney U tests or chi-square tests) to compare the differences between the regular workers/students and non-regular workers/unemployed groups. The variables with p-values <0.1 were used as independent variables multivariate logistic regression to explore predictors of employment status and academic attainment. Results: Result of the univariate analysis, intelligence quotient, SF-8 PCS, transition readiness, family function were used for multivariate logistic regression as independent variables. The stepwise likelihood method was conducted; intelligence quotient (odds ratio [OR] = 1.100; 95% confidence interval [CI] 1.015-1.193; p = 0.021), transition readiness (OR = 0.612; 95% CI 0.396-0.974; p = 0.038), and family function (OR = 2.337; 95% CI 1.175-4.645; p = 0.015) were found to be associated with survivors' regular workers/students in the final regression model. Conclusion: Long-term follow-up of pediatric cancer survivors requires the provision of total care, which supports physical, psychological, and social functions to improve health, readiness for transition to self-management, and family functioning.

Characteristics, treatment trends, and long-term outcomes of Japanese patients with pregnancy-associated breast cancer (PABC).

PURPOSE: To clarify the characteristics, treatment trends, and long-term outcomes of patients with pregnancy-associated breast cancer (PABC). METHODS: PABC includes breast cancer diagnosed during pregnancy (PBC) and breast cancer diagnosed within 1 year after childbirth or during lactation (LBC). We compared clinical characteristics of 126 patients with LBC and 49 patients with PBC who underwent surgery at our hospital from 1946 to 2018. Survival was compared between patients with LBC and those with PBC in terms of breast cancer-specific disease-free survival (BC-DFS) and overall survival (OS). RESULTS: Patients with LBC were more likely to have family history, lymph node metastasis, lymphatic invasion, and to receive chemotherapy than patients with PBC. Patients with LBC showed poorer BS-DFS and OS than patients with PBC. Among patients with LBC, those treated after 2005 were older at surgery, had a smaller tumor size, received more systemic therapy, and had a more favorable prognosis than patients treated before 2004. Family history, breast cancer within 1 year after childbirth, and surgery before 2004 as well as cStage, lymph node metastasis, and lymphatic invasion were significantly associated with poor prognosis in patients with LBC. In the multivariate analysis for BC-DFS and OS among patients with PABC, LBC vs PBC did not remain as an independent prognostic factor while cStage remained. CONCLUSION: Patients with LBC had a poorer prognosis than those with PBC, most likely due to disease progression rather than biological characteristics. Early detection and optimization of systemic treatments are critical for improving the outcomes of patients with LBC.

Preterm toddlers have low nighttime sleep quality and high daytime activity.

A number of studies have been made on the sleep characteristics of children born preterm in an attempt to develop methods to address the sleep problems commonly observed among such children. However, the reported sleep characteristics from these studies vary depending on the observation methods used, i.e., actigraphy, polysomnography and questionnaire. In the current study, to obtain reliable data on the sleep characteristics of preterm-born children, we investigated the difference in sleep properties between 97 preterm and 97 term toddlers of approximately 1.5 years of age using actigraphy. Actigraphy units were attached to the toddlers' waists with an adjustable elastic belt for 7 consecutive days, and a child sleep diary was completed by their parents. In the study, we found that preterm toddlers had more nocturnal awakenings and more daytime activity, suggesting that preterm-born children may have a different process of sleep development in their early development.

Intellectual development after treatment in children with acute leukemia and brain tumor.

BACKGROUND: The influence of central nervous system (CNS)-directed chemotherapy on intelligence remains controversial. In this study, we investigated the influence of treatment on intellectual development in acute lymphoblastic leukemia (ALL) and brain tumor patients undergoing CNS-directed treatments. METHODS: Among patients treated in the Department of Pediatrics, St Luke's International Hospital between April 2000 and March 2009, the subjects were 38 patients with ALL or brain tumors who underwent regular Wechsler intelligence tests. RESULTS: The subjects consisted of 26 patients with ALL and 12 with brain tumors. Prophylactic cranial irradiation was not performed in patients with ALL, whereas it was done for all those with brain tumor. In patients with ALL, the IQ 1 year later was not changed from the start of treatment. In those with brain tumors, the verbal IQ 1 year later was significantly lower than that at the start of treatment. In patients with ALL, intelligence tests were performed 3 years after the start of treatment and there were no marked changes between the two time-points (n = 11). In those with a brain tumor, intellectual functions further decreased after the completion of treatment to as late as 5 years after the initiation of treatment (n = 7). CONCLUSIONS: There is no intellectual impairment in any patient with ALL at post-treatment follow-up 3 years after the start of treatment, while intelligence is serially reduced in brain tumor patients. An innovative intervention may be needed for this group of patients.

Hereditary paraganglioma presenting with atypical symptoms: Case report.

RATIONALE: Paraganglioma (PGL), an extra-adrenal pheochromocytoma, is a rare tumor, especially in children. While hypersecretion of catecholamines causes the classic triad of headaches, palpitations, and profuse sweating, prompt diagnosis is still challenging. PATIENT CONCERNS: For 7 months, an 8-year-old boy complained of polyuria and weight loss, followed by proteinuria and headache for 1 month prior to admission. He was admitted to our hospital due to an afebrile seizure. DIAGNOSIS: His blood pressure remained markedly elevated even after cessation of the convulsion. Magnetic resonance imaging of the brain revealed posterior reversible encephalopathy syndrome. Abdominal computed tomography showed a mass lesion encasing the left renal artery, measuring 41 mm in length along its major axis. The plasma and urine levels of normetanephrine were elevated. Additionally, iodine-123-metaiodobenzylguanidine scintigraphy showed an abnormal uptake in the abdominal mass with no evidence of metastasis. Based on these findings, we tentatively diagnosed him with PGL. INTERVENTION: Substantial alpha- and beta-blocking procedures were performed, followed by a tumor resection and an extended left nephrectomy on day 31 of hospitalization. Pathological findings confirmed the diagnosis of PGL. OUTCOME: The postoperative course was uneventful, and his blood pressure normalized without the use of antihypertensive agents. Genetic testing revealed a known SDHB germline mutation. The same mutation was also detected on his father and paternal grandfather without any history of hypertension or malignant tumor. LESSON: It remains challenging to diagnose pheochromocytoma/paraganglioma (PPGL) promptly because PPGL can present with a variety of symptoms. Preceding symptoms of the presented case might be caused by PGL. Although PPGL is a rare disease, especially in children, it should be considered in differential diagnosis when various unexplained symptoms persist.

Daytime nap and nighttime breastfeeding are associated with toddlers' nighttime sleep.

The purpose of the present study is to examine the association between toddlers' sleep arrangements and their nighttime sleep duration and other sleep variables. For this investigation, we performed a study in which child activity and sleep levels were recorded using actigraphy. The parents of 1.5-year-old toddlers (n = 106) were asked to attach an actigraphy unit to their child's waist with an adjustable elastic belt and complete a sleep diary for 7 consecutive days. Questionnaires were used to assess the sleep arrangements of the toddlers. There was a significant negative correlation between nap duration and nighttime sleep duration, suggesting that longer nap sleep induces shorter nighttime sleep duration. Among the sleep arrangements, such as nighttime breastfeeding or co-sleeping, only nighttime breastfeeding predicted shorter nighttime sleep duration. Our findings indicate that shorter naps induce a longer nighttime sleep in 1.5-year-old toddlers while nighttime breastfeeding decreases their nighttime sleep duration.

Sleep maturation influences cognitive development of preterm toddlers.

Our recent study on full-term toddlers demonstrated that daytime nap properties affect the distribution ratio between nap and nighttime sleep duration in total sleep time but does not affect the overall total amount of daily sleep time. However, there is still no clear scientific consensus as to whether the ratio between naps and nighttime sleep or just daily total sleep duration itself is more important for healthy child development. In the current study, to gain an answer to this question, we examined the relationship between the sleep properties and the cognitive development of toddlers born prematurely using actigraphy and the Kyoto scale of psychological development (KSPD) test. 101 premature toddlers of approximately 1.5 years of age were recruited for the study. Actigraphy units were attached to their waist with an adjustable elastic belt for 7 consecutive days and a child sleep diary was completed by their parents. In the study, we found no significant correlation between either nap or nighttime sleep duration and cognitive development of the preterm toddlers. In contrast, we found that stable daily wake time was significantly associated with better cognitive development, suggesting that sleep regulation may contribute to the brain maturation of preterm toddlers.