Objective Neurocognitive Assessment of Young Children With Sickle Cell Disease by Eye-Tracking (ONSET)

Evidence indicates that Sickle Cell Disease (SCD) threatens neurodevelopmental outcome. Although children with SCD may be heterogeneously affected, neurocognitive impairment may already be present in toddlers. Neurocognitive functioning is an important determinant of adaptive daily life functioning later in life and is influenced by both the course of the disease and the often suboptimal environment in which afflicted children grow up. Early identification of children at the highest risk of neurocognitive impairment would enable the deployment of early interventions to mitigate the detrimental effects of SCD on the developing brain. In order to develop such interventions, a deeper understanding of the underlying pathophysiological mechanisms is required. Therefore the main aim is to study early neurocognitive functioning and development in children with SCD between the ages of 6 and 24 months old.

Study Overview

• Status: Completed
• Conditions: Sickle Cell Disease; Sickle Cell; Neurocognition, Child
• Intervention / Treatment: Other: eyetracking; Diagnostic test: blood work; Other: Strengths and difficulties questionnaire (SDQ); Other: TNO AZL Preschool Children Quality of Life (TAPQOL); Other: Bayley Scale of Infant Development III (BSID)

Detailed Description

Objective: The main aim is to study early neurocognitive functioning and development in very young children with SCD. The secondary aims are to 1) (i) identify demographic, psychosocial and clinical determinants and (ii) identify biomarkers associated with early neurocognitive deficits in young children with SCD. 2) Analyze the association between early neurocognitive functioning and adaptive daily life functioning.

Study design: Prospective observational study with an accelerated longitudinal design. The accelerated longitudinal design allows for the inclusion of children from a broad age range (6 - 24 months). During the total study period of 30 months, children can enroll in the study at the ages of 6, 12, 18 and 24 months. After enrollment, children will visit every 6 months until they reach the age of 24 months. This design spans the age range of interest in a shorter period of time and a smaller load on participants as compared to a conventional longitudinal design.

Methods: Eye-tracking measurements will take place at every study visit. Demographic, psychosocial and clinical characteristics of the SCD group will be collected using prospective and structured clinical registration as part of regular clinical care. Demographic, psychosocial and clinical information of the control group will be collected using a parent questionnaire administered during the first and last study visit. Blood samples of children with SCD will be taken as part of regular blood checks at the age of 12 and/or 24 months (depending on the age of enrollment in the study). The Child Behavior Checklist, TNO AZL Preschool Children Quality of Life and the Bayley Scale of Infant and Child Development will be administered to all children at the age of 24 months.

Main study parameters/endpoints: Neurocognitive functioning, as measured using eye-tracking.

Secondary study parameters/ endpoints: The following determinants will be measured: Demographic, psychosocial and clinical characteristics, as measured as part of regular clinical care (SCD group) or via parent questionnaire (control group) and Biomarkers, as measured in blood (SCD group). Adaptive daily life functioning, as measured by quality of life, behavioural and emotional functioning questionnaire, and general (cognitive) development assessment.

• Study Type: Observational
• Enrollment (Actual): 93

Contacts and Locations

Study Locations

• Netherlands
  • Amsterdam, Netherlands, 1105AZ
    • Amsterdam UMC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Children between the 6 and 24 months are invited to participate in the study.

Description

Inclusion Criteria:

• Age 6 - 24 months old
• Inhabitant of the Netherlands
• Written informed consent from parent/caretaker.

Exclusion Criteria:

• Refused informed consent from parents/care-taker
• Diagnosis of visual impairment (which cannot be corrected by glasses)
• Diagnosis of a (co-morbid) congenital developmental condition
• Any neurological condition, unrelated to SCD, that could affect the central nervous system, such as brain trauma, epilepsy and meningitis/encephalitis.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patient group; Infants between 6 and 24 months of age diagnosed with sickle cell disease	Other: eyetracking; Eye-tracking is an objective, non-invasive method and particularly suited to assess neurodevelopmental outcome in infants.; Diagnostic test: blood work; proteomics analyses methylation analyses; Other: Strengths and difficulties questionnaire (SDQ); The strengths and difficulties questionnaire is a conventional instrument used to measure the presence of psychosocial problems, the child's strengths and the influence of psychosocial problems on daily functioning.; Other: TNO AZL Preschool Children Quality of Life (TAPQOL); The TNO-AZL Preschool Children Quality of Life is a questionnaire that measures the health-related quality of life of children over the last three months; Other: Bayley Scale of Infant Development III (BSID); The Bayley Scale of Infant Development is a conventional instrument used to measure developmental outcome in infants
Healthy subject group; Infants between 6 and 24 months of age without sickle cell disease	Other: eyetracking; Eye-tracking is an objective, non-invasive method and particularly suited to assess neurodevelopmental outcome in infants.; Other: Strengths and difficulties questionnaire (SDQ); The strengths and difficulties questionnaire is a conventional instrument used to measure the presence of psychosocial problems, the child's strengths and the influence of psychosocial problems on daily functioning.; Other: TNO AZL Preschool Children Quality of Life (TAPQOL); The TNO-AZL Preschool Children Quality of Life is a questionnaire that measures the health-related quality of life of children over the last three months; Other: Bayley Scale of Infant Development III (BSID); The Bayley Scale of Infant Development is a conventional instrument used to measure developmental outcome in infants

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Processing speed in the gap condition (Gap/Overlap task)	The speed of responding to a novel peripheral stimulus when the central stimulus disappears before the peripheral target appears. Measured as reaction time (RT) via eye-tracking in infants with sickle cell disease (SCD). Unit of Measure: Milliseconds (ms)	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Processing accuracy in the gap condition (Gap/Overlap task)	The precision of responding to a novel peripheral stimulus when the central stimulus disappears before the peripheral target appears. Measured as a binomial outcome (accurate/inaccurate) per trial via eye-tracking in infants with SCD. Unit of Measure: Proportion of accurate trials	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Orienting attention speed in the overlap condition (Gap/Overlap task)	The speed of orienting attention away from a central stimulus toward a peripheral target when the central stimulus remains on screen. Measured as RT in the overlap condition expressed as percentage change relative to mean RT in the gap condition, via eye-tracking in infants with SCD. Unit of Measure: Percentage (%)	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Orienting attention accuracy in the overlap condition (Gap/Overlap task)	The precision of orienting attention toward a peripheral target when the central stimulus remains on screen. Measured as a binomial outcome (accurate/inaccurate) per trial via eye-tracking in infants with SCD. Unit of Measure: Proportion of accurate trials	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Alerting attention without external cues (Gap/Overlap task)	The ability to maintain focus on the task without external attention-grabbing cues. Measured as a binomial outcome per trial (completed without attention grabber: yes/no) via eye-tracking in infants with SCD. Unit of Measure: Proportion of trials completed without attention grabber	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Sustained attention across trials (Gap/Overlap task)	The ability to attend to the task over a longer period. Measured as the number of trials completed expressed as a percentage of the total possible trials, via eye-tracking in infants with SCD. Unit of Measure: Percentage (%)	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Fixation duration during free viewing (Freeview task)	The amount of time the eyes remain stably focused on a specific location, defined as periods of stable gaze between successive saccades. Measured as mean fixation duration via eye-tracking in infants with SCD. Unit of Measure: Milliseconds (ms)	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Habituation (Habituation task)	The process of becoming accustomed to a repeatedly presented stimulus. Measured as the number of trials required to reach the pre-defined habituation criterion via eye-tracking in infants with SCD. Unit of Measure: Number of trials	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Recognition (Habituation task)	The ability to distinguish a previously presented stimulus from a novel one. Measured as the absolute difference in looking time toward the habituation stimulus versus the novel stimulus, via eye-tracking in infants with SCD. Unit of Measure: Percentage (%)	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)
Novelty preference (Habituation task)	The tendency to inspect a novel stimulus relative to a previously presented one. Measured as looking time toward the novel stimulus as a percentage of total looking time, via eye-tracking in infants with SCD. Unit of Measure: Percentage (%)	T1 (age 6 months), T2 (age 12 months), T3 (age 18 months), T4 (age 24 months)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Demographic and perinatal characteristics assessed via parent-reported questionnaire	Demographic and perinatal information collected via a structured parent/caretaker questionnaire, including child age, sex, ethnicity, country of origin, parental education level (as proxy for socioeconomic status), and perinatal information (e.g. breastfeeding, birth characteristics). Clinical characteristics (e.g. SCD genotype, disease severity, treatment) are extracted from electronic health records. Unit of Measure: Categorical and continuous variables (reported descriptively)	At study visit of 6, 12 18 or 24 months of age, depending on the enrollment age. The first visit in the study
Behavioral and emotional functioning assessed using the Strengths and Difficulties Questionnaire (SDQ)	Parent-reported behavioral and emotional functioning measured using the SDQ, a validated screening instrument. The SDQ assesses five domains: emotional symptoms, conduct problems, hyperactivity/inattention, peer relationship problems, and prosocial behavior. Scores are reported per subscale and as a total difficulties score. Unit of Measure: Scale score (0-40 total difficulties score)	study visit at 24 months of age
Development assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III)	Standardized assessment of development administered by a trained examiner at age 24 months using the BSID-III (Cognitive and Motor Scale). Scores are reported as scaled scores with a normative mean of 10 (SD=3). Unit of Measure: Scaled score	study visit at 24 months of age
Plasma proteomic biomarker profile assessed via blood sample in children with SCD	A blood sample is collected from children with SCD to identify plasma proteomic biomarkers related to disease severity and neurological functioning. Samples are analyzed using unbiased proteomics analyses to characterize protein expression profiles. Unit of Measure: Protein expression levels (reported as relative abundance)	study visit at 12 months of age and study visit at 24 months of age

Collaborators and Investigators

• Sponsor: Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)

Study record dates

Study Major Dates

• Study Start (Actual): March 16, 2023
• Primary Completion (Actual): November 27, 2025
• Study Completion (Actual): December 2, 2025

Study Registration Dates

• First Submitted: June 22, 2026
• First Submitted That Met QC Criteria: July 20, 2026
• First Posted (Actual): July 22, 2026

Study Record Updates

• Last Update Posted (Actual): July 22, 2026
• Last Update Submitted That Met QC Criteria: July 20, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: cognition; sickle cell
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Hematologic Diseases; Anemia, Hemolytic, Congenital; Anemia, Hemolytic; Anemia; Hemoglobinopathies; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Hemic and Lymphatic Diseases; Anemia, Sickle Cell
• Other Study ID Numbers: NL82004.018.22; 2022.0539 (Other Identifier: Amsterdam UMC)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: We intend to make IPD available to other researchers. However, we still need to develop the plan in collaboration with the privacy officer and legal research support.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No