Clinical Application and Functionality for an Application for Measurement of Head Circumference.

An accurate head circumference (HC) measurement is a quick and cost-effective assessment which is essential when clinically evaluating a neonate or infant. HC outside the normal range may indicate a disorder of brain development, hydrocephalus, or an intracranial mass lesion. The growth pattern of HC, determined from serial measurements, also provides useful clinical information. For example, changes in HC are used to help determine whether hydrocephalus needs treatment. HC growth is also predictive of neurodevelopmental outcomes. [Lippé et al. 2018]

HC is measured by measuring the widest circumference of the head with a tape measure. Typically, this is performed by health care workers, but parents can be taught to take measurements reliably. With the increasing use of telephone and virtual clinics as a substitute to face-to-face appointments, parental measurement of HC is increasingly used to help guide clinical management in a wide variety of clinical specialties including Neurosurgery, Neonatology, Paediatrics, and General Practice.

Tape measure HC measurements are prone to error, particularly when performed by parents, due to individual differences in head shape, hair style and texture, subject cooperation, and examiner differences in tape measure placement and tautness.6 There is therefore the need for a more reliable method.

Rationale for the study:

We have developed a HC mobile application (HCMA) that can measure the head circumference of an infant and plot it against standardised growth charts.

The rationale of this study is to validate the HCMA in a clinical setting and to review its usability by parents in the community.

Research objective and purpose

The main objective of the study is to validate the accuracy of the HC app and to prove its utility and feasibility in clinical practice.

Secondary objectives will be to evaluate parent/guardian reliability and satisfaction of using the HC app.

Primary Objective:

Hypothesis 1: There is no statistically significant difference between HC measured with a tape measure and HC measured with HCMA;

Secondary Objectives:

Hypothesis 2: Intra-rater Reliability(precision/repeatability) - The variability of series of three measurements of HC using HCMA (performed by a healthcare professional) is within 0.5 cm -(the standard error margin for measurement measurements) Hypothesis 3: Inter-rater Reproducibility - HC measurements made using the HCMA will not be significantly different when measured by parents or healthcare professionals we will then compare measurements of HC using HCMA performed by healthcare professional with the measurements performed by the parents/guardians using the HCMA. These should be within the standard error of margin for the measurement with tape measure.

Hypothesis 4: Parents are satisfied using the HCMA and find it easy to use'

Inclusion criteria

• Infants up to 18 months old seen in a paediatric clinic with a requirement for continuous head circumference measurements.

Exclusion criteria

• Infants above the age of 18 months, Patients in emergency setting, Withdrawal of consent of parents/guardians