This study has two primary objectives. The first is to determine if it is feasible and reliable for children and families with a diagnosis of Neurofibromatosis Type 1 (NF1) to use of blood pressure (BP) monitor at home.

The second is to determine if there is a difference between a child's measured home BP using standard instructions or using a clinical hypnosis script. This will be determined by a randomised control trial design.

Standard and hypnosis Home BP will be compared to the gold standard measurement of BP measured by a trained health care professional in clinic.

Children who participate will complete a clinic-based BP with a health care professional, then will be randomised into either the standard home BP measurement or using a hypnosis script prior to BP measurement.

Neurofibromatosis Type 1 (NF1) is a rare autosomal dominate genetic disorder that affects an estimated that 1 in 2500 people or 10000 Australians. NF1 affects multiple systems throughout the body. The prevalence of hypertension(HTN) in children and adolescents in the general population is approximately 3.5%. Children and adolescents with a diagnosis of NF1 have an increased incidence of HTN, and has been documented as high as 6.1% to 12%. This is two times higher than the general population.

Clinical adherence to the recommendation of recording annual blood pressure on patients has not been audited. The anecdotal experience of the authors is that most children do not have annual blood pressure (BP) measurements. With the increased uptake of telehealth following the COVID-19 pandemic, children and families may not be reviewed in person for significant periods of time as they prefer consultations over telehealth. As a result, children may miss having their annual blood pressure measured. As a young people with a diagnosis of NF1 have twice the risk of HTN, annual BP measurement is essential.

The American Academy Paediatrics guideline outlines the best practice for BP measurement to ensure true BP reading: The child should be seated in a quiet room for 3-5 minutes before measurement, with back supported and feet uncrossed on the floor. The blood pressure should be measured on the right arm, using the correct sized cuff. This should be completed by a trained clinician. As part of this study, all participants will have a manual sphygmomanometer in clinic-based BP taken on day of recruitment.

One of the primary objectives of this study is to determine if is feasible to use home blood pressure monitoring to screen children with NF1 for hypertension.

Clinical Hypnosis is used as a non-pharmacological technique for reducing procedural anxiety, distress and discomfort with patients. Hypnosis scripts have been successfully used as non-pharmacological adjuncts to reduce pain and anxiety in adult patients undergoing interventional radiological procedures, demonstrating that the benefits of hypnosis techniques can be accessible to patients with little or no training or preparation. Furthermore, healthcare workers who are not experts in hypnosis can be trained to deliver scripts effectively.

If a hypnosis script used while taking home blood pressure readings allows for a calm child and an equivalent clinic BP measure, hypnosis script and home BP monitoring could have greater application across the Royal Children's Hospital.

Therefore the second aim of the study is to see if there is a difference in a child's BP measurements comparing a standard home BP measurement or utilising a calming hypnosis script prior to home BP measurement. This will be compared to the gold standard clinic-based BP measurement completed by a trained professional. The child's self-reported level of anxiety using the Children's Anxiety Meter Scale (CAM-S) will be measured after every BP measurement. In addition, family's perceptions of the process of home BP monitoring will also be collected.

Inclusion Criteria:

• Is between the ages of 5 and 18 years old at enrolment.
• Has a diagnosis of neurofibromatosis type 1(NF1), confirmed by a physician, and usually attends the NF clinic at The Royal Children's Hospital, Melbourne, Australia (RCH). Including children with known kidney and cardiac disease.
• Primary residence and residential postal address in Victoria.
• The child can sit quietly for 10-15 minutes at home to complete a blood pressure assessment.
• Provide a signed and dated participant and/or parent guardian information and consent form and or has a legally acceptable representative capable of understanding the informed consent document and providing consent on the participant's behalf.
• For inclusive diverse study group, Parent/caregiver who require an interpreter can be enrolled in this study. Only inhouse interpreter services able to be included,

Exclusion Criteria:

• Has clinically significant cognitive impairment or attention disorder preventing ability to sit in a chair for 15 minutes
• Has confirmed hypertension on previous testing
• Parent/caregiver who require an interpreter and cannot upload BP and Heart rate (HR) values online independently will be excluded from the study.
• Parent/caregiver requiring an interpreter, but the interpreter not present within the face-to-face appointment eg, phone interpreter services.

The de-identified data set collected for this study will be available six months after publication of the primary outcome.

The study protocol, analysis plan and consent forms will also be available. The data may obtained from the Murdoch children's Research institute by emailing gabriel.dabscheck@rch.org.au Prior to releasing any data the following are required: a data access agreement must be signed between relevant parties, the trial steering committee must see and approve the analysis plane describing how the data will be analysed, there must be and agreement around appropriate acknowledgement and and additional costs involve must be covered. Should the trial steering committee be unavailable, this role is delegated to the Murdoch children's Research Institute. Data will only be shared with a recognised research institution which has approved the proposed analysis plan.

6 months after publication of primary outcome

1. Data access agreement
2. Approval by Trial Steering Committee
3. Recognised Research Institute