Single-arm tool for assessment of anomalous head posture

Anomalous head posture (AHP) measurement is crucial in the management of nystagmus and incomitant strabismus and also during follow-up assessments. The types of AHP include chin posture, head tilt, and face turn. Goniometer is a low-cost tool widely used to measure head posture. This has two arms: one reference arm and one measuring arm. The drawback of this device is that the examiner has to maintain the reference arm exactly parallel or perpendicular to the floor and the other arm has to align the AHP. Since not all the examiners are comfortable in aligning both the arms simultaneously, the measurements obtained by a goniometer end up being less accurate. A device named cervical range of motion (CROM) is more reliable but expensive. There is an iOS application created for the purpose of head posture assessment, but an iPhone is expensive.

To demonstrate a low-cost, innovative, reliable single-arm tool (SAT) for assessment of AHP.

A clinometer is a device that is used to measure the heights of buildings. In this device, the gravitational force of the earth determines the reference line. We have modified a clinometer into a SAT by incorporating a long plastic arm to it, which is used to measure head tilt and chin up/down measurements. For the purpose of face-turn measurement, we modified a compass for direction into another type of SAT by fitting a yoke dial and a long plastic arm to measure face turn. Here, the principle is to have the line of direction as a reference. The direction of the patient's seating arrangement is determined and taken as the reference direction. The amount of the patient's face turn is measured by finding out the angle between reference direction and direction of the nose.

This video shows the method of making SAT in a do-it-yourself manner and also demonstrates the method of measuring AHP. SAT is a reliable and low-cost device.

https://youtu.be/UwoHARok85c.