The measurement of the facial deformation according to the body posture will be conducted by 3D scanning for each posture after marking the landmarks on the face. A 3D scan of the face will be conducted for 1 minute in a static state for the sitting posture to be used as a reference, the supine posture to gaze at the ceiling while lying down correctly, and the lateral posture to the side with the upper body facing left. Healthy volunteer and ALS with bulbar palsy participants will be asked to keep their mouths closed gently while the 3D scan was being processed. A post-processing of the 3D face scan data will be conducted to analyze facial deformation by the body postures. A facial deformation will be analyzed by measuring the amount of change in position for each reference point after aligning and rotating the facial data on the same basis. The relative ratio of the amount of position change to the size of the face will be analyzed. The present study will analyze the effect of the body posture on the position changes of the landmarks.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that eventually affects the respiratory muscles. In most cases of the slow progression of respiratory failure, noninvasive ventilation (NIV) is the first treatment option. NIV treatment provides a better quality of life and is, therefore, strongly recommended; however, its use must consider the type of ALS. Severe bulbar dysfunction limits NIV treatment. Aside from additional NIV options in ALS, including mouthpiece ventilation and intermittent abdominal pressure ventilation, prolonged use of a ready-made face mask is impractical for several reasons. Cognitive impairments can affect the maintenance of NIV. Hypersalivation and bronchial secretion disrupting ventilation can lead to poor NIV adherence. Pressure injuries are another clinical issue. The incidence of pressure injuries associated with NIV masks ranges from 10-31%. Long-term use of NIV face masks can result in pressure injuries at the contact area, and skin-protective patches may not prevent skin problems. Patients with bulbar ALS frequently have postural facial deformations, and these can lead to difficulties in wearing the NIV mask.

The aim of this study was to compare the deformations of the face in different postures in subjects with bulbar ALS and healthy participants. This study also virtually fitted an NIV mask to understand how the NIV mask interface affects the face in different postures.

Inclusion Criteria:

1. Patient

   • a patient with Amyotrophic Lateral Sclerosis over 16 years
   • a patient with respiratory difficulty
   • a patient who requires or anticipates mechanical ventilation
   • a patient who visit out- or inpatient clinic at rehabilitation hospital

2. Healthy volunteer

   • a volunteer without history of facial surgery or neuromuscular disease
   • a volunteer without respiratory difficulty

Exclusion Criteria:

1. Patient

   • a patient who cannot scan due to respiratory instability
   • a patient who cannot bear posture for 3D scanning

2. Healthy volunteer

   • a volunteer with neuromuscular disease
   • a volunteer with history of facial surgery or palsy

Patient: a patient who visit out- or inpatient clinic at rehabilitation hospital Healthy volunteer: community dwelling volunteer

Number of people enrolled in the study

Adverse events are observed from the time of study enrollment until all procedures are performed and outcome measures are measured. Participants usually complete all procedures within 1 day.

The face in a real situation with the NIV strap may differ from that in the virtual simulation without the NIV strap. Wearing an NIV mask could alleviate the effect of facial deformation caused by posture, but 3-dimensional scanning could not be accomplished while wearing a mask.