Study to Explore Post Surgical Outcomes Using Point-of-Gaze, Electromyography and Elastography of the SCM
Condition: Head and Neck Cancer
MeSH terms: Head and Neck Neoplasms
Study type: Observational

Summary: 
      The side effects following post surgical neck dissection treatment for tumours in the head
      and neck (HN) region are weakness of the shoulder and neck muscles, numbness and reduced
      sensation around the neck and shoulder region and a general impact on the participant's
      overall fitness. While survival has been emphasized as an important outcome, recovery of
      treatment-related morbidity and return to pre-treatment quality of life (QOL) for
      participants after cancer treatment is equally important.

      Sternocleidomastoid (SCM) muscle functions to turn the head to the left or right. In
      particular while performing neck dissections, SCM dissection is a common step. The side
      effects of SCM dissection is a stiff neck or reduced neck movements. To objectively measure
      the outcome of the SCM muscle function, it is necessary to determine what is the normal range
      of motion in healthy subjects turning to the left and right to look at objects in a specific
      location or Point-of gaze (POG) procedure, as well as the Electromyography (EMG) of the SCM
      during the movement.

      In this normative study, 20 healthy subjects will be recruited to perform this POG assessment
      as well as EMG and Elastography (ETG) testing of the SCM on the left and right side. Outcome
      measures will include

        1. neck range of motion for flexion, side flexion and rotation

        2. EMG activation patterns for SCM

      2) muscle thickness & stiffness (as determined by grey scale ultrasound (US) and ETG,
      respectively) of the SCM

      The investigators hypothesize that there will not be any significant differences of POG, EMG
      and ETG measurements between the left and right side of the SCM in healthy subjects.
    

Detailed description: 
      20 healthy subjects who are staff working in the SGH (Singapore General Hospital) campus,
      will be recruited for the normative study. Subjects will be recruited through email
      invitations to participate in the study. Those who meet the inclusion and exclusion criteria
      will be selected for testing. In order to ensure there are sufficient gender representation
      in the normative data, the team will select 10 male and 10 female subjects. Consent will be
      taken from the subjects.

      All subjects will have to undergo the following standard tests; Point of gaze (POG)
      measurement, Electromyography (EMG) and Ultrasound Elastography (ETG) measurement:

        1. POG or Point of gaze measurement: This is a non-invasive assessment tool to assess head
           and neck movement via 3D motion analysis. Neck range of movement will be assessed using
           a light source together with the 3D motion capture system.

           Participants will be seated in the middle of the room with reflective markers placed on
           their head and shoulders. The participants will keep their gaze fixed on an object as
           the starting position in the neutral position. A light source will appear either to the
           left or right of the neutral position, and the subject will have to detect this light
           source and indicate to the researcher when they have located the light source. The light
           source is pre-set at either 60 or 90 degrees diagonally to the left and right of the
           subjects. The sequence of the light locations is also pre-set for all subjects so that
           all subjects follow the same sequence to turn either to the left or right, and if it is
           located 60 or 90 degrees position. Subjects will turn in total, 6 times to the left and
           6 times to the right to complete the measurement.

           The 3D motion analyser will capture the neck turning moment in 3 anatomical planes,
           flexion-extension, lateral flexion, and rotation, relative to the thorax. Angular
           velocity and acceleration will also be recorded during the movement.

        2. Electromyography (EMG) of the SCM during POG testing will be recorded using electrodes
           on the left and right SCM. The wireless EMG unit Cometa PICO, will be used to record the
           EMG during POG assessment simultaneously during the movement. This data will be
           correlated to the range of motion of the neck.

        3. Ultrasound Elastography (ETG) measurement:

      Stiffness:

      Measurement will be performed using Supersonic Ultrasound Machine (Aixplorer; SuperSonic
      Imagine, Aix-En-Provence, France) that is equipped with a L15-4 high resolution linear
      transducer with predefined anatomical landmarks. These landmarks are: the height of the hyoid
      bone (sternocleidomastoid and upper trapezius muscle) and the acromial process for the middle
      trapezius, the inside border of the rib to the inside edge of the muscle border (for the
      serratus anterior), medial edge of the medial side of the spine of scapula (for the rhomboid
      major). The whole SCM will be separated into 3 sections for the measurement of the stiffness
      of the muscle - Proximal SCM, Mid SCM & Distal SCM. For each section, 3 stiffness
      measurements will be obtained. This will result in a total of 9 stiffness (elasticity)
      measurements for each side of the SCM. The average (mean) reading of the 9 measurements will
      be taken as the final muscle stiffness for analysis. Bilateral SCM will be evaluated.

      Thickness (Grey scale):

      The full length of the patient's SCM will be physically measured from the mastoid process to
      the sternal notch. The mid length (measured from the Mastoid Process) will be marked on the
      skin and scan will be performed at the marked level. The thickness of the SCM muscle will be
      measured in the transverse and longitudinal planes at the mid-length of the SCM; and the mean
      thickness score will be used for final analysis. Subjects are scanned in the supine position
      with head tilted 15 degrees away from the scanned side. This will be performed on the
      bilateral SCM of the patient.

      All POG, EMG and ETG measurements are taken only once with no follow up visits.

      The research data will be sent to the Trusted Third Party appointed by the institution for
      data de-identification prior to data analysis.
    

Observational model: Case-Only
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Healthy SGH staff with no previous head or neck injuries.