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The airflow maximization search continues until a respiratory event occurs, whereupon the system shifts back to
the RE elimination condition. By reviewing the data, the two different functions or conditions of the control loop
in this first night of study can be identified. In the RE elimination function, the system is seen to protrude after
occurrence of respiratory events that are associated with transient decreases in airflow and oxygen saturation.
Note
Classic oxygen desaturation events are displayed on the review screen. However, these do not correspond to the stratified
respiratory feedback events that are used internally to control the system in the RE elimination condition.
Next, the presence of the airflow maximization mode can be noted by the temporal pattern of the mandibular
position signal, which alternates in protrusive and retrusive steps of 0.6mm. The only time the system makes a
retrusive movement is in the airway maximization condition.
Static Study Night
After a successful Dynamic Study Night, as described above, the system will automatically initiate a second study
night, called a “Static Study Night”. In this study, the controller will move the mandible to the preliminary target
protrusive position calculated from data gathered during the dynamic study night, and then will refine the position
only as needed. As with the first night, the test begins with a 30 minute delay period for the patient to fall asleep
which may be shortened by the appearance of at least 3 significant respiratory events. Thereafter, the control
function of the device during the static study night differs substantially from that of the dynamic study night.
The mandible is protruded from the habitual bite to the predicted target value in a series of 0.2mm steps separated
by 30 second rest intervals. The possibility of a protrusive intervention is first assessed only after an initial 2
hours have elapsed after reaching the preliminary target position, and a protrusive movement occurs only if the
cumulative count of respiratory events exceeds a predefined threshold (5 events per hour). The intervention
is a protrusive move of 0.6mm in amplitude executed as three 0.2mm steps separated by at least a 5 second
delay. Another identical intervention is possible after each additional hour of the study if the value of cumulative
respiratory event index stays above the predefined threshold. At no point will the control algorithm command the
mandibular positioner to move outside the range defined by the upper and lower limits set by the HCP.
Target Refinement Study Night
The target refinement study night utilizes the same control function as the static study night and is used to gather
information from protrusion levels that are either lower or higher than the value at which they were tested in
the static night. This additional night is needed only occasionally based on the data collected from the first two
nights. For example, the need for this night is assessed if a range less than 70-90% of maximum was not fully
explored during the dynamic and first static study nights and as a result the target protrusion value was selected
above 90% of the maximum protrusion. The starting protrusion value would be 70% for the patient. In a second
example, the upper range of protrusions, > 90% of maximum, may not have been fully explored during the
dynamic and first static evaluation nights and the target value is chosen below 90% of the maximum protrusion.
The second static study night is run to explore the possibility of increasing the predicted protrusion value above
90%. The starting protrusion value would be 90% and the upper limit will be set at the maximum protrusion value
for the patient. At no point will the decision-making algorithm command the mandibular positioner to move
outside the range defined by the upper and lower limits.
