Structured Light Plethysmography (SLP) for Diagnosis and treatment of Dysfunctional Breathing (DB)

1. R.Boulding,R.Stacey,R.Niven,andS.J.Fowler,“Dysfunctionalbreathing:areviewoftheliteratureandproposalforclassification,”Eur.Respir.Rev.,vol.25,no.141,p.287LP–294,Sep.2016.2.N.BarkerandM.L.Everard,“Gettingtogripswith‘dysfunctionalbreathing,’”Paediatr.Respir.Rev.,vol.16,no.1,pp.53–61,2015.

What is Dysfunctional Breathing (DB)?A group of respiratory disorders that can bedefined by a chronic or recurrent altered patternof breathing in the absence of, or in excess of,organic disease. Although Hyperventilationsyndrome (HVS) is the most recognised formof DB in adults (rarer in children), it is just oneof a proposed five point classification recentlysuggested1thatincludes:

1. Hyperventilationsyndrome(HVS)

2.Periodicdeepsighing:frequentsighingwithanirregularbreathingpattern

3.Thoracicdominantbreathing

4.Forcedabdominalexpiration

5.Thoraco-abdominalasynchrony(TAA)

It is also possible for some patients to have anumber of the above patterns at the same timeorswitchbetweenthem.

What is the cause of DB?DBmayoccurasaresponseto,or inassociationwithanunderlyingpathophysiology(Asthma,COPD)ormaybeofpsychogenicorigin(e.g.stress,anxiety).

What are the symptoms?Symptoms may be respiratory related such asbreathlessness and wheeze or non-respiratoryrelatedsuchaschestpainand/ordizziness.

What is the significance of DB? Why is it important?DBreducesqualityoflifeforthepatientandputsa considerable financial strain on the health careproviderastheconditionischallengingtoidentify.Misdiagnosis and multiple unnecessary andcostly clinical investigations and interventionsarecommon.

What is the prevalence of DB?The general consensus seems to be that DB iscommon2, with estimates of HVS alone being ashighas6-10%ofthegeneralpopulationrisingto34%inasthmatics1.

Can we do anything about DB?Yes, DB is treatable. The challenge is in gettingan accurate diagnosis, which in itself may gosome way to alleviate symptoms. Physiotherapyand breathing retraining can also have a positiveand lasting effect on patients’ symptoms andqualityoflife.

Where does SLP fit in all of this?SLPcapturesmovementofthethoraco-abdominalwallandprovidesbothnumericaloutputs and a visual 3D reconstruction of the thoraco-abdominal wall motion.Assuch,itcanpotentiallyplayaroleinbothdiagnosisandtreatmentofDB.

SLP provides data and visual clues to help identify each of the 5 proposedclassifications.ForHyperventilationSyndromeitcancalculateandshowrespiratoryrate; itprovidesavisualisationofsighdepthandrateanditprovidesvisualandnumericaloutputsforthoracicdominantbreathing,abdominaldominantbreathingandthoraco-abdominalasynchrony(TAA).

SLPcanalsoactasapowerfulvisualassistivetooltoguidethecliniciansinbothdiagnosis,andintreatmentofthepatientasapartofthephysiotherapy/retrainingprogram.Itcanalsobeusedtoprovidebiofeedbacktothepatientwhichcanhaveapositiveeffectontheirrecoveryfromthisdebilitatingcondition.

Figure 1. Working principle of SLP. Note that the TA wall is split into two sections, one representing the chest and the other representing the abdomen. Average displacement of the surfaces corresponding to the chest and abdomen are measured and displayed over time. A number of tidal breathing parameters can be extracted from these traces. Using the regionalised traces one can also calculate regional tidal breathing parameters such as relative thoracic contribution and thoraco-abdominal asynchrony (TAA).

Figure 1. Working principle of SLP

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