Biomechanical analysis of specific motor impairments contributing to early functional decline in adults living with HIV-1 infection : a sub-study to the Cape Winelands HAART to HEART (Prevalence)/EndoAfrica study

Thesis (PhD)--Stellenbosch University, 2019.ENGLISH SUMMARY : Background: HIV-1 infection has become a chronic condition. Although people living with HIV-1 infection (PLHIV) now have near-normal life expectancies, walking-related impairments remain concerning as they occur early and may lead to falls. A poor understanding remains of how movement patterns are affected due to a lack of biomechanical studies. Three-dimensional (3D) motion analysis can provide insight into movement patterns and assist in identifying a valid performance-based screening test for detecting early motor impairments in PLHIV. Aim: The aim of this research was to investigate gait and balance impairments existing in PLHIV using 3D motion analysis. It further aimed to correlate 3D analysis findings (via a gait summary score), as well as self-reported function and history and fear of falling, to physical performance tests which may be considered in clinical practice to screen for early functional decline in PLHIV. Methods: The research was divided into three parts: Part I presented a systematic review describing objective gait and balance impairments in PLHIV. Results contributed to the theoretical groundwork for study conceptualisation and aided in selecting clinically relevant biomechanical outcomes and performance-based tests. Part II comprised validity and reliability testing of a portable 3D gait analysis (3DGA) system, newly obtained by the motion laboratory, in 16 healthy student volunteers, as well as in eight consecutively recruited PLHIV and eight community-matched seronegative participants (SNP). The studies determined the psychometric properties of specific 3DGA outcomes to aid appropriate data interpretation in the next phase. Part III comprised the main observational study to cross-sectionally describe key biomechanical characteristics in 50 PLHIV relative to 50 community-matched SNP (consecutively sampled). The study was conducted in a clinical setting, and performancebased tests were assessed in addition to the 3D motion analysis. Gait analysis results, fallrelated outcomes and self-reported function were correlated to clinical test performance to identify the most valid performance-based screening test. Main results: The systematic review (Part I) revealed some agreement that PLHIV walk slower and have increased centre of pressure (COP) excursions and postural reflex latencies, particularly under challenging conditions. No included studies used 3DGA. The validity and reliability studies (Part II) demonstrated that, with regular recalibration, the 3DGA system reliably measures gait biomechanics in SNP and PLHIV, except for four discrete angles. The system/model highly compares to the reference model after accounting for modelling differences. The field study (Part III) revealed that the gait of PLHIV (median age: 36.61 years) was significantly slowed and rigid relative to SNP (median age: 31.10 years). This pattern manifested when walking at a usual pace or when performing a dual task. Dual task walking further revealed joint range of motion (ROM) changes at the hip and knee in a distal-to-proximal pattern-shift. PLHIV also demonstrated increased COP excursion in dual task single-leg stance. PLHIV were significantly slower in completing the Five-Times Sit-To-Stand (5STS) Test. Slowed sit-tostand was significantly related to gait rigidity, worse self-reported function, and fear of falling. Conclusion: Relatively young PLHIV present with biomechanical gait and balance impairments that resemble patterns noted in elders, especially under dual task conditions. The 5STS test is recommended as a valid clinical screening test. These findings improve understanding of movement impairments in PLHIV and highlight the need for early screening. Further research is needed to determine whether the 5STS test predicts falls, and whether the impairments noted in PLHIV are reversible. Early identification and rehabilitation can reduce healthcare utilisation needs in PLHIV.AFRIKAANSE OPSOMMING : Agtergrond: MIV-1 infeksie het ontaard in ‘n kroniese toestand. Alhoewel persone wat leef met MIV-1 infeksie (PLMIV) nou ‘n bykans normale lewensverwagting het, is loopverwante aantastings steeds kommerwekkend aangesien dit vroeg voorkom en kan lei tot valverwante beserings. Tans heers ‘n swak begrip van hoe bewegingspatrone aangetas word, weens ‘n tekort aan biomeganiese studies. Drie-dimensionele (3D) bewegingsanalise kan insig verleen aangaande beweginspatrone en bydra tot die identifisering van ‘n geldige verrigtingsgebaseerde siftingstoets vir die waarneming van vroeë bewegingsaantastings in PLMIV. Doel: Die doel van hierdie navorsing was om looppatroon- en balansaantastings in PLMIV te ondersoek deur middel van 3D-bewegingsanalise. ‘n Verdere doelwit was om die 3D-analise bevindinge (via ‘n looppatroon opsommings-telling), selfvermelde funksie, asook geskiedenis van en vrees vir neerval te korreleer met fisiese verrigtings-toetse wat in kliniese pratkyk oorweeg mag word om te sif vir vroeë funksionele agteruitgang in PLMIV. Metodes: Die studie het drie dele behels: Deel I het ‘n sistematiese oorsig behels wat objektiewe looppatroon- en balansaantastings in PLMIV beskryf. Resultate het bygedra tot die teoretiese grondwerk vir die studie se konsepsualisering en ook tot die keuse van klinies-relevante biomeganiese uitkomste en verrigtingsgebaseerde toetse. Deel II het bestaan uit geldigheids- en betroubaarheids-toetsing van ‘n 3D-loopanalise (3DLA) stelsel, nuut aangeskaf deur die bewegingslaboratorium, in 16 gesonde studente vrywilligers asook in agt opeenvolgend-vervorwe PLMIV en agt gemeenskaps-ooreenstemmende seronegatiewe deelnemers (SND). Die studies het die geldigheid en betroubaarheid van spesifieke 3DLA uitkomste bepaal om gepaste data interpretasie in die volgende fase moontlik te maak. Deel III het die hoof waarnemingstudie behels wat ‘n dwarssneebeskrywing verskaf het van die kern biomeganiese kenmerke in 50 PLMIV vergeleke met 50 gemeenskapooreenstemmende SND (opeenvolgende steekproefneming). Die studie is uitgevoer in ‘n kliniese omgewing en verrigtingsgebaseerde toetse is geëvalueer bykomstig tot die 3Dbewegingsanalise. Resultate van die looppatroonanalise, valverwante uitkomste en selfvermelde funksie is gekorreleer met die kliniese toetsverrigting om die mees geldige verrigtingsgebaseerde siftingstoets te bepaal. Hoofresultate: Die sistematiese oorsig (Deel I) het ‘n mate van konsensus bevind dat PLMIV stadiger loop en ‘n verhoogde middelpunt van drukking (MVD) omvang van beweging (OVB) het, asook posturale reflekslatentheid, veral onder uitdagende toestande. Geen ingeslote studies het gebruik gemaak van 3DLA nie. Die geldigheid- en betroubaarheid-studies (Deel II) het demonstreer dat, met gereelde herkalibrering, die 3DLA stelsel looppatroon-biomeganika betroubaar meet in SND en PLMIV, met die uitsondering van vier diskrete gewrigshoeke. Die stelsel/model is hoogs vergelykbaar met die verwysingstelsel na die inagneming van die verskille in die biomeganiese model. Die veldwerkstudie (Deel III) het getoon dat die looppatroon van PLMIV (mediaan-ouderdom: 36.61 jaar) beduidend stadiger en oormatig rigied was vergeleke met SND (mediaan-ouderdom: 31.10 jaar). Hierdie patroon het manifesteer tydens ‘n selfgekose loopspoed of tydens die uitvoer van ‘n dubbele taak. Dubbeltaak-loop het verder veranderinge getoon in heup- en kniegewrigs OVB in ‘n distaaltot- proksimale patroon-aanpassing. PLMIV het ook verhoogde MVD OVB getoon tydens dubbeltaak-eenbeenstaan. PLMIV was beduidend stadiger om die Vyfmaal Sit-Tot-Staan (5STS) Toets te voltooi. Stadiger sit-tot-staan het ‘n beduidende verwantskap getoon met ‘n meer rigiede looppatroon, laer vlakke van selfvermelde funksie en ‘n vrees vir val. Gevolgtrekking: Relatiewe jong PLMIV toon verskeie aantastings van looppatroon- en balansbiomeganika wat tot ‘n mate ooreenstem met patrone wat gewoonlik in ouer volwassenes waargeneem word, veral tydens die uitvoer van ‘n dubbele taak. Die 5STS-toets word aanbeveel as ‘n geldige siftingstoets. Hierdie bevindinge verbeter die begrip van bewegingsaantastings in PLMIV en beklemtoon die belang van vroeë siftingstoetsing. Verdere navorsing word benodig om te bepaal of die 5STS-toets val-insidente kan voorspel, en of die aantastings in PLMIV omkeerbaar is. Vroeë identifisering en rehabilitasie kan die behoeftes aan gesondheidsorg onder PLMIV verminder