The effect of sensory-motor training on brain activation and functional recovery in chronic stroke survivors

Thesis (PhD)--Stellenbosch University, 2018.ENGLISH ABSTRACT: Introduction: Functional loss is greatly determined by postural control impairment in chronic stroke survivors causing reduced ability to execute activities of daily living, impaired mobility and increases the risk of falling. It is known that the basal ganglia network play an important role in postural control, however the effect of sensory-manipulated balance training on structural connectivity in chronic stroke survivors remains unknown. Objective: To assess the influence of sensory-manipulated balance training, i.e. sensory-motor training (SMT), on structural connectivity and functional recovery in chronic stroke survivors. Study design: Double-blind randomised controlled trial. Methods: Twenty-two individuals with chronic stroke (≥6 months post-stroke) were randomly divided into two groups, namely the sensory-motor training (SMT; n = 12) and attention-matched control group (CON; n = 10). The SMT group participated in task-specific balance training, which focused on manipulating the visual, vestibular and somatosensory systems, three times a week for 45 to 60-minute sessions, over an eight-week period. The CON group attended educational talks regarding various lifestyle topics for the same duration as the SMT group. Both interventions were delivered by experienced clinical exercise therapists and were executed in a group setting. Primary outcome measures included changes in structural connectivity strength (diffusion tensor magnetic resonance imaging (MRI) scan), postural sway and sensory dependency (modified Clinical Test for Sensory Interaction and Balance (m-CTSIB), as well as functional mobility (Timed-Up and Go (TUG). Structural connectivity strength was specifically investigated between the twosubcortical basal ganglia nuclei, caudate and lentiform nucleus, with other regions of interest. Furthermore, the m-CTSIB and TUG tests were executed with APDM’s Mobility LabTMbody-worn inertial sensors. Secondary outcome measures were health-related quality of life (Short Form Health Survey (SF-36)) and fall efficacy (Fall Efficacy Scale - International (FES-I)). Participants were tested pre- and post-intervention. Results: Diffusion tensor MRI results showed interaction effects for increased connectivity strength between the basal ganglia and sensory-motorfronto-parietal areas in the SMT group (n = 5; p<0.05), where as the CON group (n = 4 ) presented increased structural connectivity in the higher cognitive orbitotemporal and frontal lobe areas (p<0.05). For the behavioural outcome measures, interaction effects were found for turning performance(p = 0.02), perceived physical functioning (p = 0.005) and fall efficacy (p= 0.03). Moreover, the SMT group (n = 12) showed improved postural sway when standing on a foam pad with eyes open (p = 0.04, ES = 0.61M, 95% CI= -0.27 to 1.36), reduced somatosensory dependence (p = 0.02, ES = 0.63M,95% CI = -0.24 to 1.40), improved turning performance (p≤0.05) as well as improvements in perceived physical (p = 0.01, ES = 0.52M, 95% CI = -0.33to 1.29) and social functioning (p = 0.02, ES = 1.03L, 95% CI = 0.11 to 1.80)after participating in the SMT programme. Lastly, a group difference wasobserved for perceived physical (p = 0.003, ES = 0.90L, 95% CI = -0.05 to1.70) and social functioning (p = 0.02, ES = 1.01L, 95% CI = 0.04 to 1.81) at post-intervention. Conclusions: This study highlights postural control-related improvements induced by SMT, which may be associated with structural connectivity changes in chronic stroke survivors. Therefore, the preliminary results support the notion that the human brain has the ability to undergo activity-dependent neuroplasticity.AFRIKAANSE OPSOMMING: Inleiding: Funksionele verlies word grootliks bepaal deur aantasting van postuurbeheer in individue met kroniese beroerte, wat veroorsaak dat die vermoë om alledaagse aktiwiteite uit te voer verswak, mobiliteit aangetas word en valrisiko verhoog. Dit is bekend dat die basale ganglia ’n belangrike rol in postuurbeheer speel, maar die effek van sensories-gemanipuleerde balans-oefening op strukturele konnektiwiteit in individue met kroniese beroerte bly onbekend. Doelwit: Om die invloed van sensories-gemanipuleerde balansoefening, d.i. sensories-motoriese oefening (SMO), op strukturele konnektiwiteit en funksionele herstel te evalueer in individue met kroniese beroerte. Studie ontwerp: Dubbelblind ewekansige gekontroleerde proefneming. Metodes: Twee-en-twintig individue met kroniese beroerte (≥6 maandegelede) is ewekansig in twee groepe verdeel, naamlik die sensories-motorieseoefening (SMO; n = 12) en gelyke-aandag kontrolegroep (KON; n = 10). Die SMO-groep het drie keer per week in 45- tot 60 minuut sessies deelgeneem aan taak-spesifieke balansoefeninge, wat gefokus het op die manipulering van die visuele, vestibulêre en somato sensoriese stelsels oor ’n tydperk van agt weke. Die KON-groep het opvoedkundige praatjies met betrekking tot verskeie onderwerpe oor lewenstyl bygewoon vir dieselfde tydsduur as die SMO-groep. Beide intervensies was deur ervare kliniese oefenterapeute gelewer en in groepsverband uitgevoer. Primêre uitkomstes het die sterkte van strukturele konnektiwiteit (diffusion tensor magnetic resonance imaging (MRI) scan), postuurswaai en sensoriese afhanklikheid (modified Clinical Test for Sensory Interaction and Balance (m-CTSIB)), sowel as funksionele mobiliteit (Timed-Up and Go (TUG)) ingesluit. Die sterkte van strukturele konnektiwiteit was spesifiek ondersoek tussen die twee subkortikale basale ganglia kerne, koudaat en lensvormige kern, met ander areas van belang. Verder was diem-CTSIB en TUG-toetse uitgevoer met APDM se Mobility LabTM traagheidsensors. Sekondêre uitkomstes was gesondheidsverwante lewenskwaliteit (Short Form Health Survey (SF-36)) en valpersepsie (Fall Efficacy Scale - International (FES-I)).Deelnemers was voor- en na-intervensie getoets. Resultate: Diffusion tensor MRI resultate het interaksie effekte vir ver-hoogde konnektiwiteitsterkte tussen die basale ganglia en sensories-motoriesefronto-pariëtale areas in die SMO-groep (n = 5; p<0.05) getoon, terwyl die KON-groep (n = 4) verhoogde strukturele konnektiwiteit in die hoër orbito-temporale- en frontale lobareas (p<0.05) getoon het. Vir die gedragsuitkomste was interaksie effekte gevind vir omdraai-prestasie (p = 0.02), self-waargenome fisiese funksionering (p = 0.005) en valpersepsie (p = 0.03). Verder het die SMO-groep (n = 12) die volgende getoon: verbeterde postuurswaai wanneer daar op ’n sponsmat met oop oë gestaan word (p = 0.04, ES = 0.61M,95% CI = -0.27 to 1.36), verlaagde somatosensoriese afhanklikheid (p = 0.02,ES = 0.63M, 95% CI = -0.24 to 1.40), verbeterde omdraai-prestasie (p≤0.05) sowel as ’n verbetering in self-waargenome fisiese- (p = 0.01, ES = 0.52M,95% CI = -0.33 to 1.29) en sosiale funksionering (p = 0.02, ES = 1.03L,95% CI = 0.11 to 1.80) na deelname aan die SMO-program. Laastens was ’n groepsverskil opgemerk vir waargenome fisiese- (p = 0.003, ES = 0.90L,95% CI = -0.05 to 1.70) en sosiale funksionering (p = 0.02, ES = 1.01L, 95%CI = 0.04 to 1.81) na-intervensie. Gevolgtrekkings: Hierdie studie beklemtoon postuurbeheer verwante verbeteringe wat deur SMO geïnduseer is, en word geassosieer met veranderinge instrukturele konnektiwiteit in individue met kroniese beroerte. Die voorlopige resultate ondersteun daarom die idee dat die menslike brein die vermoë het om aktiwiteits-afhanklike neuroplastisiteit te ondergaan.Doctor

HIGH-INTENSITY EXERCISE AND MOTOR IMAGERY TRAINING PROGRAM: A THERAPEUTIC APPROACH IN NON-SPECIFIC CHRONIC LOWER BACK PAIN.

A dor lombar crónica não específica (DLC) tem, nos últimos anos, sido um dos flagelos da humanidade, apresentando elevadas taxas de prevalência e incidência, com reflexo nas altas taxas de absentismo, nos grandes custos sociais e sobrecarga de utilização dos cuidados de saúde. Esta doença não encontrou ainda a resposta terapêutica eficaz, seja na vertente farmacológica, seja na não farmacológica. Trata-se de uma doença de carácter global, e não apenas local, resultado das múltiplas disfunções que promove no indivíduo. Uma destas reflete-se a nível do sistema nervoso central e do sistema nervoso periférico, influenciando negativamente as conexões neuronais, a espessura cortical e o volume da substância cinzenta em determinadas áreas do encéfalo. A presença crónica da dor tem, por isso, repercussões na organização cerebral e no desempenho desta sobre a capacidade de modular e inibir a dor. Como reflexo, estão descritas alterações de sensibilidade discriminativa localizadas à região lombar dolorosa, no entanto, não se sabe ainda se a restante região do dorso é, ou não, também afetada. Dada a importância clínica desta informação para a correção postural e reforço muscular, o objetivo do primeiro trabalho foi o de averiguar a capacidade de discriminação sensorial táctil superficial e dolorosa em todo o dorso e compará-la com indivíduos saudáveis. Os resultados permitiram concluir que os doentes DLC apresentam menor capacidade de discriminação sensorial em todo o dorso, com diferenças acentuadas entre várias regiões. É sabido que programas de exercício físico têm sido os instrumentos de maior sucesso para diminuir os sintomas da DLC, pelo aumento do limiar de percepção da dor e da capacidade física destes doentes. Como exercício físico, particularmente o de alta intensidade, parece ter repercussões orgânicas favoráveis, periféricas e centrais, colocouse a hipótese que o treino físico de alta intensidade melhora a capacidade discriminativa da sensibilidade táctil superficial e dolorosa destes doentes e diminui a intensidade da sua dor, hipótese essa que foi testada no segundo trabalho desta tese. Os resultados obtidos confirmaram a hipótese de estudo, concluindo-se que o treino físico de alta intensidade melhora a discriminação sensorial no dorso e reduz a intensidade da dor referida assim como a extensão da área dolorosa. Sabe-se que, dependendo da intensidade do exercício físico, há produção de um vasto conjunto de neurotrofinas, fundamentais para a criação de uma nova rede de conexões cerebrais com a ativação do sistema de modulação de inibição descendente e com a proliferação de novas conexões cerebrais. A criação de novas conexões cerebrais está também associada ao treino da imagética motora, cuja eficácia terapêutica tem sido testada, de forma isolada, na DLC. Considerando este facto, assim como os resultados do segundo estudo desta tese, colocou-se a hipótese que o treino de imagética motora conjugado com o treino físico de alta intensidade possui melhores resultados comparativamente aos do treino físico quando aplicado de forma isolada. Esta hipótese foi testada no terceiro e quarto trabalhos desta tese, tendo os resultados confirmado a hipótese de trabalho, com melhoria na intensidade e na área da dor dos doentes. Os resultados dos quatro estudos realizados permitem concluir que a DCL tem um componente de afeção central, com repercussões periféricas na intensidade e extensão da área da dor, na discriminação da sensibilidade do dorso e na capacidade funcional. O treino físico de alta intensidade, especialmente quando associado com o treino de imagética motora, minimiza estas consequências.The non-specific chronic lower back pain (CLBP) has been for the last few years one of the mankind "scourges", with high prevalence and incidence rates, reflected in high rates of absenteeism, high social costs and overburden of the healthcare systems. This disease is yet to find an effective therapeutic response, either in the pharmacological or non-pharmacological treatments. It is a systemic condition, not just a local one, considering all the multiple dysfunctions it entails. One of these is reflected on the central nervous system and the peripheral nervous system, negatively influencing the neuronal connections, the cortical thickness and the volume of the gray matter in certain areas of the brain. The chronic pain has therefore repercussions on brain organization and its performance on the ability to modulate and inhibit pain. As a result, changes in discriminatory sensitivity located in the painful lumbar region are described, however, it is not yet known whether the remaining region of the dorsum is also affected. Given the clinical importance of this information for postural correction and muscle strengthening, the purpose of the first work of this thesis was to investigate the ability for superficial and painful tactile sensory discrimination throughout the dorsum of CLBP patients and compare it with healthy individuals. The results led to the conclusion that CLBP patients have less capacity for sensitive discrimination throughout the dorsum, with marked differences between various regions. It is known that physical exercise programs have been the most successful instruments to decrease CLBP symptoms by raising the threshold of pain perception and physical capacity of these patients. Given that physical exercise, specially of high-intensity seems to have favourable physiological responses, either peripheral and central, the second work of this thesis tested the raised hypothesis that high-intensity physical training improves the discriminative ability of these patients' superficial and painful tactile sensitivity and decreases the intensity of their pain. The results supported the hypothesis, leading to the conclusion that high-intensity physical training improves sensitive discrimination in the dorsum, reduces the intensity of referred pain as well as the extent of the painful area. It is known that, depending on the intensity of physical exercise, there is production of a vast set of neurotrophins, crucial for the creation of a new network of brain connections with the activation of the modulation system of descending inhibition and with the growth of new brain connections. The creation of new brain connections is also associated with the training of motor imaging, whose therapeutic efficacy has been tested, in isolation, in CLBP. Considering this, as well as the results of the second study, it was hypothesized that motor imaging training combined with high-intensity physical training would have better results compared to physical training when applied on its one. This hypothesis was tested in the third and fourth works of this thesis, and the results confirmed the working hypothesis, with improvement in the intensity and pain area of the patients. The results of the four studies carried out allow us to conclude that CLBP has a central affection component, with peripheral repercussions on the intensity and extent of the pain area, on the discrimination of the sensitivity of the dorsum and on the functional ability. High-intensity physical training, especially when associated with motor imaging training, minimizes these consequences

Neuroplasticity and chronic low back pain: an investigation into altered tactile discrimination, body schema and motor function.

Chronic low back pain (CLBP) ranks 3rd in the Global Burden of Non-Communicable Diseases, behind heart disease and stroke and the problem is increasing with an aging and growing population. It is a painful, long-term condition contributing to increased morbidity, low quality-of-life and a significant socio-economic burden. Aetiologies are often unknown and unrelated to specific spinal pathology. Treatments typically focus on pain management and improving motor function. However, the outcomes are inadequate, remaining moderate at best with one approach no better than another. Sadly, many sufferers stop seeking help and their quality of life deteriorates. In other chronic pain conditions such as Phantom Limb Pain (PLP) and Complex Regional Pain Syndrome (CRPS), cortical neurophysiology and sensory outputs such as body schema and perception are altered alongside motor function impairments. Novel interventions to reverse these impairments coincide with reductions in pain intensity and perception. CLBP shares some characteristics with PLP and CRPS so it is plausible that novel interventions may improve CLBP outcomes. However, for intervention studies to be considered reliable they must be underpinned by robust research to identify the baseline characteristics within the population. This study explored sensory and motor characteristics in adults with CBLP. A systematic review of peer reviewed publications identified seven studies which utilised different techniques and populations to explore tactile discrimination, body schema and motor function. Critically, none explored all three and the review revealed the characteristics of these constructs to be unclear in the CLBP samples. A narrative synthesis concluded two-point discrimination threshold (TPDT) to be impaired at the anatomical region of pain. Limited evidence suggested that sub-groups within the CLBP group may exist and may be related to impaired body schema. Body schema impairment may also be anatomically linked. TPDT appears negatively correlated with body schema and lumbopelvic motor function but the relationship between body schema and motor control was unexplored. This study sought to address this gap by comparing key measures of TPDT, body schema (motor imagery performance and back perception) and motor function from 31 adults with CLBP which affected their activities of daily living (ADL’s), with an equivalent sized control group, within a UK context. Following two reliability studies to select appropriate methods of data collection, a cross-sectional research design identified differences between the two groups. Correlations between the key measures and pain, disability and kinesiophobia were explored. Significant differences between the groups were observed for measures of low back TPDT, back-perception and motor function, but not for measures of tactile threshold or motor imagery performance using left/right discrimination tasks. The left/right discrimination results and the predominantly absent correlations between the key variables differed from the findings in previous studies. New discoveries from this study included; 1) the most accurate and preferred tool to measure low back and fingertip TPDT was identified; 2) that Luomajoki’s Battery of Tests were reliable for use by registered chiropractors and osteopaths without the need for further training; 3) TPDT was impaired at and near to the ‘typical’ region of CLBP; 4) higher ‘typical’ pain scores moderately correlated with greater low back TPDT impairment; 5) a significant moderate positive correlation occurred between low back motor control and back perception scores; 6) this was the first study to explore tactile threshold, TPDT, body schema and motor function together in the same groups, and 7) it was the first to explore this combination of variables within the UK population. This study provides reliable baseline measures of factors known to be impaired in other chronic pain conditions. Small studies have found therapeutically targeting these factors reduces pain and disability in some chronic pain conditions. It is anticipated that this new knowledge may guide future sensorimotor therapeutic interventions to support pain management in those with CLBP

Caractérisation électromyographique des lombalgies non-spécifiques chroniques de l'enfant et de l'adolescent

The majority of the worldwide population (80%) suffers from low back pain (LBP) over life. LBP becomes chronic (CLBP) in 10 to 15% of (all) adult cases yielding important functional and socio-economic adverse repercussions. The majority of LBP (85%) is classified as “non-specific” (NSCLBP), i.e. with an absence of any identified cause. LBP prevalence on children and adolescents is comparable to adults. Despite the low incidence of serious associated diseases, the fear of missing them increased patient’s exposure to radiation. However, an absence of significant correlation between radiology changes in the lower spine and low back pain was reported for school children. In this context, it is necessary to identify new tools, if possible non-irradiating and inexpensive, to identify specific characteristics of children and adolescents suffering from NSCLBP and thus improve the understanding of this pathology.An interesting tool, highlighted in adult population, is to evaluate surface electromyography (EMG) of low back muscles. Existing EMG phenomena were reported to discriminate adults with and without NSCLBP: reduced trunk muscle endurance, absence of flexion-relaxation phenomenon and guarding hypothesis during gait at different velocities. These EMG characteristics have not yet been confirmed for children and adolescents suffering of NSCLBP.This clinical context justifies the present doctoral work. The aim was to evaluate EMG characteristics in children and adolescents with NSCLBP in comparison with control participants. To achieve these objectives, several complementary studies were successively conducted.Taken together, the results of this doctoral work showed that the EMG characteristics frequently reported for NSCLBP in adults were absent or reduced in children and adolescent suffering from NSCLBP. These findings are inconsistent with the existing literature on adults and might affect the future therapeutic management of children and adolescents with NSCLBP, which is, to date, an imitation of the adult model. It would be interesting to confirm these results on the basis of a larger cohort and to reassess the same children and adolescents in adulthood to identify whether the EMG phenomenon, as known in NSCLBP adults, appears over time.La lombalgie (LBP) touche 80% de la population mondiale adulte et devient chronique dans 10 à 15% des cas. Pour la grande majorité des cas adultes (85%), aucune cause ne peut être clairement identifiée pour expliquer ces douleurs et l’on parle alors de lombalgie chronique « non-spécifique » (NSCLBP). Chez l’enfant et l’adolescent, la prévalence de la NSCLBP est semblable à celle de l’adulte. Malgré la faible incidence de pathologies graves associées, la lombalgie de l’enfant et de l’adolescent implique, souvent dans sa prise en charge diagnostique, une exposition augmentée aux radiations et un stress parental important. Cependant, la présence d’anomalies radiologiques est aussi fréquente dans la population asymptomatique que dans la population avec NSCLBP. Ceci remet en question l’intérêt clinique de la radiologie pour dépister une cause possible de NSCLBP. Dans ce contexte, il est nécessaire d’identifier de nouveaux outils, si possible non-irradiants et peu coûteux, pour identifier des caractéristiques spécifiques aux enfants et adolescents souffrant de NSCLBP et ainsi améliorer la compréhension de cette pathologie.L’analyse électromyographique (EMG) de l’activité des muscles paravertébraux lombaires s’est avérée cliniquement pertinente dans la population adulte pour discriminer les patients souffrant de NSCLBP des participants asymptomatiques. Plusieurs paramètres EMG enregistrés lors de différentes tâches ont été identifiés chez l’adulte pour caractériser les participants NSCLBP. Les paramètres EMG des muscles lombaires les plus couramment rapportés dans la littérature sont : un temps de maintien réduit ainsi qu’une fatigue musculaire accélérée pendant le test d’endurance des muscles extenseurs du tronc, la réduction ou l’absence du phénomène de flexion-relaxation (FRP) pendant la tâche de flexion maximale du tronc ainsi qu’un pattern atypique supportant l’hypothèse de précaution pendant la marche à différentes vitesses. Si ces caractéristiques EMG spécifiques aux patients souffrant de NSCLBP ont été bien établies chez l’adulte, la question est désormais de savoir ce qu’il en est chez l’enfant et l’adolescent souffrant de NSCLBP.Dans ce contexte clinique, l’objectif de ce travail doctoral était d’évaluer les caractéristiques EMG décrites ci-dessus dans une cohorte d’enfants et d’adolescents souffrant de NSCLBP en comparaison à des participants asymptomatiques (CTRL). Pour y répondre, plusieurs études complémentaires ont été effectuées.Dans leur ensemble, les travaux de cette thèse de doctorat ont montré que les phénomènes EMG reportés dans une population adulte avec NSCLBP ne sont pas retrouvés dans une population pédiatrique avec NSCLBP. Ces résultats remettent en question le diagnostic et la prise en charge actuelle des enfants et adolescents souffrant de NSCLBP, qui est, à ce jour, calquée sur le modèle adulte. Des études supplémentaires sont cependant nécessaires pour confirmer ces résultats sur une cohorte plus importante. Il serait aussi intéressant d’évaluer une même cohorte à partir de l’enfance jusqu’à l’âge adulte afin d’évaluer quels facteurs pourraient prédire l’apparition des phénomènes rapportés dans la littérature adulte