Vpliv sočasnih kognitivnih nalog na ravnotežje, začetek hoje in hojo pri bolnikih s klinično izoliranim sindromom

Brecl Jakob, Gregor (avtor), Rot, Uroš (mentor)

Ozadje: Pri četrtini bolnikov z multiplo sklerozo (MS) prvi zagon bolezni, ki ga imenujemo tudi klinično izoliran sindrom (angl. clinically isolated syndrome - CIS), predstavlja optični nevritis (ON). Pri več kot 50 % bolnikov s CIS lahko zaznamo težave z ravnotežjem ter kognitivnimi procesi vključno z delovnim spominom. Za raziskovanje medsebojnega vpliva motoričnih in kognitivnih procesov se lahko uporablja paradigma dvojnih nalog. Ker so podatki o vplivu začetne demielinizacijske bolezni na ravnotežje in izvajanje dvojnih nalog pomanjkljivi, je bil namen naše raziskave opredeliti medsebojen vpliv delovnega spomina in treh različnih vidikov vzdrževanja ravnotežja pri bolnikih z ON brez pomembne nevrološke prizadetosti. Dokazi o tovrstnih interakcijah so pomembni predvsem kot osnova za nadaljnje raziskave v smeri iskanja novih biomarkerjev za oceno poteka bolezni. Dodatno bomo takšna znanja lahko uporabljali pri svetovanju bolnikom s CIS ter zasnovi rehabilitacijskih strategij za te bolnike. Metode: Dvajset bolnikov po prvem zagonu bolezni z ON (CIS) in dobro ostrino vida ter 20 zdravih posameznikov je opravilo testiranje treh vidikov ravnotežja (stoje, začetka hoje in hoje) brez in s sočasnim izvajanjem kognitivnih nalog besednega in vidnoprostorskega delovnega spomina. Ravnotežje smo ocenjevali z merami gibanja navideznega središča pritiska (angl. centre of pressure) na podlagi pod nogami. Bolniki so opravili nevropsihološko testiranje za oceno izhodiščne kognitivne oškodovanosti. Rezultati: Z nevropsihološkimi testi pomembnejše oškodovanosti delovnega spomina pri bolnikih nismo ugotovili. V največji meri smo opažali oškodovanost pozornosti in izvršilnih funkcij. Bolniki so med stojo v primerjavi z zdravimi slabše vzdrževali statično ravnotežje. Pri bolnikih je bil vpliv naloge vidnoprostorskega delovnega spomina na ravnotežje večji v primerjavi z nalogo besednega delovnega spomina. Vzdrževanje dinamičnega ravnotežja v sklopu začetka hoje se med skupinama ni razlikovalo. Le pri začetku hoje smo opažali značilno nižjo uspešnost na kognitivnih nalogah ob dvojnih nalogah. Medsebojni vpliv začetka hoje in nalog delovnega spomina je bil večji pri bolnikih v primerjavi z zdravimi. Hkrati smo pri obeh skupinah opažali značilno večji medsebojni vpliv med nalogo besednega delovnega spomina in začetkom hoje v primerjavi z nalogo vidnoprostorskega delovnega spomina. Bolniki so izbrali značilno nižjo izhodiščno hitrost hoje glede na zdrave. Obe skupini sta ob dvojnih nalogah neodvisno od vrste sočasne kognitivne naloge enako znižali hitrost. Zaključek: Upoštevajoč rezultate naše raziskave in podatke iz literature lahko sklepamo, da so za interakcijo med delovnim spominom in statičnim ravnotežjem odgovorna predvsem področja parietalne možganske skorje, saj so omenjena področja hkrati odgovorna za procesiranje aferentnih signalov ter ustvarjanje predstave o položaju telesa v prostoru in za tvorbo vidnoprostorskega delovnega spomina in pozornosti. Po drugi strani so glede na rezultate za podobno interakcijo delovnega spomina z začetkom hoje pomembnejša področja prefrontalne in premotorične skorje, saj so ta področja ključna pri tvorbi vnaprejšnjih posturalnih prilagoditev in besednega delovnega spomina. Hkrati prihaja ob dvojni nalogi med začetkom hoje do interakcij na nivoju centralnega izvršitelja (nižja uspešnost na obeh kognitivnih nalogah). Pri bolnikih je tako kot pri zdravih prišlo do enake in ustrezne prilagoditve hoje (zmanjšana hitrost) ob sočasnih kognitivnih nalogah. Nižjo izhodiščno hitrost hoje bolnikov lahko glede na navedeno pripišemo ustrezni prilagoditvi s strani prefrontalnih področij za nadzor hitrosti hoje. Če želimo opisane zaključke pri enotni skupini bolnikov, kjer pomembnejše izhodiščne oškodovanosti delovnega spomina nismo beležili, pojasniti z istim bolezenskim procesom, pridemo do zaključka, da je za večino opisanih interakcij ob izhodiščni oškodovanosti pozornosti in izvršilnih funkcij v največji meri odgovorna slabša kvaliteta aferentnih prilivov v omenjena področja, kot tudi eferentnih motoričnih signalov, kar zahteva obsežnejše vključevanje kognitivnih procesov v nadzor ravnotežja. Motnje pozornosti in izvršilnih funkcij postanejo glede na rezultate še posebej pomembne za vzdrževanje ravnotežja pri zahtevnejših motoričnih nalogah, kot je začetek hoje. Pridobljeni podatki bodo podlaga za nadaljnje prospektivne analize, s katerimi bomo poskušali identificirati morebitne nove biomarkerje za oceno prognoze bolezni pri bolnikih s CIS. Glede na opažanje, da se ob dvojnih nalogah, ki vključujejo izvajanje zahtevnejših motoričnih nalog, pri bolnikih odkrijejo motnje na nivoju pozornosti in izvršilnih funkcij, zdravstvenim delavcem svetujemo krepitev omenjenih kognitivnih domen v sklopu rehabilitacijskih programov.

• Jezik: Slovenski jezik
• Ključne besede: klinično izoliran sindrom, ravnotežje, delovni spomin, dvojne naloge
• Vrsta gradiva: Doktorsko delo/naloga
• Organizacija: MF - Medicinska fakulteta
• Leto izida: 2018
• PID: 20.500.12556/RUL-105407
• COBISS.SI-ID: 297531904
• Datum objave v RUL: 26.11.2018

BRECL JAKOB, Gregor, 2018, Vpliv sočasnih kognitivnih nalog na ravnotežje, začetek hoje in hojo pri bolnikih s klinično izoliranim sindromom [na spletu]. Doktorska disertacija. [Dostopano 5 maj 2025]. Pridobljeno s: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=slv&id=105407

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: The influence of concurrent cognitive tasks on balance, gait initiation and walking in patients with clinically isolated syndrome

Izvleček

Background: Multiple sclerosis (MS) starts with clinically isolated syndrome (CIS), which in approximately 25 % represents optic neuritis (ON). Balance and cognitive problems including working memory deficits can be detected in majority of CIS patients. Dual-task paradigm is often used to study cognitive-motor interference (CMI). Due to the lack of consistent data about the effect of demyelinating disease in its earliest stages on balance and CMI, we aimed to study interactions between working memory and three different aspects of balance in highly selected patients with ON without significant neurological impairment. Such data are important in order to identify and further study possible prognostic biomarkers to better predict the course of the disease. Additionally, new information could be used for counselling and establishing better rehabilitation strategies. Methods: Twenty patients with ON (CIS) and good visual acuity and 20 healthy subjects underwent assessments of three aspects of balance (standing, gait initiation and gait). The assessments were performed with and without concurrent verbal and visuospatial working memory tasks. Balance was assessed using centre of pressure measures. Patients underwent neuropsychological assessment to estimate baseline cognitive functioning. Results: Neuropsychological testing did not reveal important deficits of working memory in patients. In majority impairment of attention and executive functions was noted. Static balance (while standing) was impaired in patients. We observed a higher effect of concurrent visuospatial cognitive task on balance performance compared to verbal working memory task in patients. Dynamic balance while initiating gait was not different between the groups. Performance on both cognitive tasks was lower in patients while dual-tasking compared to cognitive task alone. Additionally, CMI was higher in patients compared to healthy subjects. We observed higher CMI between verbal working memory task and gait initiation compared to visuospatial working memory task in both groups. Patients walked significantly slower compared to healthy controls. Both groups lowered gait speed while dual-tasking regardless of the nature of the concurrent cognitive task. Conclusions: Our results and the data from the literature suggest that interference between working memory and static balance largely occurs at the level of parietal cortex, which is involved in afferent signal processing and perception of the body in space as well as visual working memory and attention. On the other hand, interference between working memory and gait initiation occurs mainly in the frontal cortex (prefrontal area), since these regions are involved in generation of anticipatory postural adjustments and verbal working memory. Additionally, impaired performance on both cognitive tasks while initiating gait suggests CMI is happening at the level of central executive. Similar responses to cognitive tasks while walking in patients and healthy subjects suggest slower gait to be an appropriate response to dual-tasking. Similarly, we consider lower baseline gait speed observed in patients to be an appropriate response from prefrontal areas responsible for gait speed control. Baseline working memory performance of the patients was normal. Taking this into account, all our findings can be explained by impaired quality of afferent and efferent signals to the brain resulting in higher need for cognitive involvement while balancing. Attention deficits and impairment of executive functions might lower the threshold for the observed interactions in some instances and become especially important when demanding motor tasks such as gait initiation are involved. New data from our study represents foundation for further prospective research to identify possible biomarkers for the disease prognosis. The observation of executive functions and attention deficits becoming important only while performed along with demanding motor tasks allows us to counsel the patients properly and suggest health-care workers to focus on these cognitive domains while planning rehabilitation programmes for the patients. Methods: Twenty patients with ON (CIS) and good visual acuity and 20 healthy subjects underwent assessments of three aspects of balance (standing, gait initiation and gait). The assessments were performed with and without concurrent verbal and visuospatial working memory tasks. Balance was assessed using centre of pressure measures. Patients underwent neuropsychological assessment to estimate baseline cognitive functioning. Results: Neuropsychological testing did not reveal important deficits of working memory in patients. In majority impairment of attention and executive functions was noted. Static balance (while standing) was impaired in patients. We observed a higher effect of concurrent visuospatial cognitive task on balance performance compared to verbal working memory task in patients. Dynamic balance while initiating gait was not different between the groups. Performance on both cognitive tasks was lower in patients while dual-tasking compared to cognitive task alone. Additionally CMI was higher in patients compared to healthy subjects. We observed higher CMI between verbal working memory task and gait initiation compared to visuospatial working memory task in both groups. Patients walked significantly slower compared to healthy controls. Both groups lowered gait speed while dual-tasking regardless of the nature of the concurrent cognitive task. Conclusions: Our results and the data from the literature suggest that interference between working memory and static balance largely occurs at the level of parietal cortex, which is involved in afferent signal processing and perception of the body in space as well as visual working memory. On the other hand interference between working memory and gait initiation occurs mainly in the frontal cortex (prefrontal area), since these regions are involved in generation of anticipatory postural adjustments and verbal working memory. Additionally, impaired performance on both cognitive tasks while initiating gait suggests CMI is happening at the level of central executive. Similar responses to cognitive tasks while walking in patients and healthy subjects suggest slower gait to be an appropriate response to dual-tasking. Similarly we consider lower baseline gait speed observed in patients to be an appropriate response from prefrontal areas responsible for gait speed control. Baseline working memory performance of the patients was normal. Taking this into account, all our findings can only be explained by impaired quality of afferent and efferent signals to the brain resulting in higher need for cognitive involvement while balancing. Attention deficits and impairment of executive functions become important only when demanding motor tasks such as gait initiation are involved. New data from our study represents foundation for further prospective research to identify possible biomarkers for the disease prognosis. The observation of executive functions and attention deficits becoming important only while performed along with demanding motor tasks allows us to counsel the patients properly and suggest health-care workers to focus on these cognitive domains while planning rehabilitation programmes for the patients.

• Ključne besede: clinically isolated syndrome, balance, working memory, dual-tasking