Obesity Impact on the Attentional Cost for Controlling Posture

Abstract

BackgroundThis study investigated the effects of obesity on attentional resources allocated to postural control in seating and unipedal standing.MethodsTen non obese adults (BMI = 22.4±1.3, age = 42.4±15.1) and 10 obese adult patients (BMI = 35.2±2.8, age = 46.2±19.6) maintained postural stability on a force platform in two postural tasks (seated and unipedal). The two postural tasks were performed (1) alone and (2) in a dual-task paradigm in combination with an auditory reaction time task (RT). Performing the RT task together with the postural one was supposed to require some attentional resources that allowed estimating the attentional cost of postural control. 4 trials were performed in each condition for a total of 16 trials.Findings(1) Whereas seated non obese and obese patients exhibited similar centre of foot pressure oscillations (CoP), in the unipedal stance only obese patients strongly increased their CoP sway in comparison to controls. (2) Whatever the postural task, the additional RT task did not affect postural stability. (3) Seated, RT did not differ between the two groups. (4) RT strongly increased between the two postural conditions in the obese patients only, suggesting that body schema and the use of internal models was altered with obesity.InterpretationObese patients needed more attentional resources to control postural stability during unipedal stance than non obese participants. This was not the case in a more simple posture such as seating. To reduce the risk of fall as indicated by the critical values of CoP displacement, obese patients must dedicate a strong large part of their attentional resources to postural control, to the detriment of non-postural events. Obese patients were not able to easily perform multitasking as healthy adults do, reflecting weakened psycho-motor abilities.

Influencia do indice de massa corporal no equilibrio e na configuracao plantar em obesos adultos

“…Alguns estudos utilizando plataforma de força avaliaram o tempo de manutenção em apoio estático unipodal. Observaram que indivíduos com IMC acima de 30 Kg/m² apresentaram redução no tempo de manutenção quando comparados com não obesos 12,13 . Outros estudos demonstraram atraso de 20 a 40% do impulso motor e sensorial sobre o nervo mediano, ulnar, fibular e tibial, quando comparado com sujeitos não obesos sugerindo redução do recrutamento de unidades motoras e da força muscular 14 .…”

The impact of obesity on balance control in community-dwelling older women

“…However, the obese individuals had a higher prevalence of falling and ambulatory stumbling, as well as lower quality of life in multiple health domains than the normal weight counterparts (Fjeldstad et al 2008). Also, situations that are cognitively challenging might place additional demands on maintaining balance to reduce the risk of fall, and this has been shown to be additionally detrimental for balance control in obese persons (Mignardot et al 2010). In older persons, postural contexts requiring a reweighting of sensory inputs could lead to an increased risk for loss of balance and falls if insufficient attentional resources are allocated to the postural task .…”

Obesity and fractures

“…On the other hand, obese subjects are at higher risk of falling and less well able to protect themselves against a fall (24)(25)(26). Falls in individuals who are overweight or obese are more likely to occur backwards or sidewards, in contrast to forward falls in leaner individuals (27). Exaggeration of introversion and extroversion of the ankle and lower leg in obese subjects may be also responsible for a higher prevalence of fractures at these sites.…”