Effect of diabetic neuropathy severity classified by a fuzzy model in muscle dynamics during gait

Abstract

BackgroundElectromyography (EMG) alterations during gait, supposedly caused by diabetic sensorimotor polyneuropathy, are subtle and still inconsistent, due to difficulties in defining homogeneous experimental groups with a clear definition of disease stages. Since evaluating these patients involve many uncertainties, the use of a fuzzy model could enable a better discrimination among different stages of diabetic polyneuropathy and lead to a clarification of when changes in muscle activation start occurring. The aim of this study was to investigate EMG patterns during gait in diabetic individuals with different stages of DSP severity, classified by a fuzzy system.Methods147 subjects were divided into a control group (n = 30) and four diabetic groups: absent (n = 43), mild (n = 30), moderate (n = 16), and severe (n = 28) neuropathy, classified by a fuzzy model. The EMG activity of the vastus lateralis, tibialis anterior, and gastrocnemius medialis were measured during gait. Temporal and relative magnitude variables were compared among groups using ANOVA tests.ResultsMuscle activity changes are present even before an established neural involvement, with delay in vastus lateralis peak and lower tibialis anterior relative magnitude. These alterations suggest an impaired ankle shock absorption mechanism, with compensation at the knee. This condition seems to be more pronounced in higher degrees of neuropathy, as there is an increased vastus lateralis activity in the mild and severe neuropathy groups. Tibialis anterior onset at terminal stance was anticipated in all diabetic groups; at higher degrees of neuropathy, the gastrocnemius medialis exhibited activity reduction and peak delay.ConclusionEMG alterations in the vastus lateralis and tibialis anterior occur even in the absence of diabetic neuropathy and in mild neuropathic subjects, seemingly causing changes in the shock absorption mechanisms at the heel strike. These changes increase with the onset of neural impairments, and the gastrocnemius medialis starts presenting altered activity in the later stages of the disease (moderate and severe neuropathy). The degree of severity of diabetic neuropathy must be taken into account when analyzing diabetic patients’ biomechanical patterns of locomotion; we recommend the use of a fuzzy model for classification of disease stages.

How to Define Pathogenicity, Health, and Disease?

“…] aim at taking into account uncertainties often by applying fuzzy logic where truth values of variables vary [Watari et al. ; Mak, ; Miranda and Felipe, ]. Fuzzy sets and logic are largely dependent on the initial setup.…”

Padrões dinâmicos de recrutamento muscular por EMG de alta densidade de diabéticos em diferentes níveis de severidade de neuropatia classificados por um modelo linguistico fuzzy

“…Altered activity at the knee muscles, especially the extensors, have also been found on DPN individuals. Studies have described a delayed peak activity and a lower activity of the vastus lateralis muscle at heel strike during gait (Abboud, Rowley and Newton, 2000;Akashi et al, 2008;Sacco, Akashi and Hennig, 2010;Watari et al, 2014) and an earlier onset at initial contact with a diminished activity was reported during pre-swing phase for rectus femoris (Sawacha, Spolaor, et al, 2012). Altered activity of vastus lateralis has also been described during stair descent/ascent , suggesting that the presence of DPN alters the muscle coordination in different locomotor tasks.…”

“…The motor dysfunction caused by DPN interferes with muscular activity of the lower limbs while performing daily living tasks (Abboud, Rowley and Newton, 2000;Akashi et al, 2008;Sacco, Akashi and Hennig, 2010;Watari et al, 2014). The existing literature has shown altered activity at the ankle muscles in the presence of DPN during gait stance phase, reporting a delayed (Akashi et al, 2008;Sacco, Akashi and Hennig, 2010) and lower activation of gastrocnemious muscles, and a delayed activation of tibialis anterior muscle (Abboud, Rowley and Newton, 2000;.…”

“…But the observed changes in the structural variability clearly show that motor control is degraded in these subjects. The controversial results of the sEMG studies during dynamic tasks with DPN population can be partially explained by the supposed motor control degradation and complexity alterations that are not easily extracted from bipolar electrodes and discrete/ linear analysis, which are the usual method used in these previous studies (Abboud, Rowley and Newton, 2000;Akashi et al, 2008;Sacco, Akashi and Hennig, 2010;Sawacha, Spolaor, et al, 2012;Watari et al, 2014).…”

“…The model gives scores between 0-10 for the DPN degree and classifies the patients between mild, moderate and severe neuropathic individuals. Watari et al (2014) refined this model using as inputs (i) the presence of typical DPN symptoms, based on Michigan Neuropathy Screening Instrument , (ii) tactile sensitivity, evaluated with 10-g Semmes-Weinstein monofilament under 4 areas of both feet Bakker, Apelqvist and Schaper, 2012) and (iii) vibratory perception, evaluated with a 128-Hz tuning fork . The model classified the patients in absent, mild, moderate and severe DPN, and presented a very strong correlation with the experts' opinion (Pearson's coefficient r = 0.94) and a high accuracy level when classifying patients as having DPN (ROC curve area = 0.91).…”