Automated design of robust discriminant analysis classifier for foot pressure lesions using kinematic data

In the recent years, the use of motion tracking systems for acquisition of functional biomechanical gait data, has received increasing interest due to the richness and accuracy of the measured kinematic information. However, costs frequently restrict the number of subjects employed, and this makes the dimensionality of the collected data far higher than the available samples. This paper applies discriminant analysis algorithms to the classification of patients with different types of foot lesions, in order to establish an association between foot motion and lesion formation. With primary attention to small sample size situations, we compare different types of Bayesian classifiers and evaluate their performance with various dimensionality reduction techniques for feature extraction, as well as search methods for selection of raw kinematic variables. Finally, we propose a novel integrated method which fine-tunes the classifier parameters and selects the most relevant kinematic variables simultaneously. Performance comparisons are using robust resampling techniques such as Bootstrap$632+$and k-fold cross-validation. Results from experimentations with lesion subjects suffering from pathological plantar hyperkeratosis, show that the proposed method can lead to$sim 96$correct classification rates with less than 10% of the original features

Foot kinematics in patients with two patterns of pathological plantar hyperkeratosis

Background: The Root paradigm of foot function continues to underpin the majority of clinical foot biomechanics practice and foot orthotic therapy. There are great number of assumptions in this popular paradigm, most of which have not been thoroughly tested. One component supposes that patterns of plantar pressure and associated hyperkeratosis lesions should be associated with distinct rearfoot, mid foot, first metatarsal and hallux kinematic patterns. Our aim was to investigate the extent to which this was true. Methods: Twenty-seven subjects with planter pathological hyperkeratosis were recruited into one of two groups. Group 1 displayed pathological plantar hyperkeratosis only under metatarsal heads 2, 3 and 4 (n = 14). Group 2 displayed pathological plantar hyperkeratosis only under the 1st and 5th metatarsal heads (n = 13). Foot kinematics were measured using reflective markers on the leg, heel, midfoot, first metatarsal and hallux. Results: The kinematic data failed to identify distinct differences between these two groups of subjects, however there were several subtle (generally <3°) differences in kinematic data between these groups. Group 1 displayed a less everted heel, a less abducted heel and a more plantarflexed heel compared to group 2, which is contrary to the Root paradigm. Conclusions: There was some evidence of small differences between planter pathological hyperkeratosis groups. Nevertheless, there was too much similarity between the kinematic data displayed in each group to classify them as distinct foot types as the current clinical paradigm proposes

Foot kinematics in patients with two patterns of pathological plantar hyperkeratosis

Background: The Root paradigm of foot function continues to underpin the majority of clinical foot biomechanics practice and foot orthotic therapy. There are great number of assumptions in this popular paradigm, most of which have not been thoroughly tested. One component supposes that patterns of plantar pressure and associated hyperkeratosis lesions should be associated with distinct rearfoot, mid foot, first metatarsal and hallux kinematic patterns. Our aim was to investigate the extent to which this was true.Methods: Twenty-seven subjects with planter pathological hyperkeratosis were recruited into one of two groups.Group 1 displayed pathological plantar hyperkeratosis only under metatarsal heads 2, 3 and 4 (n = 14). Group 2displayed pathological plantar hyperkeratosis only under the 1st and 5th metatarsal heads (n = 13). Foot kinematicswere measured using reflective markers on the leg, heel, midfoot, first metatarsal and hallux.Results: The kinematic data failed to identify distinct differences between these two groups of subjects, howeverthere were several subtle (generally <3°) differences in kinematic data between these groups. Group 1 displayed aless everted heel, a less abducted heel and a more plantarflexed heel compared to group 2, which is contrary tothe Root paradigm.Conclusions: There was some evidence of small differences between planter pathological hyperkeratosis groups.Nevertheless, there was too much similarity between the kinematic data displayed in each group to classify themas distinct foot types as the current clinical paradigm proposes

Development and validation of the Multi-dimensional University Research Workplace Inventory (MDURWI)

WOS:000454839600005This study describes the development and validation of an instrument aimed toward measuring organizational features of an academic research workplace. The question pool was developed based on data from a pilot study (N = 43). The survey was deployed to academic researchers in the field of higher education research worldwide (N = 850). An exploratory factor analysis conducted on 36 questions, followed by confirmatory factor analysis, which lead to a final pool of 27 questions in five subscales, one of which divided into three lower-order factors. The final model exhibited very good fit (X2/df = 2.561; CFI = 0.972; PCFI = 0.784; RMSEA = 0.043; P[rmsea ? 0.05] < 0.001; AIC = 891.018; BCC = 987.839) and psychometric properties, in the form of factorial, convergent, and discriminant validity, as well as reliability and sensitivity. Implications of this instrument for research and policymaking are discussed, as well as future research directions.info:eu-repo/semantics/acceptedVersio

Kinematics of the lower leg and foot during gait in subjects with pathological plantar hyperkeratosis

This study seeks to consider the functional characteristics of a five segmentlower leg and foot model during gait, using the application of elementary kinematics tomeasure, analyse and describe lower leg and foot motion and compare these parametersbetween two subject groups with plantar pathological hyperkeratosis (PPH); PPH groupone having callus under metatarsal heads 2, 3 and 4, and PPH group two having callusunder metatarsal heads 1 and 5.Root's elegant theory of foot function (Root et al. 1966; Root et al. 1977) hasbecome widely accepted in podiatry. This theory suggests the orientation of the subtalarjoint axis influences the amount of motion in all the cardinal body planes. Therefore, afoot which has a joint axis which is highly inclined will exhibit more transverse planelower leg rotation than frontal plane calcaneal motion; will be a less mobile foot; andtend to present with callus under metatarsal heads 1 and 5. Conversely, a foot with alower inclined subtalar joint axis will exhibit more frontal plane calcaneal motion thantransverse plane leg rotation; will be more mobile; and tend to have callus under the 2, 3and 4 metatarsal heads.A non-invasive in vivo kinematic method was developed to collect threedimensional coordinates of markers attached to a novel five segment model of the lowerleg and foot in order to estimate the angular displacement and motion between the lowerleg and foot segments.The results have shown that there are statistically significant differences in thelower leg and foot kinematics between the PPH groups (p < 0.05) during variousperiods within the stance phase. These differences suggest that the motions of the lowerleg and foot are similar to those proposed by the podiatric theory. However the findingscontradict Root's theory within the latter stages of midstance and propulsive periods ofgait

Clinical and experimental models of the midtarsal joint: proposed terms of reference and associated terminology.

Recent debate and literature have provided impetus to the growing body of thought that we should not model the midtarsal joint as having two simultaneous axes of rotation but as having a single instantaneous axis of rotation. Building on this concept, we present new reference terminology and propose that descriptions of midtarsal joint kinetics and kinematics relate to moments and motion in the cardinal body planes as defined by the x-, y-, and z-axes of the local reference system of the calcaneus. This replaces the existing terminology that describes the oblique and longitudinal axes for the midtarsal joint. The purpose of the new terms of reference and terminology is to aid in the communication of ideas and concepts regarding the biomechanics of the midtarsal joint among clinicians and between researchers and clinicians. It will also allow integration of the midtarsal joint into the emerging biomechanical model of the lower limb, promote consistency in discussions of the joint, and ease understanding of the interrelationships between the kinetics and the kinematics of the articulations in the foot and lower limb and their relationship to pathology and clinical practice

A cross-sectional study of age-related changes in plantar pressure distribution between 4 and 7 years : a comparison of regional and pixel-level analyses

Quantifying morphological and functional development in children's feet, and thereby establishing development norms is difficult. In addition to practical challenges of experimentation on children, measurement equipment like plantar pressure (PP) platforms are almost exclusively geared towards adult-sized feet. These PP quantification problems may be exacerbated by typical regional data analysis techniques, which further reduce spatial resolution. The goal of this study was to quantify PP distributions in developing children, and also to compare the results obtained from typical (regional) techniques with those obtained from a higher-resolution (pixel-level) technique. Ninety-eight children between four and seven years of age were assessed in a cross-sectional design. Maximum PP distributions were collected for each child, and these pressures were linearly regressed against age. Present results agree with previous investigations in that maximum pressures and maximum pressure changes occurred in the forefoot. However, results from the present pixel-level technique suggest that these changes are limited to the central metatarsals, and that regional methods can suggest significance where none exists in the actual raw (pixel-level) data, due to signal aliasing and, in particular, to conflation of regional boundaries. We postulate that increased central metatarsal pressures are reflective of the coupling between generalised joint laxity decreases and relatively increasingly inclined central metatarsal bones with age

Evaluating the effect of a haemoglobin spray on size reduction in chronic DFUs

Aim: The aim of this multi-centre observational evaluation was to assess the percentage reduction in wound area of non-healing diabetic foot ulcers (DFUs), treated with Granulox haemoglobin spray over a 4-week period. Secondary outcome parameters—for example, adverse events, patient acceptability and ease of use—were also recorded. Method: After a run-in-period (2 weeks for existing patients and 4 weeks for new patients) to determine if the wounds were non-healing despite receiving local best practice, patients whose foot ulcers had decreased in size by < 20% were then entered into the evaluation. A sample of 17 patients (4 females and 13 males), comprising 4 with type 1 and 13 with type 2 diabetes, with a total of 20 DFUs, met the inclusion criteria. These data were collected from six sites across the UK. Results: There was an overall positive reduction in size in 14 of the wounds, equating to a mean reduction of 53.8% (standard deviation (SD): 26.6; range: 11.9–100%). One participant, with two ulcers, had to be withdrawn due to infection. All clinicians and participants found the product easy to use. Conclusion: The addition of a topical oxygenation therapy in this cohort of non-healing DFUs showed reduction in wound surface area and progression to healing. The product was also found to be acceptable and very easy to use by both participants and clinicians

Automated Nonlinear Feature Generation and Classification of Foot Pressure Lesions

Plantar lesions induced by biomechanical dysfunction pose a considerable socioeconomic health care challenge, and failure to detect lesions early can have significant effects on patient prognoses. Most of the previous works on plantar lesion identification employed the analysis of biomechanical microenvironment variables like pressure and thermal fields. This paper focuses on foot kinematics and applies kernel principal component analysis(KPCA) for nonlinear dimensionality reduction of features, followed by Fisher’s linear discriminant analysis for the classification of patients with different types of foot lesions, in order to establish an association between foot motion and lesion formation. Performance comparisons are made using leave-one-out cross-validation. Results show that the proposed method can lead to∼ 94% correct classification rates, with a reduction of feature imensionality from 2100 to 46, without any manual preprocessing or elaborate feature extraction methods. The results imply that foot kinematics contain information that is highly relevant to pathology classification and also that the nonlinear KPCA approach has considerable power in unraveling abstract biomechanical features into a relatively lowdimensional pathology-relevant space