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Biomedical subjects

Hylton B Menz

Publications and source records attributed to Hylton B Menz.

At least 19 recordsLinked to original sources
PubMed2006

Age-related differences in foot structure and function.

The aim of this study was to compare foot characteristics and plantar force and pressure patterns in young and older people. Fifty young (mean age 20.9+/-2.6 years) and 50 older (mean age 80.2+/-5.7 years) people without foot problems underwent tests of foot posture, range of motion, strength, sensation and deformity. Plantar force and pressure distribution during gait were evaluated using a floor-mounted resistive sensor mat system. Older participants exhibited flatter/more pronated feet, reduced range of motion of the ankle and 1st metatarsophalangeal joints, a higher prevalence of hallux valgus, toe deformities and toe plantarflexor weakness, and reduced plantar tactile sensitivity. Plantar pressure analysis revealed decreased magnitude of forces and pressures under the heel (-13% to 16%), metatarsophalangeal joints (-11% to 16%) and hallux (-19% to 25%), but greater relative contact time under the heel (+21%), midfoot (+14%) and metatarsophalangeal joints (+5% to 8%) in older participants. Multiple regression analysis revealed that these age-related differences could be largely explained by differences in step length and various foot characteristics, particularly foot posture and the severity of hallux valgus. These findings indicate that ageing is associated with significant changes in foot characteristics which contribute to altered plantar loading patterns during gait.

Adult↗
PubMed2006

A tactile stimulus applied to the leg improves postural stability in young, old and neuropathic subjects.

The purpose of this study was to determine whether the application of passive tactile cues to the lower limb could improve postural stability in healthy young controls, older people and people with diabetic peripheral neuropathy. Antero-posterior sway was measured with eyes open and closed in 10 healthy young subjects (mean age 27 years, 5 male, 5 female), 10 older subjects without diabetic peripheral neuropathy (mean age 88 years, 2 male, 8 female) and 10 subjects with diabetic peripheral neuropathy (mean age 65 years, 6 male, 4 female) while a small piece of Velcro attached to a flexible mount was applied to three different sites on the leg (ankle, calf, and knee). Across all conditions, the mean sway of the neuropathic subjects was 93% greater than for the young subjects and 11% more than the older subjects. On average, subjects swayed 10% more with the eyes closed than with the eyes open. Each stimulus reduced sway, but the effect increased approximately in proportion to the height of the stimulus above the ankles (ankle 7.6%, calf 13.5%, knee 20.1% reduction compared to the no stimulus condition). This experiment demonstrates that a passive stimulus applied to the skin of the leg, which provides sensory information about body movement, significantly reduces body sway during standing. This applies to older subjects and subjects with peripheral neuropathy as well as healthy young subjects. These results have implications for novel approaches for improving stability in people with peripheral sensory loss.

Adult↗
PubMed2006

A structural equation model relating impaired sensorimotor function, fear of falling and gait patterns in older people.

Many falls in older people occur while walking, however the mechanisms responsible for gait instability are poorly understood. Therefore, the aim of this study was to develop a plausible model describing the relationships between impaired sensorimotor function, fear of falling and gait patterns in older people. Temporo-spatial gait parameters and acceleration patterns of the head and pelvis were obtained from 100 community-dwelling older people aged between 75 and 93 years while walking on an irregular walkway. A theoretical model was developed to explain the relationships between these variables, assuming that head stability is a primary output of the postural control system when walking. This model was then tested using structural equation modeling, a statistical technique which enables the testing of a set of regression equations simultaneously. The structural equation model indicated that: (i) reduced step length has a significant direct and indirect association with reduced head stability; (ii) impaired sensorimotor function is significantly associated with reduced head stability, but this effect is largely indirect, mediated by reduced step length, and; (iii) fear of falling is significantly associated with reduced step length, but has little direct influence on head stability. These findings provide useful insights into the possible mechanisms underlying gait characteristics and risk of falling in older people. Particularly important is the indication that fear-related step length shortening may be maladaptive.

Accidental Falls↗
PubMed2006

[Characteristics of falls in physically active community-dwelling older people: findings from the "Standfest im Alter" study].

BACKGROUND: Falls are common in physically active older people due to their increased exposure to hazardous situations. However, most studies of the characteristics and circumstances of falls are based on frail older people. OBJECTIVE: To describe the location, time, cause, injuries and medical treatment associated with falls in a physically active group of older people. METHODS: Prospective falls data over a 12-month period were obtained from 293 people (163 men and 130 women) aged between 70 and 90 years who took part in the "Standfest im Alter" study, a randomized controlled trial conducted in Erlagen, Germany. RESULTS: During the study period, there were 322 falls. 122 participants (42%) fell at least once and 62 (21%) fell on multiple occasions. The typical fall occurred outside the home during leisure activities, at midday or in the afternoon and did not result in injury or admission to hospital. There were no differences in the rate of falls according to gender; however, fall location, time of fall, fall injury and visits to the doctor after the fall were all influenced by gender. CONCLUSIONS: The results of this study provide useful insights into the characteristics and circumstances of falls in physically active older people living in the community, which may assist with the development of future falls prevention activities.

Accidental Falls↗
PubMed2006

Home environment risk factors for falls in older people and the efficacy of home modifications.

Most homes contain potential hazards, and many older people attribute their falls to trips or slips inside the home or immediate home surroundings. However, the existence of home hazards alone is insufficient to cause falls, and the interaction between an older person's physical abilities and their exposure to environmental stressors appears to be more important. Taking risks or impulsivity may further elevate falls risk. Some studies have found that environmental hazards contribute to falls to a greater extent in older vigorous people than in older frail people. This appears to be due to increased exposure to falls hazards with an increase in the proportion of such falls occurring outside the home. There may also be a non-linear pattern between mobility and falls associated with hazards. Household environmental hazards may pose the greatest risk for older people with fair balance, whereas those with poor balance are less exposed to hazards and those with good mobility are more able to withstand them. Reducing hazards in the home appears not to be an effective falls-prevention strategy in the general older population and those at low risk of falls. Home hazard reduction is effective if targeted at older people with a history of falls and mobility limitations. The effectiveness may depend on the provision of concomitant training for improving transfer abilities and other strategies for effecting behaviour change.

Accidental Falls↗
PubMed2006

Foot and ankle risk factors for falls in older people: a prospective study.

BACKGROUND: Foot problems are common in older people and are associated with impaired balance and functional ability. Few prospective studies, however, have been undertaken to determine whether foot problems are a risk factor for falls. METHODS: One hundred seventy-six people (56 men and 120 women, mean age 80.1, standard deviation 6.4 years) residing in a retirement village underwent tests of foot and ankle characteristics (including foot posture, range of motion, strength, and deformity) and physiological falls risk factors (including vision, sensation, strength, reaction time, and balance) and were followed for 12 months to determine the incidence of falls. RESULTS: Seventy-one participants (41%) reported falling during the follow-up period. Compared to those who did not fall, fallers exhibited decreased ankle flexibility, more severe hallux valgus deformity, decreased plantar tactile sensitivity, and decreased toe plantarflexor strength; they were also more likely to have disabling foot pain. Discriminant function analysis revealed that decreased toe plantarflexor strength and disabling foot pain were significantly and independently associated with falls after accounting for physiological falls risk factors and age. CONCLUSIONS: Foot and ankle problems increase the risk of falls in older people. Interventions to address these factors may hold some promise as a falls prevention strategy.

Accidental Falls↗
PubMed2006

Footwear characteristics and risk of indoor and outdoor falls in older people.

BACKGROUND: Footwear characteristics have been shown to influence balance in older people; however, the relationship between footwear and falls is unclear. OBJECTIVE: To determine the relationships between footwear characteristics and the risk of indoor and outdoor falls in older people. METHODS: Footwear characteristics (shoe type, heel height, heel counter height, heel width, critical tipping angle, method of fixation, heel counter stiffness, sole rigidity and flexion point, tread pattern and sole hardness) were assessed in 176 people (56 men and 120 women) aged 62-96 (mean age 80.1, SD 6.4) residing in a retirement village. Falls were recorded over a 12-month follow-up period and comparisons made between fallers and non-fallers. RESULTS: 50 participants (29%) fell indoors and 36 (21%) fell outdoors. After controlling for age, gender, demographic characteristics, medication use, physiological falls risk factors and foot problems, those who fell indoors were more likely to go barefoot or wear socks inside the home (OR = 13.74; 95% CI 3.88-48.61, p < 0.01). However, there were no significant differences in indoor or outdoor footwear characteristics between fallers and non-fallers. Five indoor fallers (10%) and three outdoor fallers (8%) stated that their shoes contributed to their fall. CONCLUSION: Footwear characteristics were not significantly associated with falls either inside or outside the home. Risk of falling indoors was associated with going barefoot or wearing socks. Older people at risk of falling should therefore be advised to wear shoes indoors where possible.

Accidental Falls↗
PubMed2006

Plantarflexion strength of the toes: age and gender differences and evaluation of a clinical screening test.

BACKGROUND: The toes play an important stabilizing role in weightbearing activities. However, the factors that influence toe plantarflexion strength are poorly understood, and there are no validated measures for assessing toe weakness in the clinical setting. Therefore, the objectives of this study were to determine whether plantarflexion strength of the toes differs according to age and gender and to evaluate the validity of a clinical screening test for assessing toe plantarflexor weakness (the paper grip test). METHODS: Plantarflexion strength of the hallux and lesser toes was measured in 40 young participants (20 men and 20 women, mean age 20.8 +/- 2.2 years) and 40 older participants (20 men and 20 women, mean age 74.6 +/- 5.7 years) using a pressure platform in conjunction with clinical assessment using the paper grip test. RESULTS: Older participants exhibited 32% less plantarflexion strength of the hallux and 27% less plantarflexion strength of the lesser toes compared to younger participants, and women exhibited 42% less hallux plantarflexor strength than men. Gender did not influence lesser toe plantarflexor strength. Participants who failed the paper grip test exhibited significantly reduced plantarflexion strength for both the hallux and lesser toes. The sensitivity and specificity of the paper grip test of the hallux to predict plantarflexor strength less than 2.6 kg was 80% and 79%, respectively, and the sensitivity and specificity of the paper grip test of the lesser toes to predict plantarflexor strength less than 2.2 kg was 75% and 74%, respectively. CONCLUSIONS: These findings indicate that aging is associated with reduced plantarflexion strength of the toes. The paper grip test may be a useful screening tool to detect toe weakness in the clinical setting.

Adult↗
PubMed2005

Clinical determinants of plantar forces and pressures during walking in older people.

The aim of this study was to determine the extent to which clinical tests of structural characteristics of the foot and ankle could account for variation in the magnitude of regional forces and pressures under the foot during walking in older people. Plantar forces and pressures were obtained from 172 older people (53 men, 119 women) aged 62-96 years (mean 80.0, S.D. 6.4) using a floor-mounted resistive sensor mat system. Subjects also completed tests of foot posture, range of motion, strength, sensation and toe deformity. Multiple regression analysis was then used to determine which clinical variables were most strongly correlated with plantar forces and pressures. Maximum forces and peak pressures under most regions of the foot were largely explained by differences in bodyweight, with some important exceptions. Loading under the midfoot was associated with the arch index, loading under the first metatarsophalangeal joint (1st MPJ) was associated with 1st MPJ range of motion, and loading under the hallux was associated with hallux plantarflexor strength, 1st MPJ range of motion and the degree of hallux valgus deformity. Clinical measurements accounted for 13-53% of the variance in maximum force and 4-40% of the variance in peak pressures. These findings indicate that structural foot and ankle characteristics identified from clinical measurements can explain some key aspects of plantar loading patterns of the foot. This information provides further insights into the dynamic function of the foot, which might assist in the development of interventions for pressure-related foot complaints in older people.

Aged↗
PubMed2005

Foot and leg problems are important determinants of functional status in community dwelling older people.

PURPOSE: To determine whether foot and leg problems are independently associated with functional status in a community sample of older people after adjusting for the influence of socio-demographic, physical and medical factors. METHOD: Data were analysed from the Health Status of Older People project, a population-based study involving a random sample of 1000 community-dwelling people aged 65 - 94 years (533 females, 467 males, mean age 73.4 years +/- 5.87). A structured interview and brief physical examination were used to investigate the associations between self-reported foot and leg problems and functional status. Functional status was assessed using: (i) timed 'Up & Go' test, (ii) self-reported difficulty climbing stairs, (iii) self-reported difficulty walking one kilometer, (iv) self-reported difficulty performing instrumental activities of daily living (IADLs), and (v) self-reported history of one or more falls in the previous 12 months. These associations were then explored after adjusting for socio-demographic, physical and medical factors. RESULTS: Thirty-six percent of the sample reported having foot or leg problems. Univariate analyses revealed that people with foot and leg problems were significantly more likely to exhibit poorer functional status in all parameters measured. After adjusting for socio-demographic, physical and medical factors, foot and leg problems remained significantly associated with impaired timed 'Up & Go' performance (OR = 2.15, 95%CI 1.55 - 2.97), difficulty climbing stairs (OR = 3.33, 95%CI 1.98 - 5.61), difficulty walking one kilometer (OR = 3.13, 95%CI 2.09 - 4.69), and history of falling (OR = 1.73, 95%CI 1.26 - 2.37). CONCLUSIONS: Foot and leg problems are reported by one in three community-dwelling people aged 65 years and older. Independent of the influence of age, gender, common medical conditions and other socio-demographic factors, foot and leg problems have a significant impact on the ability to perform functional tasks integral to independent living.

Accidental Falls↗
PubMed2005

What is the role of falls?

There is now firm evidence to support interventions in the prevention of falls in older people, and emerging data support prevention of falls as a method of fracture prevention. This chapter discusses the epidemiology of falls, risk factors associated with an increased risk of falling, assessment of the older faller, and evidence-based approaches to the prevention of falls in the older person. Several randomized controlled trials have found that hip protectors, if worn, probably prevent hip fractures, but that poor compliance is a major issue limiting the effectiveness of this form of intervention. More data are needed to support the role of prevention of falls in preventing fractures, as well as comparative cost-effectiveness data with other evidence-based approaches to preventing fractures in an older population.

Accidental Falls↗
PubMed2005

Foot and ankle characteristics associated with impaired balance and functional ability in older people.

BACKGROUND: Ageing is associated with changes to the structure and function of the foot and ankle, and there is preliminary evidence that foot problems impair balance and increase the risk of falls. To explore this in more detail, we conducted a study to determine the relative contribution of several foot and ankle characteristics to performance on a range of balance and functional tests. METHODS: One hundred seventy-six people (56 men and 120 women, mean age 80.1 years, standard deviation 6.4 years) residing in a retirement village underwent tests of foot and ankle characteristics (including foot posture, range of motion, strength, and deformity), sensorimotor function (including vision, sensation, strength, and reaction time), and balance and functional ability (including tests of standing balance, leaning balance, stepping, sit-to-stand, and walking speed). RESULTS: Many foot and ankle characteristics and sensorimotor measures were associated with performance on the balance and functional tests in univariate analyses. Multiple regression analysis consistently revealed that ankle flexibility, plantar tactile sensitivity, and toe plantarflexor strength were significant and independent predictors of balance and functional test performance, explaining up to 59% of the variance in these test scores. CONCLUSIONS: Foot and ankle characteristics, particularly ankle flexibility, plantar tactile sensation, and strength of toe plantarflexor muscles, are significant independent predictors of balance and functional ability in older people. Programs to improve the strength and flexibility of the foot and interventions to augment plantar sensation may be beneficial in improving mobility and reducing the risk of falls.

Aged↗
PubMed2005

Gait instability in older people with hallux valgus.

BACKGROUND: Hallux valgus is a common condition that may lead to considerable pain and disability. There is also evidence that hallux valgus may impair balance and increase the risk of falling in older people. Although a number of plantar pressure studies have been undertaken in people with and without hallux valgus, little is known about how hallux valgus affects basic gait patterns or the movement of the upper body when walking. METHODS: Measurements of temporospatial parameters of gait and acceleration patterns of the head and pelvis were obtained in 71 people (24 men, 47 women) between 75 and 93 (mean 80 +/- 4) years of age when walking on both a level surface and a specially designed irregular walkway. Foot problems, vision, peripheral sensation, strength, and reaction time also were evaluated. RESULTS: After adjusting for potential confounders, subjects with moderate to severe hallux valgus were found to exhibit significantly reduced velocity and step length on both walking surfaces and less rhythmic acceleration patterns in the vertical plane when walking on the irregular surface compared to subjects with no or mild hallux valgus. CONCLUSION: These findings indicate that hallux valgus has a significant detrimental impact on gait patterns that may contribute to instability and risk of falling in older people, particularly when walking on irregular terrain.

Accidental Falls↗
PubMed2005

Validity of 3 clinical techniques for the measurement of static foot posture in older people.

STUDY DESIGN: Concurrent validity study. OBJECTIVES: To determine the validity of 3 clinical methods for assessing static foot posture in older people. BACKGROUND: Variations in the structure of the medial longitudinal arch are thought to influence lower extremity function; however, the validity of clinical measurements has not been fully established. METHODS AND MEASURES: Clinical measurements of arch index (AI), navicular height (NH), and Foot Posture Index (FPI) were performed on 95 subjects (31 men and 64 women), aged 62 to 94 years (mean +/- SD, 78.6 +/- 6.5 years). These clinical measurements were then correlated with 3 arch-related measurements from radiographs: navicular height (NHr), calcaneal inclination angle (CIA), and calcaneal first metatarsal angle (C1MA). RESULTS: All 3 clinical measures demonstrated significant associations with each of the radiographic parameters (P<.01). NH was highly correlated with NHr (Pearson r = 0.79), followed by C1MA (r = -0.53), and CIA (r = 0.44). The AI was highly correlated with the C1MA (r = 0.71) and CIA (r = -0.68), but only moderately correlated with NHr (r = 0.52). The FPI demonstrated weaker correlations with the radiographic parameters (NHr, r = 0.59; CIA, r = 0.36; C1MA, r = 0.42). CONCLUSION: Clinical measurements of AI, NH, and FPI provide valid information regarding the structure of the medial longitudinal arch; however, each test may reflect different aspects of arch structure. NH would appear to be the most useful clinical measure, as it is simple to perform and provides an accurate representation of the skeletal alignment of the medial longitudinal arch. Further refinement of the clinical measurement of NH is now required to improve its moderate intratester and intertester reliability.

Aged↗
PubMed2004

Walking stability and sensorimotor function in older people with diabetic peripheral neuropathy.

OBJECTIVE: To evaluate, in older people with diabetic peripheral neuropathy (DPN) and in age-matched controls, acceleration patterns of the head and pelvis when walking to determine the effect of lower-limb sensory loss on walking stability. DESIGN: Case-control study. SETTING: Falls and balance laboratory in Australia. PARTICIPANTS: Thirty persons with diabetes mellitus (age range, 55-91 y) and 30 age-matched controls. INTERVENTIONS: Acceleration patterns of the head and pelvis were measured while participants walked on a level surface and an irregular walkway. Participants also underwent tests of vision, sensation, strength, reaction time, and balance. MAIN OUTCOME MEASURES: Temporospatial gait parameters and variables derived from acceleration signals. RESULTS: Participants with DPN had reduced walking speed, cadence, and step length, and less rhythmic acceleration patterns at the head and pelvis compared with controls. These differences were particularly evident when participants walked on the irregular surface. Participants with DPN also had impaired peripheral sensation, reaction time, and balance. CONCLUSIONS: Older people with DPN have an impaired ability to stabilize their body when walking on irregular surfaces, even if they adopt a more conservative gait pattern. These results provide further insights into the role of peripheral sensory input in the control of gait stability, and suggest possible mechanisms underlying the increased risk of falling in older people with diabetic neuropathy.

Acceleration↗
PubMed2004

Effects of experimentally induced plantar insensitivity on forces and pressures under the foot during normal walking.

Pressures under the foot during level walking were measured in 15 healthy young adults (8 females, 7 males, mean age 25.7, S.D. 5.3) before and after immersing the feet in ice-cold water (2 degrees C) for 30 min to evaluate the role of plantar insensitivity on gait patterns. Following ice water immersion, there was a significant decrease in walking speed. Maximum forces and peak pressures under the foot decreased, with the exception of an increase in loading under the third to fifth metatarsal heads. Contact times increased under all regions of the foot, and force-time and pressure-time integrals increased under the second and third to fifth metatarsal head regions. It is concluded that plantar insensitivity significantly alters the distribution, duration, and to a lesser extent, the magnitude of forces and pressures under the foot when walking. These results suggest that in the neuropathic foot, gait changes caused by plantar insensitivity may be partly responsible for the redistribution and altered duration of loading, whereas the increase in the magnitude of forces and pressures are primarily due to other disease-related factors.

Adult↗