Vibration perception threshold--a valuable assessment of neural dysfunction in people with diabetes

Understanding the relationship between type 2 diabetes mellitus and falls in older adults: a prospective cohort study

Background

Older adults with type 2 Diabetes Mellitus are at increased risk of falling. The current study aims to identify risk factors that mediate the relationship between diabetes and falls.

Methods

199 older adults (104 with diabetes and 95 healthy controls) underwent a medical screening. Gait (GAITRite®), balance (AccuGait® force plate), grip strength (Jamar®), and cognitive status (Mini-Mental State Examination and Clock Drawing Test) were assessed. Falls were prospectively recorded during a 12-month follow-up period using monthly calendars.

Results

Compared to controls, diabetes participants scored worse on all physical and cognitive measures. Sixty-four participants (42 diabetes vs. 22 controls) reported at least one injurious fall or two non-injurious falls (“fallers”). Univariate logistic regression identified diabetes as a risk factor for future falls (Odds Ratio 2.25, 95%CI 1.21–4.15, p = 0.010). Stepwise multiple regressions defined diabetes and poor balance as independent risk factors for falling. Taking more medications, slower walking speed, shorter stride length and poor cognitive performance were mediators that reduced the Odds Ratio of the relationship between diabetes and faller status relationship the most followed by reduced grip strength and increased stride length variability.

Conclusions

Diabetes is a major risk factor for falling, even after controlling for poor balance. Taking more medications, poorer walking performance and reduced cognitive functioning were mediators of the relationship between diabetes and falls. Tailored preventive programs including systematic medication reviews, specific balance exercises and cognitive training might be beneficial in reducing fall risk in older adults suffering from diabetes.

Vibration perception threshold in relation to postural control and fall risk assessment in elderly

PURPOSE

This study investigates (i) the potential discriminative role of a clinical measure of peripheral neuropathy (PN) in assessing postural performance and fall risk and (ii) whether the integration of a simple screening vibration perception threshold (VPT) for PN in any physical (fall risk) assessment among elderly should be recommended, even if they do not suffer from DM.

METHOD

One hundred and ninety-five elderly were entered in a four-group model: DM with PN (D+; n = 75), DM without PN (D-; n = 28), non-diabetic elderly with idiopathic PN (C+; n = 31) and non-diabetic elderly without PN (C-; n = 61). Posturographic sway parameters were captured during different static balance conditions (AMTI AccuGait, Watertown, MA). VPT, fall data, Mini-Mental State Examination and Clock Drawing Test were registered. Two-factor repeated-measures ANOVA was used to compare between groups and across balance conditions.

RESULTS

The groups with PN demonstrated a strikingly comparable, though bigger sway, and a higher prospective fall incidence than their peers without PN.

CONCLUSIONS

The indication of PN, irrespective of its cause, interferes with postural control and fall incidence. The integration of a simple screening for PN (like bio-thesiometry) in any fall risk assessment among elderly is highly recommended. Implications for Rehabilitation The indication of peripheral neuropathy (PN), irrespective of its cause, interferes with postural control and fall incidence. Therefore, the integration of a simple screening for PN (like bio-thesiometry) in any fall risk assessment among elderly is highly recommended. It might be useful to integrate somatosensory stimulation in rehabilitation programs designed for fall prevention.

Normal inter-limb differences during the straight leg raise neurodynamic test: a cross sectional study

Background

The straight leg raise (SLR) neurodynamic test is commonly used to examine the sensitivity of the lower quarter nervous system to movement. Range of motion during the SLR varies considerably, due to factors such as age, sex and activity level. Knowing intra-individual, inter-limb differences may provide a normative measure that is not influenced by such demographic characteristics. This study aimed to determine normal asymmetries between limbs in healthy, asymptomatic individuals during SLR testing and the relationship of various demographic characteristics.

Methods

The limb elevation angle was measured using an inclinometer during SLR neurodynamic testing that involved pre-positioning the ankle in plantar flexion (PF/SLR) and neutral dorsiflexion (DF/SLR). Phase 1 of the study included 20 participants where the ankle was positioned using an ankle brace replicating research testing conditions. Phase 2 included 20 additional participants where the ankle was manually positioned to replicate clinical testing conditions.

Results

The group average range of motion during PF/SLR was 57.1 degrees (SD: 16.8 degrees) on the left and 56.7 degrees (SD: 17.2 degrees) on the right while during DF/SLR the group average was 48.5 degrees (SD: 16.1 degrees) on the left and 48.9 degrees (SD: 16.4 degrees) on the right. The range of motion during SLR was moderately correlated to weight (−0.40 to −0.52), body mass index (−0.41 to −0.52), sex (0.40 to 0.42) and self-reported activity level (0.50 to 0.57). Intra-individual differences between limbs for range of motion during PF/SLR averaged 5.0 degrees (SD: 3.5 degrees) (95% CI: 3.8 degrees, 6.1 degrees) and during DF/SLR averaged 4.1 degrees (SD: 3.2 degrees) (95% CI: 3.1 degrees, 5.1 degrees) but were not correlated with any demographic characteristic. There were no significant differences between Phase 1 and Phase 2.

Conclusions

Overall range of motion during SLR was related to sex, weight, BMI and activity level, which is likely reflected in the high variability documented. We can be 95% confident that inter-limb differences during SLR neurodynamic testing fall below 11 degrees in 90% of the general population of healthy individuals. In addition, inter-limb differences were not affected by demographic factors and thus may be a more valuable comparison for test interpretation.

Elevated skin autofluorescence is strongly associated with foot ulcers in patients with diabetes: a cross-sectional, observational study of Chinese subjects

OBJECTIVE

This study was designed to evaluate the association between skin autofluorescence (AF), an indicator of advanced glycation end-products (AGEs), and foot ulcers in subjects with diabetes.

METHODS

In this study, 195 Chinese diabetic subjects were examined. Their feet were examined regardless of whether an ulcer was present or not. Skin AF was measured with an AGE reader. Demographic characteristics and blood data were recorded.

RESULTS

The mean values of skin AF were 2.29 ± 0.47 for subjects without foot ulcers, and 2.80 ± 0.69 for those with foot ulcers, a significant difference (P<0.05). Skin AF was strongly correlated with age and duration of diabetes. After adjusting for these factors, multivariate logistic regression showed that skin AF was independently associated with foot ulcerations.

CONCLUSIONS

Skin AF is independently associated with diabetic foot ulcerations. It might be a useful screening method for foot ulceration risk of diabetic patients.

Screening patients at risk for diabetic foot ulceration: a comparison between measurement of vibration perception threshold and 10-g monofilament test

The aim is to compare the frequency of increased vibration perception threshold (VPT) with abnormal 10-g Semmes-Weinstein monofilament (SWF) testing in a non-selected diabetic population, and to assess the agreement between these two screening methods. VPT was measured using a neurothesiometer at the pulp of the hallux and 10-g SWF was applied on three plantar sites on each foot according to the guidelines of the International Working Group on the Diabetic Foot, in 400 consecutive diabetic patients. VPT was considered as abnormal if ≥25 V and SWF was considered as abnormal if the patient was unable to feel ≥2 applications at a single site. Both tests were normal in 240 patients (60%) and both abnormal in 78. In 21 patients, only SWF was abnormal whereas only VPT was abnormal in 61. As a whole, 160 patients (40%) were considered at risk for foot ulceration by VPT and/or SWF. Agreement between the two screening methods was only moderate with a kappa coefficient of 0·52 (95% CI: 0·43-0·60). Using VPT as a predictor for foot ulceration, the number of patients at risk is much higher than identified by SWF. This discrepancy might have potential effects on costs and prevention policies.

The usefulness of vibration perception threshold as a significant indicator for erectile dysfunction in patients with diabetes mellitus at a primary diabetes mellitus clinic

INTRODUCTION

The aim of this study is to clarify the relationship of erectile dysfunction (ED) and diabetes mellitus (DM) parameters (referred to with '1'), including peripheral neuropathy (referred to with '2').

METHODS

(1) The DM parameters including age, serum levels of blood sugar, hemoglobin A1c, duration of DM and number of DM complications were obtained from 145 patients at a general DM clinic. (2) The peripheral neuropathy examinations by vibration perception threshold (VPT) and Achilles tendon reflex were performed in 97 DM patients. Erectile functions in DM patients were evaluated by the International Index of Erectile Function (IIEF 5). The DM patients' parameters were compared with the IIEF 5 scores.

RESULTS

(1) The data showed IIEF 5 scores were significantly correlated with patient age, duration of DM and number of DM complications. (2) IIEF 5 scores were significantly correlated with VPT time. Furthermore, multiple regression analysis revealed that patient age and VPT time were independent risk factors for predicting ED in DM patients.

CONCLUSIONS

The severity of ED in DM patients depended on age, duration of DM, number of DM complications and VPT. Significantly, the age of DM patients and the measurement of VPT are considered to be simple and useful indicators to diagnose ED in DM patients.

Mechanosensitivity during lower extremity neurodynamic testing is diminished in individuals with Type 2 Diabetes Mellitus and peripheral neuropathy: a cross sectional study

Background

Type 2 Diabetes Mellitus (T2DM) and diabetic symmetrical polyneuropathy (DSP) impact multiple modalities of sensation including light touch, temperature, position sense and vibration perception. No study to date has examined the mechanosensitivity of peripheral nerves during limb movement in this population. The objective was to determine the unique effects T2DM and DSP have on nerve mechanosensitivity in the lower extremity.

Methods

This cross-sectional study included 43 people with T2DM. Straight leg raise neurodynamic tests were performed with ankle plantar flexion (PF/SLR) and dorsiflexion (DF/SLR). Hip flexion range of motion (ROM), lower extremity muscle activity and symptom profile, intensity and location were measured at rest, first onset of symptoms (P1) and maximally tolerated symptoms (P2).

Results

The addition of ankle dorsiflexion during SLR testing reduced the hip flexion ROM by 4.3° ± 6.5° at P1 and by 5.4° ± 4.9° at P2. Individuals in the T2DM group with signs of severe DSP (n = 9) had no difference in hip flexion ROM between PF/SLR and DF/SLR at P1 (1.4° ± 4.2°; paired t-test p = 0.34) or P2 (0.9° ± 2.5°; paired t-test p = 0.31). Movement induced muscle activity was absent during SLR with the exception of the tibialis anterior during DF/SLR testing. Increases in symptom intensity during SLR testing were similar for both PF/SLR and DF/SLR. The addition of ankle dorsiflexion induced more frequent posterior leg symptoms when taken to P2.

Conclusions

Consistent with previous recommendations in the literature, P1 is an appropriate test end point for SLR neurodynamic testing in people with T2DM. However, our findings suggest that people with T2DM and severe DSP have limited responses to SLR neurodynamic testing, and thus may be at risk for harm from nerve overstretch and the information gathered will be of limited clinical value.

Prevalence of distal diabetic polyneuropathy using quantitative sensory methods in a population with diabetes of more than 10 years' disease duration

OBJECTIVES

Results of studies on the prevalence of distal diabetic polyneuropathy (DPN) are contradictory. Conventional methods used for the diagnosis of DPN in clinical practice have limited effectiveness. The present study aimed to assess the prevalence of DPN in a population with long-standing diabetes (more than 10 years disease duration) by measuring vibratory, thermal and tactile sensitivities with quantitative sensory devices, as well as their relationship with associated clinical risk factors.

PATIENTS AND METHODS

A total of 1011 diabetic patients were evaluated in a multicenter, cross-sectional, observational study. The three sensitivities were assessed by ultrabiothesiometer, aesthesiometer and thermoskin devices, respectively. The prevalence of neuropathic pain was validated by the DN4 questionnaire.

RESULTS

Of the 1011 cases included, 400 (39.6%) met the diagnostic criteria of DPN, while no DPN was found in the remaining 611 (60.4%). Of the 400 patients with DPN, 253 (63.2%) showed clinical manifestations, while 147 (36.8%) were diagnosed as subclinical DPN. The prevalence of DPN increased with disease duration. There was a progressive loss of the three sensitivities with increased disease duration, particularly thermal and vibratory sensitivities. This loss was statistically significant for the latter two sensitivities. Among patients with clinical DPN, 84.2% had painful neuropathic symptoms. The prevalence of DPN was positively related to micro- and macroangiopathic complications and with dyslipidemia.

CONCLUSION

This study reveals a high degree of underdiagnosis of DPN, most likely due to the asymptomatic nature of the disease in a considerable proportion of patients. Our observations provide evidence of the usefulness of specific equipment for quantitative and objective assessment of polyneuropathy.

Redistribution of joint moments is associated with changed plantar pressure in diabetic polyneuropathy

BACKGROUND

Patients with diabetic polyneuropathy (DPN) are often confronted with ulceration of foot soles. Increased plantar pressure under the forefoot has been identified as a major risk factor for ulceration. This study sets out to test the hypothesis that changes in gait characteristics induced by DPN related muscle weakness are the origin of the elevated plantar pressures.

METHODS

Three groups of subjects participated: people diagnosed with diabetes without polyneuropathy (DC), people diagnosed with diabetic polyneuropathy (DPN) and healthy, age-matched controls (HC). In all subjects isometric strength of plantar and dorsal flexors was assessed. Moreover, joint moments at ankle, knee and hip joints were determined while walking barefoot at a velocity of 1.4 m/s. Simultaneously plantar pressure patterns were measured.

RESULTS

Compared to HC-subjects, DPN-participants walked with a significantly increased internal plantar flexor moment at the first half of the stance phase. Also in DPN-subjects the maximal braking and propelling force applied to the floor was decreased. Moreover, in DPN-subjects the ratio of forefoot-to-rear foot plantar pressures was increased. Body-mass normalized strength of dorsal flexors showed a trend to be reduced in people with diabetes, both DC and DPN, compared to HC-subjects. Plantar flexors tended to be less weak in DC compared to HC and in DPN relative to DC.

CONCLUSION

The results of this study suggest that adverse plantar pressure patterns are associated with redistribution of joint moments, and a consequent reduced capacity to control forward velocity at heel strike.

Diabetes-related microvascular and macrovascular diseases in the physical therapy setting

Physical therapists commonly treat people with diabetes for a wide variety of diabetes-associated impairments, including those from diabetes-related vascular disease. Diabetes is associated with both microvascular and macrovascular diseases affecting several organs, including muscle, skin, heart, brain, and kidneys. A common etiology links the different types of diabetes-associated vascular disease. Common risk factors for vascular disease in people with diabetes, specifically type 2 diabetes, include hyperglycemia, insulin resistance, dyslipidemia, hypertension, tobacco use, and obesity. Mechanisms for vascular disease in diabetes include the pathologic effects of advanced glycation end product accumulation, impaired vasodilatory response attributable to nitric oxide inhibition, smooth muscle cell dysfunction, overproduction of endothelial growth factors, chronic inflammation, hemodynamic dysregulation, impaired fibrinolytic ability, and enhanced platelet aggregation. It is becoming increasingly important for physical therapists to be aware of diabetes-related vascular complications as more patients present with insulin resistance and diabetes. The opportunities for effective physical therapy interventions (such as exercise) are significant.

Análise de fatores associados à ulceração de extremidades em indivíduos diabéticos com neuropatia periférica

A neuropatia periférica é o principal fator de risco para ulceração em pé de indivíduos diabéticos. Este estudo testou a associação de doença arterial periférica (DAP) à ulceração do pé em amostra de pacientes com neuropatia sensório-motora simétrica distal e se marcadores inflamatórios subclínicos também se associariam a esse evento. Foram avaliados 32 indivíduos diabéticos tipo 2 com exame do monofilamento de 10 g alterado, estratificados em 2 grupos segundo a história ou presença de úlcera nas extremidades inferiores. O grupo "com úlcera" (n = 18) incluiu aqueles que apresentavam úlcera ativa ou cicatrizada, ou que tiveram alguma amputação em membro inferior decorrente de complicações da úlcera. Além do exame neurológico e monofilamento, foram submetidos a bioestesiometria, avaliação vascular com Doppler e exames laboratoriais. Os grupos foram semelhantes quanto à distribuição dos sexos, média de idade e tempo de diabetes. O grupo com úlcera apresentou valores médios de altura (1,70 ± 0,06 vs. 1,63 ± 0,11 m; p = 0,044) e limiar de percepção vibratória no maléolo medial (40,9 ± 13,0 vs. 30,6 ± 12,3 V; p = 0,040) mais elevados que o sem a úlcera. Os grupos não diferiram entre si quanto à média dos marcadores inflamatórios. A resposta do reflexo patelar foi também pior no grupo com úlcera (p = 0,047), no qual se observou maior proporção de indivíduos com o índice hálux-braquial alterado (p = 0,030) quando comparado ao sem úlcera. Conclui-se que a DAP está associada à presença de úlcera (atual ou pregressa) em membros inferiores de indivíduos diabéticos neuropatas. A pesquisa de alteração de fluxo de artérias digitais de membro inferior (no hálux) contribuiu para detectar tal associação. Associação de neuropatia ulcerada a marcadores inflamatórios não foi observada, não sendo possível excluí-la devido às limitações do tamanho da amostra. Estudos prospectivos deverão examinar a sensibilidade do índice hálux-braquial para identificar DAP em indivíduos diabéticos sob risco de ulceração.

Diabetic neuropathy: classification, measurement and treatment

PURPOSE OF REVIEW

Diabetic neuropathies comprise a number of conditions affecting somatic or autonomic nerves and are the most common of the long-term diabetic complications. This review considers recent developments in the classification and noninvasive assessment of somatic neuropathy, and describes new approaches to the management of painful neuropathic symptoms.

RECENT FINDINGS

Classification of the diabetic neuropathies needs modifying to include the recently described 'prediabetic neuropathy' or 'neuropathy of impaired glucose tolerance'. There is increasing evidence to support the use of minimally invasive skin biopsies for evaluating small fibre neuropathies, and more recently, the noninvasive corneal confocal microscopy, which enables direct visualization of peripheral nerve in vivo. For those with painful neuropathic symptoms, a number of evidence-based therapies are now available.

SUMMARY

Patients with 'idiopathic neuropathy' should be screened for evidence of impaired glucose tolerance and considered for lifestyle management. Future trials of potential therapies will benefit from more relevant surrogate endpoints. Those with painful neuropathy should only be prescribed therapies whose efficacy has been confirmed by independent randomized controlled trials.

The global burden of diabetic foot disease

Diabetic foot problems are common throughout the world, resulting in major economic consequences for the patients, their families, and society. Foot ulcers are more likely to be of neuropathic origin, and therefore eminently preventable, in developing countries, which will experience the greatest rise in the prevalence of type 2 diabetes in the next 20 years. People at greatest risk of ulceration can easily be identified by careful clinical examination of the feet: education and frequent follow-up is indicated for these patients. When assessing the economic effects of diabetic foot disease, it is important to remember that rates of recurrence of foot ulcers are very high, being greater than 50% after 3 years. Costing should therefore include not only the immediate ulcer episode, but also social services, home care, and subsequent ulcer episodes. A broader view of total resource use should include some estimate of quality of life and the final outcome. An integrated care approach with regular screening and education of patients at risk requires low expenditure and has the potential to reduce the cost of health care.