The contributors of emotional distress in painful diabetic neuropathy

Impact of diabetes distress on glycemic control and diabetic complications in type 2 diabetes mellitus

The effect of diabetes distress on glycemic control and its association with diabetes complications is still poorly understood. We aimed to study the clinical features of patients with high diabetes distress, focusing on changes in glycemic control and risk of diabetic complications. From the Korean National Diabetes Program data, we investigated 1862 individuals with type 2 diabetes mellitus (T2DM) who completed diabetic complication studies and the Korean version of the Problem Areas in Diabetes Survey (PAID-K). A total score of PAID-K ≥ 40 was considered indicative of high distress. Individuals with high distress (n = 589) had significantly higher levels of glycated hemoglobin than those without distress (7.4% vs. 7.1%, p < 0.001). This trend persisted throughout the 3-year follow-up period. Higher PAID-K scores were associated with younger age, female gender, longer duration of diabetes, and higher carbohydrate intake (all p < 0.05). There was a significant association between high distress and diabetic neuropathy (adjusted odds ratio, 1.63; p = 0.002), but no significant association was found with other complications, including retinopathy, albuminuria, and carotid artery plaque. In conclusion, high diabetes distress was associated with uncontrolled hyperglycemia and higher odds of having diabetic neuropathy.

Female sex is a risk factor for painful diabetic peripheral neuropathy: the EURODIAB prospective diabetes complications study

AIMS/HYPOTHESIS

While the risk factors for diabetic peripheral neuropathy (DPN) are now well recognised, the risk factors for painful DPN remain unknown. We performed analysis of the EURODIAB Prospective Complications Study data to elucidate the incidence and risk factors of painful DPN.

METHODS

The EURODIAB Prospective Complications Study recruited 3250 participants with type 1 diabetes who were followed up for 7.3±0.6 (mean ± SD) years. To evaluate DPN, a standardised protocol was used, including clinical assessment, quantitative sensory testing and autonomic function tests. Painful DPN (defined as painful neuropathic symptoms in the legs in participants with confirmed DPN) was assessed at baseline and follow-up.

RESULTS

At baseline, 234 (25.2%) out of 927 participants with DPN had painful DPN. At follow-up, incident DPN developed in 276 (23.5%) of 1172 participants. Of these, 41 (14.9%) had incident painful DPN. Most of the participants who developed incident painful DPN were female (73% vs 48% painless DPN p=0.003) and this remained significant after adjustment for duration of diabetes and HbA1c (OR 2.69 [95% CI 1.41, 6.23], p=0.004). The proportion of participants with macro- or microalbuminuria was lower in those with painful DPN compared with painless DPN (15% vs 34%, p=0.02), and this association remained after adjusting for HbA1c, diabetes duration and sex (p=0.03).

CONCLUSIONS/INTERPRETATION

In this first prospective study to investigate the risk factors for painful DPN, we definitively demonstrate that female sex is a risk factor for painful DPN. Additionally, there is less evidence of diabetic nephropathy in incident painful, compared with painless, DPN. Thus, painful DPN is not driven by cardiometabolic factors traditionally associated with microvascular disease. Sex differences may therefore play an important role in the pathophysiology of neuropathic pain in diabetes. Future studies need to look at psychosocial, genetic and other factors in the development of painful DPN.

Psychosocial Care for People With Diabetic Neuropathy: Time for Action

Psychological factors and psychosocial care for individuals with diabetic neuropathy (DN), a common and burdensome complication of diabetes, are important but overlooked areas. In this article we focus on common clinical manifestations of DN, unremitting neuropathic pain, postural instability, and foot complications, and their psychosocial impact, including depression, anxiety, poor sleep quality, and specific problems such as fear of falling and fear of amputation. We also summarize the evidence regarding the negative impact of psychological factors such as depression on DN, self-care tasks, and future health outcomes. The clinical problem of underdetection and undertreatment of psychological problems is described, together with the value of using brief assessments of these in clinical care. We conclude by discussing trial evidence regarding the effectiveness of current pharmacological and nonpharmacological approaches and also future directions for developing and testing new psychological treatments for DN and its clinical manifestations.

Conventional management and current guidelines for painful diabetic neuropathy

Painful Diabetic Peripheral Neuropathy (PDN) is common, affecting around a quarter of patients with both type 1 and type 2 diabetes, and can lead to significant curtailment of functionality and quality of life. Patients may present with unremitting burning, aching or "electric-shock" type pains in their feet, legs and later, in the hands. Conventional management approaches must focus not only on pain relief, but also on concurrent sleep problems, mood disorders and functionality. The mainstay of treatment is pharmacotherapy. Most current international guidelines recommend a choice of four drugs: amitriptyline, duloxetine, pregabalin or gabapentin, as initial treatment for PDN. Recent evidence from the OPTION-DM trial demonstrated that these drugs and their combinations have equivalent efficacy. Moreover, combination treatment provided significant pain relief to patients with inadequate response to the maximum tolerated dose of monotherapy. PDN refractory to pharmacotherapy can be treated with capsaicin 8% or high frequency spinal cord stimulation.

Quality of life of persons with painful diabetic neuropathy: How can we improve it?

Painful diabetic neuropathy (PDN) is difficult to treat, with pharmacological treatments providing only partial pain relief that is limited by medication side effects. This necessitates a holistic approach to pain control,with pharmacological treatments supplemented by the management of psychosocial aspects of pain experience. Pain catastrophising and psychological flexibility are among the psychological constructs impacting persons' adaptation to PDN. While the former increases disability and reduces quality of life (QoL), the latter leads to less functional impairment and depression. Specific fears, and in particular, fear of falling, are significantly associated with pain-related disability and reduced QoL. The role of secondary parameters ofpain experience, including sleep and mood disturbancesas the potential guides to the selection of pharmacological treatmentsis yet to be established. Over the past decade there has been a steady increase in studies testing psychological interventions, including cognitive behavioural therapy and its several modifications, to manage pain in DN sufferers.Thesepilot and feasibility studies demonstrated the potential beneficial effects on pain severity and pain interference, depression and QoL in adults with PDN.Adequately powered trials are needed to confirm the effectiveness of these interventions in terms of pain experience and their impact on QoL.

The Retinal Nerve Fiber Layer Thickness Is Associated with Systemic Neurodegeneration in Long-Term Type 1 Diabetes

Purpose

To determine whether the retinal nerve fiber layer thickness can be used as an indicator for systemic neurodegeneration in diabetes.

Methods

We used existing data from 38 adults with type 1 diabetes and established polyneuropathy. Retinal nerve fiber layer thickness values of four scanned quadrants (superior, inferior, temporal, and nasal) and the central foveal thickness were extracted directly from optical coherence tomography. Nerve conduction velocities were recorded using standardized neurophysiologic testing of the tibial and peroneal motor nerves and the radial and median sensory nerves, 24-hour electrocardiographic recordings were used to retrieve time- and frequency-derived measures of heart rate variability, and a pain catastrophizing scale was used to assess cognitive distortion.

Results

When adjusted for hemoglobin A1c, the regional thickness of the retinal nerve fiber layers was (1) positively associated with peripheral nerve conduction velocities of the sensory and motor nerves (all P < 0.036), (2) negatively associated with time and frequency domains of heart rate variability (all P < 0.033), and (3) negatively associated to catastrophic thinking (all P < 0.038).

Conclusions

Thickness of the retinal nerve fiber layer was a robust indicator for clinically meaningful measures of peripheral and autonomic neuropathy and even for cognitive comorbidity.

Translational Relevance

The findings indicate that the thickness of the retinal nerve fiber layer should be studied in adolescents and people with prediabetes to determine whether it is useful to predict the presence and severity of systemic neurodegeneration.

Diagnosis, management and impact of painful diabetic peripheral neuropathy: A patient survey in four European countries

AIMS

The aim of this study was to assess patient perspectives and experiences of the impact of neuropathic pain, painful diabetic neuropathy (pDPN) diagnosis and treatment, and the patient-healthcare professional (HCP) relationship.

METHODS

We conducted a quantitative online survey in Germany, the Netherlands, Spain, and the UK among adults with diabetes who responded "yes" to at least four of ten questions of in the Douleur Neuropathique en 4 Questions (DN4) questionnaire.

RESULTS

Of 3626 respondents, 576 met the eligibility criteria. Daily pain was rated as moderate or severe by 79 % of respondents. Most participants reported a negative impact of their pain on sleep (74 %), mood (71 %), exercise (69 %), concentration (64 %) and daily activities (62 %), and 75 % of those in employment had missed work because of their pain in the past year. Overall, 22 % of respondents avoided discussing pain with their HCP, 50 % had not received formal pDPN diagnosis, and 56 % had not used prescribed pain medications. Although two-thirds (67 %) of respondents reported feeling satisfied or very satisfied with treatment, 82 % of these patients still experienced daily moderate or severe pain.

CONCLUSIONS

Neuropathic pain in people with diabetes affects daily life and remains underdiagnosed and undertreated in clinical practice.

Exploring the Needs of Adults Living With Type 1 or Type 2 Diabetes Distress Using the Problem Areas in Diabetes 5 Tool

OBJECTIVES

This study investigated the feasibility and acceptability of implementing a screening tool as a part of routine care and the subsequent screening experiences of patients and clinicians. Additionally, potential sources of diabetes distress (DD) were identified in this clinical population.

METHODS

Our investigation was a cross-sectional, mixed-methods, convenience sample of 203 patients living with type 1 or type 2 diabetes from 2 Canadian tertiary hospital-based clinics. The Problem Areas in Diabetes 5 (PAID5) scale was used to assess DD. Structured telephone interviews of patients with high DD scores and care provider focus group transcriptions were analyzed using a deductive thematic content analysis.

RESULTS

The prevalence of DD was 45%. Lack of medication coverage (p=0.02) and presence of neuropathy (p=0.04) were approximately 5- and 2-fold more likely to be predictors of high DD, respectively. Patient interviews identified DD screening as an opportunity to share and feel supported but demonstrated their fear of discussing mental health concerns. Patients found discussion about mental health helpful and often did not require a referral to a mental health specialist. Staff focus groups discussed screening as a feasible tool, but also acknowledged barriers and knowledge gaps that preclude DD screening integration in routine clinical practice. Specialized training for clinicians may help increase confidence and improve uptake of DD screening into routine clinical practice.

CONCLUSIONS

The prevalence of DD in outpatient care settings is high. Findings suggest that integrating the PAID5 screening tool into regular clinical practice is feasible by patients and care providers.

Differences in Cognitive Function in Women and Men with Diabetic Peripheral Neuropathy with or without Pain

The aim of this study was to analyse the differences in cognitive function between women and men with type-2 diabetes mellitus (DMT2) and diabetic peripheral neuropathy (DPN) with and without diabetic neuropathic pain (DNP), and the factors associated with cognitive function in each sex. A cross-sectional study of 149 patients with DMT2 and DPN was performed. Sociodemographic and clinical variables, Test Your Memory (TYM) for cognitive assessment, anxiety and depression (HADS), quality of life (SF-12v2) and sleep characteristics (MOS-sleep) were measured. A high percentage of women presented cognitive impairment (50% vs. 36.1%) and they scored lower on the TYM (mean = 40.77; SD = 6.03 vs. mean = 42.49; SD = 6.05). Women with DNP scored lower on calculation tasks (3.17 vs. 3.52) than men with DNP, while women without DNP scored lower on retrograde memory (2.70 vs. 3.74), executive function (3.83 vs. 4.25) and similarities (2.51 vs. 3.12) than men without DNP. Being older (B = -0.181) and presenting cardiovascular risk factors (B = -5.059) were associated with worse cognitive function in women, while in men this was associated with older age (B = -0.154), a longer duration of diabetes (B = -0.319) and the presence of depression (B = -0.363). Women with and without DNP obtained worse results in cognitive function. However, the presence of pain had a greater impact on the different dimensions in men.

The conundrum of diabetic neuropathies-Past, present, and future

Diabetic neuropathy (DN) remains arguably the most prevalent chronic complication in people with both type 1 and type 2 diabetes, including in youth, despite changes in the current standards of clinical care. Additionally, emerging evidence demonstrates that neuropathy affects a large proportion of people with undiagnosed diabetes and/or prediabetes, as well as those with obesity. Here we summarize the latest epidemiology of DN, recent findings regarding the pathophysiology of the disease, as well as current outcome measures for screening and diagnosis, in research and clinical settings. The authors discuss novel perspectives on the impact of social determinants of health in DN development and management, and the latest evidence on effective therapies, including pharmacological and nonpharmacological therapies for neuropathic pain. Throughout the publication, we identify knowledge gaps and the need for future funding to address these gaps, as well as needs to advocate for a personalized care approach to reduce the burden of DN and optimize quality of life for all affected individuals.

Factors related to cognitive function in type-2 diabetes and neuropathic pain patients, the role of mood and sleep disorders in this relationship

To compare cognitive function in patients with diabetes mellitus type-2 (T2DM) both with and without diabetic neuropathic pain (DNP). To analyse the relationship between mood and sleep disorders, quality of life and cognitive function in patients with DNP. Cross-sectional study conducted in patients with T2DM and neuropathy. The presence of DNP, cognitive function, mood status, sleep quality, health-related quality of life, pain intensity and phenotype of pain were measured. Descriptive, bivariate and multivariate analyses were performed. A total of 149 patients (71 with DNP) were included. Patients with and without DNP presented similar scores on the TYM (41.46; SD = 6.70 vs. 41.97; SD = 5.50) and those with DNP had a slightly higher frequency of cognitive impairment (TYM score ≤ 41: 40.8% vs. 43.6%). The patients without DNP performed better in the verbal fluency dimension (mean = 3.53; SD = 0.98 vs. mean = 3.82; SD = 0.66). Being older (B = − 0.258) and under treatment with insulin (B = − 2.919) were related with greater cognitive impairment. Obesity (OR = 17.277) and a longer duration of diabetes (OR = 1.317) were also related to greater risk of cognitive impairment. Impaired cognitive function in patients with DNP is more related to T2DM factors than pain factors. The presence of depression and a worse quality of life were related to a greater risk of cognitive impairment. Identifying and controlling these factors should be an essential intervention for maintaining the cognitive function in patients with T2DM and DNP.

Psychologic Impacts on Diabetic Neuropathic Pain

PURPOSE OF REVIEW

Many Americans cope with painful diabetic neuropathy (DN) as a sequela of high rates of diabetes mellitus in the US population. Appropriate management of this complex, debilitating chronic pain condition requires thorough evaluation through a biopsychosocial framework. This review aims to synthesize findings from original research studies and analyze the psychological factors that influence the experience of, and treatments for, DN pain.

RECENT FINDINGS

Existing clinical literature suggests a wide breadth of psychological factors impacting DN pain. One research study detailed the demographic characteristics of DN patients most likely to have significant anxiety or depressive symptoms, and have emotional distress adversely impacting their response to therapies. A retrospective study demonstrated a correlation between patients' mindfulness-based stress reduction and improvement in DN pain severity. In addtion, a small-scale, randomized controlled pilot study supported cognitive-behavioral therapy as a superior intervention to conventional medical treatments in reducing DN patients' pain severity and pain interference, even when not accompanied by significant improvement in depressive symptoms. This review of investigations into psychological factors implicated in DN pain suggests that diagnosable mental health conditions as well as discrete, adverse thinking processes both exert significant influences on DN pain. This review further brings attention to the beneficial impact that psychotherapeutic modalities can have on DN pain.

The Treatment of Painful Diabetic Neuropathy

Painful diabetic peripheral neuropathy (painful-DPN) is a highly prevalent and disabling condition, affecting up to one-third of patients with diabetes. This condition can have a profound impact resulting in a poor quality of life, disruption of employment, impaired sleep, and poor mental health with an excess of depression and anxiety. The management of painful-DPN poses a great challenge. Unfortunately, currently there are no Food and Drug Administration (USA) approved disease-modifying treatments for diabetic peripheral neuropathy (DPN) as trials of putative pathogenetic treatments have failed at phase 3 clinical trial stage. Therefore, the focus of managing painful- DPN other than improving glycaemic control and cardiovascular risk factor modification is treating symptoms. The recommended treatments based on expert international consensus for painful- DPN have remained essentially unchanged for the last decade. Both the serotonin re-uptake inhibitor (SNRI) duloxetine and α2δ ligand pregabalin have the most robust evidence for treating painful-DPN. The weak opioids (e.g. tapentadol and tramadol, both of which have an SNRI effect), tricyclic antidepressants such as amitriptyline and α2δ ligand gabapentin are also widely recommended and prescribed agents. Opioids (except tramadol and tapentadol), should be prescribed with caution in view of the lack of definitive data surrounding efficacy, concerns surrounding addiction and adverse events. Recently, emerging therapies have gained local licenses, including the α2δ ligand mirogabalin (Japan) and the high dose 8% capsaicin patch (FDA and Europe). The management of refractory painful-DPN is difficult; specialist pain services may offer off-label therapies (e.g. botulinum toxin, intravenous lidocaine and spinal cord stimulation), although there is limited clinical trial evidence supporting their use. Additionally, despite combination therapy being commonly used clinically, there is little evidence supporting this practise. There is a need for further clinical trials to assess novel therapeutic agents, optimal combination therapy and existing agents to determine which are the most effective for the treatment of painful-DPN. This article reviews the evidence for the treatment of painful-DPN, including emerging treatment strategies such as novel compounds and stratification of patients according to individual characteristics (e.g. pain phenotype, neuroimaging and genotype) to improve treatment responses.

Risk factors for depression and anxiety in painful and painless diabetic polyneuropathy: A multicentre observational cross-sectional study

Background

Despite the high prevalence of depression and anxiety in chronic pain conditions, current knowledge concerning emotional distress among painful diabetic polyneuropathy (pDSPN) and other diabetes mellitus (DM) sufferers is limited.

Methods

This observational multicentre cohort study employed the Hospital Anxiety and Depression Scale, the Beck Depression Inventory II and the State‐Trait Anxiety Inventory to assess symptoms of depression and anxiety in several groups with diabetes, as well as in a control group. The study cohort included 347 pDSPN patients aged 63.4 years (median), 55.9% males; 311 pain‐free diabetic polyneuropathy (nDSPN) patients aged 63.7 years, 57.9% males; 50 diabetes mellitus (DM) patients without polyneuropathy aged 61.5 years, 44.0% males; and 71 healthy controls (HC) aged 63.0 years, 42.3% males. The roles played in emotional distress were explored in terms of the biological, the clinical (diabetes‐, neuropathy‐ and pain‐related), the socio‐economic and the cognitive factors (catastrophizing).

Results

The study disclosed a significantly higher prevalence of the symptoms of depression and anxiety not only in pDSPN (46.7% and 60.7%, respectively), but also in patients with nDSPN (24.4% and 44.4%) and DM without polyneuropathy (22.0% and 30.0%) compared with HCs (7.0% and 14.1%, p < 0.001). Multiple regression analysis demonstrated the severity of pain and neuropathy, catastrophic thinking, type 2 DM, lower age and female sex as independent contributors to depression and anxiety.

Conclusions

In addition to the severity of neuropathic pain and its cognitive processing, the severity of diabetic polyneuropathy and demographic factors are key independent contributors to emotional distress in diabetic individuals.

Significance

In large cohorts of well‐defined painless and painful diabetic polyneuropathy patients and diabetic subjects without polyneuropathy, we found a high prevalence of the symptoms of depression and anxiety, mainly in painful individuals. We have confirmed neuropathic pain, its severity and cognitive processing (pain catastrophizing) as dominant risk factors for depression and anxiety. Furthermore, some demographic factors (lower age, female sex), type 2 diabetes mellitus and severity of diabetic polyneuropathy were newly identified as important contributors to emotional distress independent of pain.

Modulatory effects of photobiomodulation in the anterior cingulate cortex of diabetic rats

Anterior Cingulate Cortex (ACC) has a crucial contribution to higher order pain processing. Photobiomodulation (PBM) has being used as integrative medicine for pain treatment and for a variety of nervous system disorders. This study evaluated the effects of PBM in the ACC of diabetic rats. Type 1 diabetes was induced by a single dose of streptozotocin (85 mg/Kg). A total of ten sessions of PBM (pulsed gallium-arsenide laser, 904 nm, 9500 Hz, 6.23 J/cm²) was applied to the rat peripheral nervous system. Glial fibrillary acidic protein (GFAP), mu-opioid receptor (MOR), glutamate receptor 1 (GluR1), and glutamic acid decarboxylase (GAD65/67) protein level expression were analyzed in the ACC of diabetic rats treated with PBM. Our data revealed that PBM decreased 79.5% of GFAP protein levels in the ACC of STZ rats. Moreover, STZ + PBM rats had protein levels of MOR increased 14.7% in the ACC. Interestingly, STZ + PBM rats had a decrease in 70.7% of GluR1 protein level in the ACC. Additionally, PBM decreased 45.5% of GAD65/67 protein levels in the ACC of STZ rats.

Aberrant Brain Network Integration and Segregation in Diabetic Peripheral Neuropathy Revealed by Structural Connectomics

Diabetic peripheral neuropathy (DPN) is one of the most common forms of peripheral neuropathy, and its incidence has been increasing. Mounting evidence has shown that patients with DPN have been associated with widespread alterations in the structure, function and connectivity of the brain, suggesting possible alterations in large-scale brain networks. Using structural covariance networks as well as advanced graph-theory-based computational approaches, we investigated the topological abnormalities of large-scale brain networks for a relatively large sample of patients with DPN (N = 67) compared to matched healthy controls (HCs; N = 88). Compared with HCs, the structural covariance networks of patients with DPN showed an increased characteristic path length, clustering coefficient, sigma, transitivity, and modularity, suggestive of inefficient global integration and increased local segregation. These findings may improve our understanding of the pathophysiological mechanisms underlying alterations in the central nervous system of patients with DPN from the perspective of large-scale structural brain networks.

Sleep Characteristics in Diabetic Patients Depending on the Occurrence of Neuropathic Pain and Related Factors

This study aims to compare the sleep characteristics (structure and quality) in patients with type-2 diabetes mellitus with and without diabetic neuropathic pain (DNP), and to investigate the relationship of sensory phenotypes, anxiety, and depression with sleep quality in DNP patients. A cross-sectional study was performed in patients with type-2 diabetes mellitus and neuropathy. Patients were classified into two groups-with or without neuropathic pain-according to the "Douleur Neuropathique-4 (DN4)" scale. Sleep characteristics and quality (Medical Outcomes Study-MOS-sleep), pain phenotype (Neuropathic Pain Symptom Inventory-NPSI), mood status (Hospital Anxiety and Depression scale-HADS), pain intensity (Visual Analogue Scale-VAS), and quality of life (SF-12v2) were measured. The sample included 130 patients (65 with DNP). The mean scores in all the dimensions of the MOS-sleep scale were higher (more disturbances) in the DNP patients. Higher scores in anxiety or depression, greater intensity of pain or a higher score in the paroxysmal pain phenotype were associated with lower sleep quality in DNP patients. A shorter duration of the diabetes and lower levels of glycated hemoglobin were also associated with lower sleep quality. The results show the relationship between DNP and sleep quality, and the importance of assessing sensory phenotypes and mental comorbidities in these patients. Taking these factors into consideration, to adopt a multimodal approach is necessary to achieve better clinical results.

Management of Neuropathic Pain in Polyneuropathy

PURPOSE OF REVIEW

Many polyneuropathies cause significant neuropathic pain, resulting in substantial morbidity and reduced quality of life. Appropriate management is crucial for maintaining quality of life for patients with painful polyneuropathies. The US Food and Drug Administration (FDA) has only approved one new drug for painful diabetic neuropathy in the past decade, a topical capsaicin patch that was initially approved for the treatment of postherpetic neuralgia in 2009. Gabapentinoids and serotonin norepinephrine reuptake inhibitors (SNRIs) continue to have an advantage in safety profiles and efficacy. Other antiepileptic medications remain second-line agents because of fewer studies documenting efficacy.

RECENT FINDINGS

This article reviews recent literature on complementary and pharmacologic therapies for the management of painful polyneuropathies. Exercise has emerged as an important therapeutic tool and may also improve the underlying polyneuropathy in the setting of obesity, metabolic syndrome, and diabetes.

SUMMARY

The approach to management of painful polyneuropathies is multifactorial, using both pharmacologic and nonpharmacologic measures to improve pain severity and patient quality of life.

Psychosocial Factors in Painful Diabetic Neuropathy: A Systematic Review of Treatment Trials and Survey Studies

OBJECTIVE

Diabetes mellitus is associated with a number of complications that can adversely impact patients' quality of life. A common and often painful complication is painful diabetic neuropathy. The aims of this study were to systematically review and summarize evidence from studies of psychological treatments and psychosocial factors related to painful diabetic neuropathy and assess the methodological quality of these studies.

METHODS

Electronic databases, related reviews, and associated reference lists were searched. Summaries of participants' data relating to the efficacy of psychological treatments and/or to associations between psychosocial factors and outcomes in painful diabetic neuropathy were extracted from the included studies. The methodological quality of included studies was assessed using two standardized quality assessment tools.

RESULTS

From 2,921 potentially relevant titles identified, 27 studies were included in this systematic review. The evidence suggests that depression, anxiety, sleep, and quality of life are the most studied variables in relation to pain outcomes in painful diabetic neuropathy and are consistently associated with pain intensity. The magnitude of the associations ranged from small to large.

CONCLUSIONS

Research into psychosocial factors in painful diabetic neuropathy is unexpectedly limited. The available evidence is inconsistent and leaves a number of questions unanswered, particularly with respect to causal associations between variables. The evidence reviewed indicates that depression, anxiety, low quality of life, and poor sleep are associated with pain in painful diabetic neuropathy. The disproportionate lack of research into psychological treatments for painful diabetic neuropathy represents a significant opportunity for future research.

Signs and symptoms, quality of life and psychosocial data in 1331 post-traumatic trigeminal neuropathy patients seen in two tertiary referral centres in two countries

Background

Post‐traumatic trigeminal neuropathy (PTN) is a disturbance of function or pathological change of the trigeminal nerve branches following trauma and has an important impact on patient's quality of life (QoL).

Objectives

To provide diagnostic data on PTN and illustrate differences in aetiology, injured nerve, pain distribution, sensory profile and QoL between PTN subgroups.

Methods

1331 patients with painful or non‐painful PTN were retrospectively reviewed in two centres, extracting demographic data, time and cause of trauma, clinical findings including signs and symptoms, basic neurosensory testing, imaging modalities, treatments, and QoL or psychosocial assessment.

Results

More females were represented (70%) than males. The inferior alveolar nerve was most frequently damaged (60%) followed by the lingual nerve (28%). Wisdom teeth removal was considered the main cause (48%). Pain was reported in 63% of patients and pain frequency increased with age without clinically significant gender differences. Numbness was reported in 50% of PTN patients. Neurosensory testing showed larger affected dermatome involvement in persistent injuries, with no differences between the non‐painful and painful PTN groups. Patient clustering indicated different sensory profile distributions when stratified according to aetiology or affected nerve branch. High interference with lifestyle was reported (78%), and patients suffering from painful PTN had worse QoL and psychosocial outcomes.

Conclusion

Patients with painful PTN had different clinical profiles and lower QoL scores than those with non‐painful PTN. Sensory profiles may provide important prognostic and therapeutic information; however, more research is needed to assess the clustering procedure and link these clusters to therapeutic guidelines.

Anxiety, depression and sleep disorders in patients with diabetic neuropathic pain: a systematic review

Introduction: Diabetic neuropathic pain (DNP) is a disabling complication suffered by patients with diabetic neuropathy. DNP coexists with different conditions, especially mental and sleep disorders, which seem to impair the management and course of the disease. However, there is a lack of accurate results about their prevalence. Consequently, the authors analyze the prevalence of anxiety, depression and/or sleep disorders in DND patients.Areas covered: Among the 206 articles found in the search, 8 studies with data from 5 different countries fulfilled the inclusion criteria. The prevalence of anxiety reported ranged between 7.8%-60.4% and that of depression between 13.6%- 50.6%. The two conditions coexist in 26.4%-30.6% in DND patients. A higher prevalence was found when the information was obtained using scales than when it came from medical records. The prevalence of sleep disorders found ranged from 41.6%-43.8%. However, there is lack of information about and the results are often expressed using the mean scores of the scales.Expert opinion: Although the data in the literature vary, a high prevalence of anxiety, depression and sleep comorbidities exists among patients with DNP. These results reaffirm the need to perform systematic evaluations and to identity their presence using validated instruments to obtain more reliable results.

The effect of exercise therapy combined with psychological therapy on physical activity and quality of life in patients with painful diabetic neuropathy: a systematic review

Background and aims

Approximately 25% of patients with diabetes mellitus type 2 (DMII) develop painful diabetic neuropathy (PDN). PDN is known to affect both mental and physical wellbeing, resulting in anxiety, depression, low quality of life and physical disability. Pharmacological treatment of PDN aims at pain relief and is often ineffective and/or has many side effects. Rehabilitation treatment modalities that are designed to help the patient deal with PDN related complaints, are mostly focussed on either physical (e.g. exercise therapy) or psychological aspects (e.g. cognitive behavioural therapy, CBT). There is emerging evidence that PDN can be approached from a biopsychosocial perspective, in which physical and psychosocial aspects are integrated. From this biopsychosocial approach it is plausible that integrated treatment modalities such as acceptance commitment therapy (ACT) or exposure in vivo (EXP) could be effective in patients with PDN. The objective of this review was to provide an overview of the current evidence on the effects of rehabilitation treatments that combine exercise therapies with psychological therapies in order to improve physical activity (PA) and quality of life (QoL) in patients with PDN.

Methods

Systematic review of the current literature. EMBASE, MEDLINE, Medline In-Process citations and e-Pubs ahead-of-print, Pedro, Web of Science, PsycINFO, CENTRAL, PubMed and Google Scholar were searched. All studies on interventions combining exercise therapy with psychological interventions in patients with PDN, aged >18 years, were included. Outcome measures were PA, QoL.

Results

The search resulted in 1603 records after removing duplicates. After screening on titles and abstracts, 100 records remained. From these, not one study reported on interventions that combined exercise therapy with psychological interventions. Through a secondary hand search, a total of three reviews were identified that described a total of five studies regarding either physical or psychological interventions in patients with PDN. These studies reported moderate effects of (1) mindfulness meditation on QoL, (2) CBT on pain severity, (3) mindfulness-based stress reduction intervention on function, health-related QoL, pain catastrophizing and depression, (4) aerobic exercise on QoL and (5) Tai Chi on glucose control, balance, neuropathic symptoms, and some dimensions of QoL in patients with PDN. All studies were of a moderate quality, and results should be interpreted with caution.

Conclusions

Based on increasing knowledge in the domain of chronic pain, it could be assumed that integrated rehabilitation treatments for patients with PDN are beneficial. There is no literature to support this and more research should be done on integrated biopsychosocial interventions in patients with PDN.

Implications

This empty review highlights the importance that more research should be done on integrated biopsychosocial interventions in patients with PDN. Currently, our research group is performing a study on the effects of EXP treatment in patients with PDN.

[Changes in regional homogeneity of brain activity in patients with diabetic peripheral]

OBJECTIVE

To investigate the abnormalities in regional homogeneity of brain activity in patients with diabetic peripheral neuropathy (DPN) using resting-state functional magnetic resonance imaging (rs-fMRI) and explore the association between brain activity changes and DPN.

METHODS

A regional homogeneity (ReHo) approach was used to compare the local synchronization of rs-fMRI signals among 20 patients with painful DPN, 16 patients with painless DPN, and 16 type 2 diabetic patients without DPN (non-DPN group).

RESULTS

Compared with the those without DPN, the patients with painful DPN showed high ReHo in the left inferior temporal gyrus and the right central posterior gyrus, and low ReHo in the posterior cingulate gyrus, right inferior parietal gyrus, and the left superior parietal gyrus (P < 0.05);the patients with painless DPN group showed high ReHo in the left inferior temporal gyrus, the right middle temporal gyrus, and the right superior frontal gyrus, and low ReHo in the left thalamus (P < 0.05).No significant differences in ReHo were found between the patients with painful DPN and painless DPN (P>0.05).

CONCLUSIONS

The patients with DPN have altered ReHo in multiple brain regions and impairment of a default mode network, for which the left temporal gyrus may serve as a functional compensatory brain area. ReHo disturbance in the central right posterior gyrus may play a central role in the pain symptoms associated with painful DPN.

A new look at painful diabetic neuropathy

The prevalence of diabetes mellitus and its chronic complications continue to increase alarmingly. Consequently, the massive expenditure on diabetic distal symmetrical polyneuropathy (DSPN) and its sequelae, will also likely rise. Up to 50% of patients with diabetes develop DSPN, and about 20% develop neuropathic pain (painful-DSPN). Painful-DSPN can cast a huge burden on sufferers' lives with increased rates of unemployment, mental health disorders and physical co-morbidities. Unfortunately, due to limited understanding of the mechanisms leading to painful-DSPN, current treatments remain inadequate. Recent studies examining the pathophysiology of painful-DSPN have identified maladaptive alterations at the level of both the peripheral and central nervous systems. Additionally, genetic studies have suggested that patients with variants of voltage gated sodium channels may be more at risk of developing neuropathic pain in the presence of a disease trigger such as diabetes. We review the recent advances in genetics, skin biopsy immunohistochemistry and neuro-imaging, which have the potential to further our understanding of the condition, and identify targets for new mechanism based therapies.

The association of diabetes-related self-care activities with perceived stress, anxiety, and fatigue: a cross-sectional study

PURPOSE

Many people with type 2 diabetes (T2DM) do not sustain sufficient diabetes-related self-care activities (DRSCA) in their daily lives. To provide additional information about the positive influence of DRSCA, this study was conducted to examine whether DRSCA were associated with reduced perceived stress, anxiety, and fatigue among people with T2DM and to explore the level of DRSCA, perceived stress, anxiety, and fatigue and their association with background information.

PATIENTS AND METHODS

This study was a cross-sectional survey including 251 participants aged 18 years and older recruited from two hospitals in the eastern part of China. The study utilized self-report questionnaires that consisted of background information, DRSCA, perceived stress, anxiety, and fatigue. Hierarchical multiple regression analysis was conducted to explore the association of DRSCA with perceived stress, anxiety, and fatigue while adjusting for background information.

RESULTS

The results indicated that the level of self-care activities, stress, and fatigue was around middle level. The prevalence of anxiety was 19%. A high level of DRSCA was likely to reduce perceived stress but was not linked to anxiety and fatigue. Women were more susceptible to stress and anxiety, and people who had diabetes for >5 years were more likely to have anxiety. The background information included diabetes duration, standardized diabetes education, and high social support, all of which are factors that may influence DRSCA.

CONCLUSION

The findings suggest that improving the level of DRSCA might effectively reduce perceived stress. The potential benefits of DRSCA can provide both motivational and evaluative data for self-care programs. In addition, the findings show that DRSCA were not linked to anxiety and fatigue, which implies that their positive influence on anxiety and fatigue may be offset by the load of frequent DRSCA. It is suggested that helping patients to make tailored plans to integrate DRSCA into their daily lives is needed. Meanwhile, in the background information, it is suggested that standardized diabetes education and high social support can benefit DRSCA; in improving psychological health, more attention should be paid to women and patients with diabetes duration <5 years.

Sensory phenotype and risk factors for painful diabetic neuropathy: a cross-sectional observational study

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Cross-sectional observational study in a cohort of 232 diabetic polyneuropathy patients confirmed higher severity of neuropathy and predominant loss-of-function sensory profile in painful cases.

Different sensory profiles in diabetic distal symmetrical sensory-motor polyneuropathy (DSPN) may be associated with pain and the responsiveness to analgesia. We aimed to characterize sensory phenotypes of patients with painful and painless diabetic neuropathy and to assess demographic, clinical, metabolic, and electrophysiological parameters related to the presence of neuropathic pain in a large cohort of well-defined DSPN subjects. This observational cross-sectional multi-center cohort study (performed as part of the ncRNAPain EU consortium) of 232 subjects with nonpainful (n = 74) and painful (n = 158) DSPN associated with diabetes mellitus of type 1 and 2 (median age 63 years, range 21-87 years; 92 women) comprised detailed history taking, laboratory tests, neurological examination, quantitative sensory testing, nerve conduction studies, and neuropathy severity scores. All parameters were analyzed with regard to the presence and severity of neuropathic pain. Neuropathic pain was positively correlated with the severity of neuropathy and thermal hyposensitivity (P < 0.001). A minority of patients with painful DSPN (14.6%) had a sensory profile, indicating thermal hypersensitivity that was associated with less severe neuropathy. Neuropathic pain was further linked to female sex and higher cognitive appraisal of pain as assessed by the pain catastrophizing scale (P < 0.001), while parameters related to diabetes showed no influence on neuropathic pain with the exception of laboratory signs of nephropathy. This study confirms the value of comprehensive DSPN phenotyping and underlines the importance of the severity of neuropathy for the presence of pain. Different sensory phenotypes might be useful for stratification of patients with painful DSPN for analgesic treatment and drug trials.

Antiallodynic and antihyperalgesic activities of zerumbone via the suppression of IL-1β, IL-6, and TNF-α in a mouse model of neuropathic pain

Background

Neuropathic pain is a debilitating condition that severely affects the quality of life for those with this pain condition, and treatment for pain relief is greatly sought-after. Zerumbone (Zer), a sesquiterpene compound isolated from the rhizomes of a Southeast Asian ginger plant, Zingiber zerumbet (L.) Roscoe ex Smith. (Zingiberaceae), showed antinociceptive and antiinflammatory properties when previously tested on models of nociception and inflammation.

Objective

This study investigated the effects of prophylactic administration of zerumbone on allodynia and hyperalgesia in a mouse model of chronic constriction injury (CCI)-induced neuropathic pain.

Methods

Intraperitoneal administration of Zer (5–50 mg/kg) from day 1 post-surgery was carried out to identify the onset and progression of the pain condition. Responses toward mechanical and cold allodynia, and mechanical and thermal hyperalgesia were assessed on days 3, 5, 7, 9, 11, and 14 post-surgery. Blood plasma and spinal cord levels of interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and IL-10 were screened using enzyme-linked immunosorbent assay on day 15.

Results

Zer (10 and 50 mg/kg) attenuated pain symptoms on all days of behavioral testing without any signs of sedation in the rotarod test. ED₅₀ values for mechanical allodynia, cold allodynia, thermal hyperalgesia, and mechanical hyperalgesia were 9.25, 9.507, 8.289, and 9.801 mg/kg, respectively. Blood plasma and spinal levels of IL-1β, IL-6, and tumor necrosis factor-α but not IL-10 were significantly (p<0.05) suppressed by zer treatment.

Discussion and conclusion

Zer exhibits its antiallodynic and antihyperalgesic properties via reduced sensitization at nociceptor neurons possibly through the suppression of inflammatory mediators. Zer may prove to be a novel and beneficial alternative for the management of neuropathic pain.

Psychological and Biomechanical Aspects of Patient Adaptation to Diabetic Neuropathy and Foot Ulceration

PURPOSE OF REVIEW

The purpose of this review was to elucidate how psychological and biomechanical factors interrelate in shaping patients' experience with diabetic symmetric polyneuropathy (DSPN) and its sequela-diabetic foot ulceration (DFU).

RECENT FINDINGS

Recent findings emphasize the importance not only of neuropathic pain but also of other DSPN symptoms, such as unsteadiness. We highlight the negative spiral between unsteadiness, falls, and psychological distress. Moreover, unsteadiness is a key determinant of non-adherence to offloading resulting in the delayed DFU healing. While depression is an established predictor of incident DFU, findings linking depression and DFU healing remain inconclusive. Examination of physical activity in DFU development and healing represents the most recent application of research to this field. Research evidence indicates that DSPN markedly impairs physical and emotional functioning and suggests that there is an unmet need for the development of multifaceted interventions that address both psychological distress and biomechanical challenges experienced by patients with this debilitating complication of diabetes.

Neuropathy and presence of emotional distress and depression in longstanding diabetes: Results from the Canadian study of longevity in type 1 diabetes

AIM

To determine the association of neuropathy and other complications with emotional distress and depression among patients with longstanding type 1 diabetes (T1DM).

METHODS

Canadians with ≥50years of T1DM completed a questionnaire including assessment of distress and depression by the Problem Areas in Diabetes Scale (PAID) and Geriatric Depression Scale (GDS), respectively. Complications were determined using the Michigan Neuropathy Screening Instrument (Questionnaire Component), fundoscopy reports, renal function tests, and self-reported peripheral-(PVD) and cardiovascular (CVD) disease. Associations were analyzed by Poisson regression.

RESULTS

Among 323 participants, 137 (42.4%) had neuropathy, 113 (36.5%) nephropathy, 207 (69.5%) retinopathy, 95 (29.4%) CVD, and 31 (9.8%) PVD. The neuropathy subgroup had higher prevalence of distress (13 (9.5%) vs. 6 (3.3%), p=0.029) and depression (34 (24.9%) vs. 12 (6.5%), p<0.001). Adjusting for diabetes complications, neuropathy was associated with higher PAID (adjusted RR 1.44 (95% CI 1.14-1.82), p=0.003) and GDS scores (adjusted RR1.57 (1.18-2.11), p=0.002). Independent of potential confounders, neuropathy remained associated with higher PAID (adjusted RR 1.39 (1.10-1.76), p=0.006) and GDS scores (adjusted RR 1.37 (1.03-1.83), p=0.032). Associations with neuropathy were not fully explained by neuropathic pain.

CONCLUSION

Compared to other complications, neuropathy had the greatest association with distress and depression in longstanding T1DM, independent of pain. Strategies beyond pain management are needed to improve quality of life in diabetic neuropathy.

Diabetic peripheral neuropathic pain is a stronger predictor of depression than other diabetic complications and comorbidities

AIMS

To investigate the independent effect on depression of painless diabetic polyneuropathy, painful diabetic polyneuropathy, and general and diabetes-related comorbidities.

METHODS

In 181 patients, the presence of painless diabetic polyneuropathy, painful diabetic polyneuropathy, comorbidities and depression was assessed using the Michigan Neuropathy Screening Instrument Questionnaire, the Michigan Diabetic Neuropathy Score, nerve conduction studies, the Douleur Neuropathique en 4 Questions, the Charlson Comorbidity Index and the Beck Depression Inventory-II.

RESULTS

In all, 46 patients met the criteria of confirmed painless diabetic polyneuropathy and 25 of painful diabetic polyneuropathy. Beck Depression Inventory-II scores indicative of mild-moderate-severe depression were reached in 36 patients (19.7%). In a multiple logistic regression analysis (including age, sex, body mass index, being unemployed, duration, haemoglobin A1c, insulin treatment, systolic blood pressure, nephropathy, retinopathy, Charlson Comorbidity Index and painful diabetic polyneuropathy), female sex (odds ratio: 5.9, p = 0.005) and painful diabetic polyneuropathy (odds ratio: 4.6, p = 0.038) were the only independent predictors of depression. Multiple regression analysis, including Douleur Neuropathique en 4 Questions and Michigan Diabetic Neuropathy Score instead of painful diabetic polyneuropathy, showed that Douleur Neuropathique en 4 Questions, in addition to female sex, was a significant predictor of depressive symptoms severity (p =0.005).

CONCLUSION

Painful diabetic polyneuropathy is a greater determinant of depression than other diabetes-related complications and comorbidities. Painful symptoms enhance depression severity more than objective insensitivity.

Diabetic peripheral neuropathy may not be as its name suggests: evidence from magnetic resonance imaging

Diabetic peripheral neuropathy (DPN) affects up to 50% of patients with diabetes and is a major cause of morbidity and increased mortality. Its clinical manifestations include distressing painful neuropathic symptoms and insensitivity to trauma that result in foot ulcerations and amputations. Several recent studies have implicated poor glycemic control, duration of diabetes, hyperlipidemia (particularly hypertryglyceridaemia), elevated albumin excretion rates, and obesity as risk factors for the development of DPN. However, similar data are not available for painful DPN. Moreover, although there is now strong evidence for the importance of peripheral nerve microvascular disease in the pathogenesis of DPN, peripheral structural biomarkers of painful DPN are lacking. However, there is now emerging evidence for the involvement of the central nervous system in both painful and painless DPN afforded by magnetic resonance imaging. This review will focus on this emerging evidence for central changes in DPN, hitherto considered a peripheral nerve disease only.

Perceived Physical Activity Decline as a Mediator in the Relationship Between Pain Catastrophizing, Disability, and Quality of Life in Patients with Painful Diabetic Neuropathy

BACKGROUND

To fully understand the burden of painful diabetic neuropathy (PDN), we investigated the relationship of pain catastrophizing with disability and quality of life in patients with PDN. Furthermore, we studied the mediating roles of physical activity and/or decline in physical activity.

METHODS

This questionnaire-based cross-sectional study included 154 patients with PDN. Linear regression analyses, adjusted for age, gender, pain intensity, and insulin treatment, were performed to assess the association of pain catastrophizing (Pain Catastrophizing Scale [PCS]) with the outcome variables disability (Pain Disability Index [PDI]) and quality of life (Norfolk Quality of Life Questionnaire Diabetic Neuropathy Version [QOL-DN]). The mediating roles of actual physical activity (Physical Activity Rating Scale [PARS]) and perceived Physical Activity Decline (PAD) were assessed using mediation analyses according to Baron and Kenny.

RESULTS

This study included 154 patients (62% male). Mean age was 65.7 years (SD = 6.6). PCS (M = 20.3, SD = 13.1) was significantly associated with PDI (M = 32.4, SD = 17.0; R² = 0.356, P < 0.001), QOL-DN (M = 52.6, SD = 26.1; R² = 0.437, P < 0.001), and PAD (M = 7.4, SD = 5.7; R² = 0.087, P = 0.045). PAD acted as a partial mediator in the associations of PCS with PDI and QOL-DN, respectively. There was no association of PCS with PARS.

CONCLUSIONS

Pain catastrophizing was associated with increased disability and decreased quality of life in patients with PDN. Also, it was associated with a perceived decline in physical activity, which had a mediating role in the association between catastrophizing and disability and quality of life, respectively. This study emphasizes the role of catastrophic thinking about pain and the experienced loss in daily activities due to PDN.

Are there different predictors of analgesic response between antidepressants and anticonvulsants in painful diabetic neuropathy?

BACKGROUND

To investigate baseline demographics and disease characteristics as predictors of the analgesic effect of duloxetine and pregabalin on diabetic peripheral neuropathic pain (DPNP).

METHODS

Based on data from the COMBO-DN study, a multinational clinical trial in DPNP, the potential impact of baseline characteristics on pain relief after 8-week monotherapy with 60 mg/day duloxetine or 300 mg/day pregabalin was assessed using analyses of covariance. Subgroups of interest were characterized regarding their baseline characteristics and efficacy outcomes.

RESULTS

A total of 804 patients were evaluated at baseline. A significant interaction with treatment was observed in the mood symptom subgroups with a larger pain reduction in duloxetine-treated patients having no mood symptoms [Hospital Anxiety and Depression Scale (HADS) depression or anxiety subscale score <11; -2.33 (duloxetine); -1.52 (pregabalin); p = 0.024]. There were no significant interactions between treatment for subgroups by age (<65 or ≥65 years), gender, baseline pain severity [Brief Pain Inventory Modified Short Form (BPI-MSF) average pain <6 or ≥6], diabetic neuropathy duration (≤2 or >2 years), baseline haemoglobin A1c (HbA1c) (<8% or ≥8%), presence of comorbidities and concomitant medication use.

CONCLUSIONS

Our analyses suggest that the efficacy of duloxetine and pregabalin for initial 8-week treatment in DPNP was consistent across examined subgroups based on demographics and disease characteristics at baseline except for the presence of mood symptoms. Duloxetine treatment appeared to be particularly beneficial in DPNP patients having no mood symptoms.

A more pessimistic life orientation is associated with experimental inducibility of a neuropathy-like pain pattern in healthy individuals

The clinical pattern of neuropathic pain, diagnosed using the quantitative sensory testing (QST) battery (German Research Network on Neuropathic Pain), could be partly mimicked in healthy volunteers after topical capsaicin application. However, similar to clinical neuropathic pain that develops in only a subgroup of patients who have a neurologic lesion, this attempt to mimick a neuropathic pain pattern succeeded only in a small fraction (18%) of healthy individuals. In the present assessment, we pursued the hypothesis that the inducible subgroup differed from the other healthy participants with respect to their psychological phenotype. Therefore, in an observational study, participants were assessed using a comprehensive set of psychological variables comprising general psychological and pain-related cognitive-emotional mechanisms. The sum scores of the questionnaires were significantly linearly correlated with each other. Principal component analysis indicated that a major source of variance (46%) could be attributed to dispositional optimism examined via the Life Orientation Test (LOT). The LOT score significantly differed between the groups of participants, either those in whom a neuropathy-like pattern of pain assessed via QST could be partly (50-60% of the 11 QST parameters) induced (n = 20) or not (n = 90; P = .0375). It emerged again as the main selection criterion in a classification and regression tree predicting a participant's group assignment (inducible neuropathy-like QST pattern versus noninducible neuropathy-like QST pattern) at a cross-validated accuracy of 95.5 ± 2.1%. Thus, the few participants in a random sample of healthy volunteers who, after topical capsaicin application, partly resemble (to a degree of about 60%) the clinical pattern of neuropathic pain in the QST test battery, are preselectable on the basis of psychological factors, with a particular emphasis on pessimistic life attitudes.

PERSPECTIVE

In a small fraction of 18% of healthy volunteers, topical capsaicin application resulted in a neuropathy-like pattern in 50 to 60% of the components of a clinical test battery. These individuals displayed a more pessimistic life attitude as assessed by means of the LOT.

Understanding and treating painful diabetic neuropathy: time for a paradigm shift

The pathogenesis of diabetic neuropathy (DN) continues to be unclear and as a result, progress in developing effective therapies has been disappointing. In particular, there is only limited understanding of why some patients suffer severe chronic pain, whilst others have painless symptoms. Assessment of the peripheral nerves frequently shows no differences between painful and painless DN. There is growing evidence that the nerve damage in DN is more generalized, including the central nervous system, and these central changes are key to the development and persistence of pain in DN. The advent of new radiological techniques provides us with non-invasive modalities to study central pathophysiological processes in greater detail. These insights are increasingly leading to the recognition that painful DN is a complex and heterogeneous disorder, which requires a multimodal approach to treatment.