# Exercise and Manual Therapy for Diabetic Peripheral Neuropathy: A Systematic Review
## 4 Discussion  
The objective of this systematic review was to review the effectiveness of manual therapy and exercise in patients with diabetic neuropathy. We found 29 articles, of which just one analysed the combination of both techniques. There were six articles that analysed the effect of manual therapy, while the rest analysed a variety of exercise programmes. We found a lack of studies that analysed the combination of manual therapy and exercise and only manual therapy in patients with diabetic neuropathy. The selection criteria were heterogeneous among the studies. Beginning with sample age, the articles differed in the minimum age for sample inclusion, from 18 to 40 or 45 years. The mean age ranges were between 45 and 85 years old. In other reviews, the mean ages of the patients were between 50 and 60 years old [10; 12]. This can be explained by the elevated diagnosis of diabetic neuropathy in the 51-60-year age group, in patients that have type 2 diabetes [51; 52]. In addition, type 2 diabetes represents the greatest proportion of the total prevalence of diabetes (90%) and is characteristic of adult patients [53]. In line with the previous point, a great number of the analysed studies specified that the patients had to have type 2 diabetes, excluding patients with type 1 from the sample. The studies that include these patients do not provide results based on the type of diabetes that the patients have. Consequently, it is impossible to determine the effectiveness of these treatments in those patients and on diabetic neuropathy. Moreover, the typology of diabetic neuropathy was defined as diabetic peripheral neuropathy, not considering other types of diabetic neuropathy such as diabetic autonomic neuropathy, cardiac autonomic neuropathy, gastrointestinal neuropathy and genitourinary disturbances. These profiles should also be well identified in the selection criteria because of the problems that exercise can have on patients [14]. Another point to be mentioned is the heterogeneity of the criteria used to diagnose diabetic neuropathy. The articles describe the use of the Michigan Diabetic Neuropathy (MDN) questionnaire, medical diagnoses, sensitivity tests and blood parameters (HbA1c and blood glycaemia). [PERSON] et al. [54] observed that the predictive models for diagnosing diabetic neuropathy were ambiguous; electrodiagnostic studies do not enable detecting lesions in fibres of small diameter (which are the most damaged in this type of patient); imaging tests present different limitations and their usefulness has not yet been demonstrated in this type of clinical picture; and biomarkers need further studies [55]. Consequently, no agreement has been reached as to which criterion or criteria should be taken into account in diagnosing diabetic neuropathy. The studies should unify criteria so as to obtain a more representative sample that consider the alterations at the level of both large- and small-diameter nerve fibres. We have found considerable variability in the treatment with exercise. This variability exists in both the method of exercise and in the analysed variables. All the forms of treatment (aerobic exercise, balance therapy and strength-resistance treatment, as well as the combination among them) seem to be effective in improving the signs and symptoms of patients with diabetic neuropathy. Aerobic exercise, described principally as walking or using a stationary bike at moderate intensity, significantly improved all the variables analysed in the studies. Statistically significant differences were shown against control groups of standard care and/or patient education, but these results were not observed with groups using TENS interventions. [PERSON] et al. [39] showed improvements using several questionnaires in relation to a group treated with balance-focused exercise. In their systematic review, [PERSON] et al. [56] also found that moderate-intensity aerobic exercise positively impacted neural function in patients having type 2 diabetes with diabetic neuropathy.