Data collection visit 1

All participants underwent a neuropathy screening, in a lying position, to confirm their suitability to participate in the study. Light touch and vibration sensibility were tested using a monofilament and a tuning fork. In addition, subjective symptoms were recorded using the Diabetic Neuropathy Symptom Score. These screening tests were chosen because they are commonly used in day-to-day clinical practice to test neuropathy (Dixit, 2014). Once subjects were confirmed as suitable, they read the information sheet and were invited to ask questions, after which they provided informed consent to participate by signing the consent form. Socio-demographical variables were then recorded, including gender, date of birth and height, weight and BMI.

5.1.3.1 10 g Semmes-Weinstein Monofilament

Light touch sensitivity loss was assessed using a 10 g Semmes-Weinstein monofilament. Nylon monofilaments are constructed to buckle when a 10 g force is applied and loss of ability to detect pressure at the point of buckling, at one or more anatomic sites on the plantar surface of the foot, has been associated with loss of large-

82 fibre nerve function (Boulton et al., 2008). This approach is common practice and has been used in a number of prospective studies which have reported that loss of pressure sensation is highly predictive of subsequent ulceration (Boulton, 2010, Dixit&Maiya, 2014). Moreover, it has also been shown to be highly reproducible (85%) (Tan, 2010) when compared with pulse palpation. Several studies report using the monofilament on only four different sites of the forefoot, and test being positive when one or more of these was not felt. Currently, there is no consensus on the protocol for the use of the monofilament with regard to the location and number of test sites, as well as the number of insensate sites to be classified as the presence of neuropathy. Testing 10 sites (Figure 5.3) evaluates all dermatomes of the foot and may improve the sensitivity and specificity compared with testing 4 sites (Singh et al., 2005).

In this study 10 different sites on the foot were tested in random order: 1st, 3rd and 5th toes, 1st, 3rd and 5th metatarsal heads, internal arch, external arch, heel and dorsum between 1st and 2nd toes (Figure 5.3). Participants were asked to close their eyes and identify the site that the monofilament was being applied to. Areas of hard skin were avoided as it was felt that they might bias the result of the test. The test was taken to be positive for neuropathy if the patient could not feel the monofilament at one or more sites (Feng et al., 2011). The approach taken in this study was more conservative including the rear foot and the test considered positive when one or more of these was not felt.

Figure 5.3: Monofilament test areas

5.1.3.2 128 Hz tuning fork

A 128 Hz tuning fork was usedin order to test vibration sensitivity as it has been shown to be sensitive to neuropathy (Al-Geffari, 2012). It has been found that an inability

83 to sense vibration at different sites is clinically indicative of peripheral neuropathy (Takahara et al., 2014). Furthermore, in combination with the monofilament, it has been shown to be a good predictor of patients who later developed foot ulceration (Feng, 2011). The tuning fork was applied to bony prominences bilaterally: internal and external malleoli and 1st and 5th metatarsal heads (Al-Geffari, 2012). The participant had their eyes closed throughout and they were asked to indicate when they could sense the vibration. The test was considered positive for neuropathy when one or more of the vibrations could not be sensed (Dixit&Maiya, 2014).

Figure 5.4: Example of tuning fork test on the 1st _MPJ 5.1.3.3 Diabetic Neuropathy Symptom Score

The Diabetic Neuropathy Symptom Score was used to assess the subjective symptoms of neuropathy, which are important as they reflect the complaints of the patient and may be of additional diagnostic or prognostic value. Although several scores have been developed to assess symptoms of diabetic neuropathy, such as the Neuropathy Symptom Profile, the Michigan Neuropathy Screening Instrument (MNSI) and the modified NSS scores of Veves and Young (Dyck et al., 1986, Veves et al., 1993, Young

et al., 1993, Feldman et al., 1994), the Neuropathy Symptom Score has been widely studied and accepted as valid and sensitive to detect neuropathy (Meijer et al., 2002). The Diabetic Neuropathy Symptom Score tests the following areas: unsteadiness in walking, pain, burning or aching in legs or feet, prickling sensations in legs or feet, and numbness in legs or feet. The presence is scored 1 and absence 0, with the presence of any symptoms in any of the areas considered indicative of neuropathy.

At least two of the screening tests described above had to be positive for a definite diagnosis of neuropathy. Once the diagnosis of neuropathy had been confirmed, and the

84 participant deemed eligible for the study, a range of further measurements were taken (see Table 5.1) to provide the biomechanical and clinical variables required to address Study 3 (Chapter 8) and also to produce the manufacturing specification for the different insole designs tested in Study 2 (Chapter 7). Table 5.1 provides a reference to the subsequent section in which the tests are described in more detail and the chapter presenting the data.

Measurement Study/Insole

design

Chapter Number

Socio-demographical variables 3 8

Characterisation of foot segment lengths 3 8

Skin stiffness characterization 3 8

Joint mobility (ankle, subtalar, and 1st MPJ) 3 8

Lower limb motion 3 8

3D foot scan Insole design only 5

Barefoot standing plantar pressure Insole design only 5

Table 5.1: Different data sets collected on day one and details of study used in and where it is within this thesis