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Browsing by Person "Seenan, Christopher"

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    Laboratory and Clinical Investigation into Lower Limb Ischaemic Pain, and the Effect of Transcutaneous Electrical Nerve Stimulation (Tens) on Measures of Pain and Walking Performance
    (Queen Margaret University, Edinburgh, 2013) Seenan, Christopher
    Aims: The aims of this programme of research are to investigate the subjective description of ischaemic pain and to investigate the effects of TENS on lower limb ischaemic pain and walking performance in patients with Intermittent Claudication (IC). Methods: Four studies were conducted: two in the laboratory and two clinical trials. Laboratory- The first study investigated the reliability of a method of inducing lower limb ischaemic pain in healthy volunteers, the modified Submaximal Effort Tourniquet Test (mSETT). The second investigated the effects of High Frequency TENS (HF-TENS) and Placebo TENS (P-TENS) on lower limb ischaemic pain induced using the mSETT in healthy volunteers. Clinical- The first clinical study investigated the effects of HF-TENS and Low Frequency TENS (LF-TENS) on measures of pain and treadmill walking performance in patients with Peripheral Arterial Disease (PAD) and IC. The second examined patients' experiences of using TENS at home for PAD and IC. Results: The mSETT was found to have good test-retest reliability and induce pain similar in quality to that experienced by patients with IC. The pain experience induced with the mSETT was reduced by both HF- and P-TENS compared to baseline. HF-TENS however was more effective compared to P-TENS in this regard, prolonging time to pain threshold and tolerance whilst reducing the levels of pain reported throughout. In patients with PAD and IC, HF and LF-TENS interventions were found to increase maximum walking distance on a treadmill compared to P-TENS. HF-TENS was also found to increase pain-free walking distance. The experience of using TENS in daily life was characterised by feelings of both benefit and disappointment. This was interpreted through the following themes: (i) 'masking, but not taking the pain away' and (ii) 'walking further, but not far enough'. Conclusions: The mSETT is a reliable method of inducing lower limb, ischaemic pain in healthy volunteers and could be useful for the purposes of pre-clinical analgesic trials and investigation of the ischaemic pain experience. HF-TENS was found to reduce mSETT pain indicating hypoalgesic effects of TENS in experimentally induced, lower limb ischaemic pain. HF and LF-TENS have potential as interventions that increase walking performance for patients with IC. If using TENS at home for IC, expectations of treatment effect need to be managed to avoid disappointment and feelings of frustration.
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    Modification of experimental lower limb ischaemic pain with transcutaneous electrical nerve stimulation.
    (Lippincott Williams & Wilkins, 2012-10) Seenan, Christopher; Roche, Patricia; Tan, Chee-Wee; Mercer, Tom
    Introduction: Transcutaneous electrical nerve stimulation (TENS)has been shown to be effective for the reduction of experimentally induced ischemic pain in the upper limb. No studies have been published on the effects of TENS for lower limb ischemic pain. Objectives: To investigate the pain-modifying effect of TENS on experimentally induced ischemic pain in the lower limb. Methods: A modified Submaximal Effort Tourniquet Test-induced ischemic pain in the nondominant lower limb of 27 healthy volunteers. Each of the participants completed a baseline modified Submaximal Effort Tourniquet Test (No TENS) and 1 of the experimental conditions: either high-frequency TENS (HF-TENS) or placebo TENS(P-TENS). The outcome measures were the time taken (in seconds) for the participants to report pain threshold and pain tolerance. Pain endurance was calculated as the difference between these points. Pain intensity during ischemia was assessed using a numerical rating scale. The McGill Pain Questionnaire recorded participants' retrospective description of 'intolerable' induced pain. The differences in scores between these measures at the baseline and TENS intervention was calculated and used for the analysis. Results: Paired Student t-tests found significant increases in time to pain tolerance and pain endurance in both the TENS groups(P<0.001 HF-TENS and P<0.05 for P-TENS, respectively). When compared with baseline, time to pain threshold increased significantly only with HF-TENS (P<0.01). The independent Student t-tests detected greater increases in pain threshold, tolerance, and endurance in the HF-TENS group compared with the PTENS group (P<0.05, 0.002, and 0.003, respectively). Compared with P-TENS, HF-TENS significantly reduced the pain intensity between the fifth and eigth minutes. Both HF-TENS and P-TENS significantly reduced the mean McGill Pain Questionnaire Pain Rating Index scores, but did not show a between-group difference. Conclusions: HF-TENS had stronger modifying effects on several aspects of laboratory-induced ischemic pain than did P-TENS. HFTENS delayed the onset of pain, reduced pain levels, and delayed the onset of extreme pain over a period of several mi