Iain Beith

Identifying neuropathic back and leg pain: a cross-sectional study

&NA; Low back pain is a widespread debilitating problem with a lifetime prevalence of 80%, with the underlying pain mechanism unknown in approximately 90% of cases. We used the painDETECT neuropathic pain screening questionnaire to identify likely pain mechanisms in 343 patients with low back pain with or without leg pain in southeastern England referred for physiotherapy. We related the identified possible pain mechanisms nociceptive, unclear, and neuropathic to standardised measures of pain severity (Numeric Rating Scale), disability (Roland Morris Low Back Pain Disability Questionnaire), anxiety and depression (Hospital Anxiety and Depression Scale), and quality of life (Short Form 36 Health Survey Questionnaire Version 2). In addition, we investigated any relationship between these possible pain mechanisms and leg pain, passive straight leg raise, and magnetic resonance imaging evidence confirming or eliminating nerve root compression. A total of 59% of participants (n = 204) reported likely nociceptive pain, 25% (n = 85) unclear, and 16% (n = 54) possible neuropathic pain. The possible neuropathic pain group reported significantly higher pain, disability, anxiety, and depression, reduced quality of life and passive straight leg raise compared to the other pain groups (P < .05). A total of 96% of participants with possible neuropathic pain reported pain radiating to the leg (76% below the knee); however, leg pain was still more common in patients with nociceptive pain, suggesting that leg pain is sensitive to, but not specific to, possible neuropathic pain. No relationship was demonstrated between possible neuropathic pain and evidence for or absence of nerve root compression on magnetic resonance imaging scans. These findings suggest possible neuropathic pain is less common in low back pain patients referred through primary care and clarifies the usefulness of clinical tests for identifying possible neuropathic pain. Sixteen percent of participants reported neuropathic pain causing significantly higher pain levels, disability scores, anxiety and depression levels, lesser quality of life, and reduced passive straight leg raise.

Stretch reflexes in human abdominal muscles

Homonymous and heteronymous reflex connections of the abdominal muscles were investigated by the application of a tap to the muscle belly and observation of surface electromyographic responses. Reflex responses of the following abdominal muscles were investigated both ipsilateral and contralateral to the tap: rectus abdominis (RA), external oblique (EO) and internal oblique (IO). Reflexes were evoked in each of the homonymous muscles with latencies and estimated conduction velocities compatible with being evoked by Ia muscle afferents and having a monosynaptic component. Short latency heteronymous excitatory reflex connections were also observed in muscles on both ipsilateral and contralateral sides in response to the same stimulus. The latencies of the crossed responses were only marginally longer than responses evoked in the respective ipsilateral muscle. Moreover, the reflexes evoked in the IO muscle from ipsilateral and contralateral IO muscle afferents were of comparable amplitude, as were those reflexes evoked in ipsilateral and contralateral EO and RA muscles when tapping IO. These similarities in the reflex characteristics on the ipsilateral and contralateral sides suggest that abdominal muscle afferents activate similar pathways to muscles on both sides of the body. It follows that if the homonymous stretch reflex of abdominal muscles have a monosynaptic component, then a similar monosynaptic pathway activates synergistic motoneurones, not only ipsilaterally but also contralaterally.

Stretch Reflexes in the Rectus Abdominis Muscle in Man

The spinal reflex circuitry of the rectus abdominis (RA) muscle in man was investigated by the application of a mechanical tap to the muscle. Electromyographic recordings were made in ten healthy subjects, performing a series of manoeuvres, using pairs of surface electrodes placed bilaterally. The reflex responses elicited largely depended on the amount of tonic (postural) activity of the trunk. When standing in the upright position, no reflex activity was recorded in response to the tap. Reflex activity due to mechanical tap was readily recorded when the muscle became tonically active. Moderate, backward trunk extension introduced short‐latency reflexes at 18.8 ± 1.9 ms (mean ± S.D.) ipsilaterally and 20.8 ± 1.8 ms contralaterally. Excitatory reflex activity of longer latency was also recorded contralaterally in all subjects (latency 45.1 ± 4.3 ms) and ipsilaterally in five of the ten subjects (latency 47.2 ± 2.6 ms). Vibration of the tapped muscle produced a reduction in the amplitude of the early reflex responses, whilst increasing the amplitude of the late responses. Moreover, the early reflexes were facilitated by the Jendrassik manoeuvre. Such observations are consistent with the early responses being mediated, at least partly, monosynaptically, and the late responses being of polysynaptic nature. This implies that muscle spindle afferents from rectus abdominis monosynaptically activate motoneurones contralaterally.

A survey of current management of Benign Paroxysmal Positional Vertigo (BPPV) by physiotherapists’ interested in vestibular rehabilitation in the UK

OBJECTIVES Benign Paroxysmal Positional Vertigo (BPPV) is the most common cause of dizziness. Extensive research has identified the best assessment and treatment manoeuvres for each subtype of BPPV. Education in vestibular rehabilitation (VR) is inconsistent. It is unclear if the evidence has been adopted by UK physiotherapists in clinical practice and no research has investigated this specifically. DESIGN An online survey with closed- and open-text answers. PARTICIPANTS A purposive sample of physiotherapists interested in VR. A response rate of 67% (100/150) was obtained, from which 20 responses were excluded. RESULTS Participants had good evidence-based awareness in assessment (79/80, 99%) and treatment (72/80, 90%) of posterior BPPV. Horizontal BPPV assessment awareness was lower than treatment (37/80, 46% vs 60/80, 75%). Differential diagnosis was poor in subjective (20/80, 25%) and objective stages of assessment (34/80, 43%). Thirty six percent (29/80) were able to list ≥3 test precautions with all three nystagmus characteristics described by 29% (23/80). Eighty one percent (65/80) encourage activity restrictions post-treatment. Only 28% (22/80) were aware of practice guidelines or Cochrane reviews in BPPV. External courses were rated the top method for learning how to manage BPPV. Lack of peer support (26/77, 34%) was the main challenge faced whilst learning. Recommendations for improving BPPV education included more external courses (23/87, 26%) and competency guidelines (13/87, 15%). CONCLUSIONS Good awareness of research evidence was observed in some aspects of BPPV management but many areas require development. Translation and implementation of evidence remains poor and suggests changes in education and knowledge dissemination are warranted.