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.

Can activity within the external abdominal oblique be measured using real-time ultrasound imaging?

BACKGROUND: Differences in the function of the anterolateral abdominal muscles have been the subject of much investigation, but primarily using electromyography. Recently changes in thickness of transversus abdominis and internal oblique measured from real-time ultrasound images have been shown to represent activity within these muscles. However it is still unclear if such a change in thickness in external oblique similarly represents activity within that muscle. The purpose of this study was to investigate the relationship between change in thickness and muscle activity in the external oblique using real-time ultrasound and surface electromyography. METHODS: Simultaneous measurements of electromyography and real-time ultrasound images of external oblique were studied in up to 24 subjects during two tasks compared to the muscle at rest (1) isometric trunk rotation and (2) drawing in the lower abdomen. FINDINGS: Changes in muscle thickness correlated significantly with electromyography during isometric trunk rotation in the majority of subjects but with a significant difference between subjects. In contrast, the relationship between change in thickness and electrical activity in the muscle when drawing in the lower abdomen was significant in less than 50% of subjects and the muscle often got thinner. INTERPRETATION: Thickness changes of external oblique can be used as a valid indicator of electromyography activity during isometric trunk rotation, though the relationship is not as good as previously published data for transversus abdominis. Thickness changes of external oblique measured during lower abdominal drawing in cannot be used to detect activity within this muscle.

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.

The relationship between EMG and change in thickness of transversus abdominis.

OBJECTIVE: To investigate the relationship between changes in thickness and EMG activity in the transversus abdominis muscle of healthy subjects and the reliability of ultrasound measurements using different modes and transducers. DESIGN: Convenience sampling. BACKGROUND: Chronic low back pain is associated with transversus abdominis dysfunction but EMG studies of this muscle are restricted to invasive techniques. Since the thickness of transversus abdominis changes with activity, such changes measured from ultrasound images might provide insight into this muscle's function non-invasively. In addition, little is known about the comparability of ultrasound measurements from different modes and transducers, nor the reliability of transversus abdominis measurements. METHODS: In 9 healthy subjects (aged 29-52 years, four male) transversus abdominis was studied at rest and during activity (5-80% max) with simultaneous EMG and ultrasound (M mode, 5 MHz curvilinear transducer) measurements. Intra-rater reliability for thickness measurements was studied on 13 subjects using 7.5 MHz linear and 5 MHz curvilinear transducers in B and M modes. RESULTS: Muscle thickness changes correlated well with EMG activity (P < 0.001, R2 = 0.87) and there were no significant differences between subjects (P > 0.05). Using 7.5 MHz head, the ICC for B mode was 0.989 and for M mode was 0.981 for between days reliability. The ICC for between transducer reliability was 0.817. CONCLUSIONS: Changes in thickness of transversus abdominis can be used to indicate changes in the electrical activity in this muscle. RELEVANCE: Ultrasound scanning can be used in the clinical setting to provide objective information about transversus abdominis function.

The influence of initial resting posture on range of motion of the lumbar spine.

The aim of this study was to investigate the influence of initial resting posture on range of motion of the lumbar spine in 18 normal subjects. Subjects resting posture and active range of motion was measured using the CA-6000 Spinal Motion Analyser (OSI, USA) in five test positions, namely in flat standing and with a variety of heel raises. Analysis showed that there was no significant correlation between subject's normal resting posture and active range of motion. However, when subjects resting posture was artificially altered with heel raises, significant effects on the active range of motion were demonstrated. Increasing heel height significantly influenced resting posture in the sagittal plane only. As heel height increased, the lumbar lordosis decreased and a significant reduction in the range of lumbar spine flexion (P<0.001) was observed. Simulating pelvic asymmetry influenced resting posture in the frontal plane and significant effects on the range of lateral flexion (P<0.05) were observed. These results have important clinical implications in terms of using range of motion of the lumbar spine as an examination tool and suggest that studies using range of motion as an outcome measure should consider initial resting posture.

Abdominal muscle activity during the abdominal hollowing manoeuvre in the four point kneeling and prone positions.

This study investigated the pattern of recruitment of the abdominal muscles during the abdominal hollowing manoeuvre (AHM), in four point kneeling and prone. Muscle activity was detected and recorded by surface electromyography (EMG), in 20 healthy subjects, 8 male and 12 female, aged between 19 and 30 during both maximal activity, and the AHM. The degree of activation during hollowing was expressed as a percentage of maximal. There was activity in the internal abdominal oblique (IO) during all hollowing manoeuvres, in both starting positions, whilst only two subjects showed any activity in rectus abdominis (RA). Simultaneous activity in IO and EO occurred both in four point kneeling (45% of the subjects) and especially in prone (75% of the subjects). Across both positions IO activity was significantly greater than EO. There was no significant difference in EO or IO activity comparing across positions. These results suggest that the AHM when performed in four point kneeling and prone always activates IO and rarely activates RA, whilst elimination of activity in EO is more difficult to achieve, particularly in prone. Isolated activity in the deep abdominal muscles may not always be achievable in these starting positions.

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.