Patients' perceptions of the Odstock Dropped Foot Stimulator (ODFS)

OBJECTIVE

To determine the perceived benefit, pattern and problems of use of the Odstock Dropped Foot Stimulator (ODFS) and the users' opinion of the service provided.

DESIGN

Questionnaire sent in a single mailshot to current and past users of the ODFS. Returns were sent anonymously.

SETTING

Outpatient-based clinical service.

SUBJECTS

One hundred and sixty-eight current and 123 past users with diagnoses of stroke (CVA), multiple sclerosis (MS), incomplete spinal cord injury (SCI), traumatic brain injury (TBI) and cerebral palsy (CP).

INTERVENTION

Functional electrical stimulation (FES) to correct dropped foot in subjects with an upper motor neuron lesion, using the ODFS.

MAIN OUTCOME MEASURES

Purpose-designed questionnaire.

RESULTS

Return rate 64% current users (mean duration of use 19.5 months) and 43% past users (mean duration of use 10.7 months). Principal reason cited for using equipment was a reduction in the effort of walking. Principal reasons identified for discontinuing were an improvement in mobility, electrode positioning difficulties and deteriorating mobility. There were some problems with reliability of equipment. Level of service provided was thought to be good.

CONCLUSION

The ODFS was perceived by the users to be of considerable benefit. A comprehensive clinical follow-up service is essential to achieve the maximum continuing benefit from FES-based orthoses.

Long pulse biphasic electrical stimulation of denervated muscle

In recent years a number of studies have employed long pulse biphasic stimulation as a treatment for denervated muscle to improve tissue quality and in some cases to improve contractile capability sufficient to restore function. However, in the U.K., this treatment is yet to be widely adopted clinically. A 5 subject, case based pilot study of long pulse biphasic direct stimulation of peripheral limb denervated muscle is being conducted and its effect on the tissue evaluated by measurement of muscle bulk, limb blood flow, and skin temperature. In cases of partial denervation. trapezoidal shaped pulses are used to minimize sensory and motor nerve fiber recruitment.

Selecting candidates for a lower limb stimulator implant programme: a patient-centred method

OBJECTIVE

To develop an effective selection procedure for lower limb functional neurostimulation (LLFNS) for standing in paraplegia.

DESIGN

The selection procedure and exclusion criteria were based on the previous experience for two clinical centres with experience of LLFNS.

SETTING

Two Regional Spinal Injuries units in southern England.

SUBJECTS

254 fully rehabilitated paraplegics living in the community.

INTERVENTION

Patients were invited to participate in the programme, and if suitable to subject themselves to a rigorous staged selection procedure from which they could withdraw at any time.

OUTCOME MEASURE

Functionally successful home standing using closed-loop surface electrical stimulation.

RESULTS

57/254 patients were suitable on paper and were accessible. 19 of these (CI = 10-28) were interested in the project and attended one of the spinal centres for details. Twelve (CI = 5-19) of these fulfilled the selection criteria and started on the training programme; and 10 of them completed the muscle training programme successfully. Seven patients (CI = 2-12) achieved closed-loop standing in the laboratory and four patients (CI = 1-8) did so at home.

A fluorescence double-quenching study of native lipoproteins in an animal model of manganese deficiency

Iodide and acrylamide were applied simultaneously in a double-quenching experiment to compare acrylamide quenching constants for internal and external fluorophores of high-density lipoproteins (HDL1 and HDL2) from manganese-adequate (MnA) and deficient (MnD) rats, free of the electrostatic effects associated with iodide. In MnA HDL1 compared to MnD HDL1, the acrylamide quenching constant for external fluorophores was different (P < 0.1). In MnA HDL2, there were two populations of fluorophores accessible to acrylamide, whereas in MnD HDL2, all fluorophores were accessible to both quenchers. We concluded that there were structural (local environmental) differences, possibly charge-related, around the external fluorophores, and a slightly larger population of buried fluorophores in the MnD HDL1 compared with MnA HDL1. In MnA HDL2, one-third of the fluorophores were accessible to iodide, and all external and internal fluorophores were accessible to acrylamide, whereas in MnD HDL2, all fluorophores were accessible to both quenchers.

The effects of common peroneal stimulation on the effort and speed of walking: a randomized controlled trial with chronic hemiplegic patients

OBJECTIVE

To measure the effect of the Odstock Dropped Foot Stimulator (ODFS), a common peroneal stimulator, on the effort and speed of walking.

DESIGN

A randomized controlled trial.

SUBJECTS

Hemiplegic patients who had suffered a single stroke at least six months prior to the start of the trial whose walking was impaired by a drop-foot.

INTERVENTIONS

The treatment, functional electrical stimulation (FES) group, used the stimulator and received a course of physiotherapy; the control group received physiotherapy alone.

MAIN OUTCOME MEASURES

Changes in walking speed measured over 10 m and the effort of walking measured by physiological cost index (PCI).

RESULTS

Thirty-two subjects completed the trial, 16 in the FES group and 16 in the control group. Mean increase in walking speed between the beginning and end of the trial was 20.5% in the FES group (when the stimulator was used), and 5.2% in the control group. Improvement was also measured in PCI with a reduction of 24.9% in the FES group (when the stimulator was used) and 1% in the control group. No improvement in these parameters was measured in the FES group when the stimulator was not used.

CONCLUSION

Walking was statistically significantly improved when the ODFS was worn but no 'carry-over' was measured. Physiotherapy alone, in this group of subjects with established stroke, did not improve walking.

Lumbar root stimulation for restoring leg function: results in paraplegia

We have implanted an intradural array of 12 tripolar electrodes on the anterior roots L2-S2, left and right, at cauda equina level, in a 33-year-old woman with a complete T9 cord lesion of 3 years' duration. They are driven by an implanted multiplexed stimulator system using radio frequency (RF) power and control signals. All channels generate movements, in patterns that might be predicted from the known anatomy of the cauda equina. In particular, stimulation of L2 and L3 gives hip adduction; L3, L4, and L5 gives quadriceps femoris movements; L5, S1, and S2 gives hamstrings movement; and S1 and S2 give plantar flexion. Stimulation of L5 gives mixed movements at the ankle. Surprisingly, stimulation of the L2 roots has not given strong hip flexion. Responses have been stable. Some thresholds have varied, probably as a result of tissue encapsulation. The moment generated within each degree of freedom of the legs has been measured for each root, using a specially designed multimoment measurement apparatus. For several roots, a movement of lower threshold may be accompanied by a second movement of higher electrical threshold, suggesting that different muscles may have fiber populations that differ in their diameter or their location in the root. The use of stimulus forms that enable selective anodal block may, in the future, enable separation of two distinct movements from a single motor root.

Correlation of ATP/citrate lyase activity with lipid accumulation in developing seeds of Brassica napus L

The temporal distribution of ATP/citrate lyase (ACL) activity in developing seeds of Brassica napus L. closely paralleled both that of acetyl-CoA carboxylase and the overall rate of lipid biosynthesis. Maximum ACL activities (250 nmol acetyl-CoA formed min-1.g fresh seed) were recorded between 35 to 42 d after pollination and, if the in vitro data could be extrapolated to the situation in vivo, could account for half of the acetyl-CoA required for the measured rate of fatty acid biosynthesis during seed development. The enzyme appeared to be localized in a subcellular compartment, which was clearly separated from mitochondria on a sucrose gradient and by differential centrifugation, and which corresponded to the chloroplast organelle.

Between-site comparison of freshwater bacterioplankton by DNA hybridization

Natural assemblages of freshwater bacterioplankton in enriched lowland rivers had greater cell-specific metabolic activity than those in gravel-pit ponds. Similarly, cell-specific activity and mean cell Size in calcareous headstreams tended to be greater than in intermittently-acid headstreams on millstone grit. DNA was extracted and purified from bacterioplankton assemblages, and between-site comparisons were made in terms of percentage similarity as indicated by DNA hybridization. Cluster analysis, using percentage-similarity matrices, placed bacterioplankton assemblages from different site types into distinct groups. This suggested that between-site physiological differences were related to intrinsically different bacterial composition rather than to different physiological response to different environmental conditions by essentially similar bacterial assemblages.

Limb blood flow, cardiac output and quadriceps muscle bulk following spinal cord injury and the effect of training for the Odstock functional electrical stimulation standing system

As part of the assessment of the Odstock functional electrical stimulation (FES) standing system for mid to low thoracic lesion spinal cord injured (SCI) subjects, cardiac output, high blood flow and quadriceps muscle thickness were measured before and following an electrical stimulation muscle retraining programme. The same parameters were also measured in a group of uninjured subjects and in SCI subjects. It was found that there was no difference in cardiac output between the groups. However thigh blood flow was found to be around 65% of normal values in the spinally injured group. This returned to normal values following the retraining programme. The quadriceps muscle wasted to approximately 50% of its original thickness in the first 3 weeks following spinal cord injury. The retraining programme increased the muscle thickness to near normal values.

Characterisation of saporin genes: in vitro expression and ribosome inactivation

A. Saponaria (soapwort) genomic library was screened with a PCR-derived saporin-specific gene probe. The nucleotide sequences of three saporin genomic clones were determined. One of the clones contained a full-length saporin coding sequence whilst the other two were truncated. A hybrid full-length saporin coding sequence was constructed using the two truncated clones. An SP6 promoter sequence and in-frame initiation codon was added to each of the coding sequences using PCR. In vitro translation of saporin coding sequence transcripts in rabbit reticulocyte lysates resulted in the specific depurination of 28S RNA. This indicated that the saporin sequences encoded functional polypeptides with RNA N-glycosidase activity.

Use of air in double contrast barium enema--is it still acceptable?

There is conflicting evidence regarding the benefit of using carbon dioxide in a double contrast barium enema. In a double blind prospective study, 200 patients undergoing out-patient double contrast barium enemas (DCBE) were randomly allocated to receive either air or carbon dioxide (CO2) insufflation. After 24 h they were requested to complete and return a questionnaire regarding abdominal pain and distension experienced following the examination. The use of CO2 reduced the incidence of severe post-DCBE pain from 27% to 7%. There was a higher incidence of severe pain in younger patients, regardless of which gas was used. The incidence of severe pain following DCBE was unrelated to the presence or absence of abdominal pain as part of the patient's symptomatology. In the light of these findings we advocate the routine use of CO2 in DCBE.

Practical low cost stand/sit system for mid-thoracic paraplegics

The use of functional electrical stimulation (FES) to enable paraplegics to stand is not new or indeed difficult to undertake under laboratory conditions. However, there are substantial problems to overcome before such systems can be used routinely by patients without professional supervision. The overriding consideration has to be one of safety, i.e. the system must be 'fail safe'. Secondly, the system must be quick and easy to use in a wide variety of locations, otherwise it will not provide any increase in function. Finally, it must be inexpensive enough to be available to a large number of paraplegics. The primary aim of our work was to provide such a system to enable mid-thoracic lesion paraplegics to stand wherever they wish. This involved the development of a microprocessor-based stimulator to enable the stimulating envelope to be individually tailored to a given patient's requirements and the provision of closed loop control to minimize fatigue. A folding standing frame was also designed which replaces the arm rests on a standard wheelchair. Using this system, the user is able to stand within 30 s of stopping and can remain standing for up to 10 min. Cosmetic calipers (knee-ankle-foot orthoses) are also being used for paraplegics who require to stand for longer periods. It is hoped that such a system will provide stable standing for a large number of paraplegics at a unit cost of approximately 750 pound.