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Results for “Electrodes, Implanted”

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At least 73 records · Page 4Linked to original sources
PubMed1990

Easily-implantable electrodes for chronic recording of electromyogram activity in small fetuses.

A method is described for the construction of simple, robust electrodes suitable for obtaining long-term chronic recordings of electromyogram activity from delicate muscles of small experimental animals. The electrodes are equipped with small, gold-plated barbed tips which have the form of harpoons that may be pushed directly into a muscle, where they remain without being sutured into place. These features greatly facilitate the instrumentation of muscles which are very thin or of limited accessibility. The electrodes have been used successfully to obtain chronic recordings of respiratory muscle activity from early gestation fetal lambs in utero.

Animals↗
PubMed2000

Feasibility of gait training for acute stroke patients using FNS with implanted electrodes.

Following stroke, many patients do not regain a normal, safe gait pattern even after receiving conventional physical therapy. One promising technique is functional neuromuscular stimulation (FNS) with intramuscular (IM) electrodes (FNS-IM). Five subjects were admitted into the study at 3 weeks to 3 months following the stroke. For each subject, electrodes were placed intramuscularly at the motor point of up to seven lower extremity paretic muscles. Subjects were treated for 6 months, twice weekly with FNS-IM for exercise and gait training. The stimulator and software provided individualized stimulation patterns, with flexible stimulus parameters and activation timings of multiple muscles. Outcome measures were active joint movement, coordination (Fugl-Meyer scale), balance (Tinetti scale), gait (Tinetti scale), activities of daily living (functional independence measure), and therapist and subject satisfaction (survey instrument). Subjects tolerated well the placement of IM electrodes with no adverse effects, and subjects lost no conventional rehabilitation time. Therapists and subjects were satisfied with the FNS-IM system as a rehabilitation tool. Post treatment, subjects demonstrated improvements in impairment and disability in active joint movement, coordination, balance, gait and activities of daily living. Considered together with prior research for chronic stroke subjects, this research suggests that FNS-IM can be successfully and efficaciously utilized for gait training for those with acute stroke.

Acute Disease↗
PubMed2002

Pallidal activity recorded in patients with implanted electrodes predictively correlates with eventual performance in a timing task.

Here we seek to establish whether there are activities in the human pallidum that may predict a specific aspect of performance, timing. When recording from two patients with Parkinson's disease and primary generalised dystonia following functional neurosurgery we found that the amplitude of oscillatory pallidal activity occurring prior to the completion of a bimanual timing task was strongly correlated with eventual task duration. The frequency of this oscillatory activity was around 25 Hz. We conclude that the human pallidum may be involved in the prediction of movement timings and that such internal estimates may be reflected in amplitude modulation of oscillatory activity around 25 Hz.

Beta Rhythm↗
PubMed1983

Clinical evaluation of a single-pass implantable electrode for all modes of pacing. The "Crown of Thorns" lead.

Physiological pacing was instituted in 17 patients (11 men and 6 women), mean age 67 years (range 33-77 years), using a variety of multiprogramable generators attached to a permanent single-pass dual chamber electrode. Eleven patients were paced in VAT mode (Cordis 208A or Siemens-Elema 625 generator), two patients in DVI mode (Intermedics Cyberlith IV generator) and four patients in DDD mode (Siemens-Elema 664/P33 or Telectronics Autima unit). Mean intracardiac P wave amplitude was 2.0 mV +/- 0.78/SD, range 0.7-3.6 mV. and mean atrial and ventricular pacing thresholds were 1.0 V and 0.5 V, respectively. Fourteen patients had completely successful A-V pacing during a follow-up period of 4-13 months (mean 7 +/- 2.7 months). Two failures were associated with malposition of the atrial crown and occurred exclusively with the Cordis 208A generator. In both patients generator replacement using a more sensitive unit (Siemens-Elema 625) resulted in successful VAT pacing for most of the time. Complete failure of A-V pacing occurred in only one patient who died from coronary artery disease after four months of follow-up. Thus, all of the remaining 16 patients achieved long-term (6 months) satisfactory physiological pacing using this new lead. We conclude that the "Crown of Thorns" electrode is a successful single-pass unipolar lead and can be used with all types of dual chamber generator for all modes of pacing.

Adult↗
PubMedDate not supplied

Hyperthermia with implanted electrodes.

A general solution is given for the steady state form of the heat conduction equation applied to a simple tumor model which is imagined as being heated by means of electrical currents flowing between metallic electrodes. The model assumes a homogeneous tumor with no bloodflow. The solution for the special case of constant temperature and potential at the surface of the heated volume is examined in detail. The solution shows that there exists, independent of the particular tumor and electrode geometry, a close relationship between the steady state temperature distribution and the electrical potential. Among the more important implications of this relationship are that equipotential surfaces within the heated volume are also isothermal surfaces and that no areas of excessive heat at or near any sharp edges or corners of the electrodes should develop, despite the high electric field intensity. Based on the theory, a procedure is outlined which might greatly facilitate the determination of temperature distributions in phantoms. Finally, the usefulness and the limitations of the theoretical models in clinical hyperthermia are discussed.

Electric Conductivity↗
PubMed1963

Implanted electrodes: cable coupler for elimination of movement artifact.

The wires in the recording cable are connected to stainless-steel tubes supported by a ball bearing. The tips of the tubes rotate freely in mercury-filled grooves connected to the recorder through stainless-steel screws. No attenuation or distortion of the signal appears on records obtained through the coupler.

Artifacts↗
PubMed1981

[Effects of afloqualone, a centrally acting muscle relaxant, on the sleep-wakefulness cycle in cats with chronically implanted electrodes (author's transl)].

The present study was carried out to elucidate whether or whether not afloqualone has a hypnotic action because of its similarity in chemical structure to methaqualone. In the sleep-wakefulness cycles during the 8-hour observation period (9:00-17:00), afloqualone increased the percentages of resting (REST) and slow wave light sleep (SWLS) stages at a dose of 25 mg/kg (p.o.), producing a moderate muscle relaxation. Even at a dose of 50 mg/kg (p.o.) where a marked muscle relaxation was produced, afloqualone had no influence on the percentage of slow wave deep sleep (SWDS) stage, though it increased the percentages of SWLS and decreased the percentages of awake (AWK), REST and fast wave sleep (FWS) stages. On the other hand, tolperisone . HCl, chlormezanone, methaqualone and pentobarbital . Na, used as the reference drugs, all increased the percentage of SWDS stage, but either decreased or had no effect on the percentages of the other four stages at pharmacologically effective doses. From these results it was concluded that afloqualone seems to be devoid of a hypnotic action and has different effects on the sleep-wakefulness cycle than those of both the hypnotics and the other muscle relaxants used.

Animals↗