Biomedical subjects

L W Organ

Publications and source records attributed to L W Organ.

At least 19 recordsLinked to original sources

PubMed1978

Quantitative indices of short- and long-term heart rate variability.

Two quantitative indices of heart rate variability are proposed. Instantaneous variability is defined as the average of the absolute value of instantaneous rate differences over a 30 second interval. It is sensitive to short-term variability changes. Bandwidth variability is defined as twice the standard deviation of instantaneous heart rates over a 30 second interval, and it is a measure of long-term variability. The rationale for the choice of these indices is discussed, and they are compared with other published indices of variability. Samples of computer printout of instantaneous and bandwidth variability obtained from fetal heart rate records are given.

Electrocardiography↗

PubMed1978

Vestibulothalamic projections in man--a sixth primary sensory pathway.

1. Responses suggesting activation of the vestibular system, elicited by electrical stimulation of the human thalamus during 22 routine stereotaxic neurosurgical procedures, were examined in a retrospective study to determine the possible existence of vestibulothalamo-cortical projections in man. 2. Such responses were most frequently described as sensations of movement through space and were associated with two distinct vestibulothalamic projections: a) an anterior relay was situated ventral to the medial lemniscus, passing lateral to the red nucleus and dorsal to the subthalamic nucleus prior to terminating in the nucleus ventrointermedius (Vim) (comparable to VPLo in primates); b) a posterior relay associated with the auditory pathway (lateral lemniscus and brachium of the inferior colliculus) projected to the medial geniculate body. 3. The production of sensations of motion in conscious patients by stimulating areas that are similar to those reported constituting vestibulothalamic pathways in cats and primates implies a distinct primary sensory cortical projection for processing information from the vestibular receptors pertaining to the recognition of spatial movements.

Brain Mapping↗

PubMed1978

Computerized graphic display of physiological data collected during human stereotactic surgery.

An on-line computerized graphic display has been developed for use during stereotactic operations. This depicts in the form of figurine charts and alph-numeric symbols, appropriately oriented on saggital brain diagrams, the results of serial threshold stimulation of the brain. The display facilitates choice of target sites and the data can be stored in a tape library from which search-and-plot programs can be activated for any type or combination of types of response.

Brain↗

PubMed1977

Percutaneous radiofrequency lumbar rhizolysis (rhizotomy).

Low back pain may arise from degenerative changes in the posterior joints of the lumbar spine. These joints are innervated by a branch of the posterior primary ramus, which follows an anatomically constant course. Pain impulses from these joints can be interrupted by coagulating this nerve with a radiofrequency wave, the probe having been placed in the area of the nerve percutaneously. Percutaneous lumbar rhizolysis was carried out under local anesthesia on an outpatient basis in 82 patients, most of whom had multiple level rhizolysis. Rhizolysis was successful in 67% of patients with mechanical low back pain without evidence of disc herniation and nerve-root compression or psychogenic pain, who had not previously undergone an operation for relief of the pain.

Back Pain↗

PubMed1977

Computerized graphic display of results of subcortical stimulation during stereotactic surgery.

An on-line computer programme is described and illustrated which is capable of displaying graphically in the form of Woolsey-type figurine charts stimulation-induced responses obtained during stereotactic surgery. Not only can these data then be optimally utilized for lesion localization but also the programme includes facilities for a variety of types of analysis of the tape-stored data pooled from all patients studied.

Computers↗

PubMed1976

Measurement of the pre-ejection period during labor with the use of arterial pulse time.

A new fetal parameter, the arterial pulse time, is described. It is the time from the onset of the fetal electrocardiographic recording to the arrival of the arterial pulse wave recorded at the fetal head. Since arterial pulse time differs from the pre-ejection period by only an apparently constant value, it is proposed as a potential method for obtaining the pre-ejection period during labor.

Arteries↗

PubMed1976