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Biomedical subjects

T Sihvonen

Publications and source records attributed to T Sihvonen.

24 records · Page 2Linked to original sources
PubMed1987

Timing of the triggering action of shooting in relation to the cardiac cycle.

The purpose of this study was to verify the timing of triggering in relation to the cardiac cycle in shooting. The test subjects were six Finnish rifle and pistol champions as well as three beginners at shooting. The electrical activity of the trigger finger muscle (m. flexor digitorum superficialis; surface electrodes) and the heart cycle were fed into a two-channel x-t recorder. The movements of the gun were recorded using a laser technique and, at the same time, cardiac cycles were also monitored. Results showed that the champion shooters triggered during diastole whereas the beginners triggered both during diastole and systole. The results of those beginners triggering during diastole were better than those triggering during systole.

Adult↗
PubMedDate not supplied

Vector quantization as a method for integer EMG signal compression.

Vector quantization (VQ) is a well-known lossy compression method, which has not often been applied to biosignals. In this paper, VQ and its mean residual variant for encoding and decoding electromyography (EMG) signals have been tested. The methods are selected in such a way that they can be later applied in a low-resource embedded system. A neural network approach is used for codebook generation. The preservation of medical parameters is a prominent sign of quality in medical compression systems. Both signal level fidelity factors and preserving medical parameters are tested. The results show that mean residual vector quantization with short segments is a workable approach for EMG signal compression.

Algorithms↗
PubMedDate not supplied

Real-time evaluation of anaerobic threshold with rms-EMG of working and nonworking muscles during incremental bicycle ergometer test.

Surface rms-EMG measurement as a real time monitoring method for detecting the anaerobic threshold during a bicycle ergometer test was evaluated and compared with blood lactate and ventilatory parameters. The study group consisted of 12 healthy ice hockey players. The anaerobic threshold indicated as dislinearity of increase in blood lactate level, ventilatory parameters and myoelectrical activity was observed at the work level of 300 (range 270-330) W in each case. The linearity disappeared at same time in the rms-EMG-load ratio both in working (quadriceps and gastrocnemius) and nonworking (frontalis) muscles. The rms-EMG follow-up was easier to perform than measurements of blood lactate and ventilatory parameters.

Adult↗
PubMedDate not supplied

The segmental dorsal ramus neuropathy as a common cause of chronic and recurrent low back pain.

The causes of recurrent and chronic low back pain usually remain unknown. The dorsal ramus lesion was found in 57 of 200 low back pain patients in this study in L5 or L4 segment without any neurophysiologic or neuroradiologic evidence of proximal ventral root compression. The neuropathy of dorsal rami, especially in their medial branches seems to be surprisingly common finding associated with low back pain and referred symptoms.

Adolescent↗
PubMedDate not supplied

Segmental hypermobility in lumbar spine and entrapment of dorsal rami.

Low back pain patients (N = 18) having segmental hypermobility in one lumbar segment and healthy controls (N = 13) were chosen for this study. Patients had no other structural spinal pathology except displacement of one vertebra to another in lateral X-ray bending pictures. Kinetic intramuscular EMG-activity from paraspinal muscles was studied off-line during back flexion and reextension. Routine needle EMG study of paraspinal muscles was also performed in addition to measurements of the tibial nerve H-reflexes and peroneal F-responses. Results showed that the number of MUAPs in erector spinae muscle on voluntary efforts was rarefied at hypermobile levels, and spontaneous activity, positive sharp waves and high frequency discharges were found in more than half of the patients in paraspinal muscles, usually at hypermobile levels only. No signs of proximal nerve root compression were found. This indicates neuropathy of dorsal rami at the instable level.

Adult↗