Automatic detection and display of arrhythmias in long-term ECG tape recordings. SAM-TR-69-7.
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Arrhythmias, Cardiac↗
Biomedical subjects
E J Engelken
Publications and source records attributed to E J Engelken.
Cross-power spectral density analysis of pursuit tracking. Evaluation of central and peripheral pathology.
Twenty-one normal subjects were evaluated for pursuit tracking performance at frequencies of .2, .4, .8, 1.2 and 1.6 Hz. Measures of phase (lead or lag of target), gain (amplitude of response) and spectral purity (distortion of smooth tracking) were obtained by a cross-power spectrum analysis of the stimulus input and the eye movement output. It was determined that normal subjects could quite adequately track a target moving at .4 Hz. After establishing this parameter for normals, 43 patients with central and peripheral pathology related to the vestibulo-oculomotor system were tested at this frequency. Data revealed that not only central lesions but also peripheral labyrinthine impairment could cause a marked decrement in pursuit tracking ability. Also, marked changes in tracking were evident following both central and peripheral surgical procedures.
Adolescent↗
Vestibular responses to bithermal caloric and harmonic acceleration.
Vestibulo-oculomotor responses from 33 patients with either peripheral labyrinthine or central pathology were compared using the standardized Fitzgerald-Hallpike bithermal caloric and harmonic accelerations. In numerous cases (40%), patients with normal caloric responses reflected abnormalities in either their phase relationships or labyrinthine preponderance to sinusoidal acceleration. Results clearly indicate that harmonic acceleration provides additional information to the clinician in the evaluation of vestibulo-oculomotor pathology that is not reflected in the responses to standard caloric tests.
Adult↗
Low-frequency harmonic acceleration as a test of labyrinthine function: basic methods and illustrative cases.
These preliminary findings reveal that low-frequency harmonic acceleration can be used to detect unilateral peripheral deficits that agree with caloric findings. However, the responses to sinusoidal acceleration are less variable than the caloric responses and allow one to more closely evaluate changes in pathology with time. Therefore, it appears that harmonic acceleration provides additional information that is useful in confirming other test results and that a complete otoneurologic evaluation should include this type of rotational testing.
Adult↗