Effect of elastic neck strap on right thumb force and force angle during clarinet performance.
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Adolescent↗
Biomedical subjects
G Kondraske
Publications and source records attributed to G Kondraske.
Spinal range of motion. Accuracy and sources of error with inclinometric measurement.
STUDY DESIGN: A quantitative construct assessing accuracy and component analysis of sources of error rather than reliability coefficients was tested prospectively in human performance measurements of lumbar spine motion using a cohort of healthy individuals. OBJECTIVES: To evaluate the accuracy of lumbar spine sagittal motion measurements using a computerized inclinometer, which involved progressive analysis of sources of error to identify the most problematic sub-components of the measurement process and device. SUMMARY OF BACKGROUND DATA: Many previous studies have described the reliability of inclinometric lumbar motion measurement techniques, but with inconsistent analysis about sources of error to explain identified variability. Similar deficiencies exist in identifying sources of error leading to variability for other human performance measurements (e.g., strength, endurance. lifting capacity, etc.). Yet, range of motion has important clinical applications in monitoring progress and assessing temporary and/or permanent impairment. This makes it especially important for clinicians to be able to recognize and correct factors that limit accurate measurements affecting clinical utility. METHODS: A computerized inclinometer was used for measuring the sagittal lumbar mobility of 38 healthy individuals after bench testing the device itself for device error. The human performance test conditions were: 1) initial test on study participants by untrained test administrators with no control of human performance or procedural variables, 2) identical tests by procedurally trained test administrators controlling human performance variability by monitoring and controlling total motion, and 3) test by procedurally trained test administrators without controlling for human performance variability. RESULTS: The accuracy of the methodology progressively was degraded by the various sources of error. Device error was negligible relative to error associated with the test process itself. Lack of test administrator training and the magnitude of the measured quantity were the major factors in test degradation. Combined (gross) lumbar flexion was the most accurate measure (worst case > 95% accuracy for overall test conditions), whereas pelvic extension was the least accurate (worst case > 36%). CONCLUSIONS: Clinical utility of lumbar spine sagittal motion measurement is highly sensitive to test administrator training to bridge pitfalls to measurement accuracy (bony landmarks, "rocking" of inclinometer on sacrum, etc.). Magnitude of the measurement is another important accuracy factor because absolute error tends to remain relatively constant. Device accuracy is usually an insignificant component of overall test accuracy. Analysis of human performance measurements, such as spinal range of motion, may be facilitated by physics-based assessment of accuracy and procedural error in providing more sophisticated analysis than is customarily accessible through reliability coefficients. Previous studies often failed to recognize correctable procedural errors, rarely addressed them, and almost never quantitated them.
Adult↗
Laryngeal electromyographic activity in adductor and abductor spasmodic dysphonia.
Vocal symptoms in spasmodic dysphonia (SD) range from strain-strangle phonation and glottal-stop phonatory breaks of adductor SD to breathy phonation and aspirate phonatory breaks of abductor SD. Many SD subjects show both symptom types. Heterogeneity in vocal symptoms contributes to controversy surrounding the etiology(s) of SD. Acoustic/perceptual analyses of vocal symptoms are inconclusive in resolving this controversy. This investigation moves the search for distinguishing features of adductor and abductor SD to the level of neuromuscular control and analysis of intrinsic laryngeal muscle (adductor and abductor) activity. Subjects rated perceptually as primarily adductor or abductor SD sustained production of vegetative gestures and isolated speech sounds (/i/ and /s/). Qualitative and quantitative analyses of electromyographic signals recorded from thyroarytenoid (TA) failed to differentiate SD subjects by symptom type. Analysis of TA and posterior cricoarytenoid (PCA) activity in one abductor SD revealed high levels in both muscles during production of the voiced vowel. Data suggest that a possible explanation for symptom heterogeneity in SD is the relation between disrupted neuromotor input to laryngeal muscles and reflexive or conscious compensations constrained by laryngeal biomechanics.
Adult↗
Systems architecture for quantification of dynamic myoelectric and kinematic activity of the human vocal tract.
This paper describes a systems architecture useful for scientific investigations that require the acquisition and analysis of multiple, time-synchronous signals in large volume. The architecture has recently been developed by this group to enhance our capability to research and quantify central nervous system function in the production of normal and pathologic speech. The architecture utilizes modern advances in desktop microcomputers and has been designed so that vocal motor control laboratories (or similar settings) with modest funding can more fully participate in comprehensive investigations of speech production. Research experiments organized with this architecture may involve many more subjects and measures than previously possible without significant increases in time and personnel resources. This paper will demonstrate the technique and practicality of this architecture as it is being used to successfully guide research to map hierarchic central nervous system regions of involvement in two speech disorders: spasmodic dysphonia and stuttering. The architecture has broad usefulness to many areas of otolaryngology and health science.
Adult↗
Lumbar myoelectric spectral analysis for endurance assessment. A comparison of normals with deconditioned patients.
A myoelectric protocol to objectively discriminate between test subjects based on trunk muscular performance differences (endurance) was investigated in a group of 11 healthy volunteers and ten industrial patients undergoing functional restoration for chronic disabling spinal disorders. The subjects performed a standardized exercise protocol, holding their upper torso unsupported for successive fixed-time trials while electromyographic (EMG) signals were recorded from erector spinae. A Fast Fourier Transform allowed calculation of the initial mean power frequency (MPF) for each trial. Isokinetic extensor trunk strength was independently measured at each session for comparison with myoelectric signal analysis. The investigation revealed significant differences in group statistics between patients in early rehabilitation and their subsequent tests, as well as between their initial test and the normal subject scores. However, test sensitivity for identifying patients with "low endurance" is questionable. There was no significant correlation between EMG initial MPF measures and isokinetic extensor trunk strength measures, even though all patients showed isokinetic improvement. Data suggest that the protocol used and myoelectric power spectrum temporal shifts may have some value for identification of individual subjects with endurance limitations (or fatigue resistance) in patients of this type. However, lack of a "gold standard" for comparison presents difficulties in documenting the value and validity with respect to endurance. The test may be of value to measure relative loads.
Adult↗
Quantification of lumbar function. Part 3: Preliminary data on isokinetic torso rotation testing with myoelectric spectral analysis in normal and low-back pain subjects.
A prototype isokinetic torso rotation unit and an EMG signal processing system were utilized to obtain preliminary information on torso rotation. In Study 1, range-of-motion was found to be surprisingly uniform between low-back pain patients and normal subjects, although there was a significant strength variation between them at all isokinetic speeds tested. Both female patients and normal females showed approximately 70%-75% of the strength (torque/body weight) levels relative to their male counterparts. The decrement in trunk strength at high speeds was proportional for both patients and controls and was not nearly as dramatic as the decrement seen in the sagittal plane. In Studies 2 and 3, anatomic relationships evaluated by EMG testing of obliques and erector spinae showed that the contralateral abdominal obliques were the most consistent muscles providing a significant torsional moment to the spine.
Adult↗