Surgeon workload and motion efficiency with robot and human laparoscopic camera control.

BACKGROUND: Surgeons are now being assisted by robotic systems in a wide range of laparoscopic procedures. Some reports have suggested that robot-assisted camera control (RACC) may be superior to a human driver in terms of quality of view and directional precision, as well as long-term cost savings. Therefore, we setout to investigate the impact of RACC of surgeon motion efficiency. METHODS: Twenty pigs were randomized to undergo a standardized laparoscopic Nissen fundoplication with either a human or RACC system, the AESOP 2000. All procedures were performed by the same surgical fellow. Time was recorded for dissection and suture phases. Inertial motion sensors were used to monitor both the surgeon's hands and the camera. Digitized data were analyzed to produce summary measures related to overall motion. RESULTS: The operative times were slightly longer with RACC (mean 80.2 +/- 20.6 vs 73.1 +/- 15.4 min, not significant). With regard to operative times and surgeon motion measures, the only statistically significant differences were for setup and breakdown times, which contributed <15% to the total time for the procedure. CONCLUSION: In terms of impact on surgeon motion efficiency and operative time under normal surgical conditions, RACC is essentially the same as an expert human driver. However, careful planning and structuring of the surgical suite may yield some small gains in operative time.

Olanzapine: interaction study with imipramine.

Olanzapine is an "atypical" antipsychotic agent with a high affinity for serotonin 5HT2A/C, 5HT3, 5HT6, and dopamine D1, D2, D3, D4 receptors. Depressed patients with psychotic disorders frequently require treatment with concomitant antipsychotic and antidepressant medications. Imipramine pharmacokinetics serve as a marker for hepatic CYP2D6, CYP1A2, CYP3A activity. An open-label, three-way randomized crossover study was done to determine the safety, pharmacokinetics, and potential for a drug interaction between olanzapine (5 mg) and imipramine (75 mg). Each drug was administered alone and in combination. Nine healthy men, ages 32 to 54 years, enrolled in the study. Psychomotor performance capacities, plasma olanzapine, imipramine, desipramine concentrations, and clinical laboratory tests were measured. Pharmacokinetic variables, vital signs, subjective tests for liveliness, and psychomotor outcomes were analyzed using a two-way ANOVA. Olanzapine was safe. Sedation, postural hypotension, and minor vital sign alterations occurred during all treatments. On the liveliness questionnaire, patients generally reported poorer (less lively) scores with olanzapine alone or coadministered with imipramine versus baseline scores. These effects disappeared within 24 hours after administration. Olanzapine alone and in combination decreased motor-speed tasks (finger tapping and visual-arm random reach) compared with baseline or imipramine treatment. Peak 6-hour changes were statistically significant but clinical importance was only marginal. Olanzapine concentrations were < 19% greater than with imipramine. But olanzapine did not affect the kinetics of imipramine or desipramine and, therefore, did not show a metabolic drug interaction involving CYP2D6.

An elemental resource for the human-task interface.

The elemental resource model (ERM) attempts to provide a quantitative and straightforward framework for characterizing the human system, tasks, and their interface. It evolved in large part from the general systems performance theory (GSPT), which was developed first and independently. Resource constructs are used exclusively for modeling the abstract idea of system performance and for subsequent measurement of performance resource capacities. Resource economic principles provide a cause-and-effect description of the human-task interface. While argued to have immediate utility, it also provides the motivation to consider coordinated, collaborative, long-term developments that could facilitate effective decision making and technology utilization in rehabilitation.

Multichannel electromyographic observations in spasmodic dysphonia patients and normal control subjects.

Spasmodic dysphonia is primarily a disorder of vocalization. Increasing evidence, however, suggests that individuals with this disorder comprise a heterogeneous population characterized by abnormal motor control throughout the vocal tract. Multichannel simultaneous electromyography was performed on 11 spasmodic dysphonia patients and 10 normal awake subjects to investigate both the distribution of neuromotor abnormality within the vocal tract (eg, intrinsic and extrinsic laryngeal muscles, tongue, and palate) and the contribution of activation of higher central nervous system centers to observed abnormality. Experimental tasks ranged from vegetative (quiet breathing) to simple linguistic (short sentences). Digitized electromyographic signals were analyzed to compute the amplitude envelope and extract a set of parameters that represent amplitude characteristics. Electrode insertions were cross-validated by quantitative analysis of patterns of activation across selected reference tasks and by traditional qualitative methods. Between-group differences were found for measures of normalized median and peak token amplitudes. These differences are both task- and measure-dependent. Results highlight the complex and interactive effects of muscle, task, and quantitative measures on between-group differences.

Laryngeal reaction time profiles in spasmodic dysphonia: relationship to cortical electrophysiologic abnormality.

This study combines measures of linguistic and vocal performance and long-latency auditory electrophysiology to investigate task-dependent variability in spasmodic dysphonia (SD). Linguistic performance was evaluated using several measures of relatively complex linguistic ability (i.e., discourse analysis). Vocal performance was evaluated by measuring acoustic laryngeal reaction time (LRT) for tasks that differ in complexity. Normal structure of the cortex and subcortex was confirmed by magnetic resonance imaging. Cortical function was measured using multichannel quantitative auditory evoked potentials (AEPs). As a group, SD subjects who demonstrated subtle linguistic deficits also demonstrated prolonged LRT for the complex task and repeated and persistent auditory electrophysiologic abnormalities over the anterior quadrant of the left hemisphere. As a group, linguistically normal SD subjects demonstrated no significant increase in LRT for the complex task and no recurrent electrophysiologic abnormalities over the left anterior cortex relative to normal controls. Results support a neurogenic origin of SD and suggest that some aspects of inter- and intrasubject variability may be related to differences in loci and magnitude of cortical abnormalities.

Heterogeneity in spasmodic dysphonia. Neurologic and voice findings.

Spasmodic dysphonia is a disturbance of phonation with laryngeal spasms. We report voice and neurologic examination findings in 45 subjects. Neurologic abnormalities were found in 32 subjects (71.1%). Rapid alternating movement abnormalities, weakness, and tremor were common. Incoordination and spasticity were rare. Lower extremity findings were frequent. Abnormalities were bilateral. Spasmodic dysphonia severity was related to age. Type, severity, and duration of vocal symptoms were not different for subjects with or without neurologic abnormalities. Vocal tremor was more frequent in neurologically abnormal subjects. Involvement of a pallidothalamic-supplementary motor area system could account for neurologic findings, brain imaging findings, and clinical heterogeneity. The view emerging is that spasmodic dysphonia is a manifestation of disordered motor control involving systems of neurons rather than single anatomical sites.

Evidence for cortical dysfunction in spasmodic dysphonia: regional cerebral blood flow and quantitative electrophysiology.

Cortical function was evaluated in 26 subjects with spasmodic dysphonia. Quantitative topographic electrophysiologic mapping (QTE) was employed to provide quantitative analyses of EEG spectra and auditory and visual long-latency evoked potentials. Single-photon emission computed tomography (SPECT) of the cerebral transit of Xenon-133 was used to evaluate regional cerebral blood flow. Left hemispheric abnormalities in cortical function were found by both techniques in 10 subjects and by at least one technique in 18 subjects. Right hemispheric abnormalities were observed by both techniques in 8 subjects and by at least one technique in 18 subjects. Most patients with cortical dysfunction in one hemisphere had cortical dysfunction in the other, while only 4 subjects had unilateral lesions as found by one of the two techniques. Eight subjects were normal by all measurements. Underlying structural abnormalities were detected by magnetic resonance imaging in 5/24 subjects. However, functional abnormalities (SPECT or QTE) were not observed at sites of structural abnormalities. SPECT and QTE were significantly related in identification of left hemispheric dysfunction (p = .037) with a trend in the right hemisphere (p = .070), and a significant congruence of SPECT and QTE findings occurred in the left anterior cortical quadrant (p = .011). These findings indicate that dysfunction of cortical perfusion and/or cortical electrophysiology is associated with spasmodic dysphonia in the majority of subjects studied.

Rapid manual abilities in spasmodic dysphonic and normal female subjects.

This study quantitatively examined upper extremity motor performance in 18 spasmodic dysphonic females, in comparison to matched normal controls, across variables of finger lift reaction time, index finger tapping speed, and peg placing (Purdue Pegboard) speed. Significant differences were noted for both upper extremities on the finger tapping and pegboard tasks, with better performance by the controls. A linear combination of these manual variables was able to discriminate the spasmodic dysphonic from matched normal subjects with 78% accuracy. Motor performance was uncorrelated with psychometric measures of anxiety and depression in both groups. The dysphonic subjects exhibited a significant correlation between nondominant finger tapping speed and severity ratings of motor speech impairment. Possible localizing significance of these findings is discussed.

Evaluation of quantitative measures of upper extremity speed and coordination in healthy persons and in three patient populations.

Upper extremity tracking tests have been used extensively in clinical studies in patients with neurologic disorders. We evaluated several new measures of upper extremity performance derived from step-response and phase-plane analysis techniques; both techniques are founded in automatic control theory. Using a computer-based tracking test, a visual step function stimulus was applied in 15 healthy subjects and 45 patients from multiple sclerosis, myasthenia gravis, and Parkinson disease populations. The upper extremity response of the subject was analyzed to find the reliability and discriminating power measures that quantify speed, coordination, and steadiness of the upper extremity response during the tracking task. Results show that reliability of the measures, although variable across the populations tested, is generally high (greater than 0.7). The speed and coordination measures derived from phase-plane analysis are more discriminating than the measures of step-response analysis for the populations tested. Some of the measures may be useful for monitoring patient performance, the other measures can be potentially helpful in diagnosis of the disorders.

Performance characterization of human pitch control system: an acoustic approach.

The performance of the human pitch control system was characterized by measurement of the speed of pitch shift and pitch shift response speed (inverse of reaction time) at various initial pitch and loudness levels. Data from three nonsinger adult male subjects and one professional singer suggest a strong inverse correlation (r greater than 0.78) between initial pitch and rate of pitch rise. This study showed no significant relation between initial loudness and rate of pitch rise. Also, vocal response speed showed no significant relation with either initial pitch or loudness. However, it is suggested that pitch shift response speed might be related to the second formant frequency of the target vowel. A composite index of pitch control performance capacity was defined as the product of response speed and vocal fold contractile velocity. From experimental data, the composite index was able to reflect a distinct 74% superior performance by the professional singer (relative to the average maximum performance capacity of nonsingers). It is suggested that the product-based composite index of performance capacity can serve as a sensitive means for vocal proficiency determination.

Rehabilitation engineering: towards a systematic process.

Two parts of the rehabilitation engineering process, client assessment and task analysis, are examined, and an approach to further delineate and systematize these components is described. The tasks of the rehabilitation engineer are taken to be the selection of appropriate available assistive devices and the design of new devices that will enable a handicapped client to accomplish a life task for which he or she would otherwise by physically disabled. Generalizable concepts and speculations on new tools that are perceived to be needed to help rehabilitation engineers do their job are emphasized. Human performance concepts are used as a basis for analyzing processes. Analogies from traditional engineering design and practice are used for insight.

Computerized system for quantitative measurement of sensorimotor aspects of human performance.

The purpose of this article is to describe an integrated system for measuring selected aspects of human sensorimotor performance. The system consists of a computerized test battery, a database, and multiple software packages to present results for different applications. The system includes measures classified into major functional categories including sensation, range of motion, isometric muscle strength, anthropometric features, speed, reactions, muscle tone, coordination, body stability, and manual dexterity. A microcomputer is used to coordinate basic measurements obtained from a series of short-duration tests. Raw data are recorded in physical units (eg, degrees, milliseconds). A database currently consisting of over 2,000 data records of normal sensorimotor performance has been collected, permitting immediate comparison of patient data to a group of age- and sex-matched norms. This system permits an objective, reliable, and standardized method for measuring selected aspects of sensorimotor performance essential for physical therapists to quantify individual patient performance, document disability, justify reimbursement, screen employees and athletes, and demonstrate efficacy of treatment.

Myoelectric spectral analysis and strategies for quantifying trunk muscular fatigue.

Objective techniques for assessing trunk musculature with respect to fatigue-related characteristics do not exist. Based on work that relates frequency spectral shift in myoelectric signals to muscular fatigue at other body sites, a study was carried out to investigate and evaluate strategies for application of these techniques to the lumbar musculature. Through evolution of test administration procedures to reduce test time and discomfort as well as data interpretation methods to account for interindividual variability observed in data, an approach was developed for objective measurement of fatigue rate. While abdominal and lumbar muscle groups were assessed in 40 healthy subjects with results presented for 50% and 100% maximum voluntary contraction load levels, the methodology is discussed with emphasis on erector spinae results. The approach involves a normal function fatigue plot. The plot relates fatigue rate as measured by myoelectric spectral characteristics to muscle load normalized by body weight and is independent of the maximum voluntary contraction concept. This relationship forms the basis of comparison of the measured fatigue rate for a subject with questionable function to expected normal values determined from the plot, given the measured load level.

Classification of resistance to passive motion using minimum probability of error criterion.

Neurologists diagnose many muscular and nerve disorders by classifying the resistance to passive motion of patients' limbs. Over the past several years, a computer-based instrument has been developed for automated measurement and parameterization of this resistance. In the device, a voluntarily relaxed lower extremity is moved at constant velocity by a motorized driver. The torque exerted on the extremity by the machine is sampled, along with the angle of the extremity. In this paper a computerized technique is described for classifying a patient's condition as 'Normal' or 'Parkinson disease' (rigidity), from the torque versus angle curve for the knee joint. A Legendre polynomial, fit to the curve, is used to calculate a set of eight normally distributed features of the curve. The minimum probability of error approach is used to classify the curve as being from a normal or Parkinson disease patient. Data collected from 44 different subjects was processes and the results were compared with an independent physician's subjective assessment of rigidity. There is agreement in better than 95% of the cases, when all of the features are used.