Measurement of acceleration: a new method of monitoring neuromuscular function

A new method for monitoring neuromuscular function based on measurement of acceleration is presented. The rationale behind the method is Newton's second law, stating that the acceleration is directly proportional to the force. For measurement of acceleration, a piezo-electric ceramic wafer was used. When this piezo electrode was fixed to the thumb, an electrical signal proportional to the acceleration was produced whenever the thumb moved in response to nerve stimulation. The electrical signal was registered and analysed in a Myograph 2000 neuromuscular transmission monitor. In 35 patients anaesthetized with halothane, train-of-four ratios measured with the accelerometer (ACT-TOF) were compared with simultaneous mechanical train-of-four ratios (FDT-TOF). Control ACT-TOF ratios were significantly higher than control FDT-TOF ratios: 116 +/- 12 and 98 +/- 4 (mean +/- s.d.), respectively. In five patients not given any relaxant during the anaesthetic procedure (20-60 min), both responses were remarkably constant. In 30 patients given vecuronium, a close linear relationship was found during recovery between ACT-TOF and FDT-TOF ratios. It is concluded that the method fulfils the basic requirements for a simple and reliable clinical monitoring tool.     

Grundlagen des akuten Schmerzes: Voraussagbarkeit und Quantifizierung

Ohne Zusammenfassung     

Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Process, format, and clinimetric testing plan.

This article presents the revision process, major innovations, and clinimetric testing program for the Movement Disorder Society (MDS)-sponsored revision of the Unified Parkinson's Disease Rating Scale (UPDRS), known as the MDS-UPDRS. The UPDRS is the most widely used scale for the clinical study of Parkinson's disease (PD). The MDS previously organized a critique of the UPDRS, which cited many strengths, but recommended revision of the scale to accommodate new advances and to resolve problematic areas. An MDS-UPDRS committee prepared the revision using the recommendations of the published critique of the scale. Subcommittees developed new material that was reviewed by the entire committee. A 1-day face-to-face committee meeting was organized to resolve areas of debate and to arrive at a working draft ready for clinimetric testing. The MDS-UPDRS retains the UPDRS structure of four parts with a total summed score, but the parts have been modified to provide a section that integrates nonmotor elements of PD: I, Nonmotor Experiences of Daily Living; II, Motor Experiences of Daily Living; III, Motor Examination; and IV, Motor Complications. All items have five response options with uniform anchors of 0 = normal, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe. Several questions in Part I and all of Part II are written as a patient/caregiver questionnaire, so that the total rater time should remain approximately 30 minutes. Detailed instructions for testing and data acquisition accompany the MDS-UPDRS in order to increase uniform usage. Multiple language editions are planned. A three-part clinimetric program will provide testing of reliability, validity, and responsiveness to interventions. Although the MDS-UPDRS will not be published until it has successfully passed clinimetric testing, explanation of the process, key changes, and clinimetric programs allow clinicians and researchers to understand and participate in the revision process.     

Kardiovaskuläre Bildgebung

Ohne Zusammenfassung     

The effect of observation time and contrast on visual acuity

Background: Field studies of the duration of fixation during daytime driving find that it is about 0.2 seconds on average. Thus, the time available to read traffic signs is often limited. There are other circumstances where time to read alphanumeric messages is limited. Data relating time of observation are needed for purposes of ergonomic design as the data available in the literature are limited and uncertain. Method: Visual acuity was measured using Landolt rings in negative contrast, which were presented on a computer screen with a background luminance of 32 cd/m2 for durations that varied between two and 0.02 seconds at three different contrasts. Resulte: Visual acuity depends on the log of the light dose reduced by a factor that may be related to absorption of the light by the eye media. For young observers, it was found that: VA = 0.57 (log C t) + 1.705, where C is the contrast and is expressed as δL/L, where δL is the difference between target and background luminances in cd/m2 and t is the observation time in seconds. Conclusion: This formula or the functions fitted to the data obtained can be used to calculate the increase in target size needed to allow for short observation times.     

Brain perfusion territory imaging applying oblique-plane arterial spin labeling with a standard send/receive head coil.

A new method for the selective spin labeling of left- or right-sided supplying arteries of the brain without the need for additional RF coils is demonstrated. A clinical 1.5 T scanner was used. The spatial selectivity of the labeling process is based on the limited coverage of the excitation field of a standard send/receive head coil together with an oblique positioning of the labeling plane. A computer simulation was used to optimize key labeling parameters under the condition of laminar flow. The validity of the computer model results was confirmed by MRI measurements with a flow model. For human studies, a double-inversion continuous arterial spin labeling (CASL) sequence was modified to allow for arbitrary positioning of the labeling plane. The obtained perfusion-weighted images showed a clear delineation of the perfusion territories of the selected arteries in the anterior circulation of the brain and good gray/white matter contrast.     

Neurons in the Primate Superior Colliculus are Active Before and During Arm Movements to Visual Targets

The activity of single neurons in the superior colliculus was recorded while a rhesus monkey made arm movements to visual targets located on a screen in front of him. It was found that the activity of a subpopulation of cells was clearly related to these arm movements. The neurons began to discharge either with the onset of the movement, during the movement period, or well before the onset of electromyogram (EMG) activity and movement, and could be active for the entire duration of EMG activity. While the discharge pattern of some of these'reach'neurons was not different for movements to different target positions, other cells showed graded changes in activity depending on the direction of movement. The peak discharge rate could rise to > 100 impulses/s. Some units received somatosensory input; other reach cells exhibited a visual response and/or presaccadic activity. It is likely that the primate superior colliculus is not only involved in the initiation and control of orientating movements of the eyes but also in reaching movements of the arms.