Hand-held Switch Research Articles

High concurrent validity between digital and analogue algometers to measure pressure pain thresholds in healthy participants and people with migraine: a cross-sectional study

BackgroundPressure pain thresholds (PPTs) are commonly assessed to quantify mechanical sensitivity in various conditions, including migraine. Digital and analogue algometers are used, but the concurrent validity between these algometers is unknown. Therefore, we assessed the concurrent validity between a digital and analogue algometer to determine PPTs in healthy participants and people with migraine.MethodsTwenty-six healthy participants and twenty-nine people with migraine participated in the study. PPTs were measured interictally and bilaterally at the cephalic region (temporal muscle, C1 paraspinal muscles, and trapezius muscle) and extra-cephalic region (extensor carpi radialis muscle and tibialis anterior muscle). PPTs were first determined with a digital algometer, followed by an analogue algometer. Intraclass correlation coefficients (ICC3.1) and limits of agreement were calculated to quantify concurrent validity.ResultsThe concurrent validity between algometers in both groups was moderate to excellent (ICC3.1 ranged from 0.82 to 0.99, with 95%CI: 0.65 to 0.99). Although PPTs measured with the analogue algometer were higher at most locations in both groups (p < 0.05), the mean differences between both devices were less than 18.3 kPa. The variation in methods, such as a hand-held switch (digital algometer) versus verbal commands (analogue algometer) to indicate when the threshold was reached, may explain these differences in scores. The limits of agreement varied per location and between healthy participants and people with migraine.ConclusionThe concurrent validity between the digital and analogue algometer is excellent in healthy participants and moderate in people with migraine. Both types of algometer are well-suited for research and clinical practice but are not exchangeable within a study or patient follow-up.

Modification of a Motor-Response Dependent Measure of Daytime Sleepiness (OSLER-2)

Background: A simple, portable measure of daytime sleepiness is the Oxford Sleep Resistance (OSLER-2) test; however its use is limited to those with good hand function. This study modified the OSLER-2 test to assess the measurement of daytime sleepiness using two alternative, non-hand-held response switches. Methods: The unit was modified to accept the standard hand-held switch, a head-tap switch (“Jelly-bean”) and chin-tap switch (“Wand”). Participants were required to respond to a central LED light presented for one second every three seconds. It terminated following either seven consecutive missed responses (participant asleep) or forty minutes (maximum test length, “performance time”). Twenty-two able-bodied participants with no diagnosed sleep disorders were sleep restricted prior to three testing days where switch order was randomized. The test was performed four times over each day. Sleep latency, performance times and errors were recorded along with video of the switch use. Results: Sleep latency was longer with the Wand (M=1265 sec (546)) than the Jelly-bean (M=1102 (544)) and hand-held switch (M=1037 sec (557), p<0.05). Performance times were longer with the Wand (M=1788 sec (695)) than the Jelly-bean (M=1530 sec (758); p<0.05) and hand-held switch (M=1459 sec (784); p<0.01). Sleep latency, performance times and errors did not differ significantly between the Jelly-bean and hand-held switches. Video suggested the Wand was occasionally activated erroneously by forward (drowsy) head-drops. Conclusion: The Jelly-bean provides a possible alternative response switch to measure daytime sleepiness in those with limited hand function.

Electrophysiological analysis of the perception of passive movement

The goal of the present study was to determine the electrophysiological correlate of the threshold of perception of passive motion (TPPM) in a group of healthy individuals. We expect a different pattern of activation over the frontoparietal network produced by the conscious perception of the passive movement. Ten right-handed male volunteers, between 20 and 30 years of age, were submitted to the threshold of perception of passive motion (TPPM) task in a proprioception testing device (PTD). The device was designed to passively move the arm in internal and external rotations about the shoulder joint. Participants were instructed to press a hand-held switch every time movement of the shoulder was detected. Electromyographic (EMG) and electroencephalographic (EEG) activities were acquired during the task. Passive movement of the shoulder joint was followed by a clear and prolonged decrease in the signal magnitude of the electroencephalogram. The electrophysiological correlate of the TPPM was characterized by the establishment of a frontoparietal network, during the processing of somatosensory information.

Developing a dynamic elastomeric fabric orthosis to aid return to sport after lumbopelvic injury

Lumbopelvic pain (LPP) often results from trauma or overuse that can lead to conditions including adductor tears, sacroiliac joint dysfunction and osteitis pubis. Such injuries are often refractory to treatment and can limit the return to competitive sport. Previous research shows that selective compressive forces applied transversely to the pelvis can result in improved lumbopelvic stability and reduced pain, and, compression shorts may aid in preventing athletic lumbopelvic injury. This study applies transverse and diagonal compressive forces to the pelvis in athletes with LPP, and investigates the effects on pain and function. Participants with athletic LPP were screened using five clinical tests. They were included if at least two tests provoked pain. Transverse and diagonal circumferential forces were applied via a belt. Four belt arrays (anterior superior iliac spines (ASIS), right-left across the pelvis, left-right across the pelvis and in combination) and a "no-belt condition" were assessed with the order of presentation randomised. A force of 50 N was applied (determined using a load cell lying in series with the belt). The effect of the belt array on rest pain, pain associated with an active straight leg raise (ASLR) and a 1-m broad jump was assessed using a numerical rating scale. During resisted bilateral hip adduction the onset of pain was indicated using a hand held switch; the maximal force of adduction determined via a load cell. Data were analysed using paired t tests. Preliminary data on 12 participants (9 females, mean 37±10 years) indicate that different belt arrays can alleviate pain both at rest and during active tasks. Pain during ASLR (ipsilateral to the pain) improved with combined belts compared to an ASIS belt (p=0.025). Preliminary results suggest the direction and angle of force application relative to the laterality of pain is important in determining the degree and pattern of pain relief. A larger sample is needed to confirm this (required sample of 31 based on effect size of 0.51 and 80% power). Results will inform the design of a dynamic elastomeric fabric orthosis whose effect on athletic LPP and function will be assessed.

Effects of Age, Task Complexity, and Exercise on Reaction Time of Women During Ambulation Tasks

Reaction time (RT) is defined as the time lapse between the onset of a stimulus and the initiation of a response. The purpose of Study 1 was to compare RTs of young and elderly women during ambulation. The purpose of Study 2 was to investigate the effects of regular exercise on RTs of elderly women during ambulation tasks. Reaction times were measured using a portable computer, 2 transistor radios, and a radio interface box. The computer generated an auditory signal to which participants reacted by pushing a hand-held switch. Reaction times were compared in Study 1 between 17 healthy elderly women and 13 university students and in Study 2 between 15 exercising and 16 non-exercising elderly women. Testing of each participant occurred during sitting, walking on tile, and walking on foam padded carpet. The results of Study 1 revealed differences in RT between the 2 groups and between the sitting and the 2 walking conditions, but no interaction between group and task complexity. The results of Study 2 revealed differences among all conditions, but not between groups. The surprising result of Study 1 was that the elderly were not compromised to a greater extent than the young by increased task complexity. This suggests less age related RT decline during familiar activities. Results of Study 2 showed that level of exercise did not differentiate elderly participants' performance on RT. This may be because the active lifestyle of both groups of participants was more important in maintaining RT than a formal exercise program.

Perception of Large Change in Distribution of Heel Pressure during Backward Leaning

We investigated the perception of the large change in distribution of heel pressure during backward leaning. Subjects were 12 healthy adults who reported perceiving a large change in distribution of heel pressure by a handheld switch while leaning voluntarily backward on a sole pressure analyzer and on a heel force plate. The large change was indicated at the center of heel pressure. Morphological features of the foot were measured on an X-ray film. The position of heel pressure center and the morphological locations were represented as relative distance (%) from the hindmost point of the heel, where foot length represented 100%. Center of heel pressure changed largely during backward leaning, and the position at which large change occurred was the same as that of the peak of the distribution. Large change in distribution of heel pressure was perceived at a position 1.3% posterior from that at which the large change actually occurred. The correlation between perceived and actual positions was significant (r = .91). Significant correlations were found between position of a large change of center and locations of heel pressure of both the lateral process of the calcaneal tuberosity and the top of the talar trochlea (r = .86; r = .71, respectively). The results indicate that subjects accurately perceive large changes in distribution of heel pressure and that the morphological features of the foot contribute to these changes.

Clinical use of stereotactic 3-D conformal multiple dynamic arc radiotherapy for stage I non-small cell lung cancer using a linear accelerator combined with self-moving ct scanner and patient’s self-breath and beam control technique

Purpose/Objective: In the last ASTRO meeting, we presented a new irradiation system for lung cancer: patient’s self-breath-hold and self-turning radiation-beam on and off using a linear accelerator combined with a self-moving CT scanner. The purpose of the current study is to apply this system for the stereotactic 3-D conformal radiotherapy of stage I non-small cell lung cancer and to evaluate its clinical outcomes. Materials/Methods: Twenty-two patients with stage I (11 T1N0, 11 T2N0) primary non-small cell lung cancer who were treated between October 2000 and November 2001 were included in this study. The patients ranged from 68 to 92 years of age with a median of 78 years. The performance status was better than WHO grade-2 in all but two patients of Parkinson’s disease and pulmonary fibrosis. The histology was adenocarcinoma in 15, squamous cell carcinoma in 7 cases. Tumor size ranged from 13 to 48 mm with a median of 30 mm. Planning target volume (PTV) was determined to include the gross tumor volume on CT scan, 3mm for respiratory internal margin and 5mm for the safety margin. The three-dimensional treatment plannings were made using 10 different non-coplanar dynamic arcs of which couch angles were between -20deg. and 25deg. A total dose of 60Gy in 10 fractions (daily 2 fractions) at the minimum dose point in PTV was delivered with 6MV X-ray over 5 to 8 days. In the simulation, every patient was taught sufficiently how to hold the breath at a same inspiration phase, and CT scans under the patient’s self-judged breath-hold were performed 3 times to confirm that the respiratory reproducibility was within 3 mm. After the isocenter of the PTV was adjusted to the planned position by the CT combined with the linear accelerator under the patients’ self-judged breath-hold at inspiration phase, they turned the radiation-beam on and off repeatedly at their own agreeable pace by the handheld switch until they filled up the monitor units. Results: All patients completed the treatment without any complaints. During the follow up of 4-17 (median=10) months, no pulmonary complications greater than NCI-CTC criteria of grade 1 were noted in all patients. None of the patients experienced symptomatic radiation esophagitis. The one-year local control rate was 100%. One-year overall survival was 100%. No patients showed metastasis on resional lymphnodes or distant site. Conclusions: This new irradiation technique, by which patients turned the radiation beam on and off by their hand-held switch under self-judged inspired breath-hold after a precise adjustment of the isocenter to the planned position with the combination of CT scanner and linear accelerator, permitted us to perform the high dose stereotactic irradiation safely with an enough margin around the clinical target volume. Based on the initial clinical results, excellent local control with minimal symptomatic complications can be achieved for stage I non-small cell lung cancer.

EEG Power-Spectral and Coherence Differences Between Attentional States during a Complex Auditory Task

Abstract This electroencephalographic (EEG) study was designed to explore the differences in power spectra and coherence associated with subjective levels of engrossment, or absorption, in an auditory task. Quantitative referential EEG activity was recorded using 19 electrodes while subjects (n = 17) listened to a story and indicated on a continuous basis, by means of a hand held switch, whether they were engrossed or non-engrossed in the story content. Results from power spectra data indicated significant differences between subjective engrossed and non-engrossed states (particularly in the theta and betal bands) with increased mean power during engrossed states. Differences in coherence were not shown to be significantly different. The results suggest that engrossed and non-engrossed states have different EEG correlates for power measures during specific complex tasks.

Characteristics of voluntary visual sampling of the environment for safe locomotion over different terrains.

The characteristics of visual sampling required for successful locomotion over various terrains is the focus of this work. In the first experiment we directly address the role of continuous visual monitoring of the environment in guiding locomotion by allowing the subjects to choose when and where to take a visual sample of the terrain and examine the effects of different terrains on characteristics of visual sampling. Young subjects walked over travel paths of varying difficulties while wearing opaque liquid crystal eyeglasses and pressed a hand-held switch to make the glasses transparent when they needed to sample the environment. Travel time and visual sampling characteristics were recorded. Results show that intermittent sampling (less than 50%) of the environment is adequate for safe locomotion, even over a novel travel path. The frequency, duration and timing of visual samples are dependent on terrain characteristics. Visual sampling of the environment is unaffected by preview restriction of the travel path and is increased when specific foot placement is required and there is a potential hazard in the travel path. In the second experiment we dissociated steering control and obstacle avoidance from specific foot placement and examined visual sampling demands prior to the initiation of the swing phase and during the swing phase. The results show that steering control and obstacle avoidance do influence the visual sampling time, which is scaled to the magnitude of change. Vision was used in a feedforward control mode to plan for and initiate appropriate changes in the swing limb trajectory: its use during the swing phase to provide on-line control was minimal.

Geophysical variables and behavior: XXXVIII. Effects of ionized air on the performance of a vigilance task.

The effects of positively or negatively ionized air on the performance of a visual vigilance task were investigated. The ion level was 100,000 ions/cm3, +/- 10,000. Also investigated were the effects of task-induced stress and nonstress. 40 male college students were required to press a hand-held switch as soon as they detected a signal on a simulated cathode-ray display. Each subject monitored the display continuously for 3 hr. in a room specially equipped for ion exposure and for control of light and noise. All subjects received continuous identical false feedback about their performance. Half of the subjects (the stress group) were told that they would receive an electric shock when their performance fell below an acceptable level. The false feedback was programmed so subjects in this group believed that they were in danger of receiving a shock, but none were actually administered. Analysis indicated that the percentage of signals detected was higher in the presence of negatively ionized air than in the presence of positively ionized air. Also performance-contingent stress resulted in better performance than nonstress.

Motor and cognitive factors in the modification of a reflex.

By closing a hand-held switch, subjects caused a miniature solenoid to deliver a tap to their own foreheads. (1) The amplitude of elicited eyeblinks was reduced when the delay between switch closure and tap was 50 meec or less. (2) Subjects who expected that switch closure would produce an immediate tap exhibited smaller blinks to such taps than did subjects who expected switch closure to produce a delayed tap. (3) The inhibitory effects of a reflex-modifying tone prior to tap were the same when taps were self-presented as when they were presented by the experimenter. (4) When blinks could be elicited by either a tap or a loud noise, the smallest responses occurred when subjects knew which to expect. (5) On a given trial, the inhibition afforded by the particular stimulus, motor, and cognitive factors operating at the time tended to add in an algebraic fashion.

Response latency differences in speech shadowing as an indicator of distinctive features of consonants.

The purpose of this study was to determine which articulatory features serve as important distinctive features of perception by measuring latency in speech shadowing. Fifteen subjects shadowed a recording of consonant-vowel syllables orally and by means of a hand-held switch. Vocal shadowing was tape recorded and the onsets of the stimuli and the manual responses were recorded on a polygraph. The oral responses were used to indicate perceptual confusions and the manual responses were used as the basis for measuring the shadowing latency for each consonant. After eliminating the dental fricatives because of perceptual confusions, the remaining consonants (p, b, t, d, k, g, f, v, s, z, ∫, 3, m, n, 1, r, j, w,) were classified according to a feature system and the latency scores were analysed. An analysis of variance indicated significant differences among sounds arranged according to features. A post hoc comparison between all possible features (interrupted, grave, acute, diffuse, strident, voiced, tense, nasal) showed that three features were primarily responsible for the significant variance: stridency (or, minus interrupted) voicing, and nasalization. The results do not seem to support the concept of a hierarchy of features which order the decisions made in consonant identification.