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PubMed2000

Masking or blinding? An unscientific survey of mostly medical journal editors on the great debate.

I intended to end the great debate about whether "masking" is preferred to "blinding" when describing clinical trials in which group assignment is concealed from patients, data collectors, and sometimes statisticians. I conducted a highly unscientific survey, mostly of medical journal editors from the World Association of Medical Editors, but also of several strangers and distant relatives. Respondents were asked whether they preferred masking, blinding, or had no preference or considered the distinction to be unimportant. More than 80 people responded, representing 6 continents and several languages. Masking was preferred to blinding 3 to 1. However, the number of people reporting that either term is acceptable or that the issue is unimportant was about the same as the number who voted for masking. I conclude that both terms are acceptable in the context of reporting clinical research and that either may be used without confusion. I pronounce the great debate dead.

Clinical Trials as Topic↗

PubMed2001

Pupillary responses and processing resources on the visual backward masking task.

Task-evoked pupillary responses were recorded during a visual backward masking task as an index of resource allocation. Increased pupillary dilation indicates increased allocation of processing resources to the task. Consistent with numerous studies, detection accuracy increased with longer interstimulus intervals and approximated no-mask accuracy in the 300-ms condition. Pupillary dilation responses were significantly greater during task performance (cognitive load) than during a passive stimulus viewing condition (no-load) and were significantly greater in the 300-ms condition than the no-mask condition. Consistent with models of early visual information processing, the results suggest that the mask demanded extra processing resources when it followed the target by more than 100 ms. Pupillography methods may be useful in evaluating the contribution and timing of resource-demanding processes during early visual information processing.

Adult↗

PubMedDate not supplied

[Gender distinctions in recognition of partly masked geometric figures].

Visual recognition of entire and partly masked geometric figure by men and women was studied. Probabilities of correct recognition of the entire (control) and partly masked figures (without some parts of their lines or corners) under conditions of their near-threshold tachistoscopic presentation were compared. A gradual decrease in recognition probability with increasing masking was observed. It was more pronounced for figures without some corners than for figures without part of their sides. Reliable gender differences were found: men better than women recognized figures, especially, with masked corners. Possible reasons for gender differences in recognition of geometrical figures are discussed, in particular, the role of striate sensitivity to a single light bar and a line crossing in the observed phenomena.

Adult↗

PubMed2003

Face-Mask Removal: Movement and Time Associated With Cutting of the Loop Straps.

OBJECTIVE: To quantify the amount of helmet movement, time for task completion, tool satisfaction, and overall efficiency for various face-mask removal tools during football helmet face-mask removal. DESIGN AND SETTING: Each subject performed one trial with the anvil pruner (AP), Face Mask Extractor (FME), PVC pipe cutter (PVC), and Trainer's Angel (TA). Each subject cut through 4 loop straps and removed the face mask while kneeling behind the athlete's head. SUBJECTS: Twenty-nine certified athletic trainers (age = 29.5 +/- 6.2 years, athletic training experience = 6.3 +/- 5.0 years). MEASUREMENTS: Time to complete the task was recorded. Total range of motion and total movement of the helmet were assessed using a 6-camera, 3-dimensional motion-capture system. Satisfaction scores were measured for each subject for each tool. Efficiency scores were calculated using time and total helmet-movement data. RESULTS: When using the FME, subjects were significantly faster than with all other tools (P <.05), and when using the AP and TA, they were significantly faster than with the PVC. No differences were noted between tools in either movement variable. Significant differences were noted for satisfaction (P <.05) for all comparisons except TA versus AP. Efficiency scores were FME, 11.6; AP, 14.3; TA, 14.5; and PVC, 22.9, with lower scores identifying increased efficiency. CONCLUSIONS: In general, subjects using the FME were superior in all variables except the movement variables. Future researchers should assess the removal task using specific protocols to determine whether the tools truly differ in terms of the movement created.

Journal Article↗

PubMed1979

[The facial mask as a basis of clindamycin therapy for acne vulgaris].

In 29 healthy male subjects aged between 20 to 25 years a powder face mask, consisting of 1.19% clindamycin phosphate (= 1% clindamycin base) in 70% ethanol was applied to the right side of the forehead once daily over a period of 5 days. At the same time half of the test subjects were treated in the same way on the left side of the forehead with a solution consisting of 1.19% clindamycin phosphate in 70% ethanol, and the other half with the same powder mask as on the right side but without clindamycin phosphate. The face mask containing clindamycin phosphate leads to a greater reduction of P. acnes. the total propionibacteria and the total bacterial counts (anaerobic culture) in the pilosebaceous duct than both other preparations. Compared with the initial values these do, however, reduce the bacterial count. The use of face masks containing antibiotics seems to offer a successful way of topical antibiotic treatment of acne.

Acne Vulgaris↗

PubMed1992

Treatment of gas mask phobia.

Many soldiers develop feelings of claustrophobia when wearing a protective mask. In the battlefield environment of today, it is essential that soldiers be able to tolerate gas masks. This article briefly reviews the historical use of gas masks in the U.S. Army. Two cases of treatment of gas mask phobia are described. Behavioral therapy techniques useful for treatment are summarized.

Adult↗

PubMed2005

Evaluation of the changes in midfacial configuration after face mask therapy in skeletal Class III growing patients by morphometric analysis techniques.

BACKGROUND AND PURPOSE: The prevalence of Angle Class III malocclusion is relatively high in Taiwan. For children who suffer from maxillary retrognathia, face mask therapy is a promising treatment modality. The purpose of this study was to evaluate the changes in midfacial configuration after face mask therapy in skeletal Class III growing patients by morphometric analysis techniques. METHODS: Thirty children who had been treated with face masks were compared with a group of 30 gender-matched, age-matched, observation period-matched, and craniofacial configuration-matched subjects with untreated Class III malocclusions. Average geometries, scaled to an equivalent size, were generated by means of Procrustes analysis. Graphical analysis, utilizing thin-plate spline analysis and strain tensor methods, was performed for localization of differences in shape and size changes. Maximum and minimum principal extensions were drawn to express the directions of shape change. RESULTS: Maxillary protraction-induced changes resulted from a combination of both orthopedic and dental effects. A significant increase in size (7.7% to 9.9%) was noted at the supero-anterior region of the midfacial configuration (rhinion-orbitale-midpalatal point-anterior nasal spine) when subjected to an extraoral traction force; 7.7% to 12.1% of increase in size and 14.4% to 33.4% of change in shape were found at the anterior portion of the maxillary alveolar bone. The directions and amount of principal strain tensors could express the magnitudes and directions of morphological changes within the midfacial complex in an efficient way. CONCLUSIONS: We conclude that morphometric analysis techniques can be used to evaluate the changes in midfacial configuration after face mask therapy and can provide a valuable supplement for conventional cephalometric analysis.

Case-Control Studies↗

PubMed1990

PEEP-masks in patients with severe obstructive pulmonary disease: a negative report.

Positive pressure during expiration by face masks applied by the patient has gained wide acceptance in the treatment of chronic bronchitis, but the efficacy is still unproven. The effect of 6 months of treatment with PEEP-masks (positive end-expiratory pressure) was therefore studied in 47 patients with severe irreversible obstructive pulmonary disease (forced expiratory volume in one second (FEV1) about 1 l), and mucus hypersecretion. Patients were double-blindly randomized to at least 45 min daily treatment with PEEP-masks with either 10 or 0 cm water pressure. After 6 months of treatment, no statistical difference was found between the two groups in change of median values (month 6 - month 0) of FEV1, forced vital capacity (FVC), arterial oxygen tension (PaO2), amount of sputum or dyspnoea. Median values of arterial carbon dioxide tension (PaCO2) decreased significantly (0.03 kPa) in the placebo group. Cough intensity and dyspnoea during walking on staircases improved significantly in the placebo group. No difference among groups was found in number of days bedridden, hospitalized, number of exacerbations or antibiotic consumption. We conclude, that the use of PEEP-masks in these patients is without clinical documentation and cannot be recommended.

Adult↗

PubMed1987

[Role of somatic factors in the clinical picture and therapy of so-called masked depressions].

In somatic and psychiatric examination of 38 patients with masked depression under variable somatic masks the authors have revealed clear-cut symptoms of depressions and a high rate of somatic pathology. They believe that peripheral somatic disorders determine to a certain degree both nature and projection of the somatic mask. The questions of masked depressions are discussed.

Adult↗

PubMed1984

Effect of psychophysical backward masking on human brain-stem responses (ABR).

A backward-masking (BWM) paradigm was used to obtain measurements on 4 normal young adults of psychophysical BWM and of the analogous electrophysiological masking from human auditory brain-stem responses. The same stimuli and Ss were used in both experiments. Psychophysical BWM was determined to a 100-musec click masked by a 100-msec white noise after time delays of 1, 5, 10, 25, and 100 msec and at noise masker levels of 50, 65, and 80 db SPL. As previously demonstrated, more psychophysical BWM occurs at short delta ts (1 to 10 msec) than at longer delays and masked thresholds are greater as masker level increases. In the electrophysiological experiment, using delta ts = 1, 5, and 10 msec, the extent to which wave V latency was affected by the following masker was determined for various experimental conditions. Wave V latency increased with a decrease in delta t, for maskers above probe level, except that latency was not significantly affected by any masker level at delta t = 10 msec.

Acoustic Stimulation↗

PubMed1980

Puck impact response of ice hockey face masks.

A sample of new ice hockey face masks was struck over the nose or eye of a headform by pucks shot at velocities of 11-39 m/s (25-87 m.p.h.). Deformation of the masks was studied from high speed film. Acceleration pulses transmitted to the center of gravity of the headform were recorded. Peak accelerations never exceeded 86 G's and were well below reported concussion thresholds (200 G's). The film showed contact of the mask or puck with the face at puck velocities of 28 m/s (60 m.p.h.) and above. These results indicate a somewhat lower "safe" puck impact velocity (28 m/s) than that stated by the Canadian Standards Association (32 m/s) under the standard which applied to these masks. Some boys 12 years and older can shoot pucks at 28 m/s (60 m.p.h.). We urge that all manufacturers of sports protective equipment incorporate state of the science, quantitative evaluations of their products, beyond minimum CSA standard testing, in their design programs to improve the quality of information transmitted to the public.

Adolescent↗

PubMed1981

The protective effect of a cold weather mask on exercised-induced asthma.

The authors investigated the usefulness of a cold weather mask in reducing exercise-induced bronchospasm. Ten asthmatic subjects were selected because of previously demonstrated exercise-induced bronchospasm. Airway responses to submaximal exercise were measured on four separate days. Exercise was performed on the first two days at ambient temperature in a centrally air-conditioned laboratory and on the second two days in a refrigerated room. Exercise challenge was similar on each of the two days of the separate environmental conditions, with the exception that a mask was worn on one of the two days. Pulmonary function was measured using maximal and partial expiratory flow volume curves before and after exercise. On both of the days during which subjects exercised without a mask, significant decreases in all pulmonary function parameters occurred. Protection was seen under both conditions, but was more complete in the cold. These studies demonstrate the therapeutic potential of cold weather masks in protecting asthmatics against the effects of exercise and cold air.

Adolescent↗

PubMedDate not supplied

OmniMed II: a new system for use with the emphasis erodible mask.

Clinical experience has shown the emphasis erodible mask to be an effective method for performing photorefractive keratectomy (PRK) using an eyecup placed in contact with the corneal surface. A new system (OmniMed II) which incorporates the erodible mask as an element in the optical delivery system has been developed for performing photorefractive keratectomy. With this new configuration the eyecup is no longer used. We describe in detail the advantages of the erodible mask, the associated hardware of the optical delivery system, and the mask shape transfer process.

Cornea↗

PubMed1994

The effect of the M43 and M17 protective masks on stereoacuity.

The purpose of this study was to evaluate the effects of the M17 and M43 protective masks on stereoacuity. Twelve subjects were tested on the Keystone diagnostic series stereopsis test at nearpoint and the Howard-Dolman apparatus at 40 cm and 6 m. Stereopsis was evaluated without a mask and with the M43 and M17 masks. Stereoacuity was decreased at near point with both masks and was not significantly affected at the 6-m distance.

Adult↗

PubMed1994

[Masked depression].

Depressive disorders which masked by somatic symptoms is called masked depression. Masked depression is not a specific type of depression, but the general practitioners often misdiagnose it, because patients complain only somatic symptoms and most practitioners are not aware of it belongs to depression. Usually masked depression is mild, but is apt to chronic, and some patients become worse and might attempt suicide. The cause of depression is still obscure, but according to the results of many somatic tests, somatic findings are important. And differential diagnosis is also important. Concerning the treatment of mild depression, the patients dislike usual antidepressants because of the side effects. Then the author recommend to use a small dose of the drugs and some oriental herbal medicines. Oriental herbal medicines have fewer side effects, and effective for vegetative symptoms.

Antidepressive Agents↗

PubMed1998

[Inventory and follow-up of patients with surgery for (uterine) vaginal prolapse, combined with or without, (masked) stress incontinence].

OBJECTIVE: Evaluation of the development or persistence of urinary stress incontinence in patients operated on because of prolapsed uterus, with cooperation between gynaecologists and urologists. DESIGN: Retrospective. SETTING: Department of Gynaecology and Obstetrics, Leyenburg Hospital, The Hague, the Netherlands. METHODS: In 178 patients subjected to prolapse correction in the period 1992-1996, presence of urinary incontinence was analysed by means of a written enquiry after an average of 22 months. The 91 patients who had visited the gynaecological outpatient clinic and were seen together with a urologist, were subjected to urodynamic examination in the absence of symptoms of stress incontinence and were operated in cooperation with the urologist. Four groups were distinguished on the basis of preoperative features: group I (n = 37) with manifest stress incontinence, group II (n = 22) with masked stress incontinence, group III (n = 32) in whom no (masked) stress incontinence could be demonstrated and group IV (n = 87) not subjected to urodynamic examination. The patients of groups I and II, in addition to prolapse correction, were also subjected to urethral suspension. RESULTS: Twenty-five (68%) of the group with manifest stress incontinence were free of stress incontinence after the operation, while eight patients (22%) reported improvement (a total of 89%). In 22 of the 54 patients (41%) who preoperatively had no incontinence symptoms, urodynamic examination revealed a masked stress incontinence. Sixteen of them (73%) did not develop symptoms of stress incontinence after the operation, while eight (15%) did develop such symptoms. Thirty of the 32 patients (94%) who preoperatively had no (masked) stress incontinence remained symptom-free. Out of 64 patients without preoperative incontinence, who were operated without urological cooperation, 12 (19%) developed stress incontinence.

Aged↗

PubMed1999

The intubating laryngeal mask airway compared with direct laryngoscopy.

We have compared the ability of naïve intubators to intubate the trachea using a laryngoscope and an intubating laryngeal mask airway (ILMA) after receiving basic training, in a randomized, prospective, crossover study in 60 patients. Ventilation of the lungs via the ILMA was also compared with ventilation with a face mask. There was no significant difference in successful intubation between the techniques (38 of 89 with the ILMA and 33 of 93 with direct laryngoscopy; ns). In patients in whom participants failed in their intubation attempts with the ILMA, investigators achieved success in 89% (16 of 18). Satisfactory ventilation was more common with the ILMA (50 of 51) than with the face mask (43 of 60) (P = 0.0001). A total of 98% (89 of 91) of ILMA were inserted successfully, with a mean insertion time of 19.6 s, and 78% (69/89) of these insertions were achieved in less than 26 s. The ILMA may be useful for emergency oxygenation and ventilation, but these results do not support its use for intubation by those not trained in advanced airway management and ILMA use.

Adult↗

PubMed1993

Training nursing staff in airway management for resuscitation. A clinical comparison of the facemask and laryngeal mask.

The place of the laryngeal mask in emergency airway management by nonanaesthetists has yet to be established. We have compared the tidal volume achieved by nurses during hand ventilation using standard resuscitation equipment with a facemask, with or without a Guedel airway, and following placement of a laryngeal mask in the same patients. The tidal volumes measured while using the laryngeal mask were significantly greater (p < 0.01) than those measured during facemask ventilation.

Adolescent↗