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PubMed1994

Word superiority over isolated letters: the neglected case of forward masking.

Previous research shows that when briefly presented alphabetic stimuli are followed by pattern masks, letters in words are reported more accurately than are isolated letters (the "Word-Letter Phenomenon," or WLP); however, when these masks are replaced by blank fields, the WLP disappears. These findings have led to the popular notion that the WLP reflects selective masking of ongoing stimulus processing and so critically depends on the use of poststimulus masks. Here we report three experiments which re-examine the role of masking in the WLP by contrasting the effects of postmasked displays with the effects of premasked displays in which words and isolated letters were preceded by a pattern mask and followed by a completely blank field. Despite the critical role generally assigned to poststimulus pattern masks, similar WLPs were obtained with pre- and postmasked displays. Implications for theories of word and letter recognition are discussed.

Computer Simulation↗
PubMed2001

[Recovery from adaptation in human compound action potential following forward masking].

Recovery from adaptation was studied as changes in compound action potential (CAP) in response to clicks after broadband noise masking in volunteers with normal hearing. CAP was transtympanically elicited from the promontory using a needle electrode. Preceding masking noise and subsequent click stimuli were delivered separately from 2 loud speakers 80 cm from the tested ear. We evaluated the effect of masking noise duration and intensity on CAP recovery from adaptation as a function of delta t, defined as the interval between masking noise offset and click stimulus onset. Results were as follows: At delta t shorter than 200 ms or less, recovery from latency prolongation and amplitude decrease slowed with increasing masking noise duration and intensity. At delta t longer than 200 ms, no significant difference was seen in CAP recovery based on changes in masking noise duration or intensity. Recovery from adaptation, which depended on click intensity, took about 700 ms at a 40 dBnHL click and about 300 ms at a 60 dBnHL click. The influence of the middle ear muscle reflex on CAP recovery patterns is neglected when considering the intensity both masking noise and click stimulus. In CAP recovery, accumulated effects of the relative auditory-nerve refractory period may adversely affect recovery at very short delta t, while recovery from short-term adaptation, assumed involved in cochlear-hair cell synapse function, may be an important factor at delta t longer than 30-40 ms. Based on animal experiments showing different recovery times dependent on different auditory nerve spontaneous rates(SR), we concluded that at delta t of 200 ms or less, CAP recovery reflects high SR neuron activity, while at delta t longer than 200 ms, it mainly reflects that of low SR neurons.

Acoustic Stimulation↗
PubMed1993

Laryngeal mask.

The laryngeal mask, provides a totally patent airway when positioned in the hypopharynx with remarkable patient tolerance, even at very light planes of sedation. The major advantages of the laryngeal mask are its ease of insertion, the absence of contact with the vocal cards, and the fact that it frees the hands of the anesthesiologist. Contraindications to its use result from its failure to seal the airway against regurgitation of gastric content. Laryngeal masks can be used easily instead of facial masks during anesthesia with spontaneous ventilation and, with experience, can be used for longer procedures using controlled ventilation. Suspected difficult intubation and establishment of a patent airway in emergency conditions are good indications for the use of this device. The laryngeal mask does not replace endotracheal intubation. It can, however, permit better management of the airway while waiting for personnel trained in endotracheal intubation. The nature of the pulmonary pathology seen in intensive care patients limits use of the laryngeal mask during intensive care. In the operating room few complications have been described, and postoperative discomfort is minimal. The laryngeal mask is a device positioned in the hypopharynx which allows separation of the digestive tract from the airway, without violation of either the larynx or the upper oesophageal sphincter. An endotracheal tube, because of its positioning, hinders normal glottic movement and narrows the airway.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMedDate not supplied

Peritonitis prevention in CAPD: to mask or not?

OBJECTIVE: To assess the efficacy of wearing a face mask to prevent peritonitis during continuous ambulatory peritoneal dialysis (CAPD) bag exchange. SETTING: Renal unit at a university hospital. PATIENTS: Two groups of patients on CAPD were compared: those performing bag exchange with (n = 24) and those without a face mask (n = 40). OUTCOMES: Occurrence of first episode of peritonitis and total number of episodes. RESULTS: No difference was found between groups with respect to probability of developing the first episode of peritonitis (p = 0.757). Patients holding university degrees had evidence of protection, with borderline significance [relative risk (RR) 0.52; confidence interval (CI) 95%, 0.23 -1.18; p= 0.109]. Cox's proportional hazard regression analysis also demonstrated a significant protective factor for patients with university level education (RR 0.42; Cl 95%, 0.18 - 0.98; p = 0.04). Incidence of peritonitis was not significantly different between groups: with-mask group had 1.0 episode/year, and without-mask group had 0.94 episodes/year. Staphylococcus epidermidis was the most commonly identified agent. Staphylococcus aureus was found more frequently in the with-mask group (p = 0.003). Peritonitis due to Streptococcus viridans and Enterococci were detected only in the without-mask group. CONCLUSION: The current study suggests that routine use of face masks during CAPD bag exchanges may be unnecessary and could be discontinued.

Adult↗
PubMed2000

Comparison of bilevel positive airway pressure and volume ventilation via nasal or facial masks in patients with severe, stable COPD.

BACKGROUND: In the past decade, noninvasive positive pressure ventilation (NIPPV) has been successfully used in chronic obstructive pulmonary disease (COPD) with acute exacerbation. Nonetheless, its effect in stable COPD remains controversial. Theoretically, differences in the mode of ventilation such as pressure versus volume preset, or interfaces such as nasal versus full facial mask could have an impact on the efficacy of NIPPV. Few published studies have focused on this topic. METHODS: In this crossover study, bilevel positive airway pressure (BiPAP) for pressure preset ventilation or PLV-100 as a home-care volume preset ventilator was used via a nasal or facial mask in 12 patients with stable hypercapnic COPD. The four types (2 ventilators and 2 masks) of NIPPV were used for 20 minutes each, with a randomized sequence. The patient breathed spontaneously for 10 minutes before and between each type of NIPPV as a baseline for comparison. RESULTS: Respiratory rate, tidal volume, pulse rate, Borg scale and phase angle were all significantly improved during BiPAP ventilation via either a nasal or facial mask (p < 0.05 for all). Suppression of inspiratory muscle activity was obvious, although not statistically significant. In contrast, inspiratory muscle activity, phase angle and respiratory rate increased and tidal volume decreased significantly during PLV-100 ventilation with either nasal or facial masks (p < 0.05 for all). Peak expiratory flow rate and maximum inspiratory and expiratory mouth pressures remained unchanged after each type of NIPPV. CONCLUSIONS: For patients with stable hypercapnic COPD, short-term use of BiPAP via either a nasal or facial mask markedly rests the inspiratory muscles, improves the respiratory pattern and reduces the sense of dyspnea for patients. In contrast, short-term use of PLV-100 via either a nasal or facial mask worsens the above parameters.

Aged↗
PubMed2000

Mountaineering oxygen mask performance at 4572 m.

BACKGROUND: Supplemental oxygen delivered by mask at high altitude is used to increase arterial oxygen saturation (SaO2) thereby mitigating physiological and cognitive dysfunction secondary to hypoxemia. Historically, mask performance has not been well documented although it may be a critical factor in determining the success of an expedition. METHODS: Three mountaineering masks were used by ten healthy, nonaltitude-acclimatized participants (eight males, two females) to compare ventilatory responses, SaO2, heart rate, and end-tidal gases. Masks tested were: Life Support Engineering Ltd. (LSEL); Zvezda Enterprise (ZE); and a prototype of our own design (Duke). Test conditions were as follows: simulated altitude at 0 and 4572 m (15,000 ft); rest and cycle exercise at 75 W; and supplemental oxygen flow at 0, 1.1 +/- 0.05, and 1.7 +/- 0.06 L x min(-1) (mean +/- SD). Statistical analysis was completed using GLM (SAS software). RESULTS: As there were no differences between the 1.1 and 1.7 L x min(-1) flow rates, the data were pooled. All three masks improved SaO2 with the ZE and Duke masks being more effective during exercise, maintaining mean SaO2 >90%. CONCLUSIONS: All three masks provided at least partial protection of physiological norms during rest and exercise at 4572 m. The ZE and Duke systems offered the best performance. The need for performance evaluation as part of system design is evident as subtle differences in design can significantly affect performance.

Adult↗
PubMed2002

Evaluation of airway leakage using reinforced laryngeal mask during dental anesthesia with spontaneous breathing.

BACKGROUND: The purpose of this study was to evaluate whether manipulation or position change of the head during dental procedures for handicapped patients (mentally retarded) using a reinforced laryngeal mask airway for ventilation would lead to air leak. METHODS: All patients had a reinforced laryngeal mask airway inserted after induction of anesthesia; anesthesia was maintained with sevoflurane. Normal saline stained with methylene blue was instilled into the oral cavity of the patient. Then, the patient's laryngeal region was checked for blue staining with a fiberoptic bronchoscope. After dental treatment, the laryngeal region was checked again under fiberoptic bronchoscopy. The staining results were recorded and analyzed. RESULTS: In one of 51 patients (1.96%), the laryngeal region was stained blue after the flexible laryngeal mask airway was inserted. In ten of 51 (19.6%) patients, the laryngeal area was stained blue after the dental procedure. One of the ten patients who had a leak because the laryngeal mask was pulled out during the dental procedure. And in another one patient endotracheal tube was placed in lieu of laryngeal mask due to severe leakage. No oxygen desaturation below 90% occurred in all patients. No major complications such as fever or aspiration pneumonia were reported. CONCLUSIONS: The use of a reinforced laryngeal mask airway eliminates the complications due to endotracheal intubation and enhances the progress of the dental procedure. Although leakage may happen during dental manipulation, it usually does not raise serious problem. No serious complications such as aspiration were found in our cases. So a reinforced laryngeal mask airway may be considered to be another safe choice for maintenance of a patent airway in handicapped patients during dental procedures.

Adolescent↗
PubMed1992

[Fiberoptic determination of the position of the laryngeal mask].

The laryngeal mask airway (LMA) provides a patent airway when placed 'blindly' into the hypopharynx. At the laryngeal side it is supposed to form a seal surrounding the laryngeal inlet with the epiglottis lying outside the mask aperture. This study is designed to assess the prelaryngeal position of the mask by the fibreoptic technique. METHODS. After approval by the local ethical committee and informed consent, 100 adult patients (ASA groups I and II) undergoing general anaesthesia for extracorporal stroke wave lithotripsy (ESWL, Lithotripter HM 3, Dornier) of the kidney were studied. Anaesthesia was induced with propofol (1.5-2.5 mg.kg-1) and fentanyl (1-1.5 micrograms.kg-1) and maintained with isoflurane and N2O (65% in O2) as clinically indicated. The LMA was left in situ until the patients opened their mouth on command. Monitoring consisted of an ECG (SMV 104-D, Dornier), a pulse oximeter (Nellcor 200, Draeger), and a non-invasive blood pressure monitor (BP 103 N, Hoyer). Clinical assessment of airway patency and fibreoptic laryngoscopy (BF Typ 10, Olympus)--immediately and 20 min following the insertion of the LMA--were performed by two observers. RESULTS. The insertion of the LMA was successful on the first attempt in 89 patients while 5% required two, 4% three and 2% four attempts. 'Blindly' inserted without neuromuscular blockade the LMA provided a clinically sufficient airway in all patients. A central position of the LMA was assessed in only 59% of the cases. In 4 patients the mask was riding on the vocal folds. Positioned at the posterior larynx the cuff produced a compression of the laryngeal orifice when insufflated. Oblique insertion of the LMA or oblique head position during insertion produced a misplacement of the LMA. In 5 cases the LMA followed lateral movements of the head without losing its central position. In 87% the epiglottis was within the lumen of the LMA. Secretions inside the mask lumen or at the anatomic structures were seen in 36%. During manual ventilation with high inspiratory pressure (> 25 cm H2O) the oesophagus opened in 10 cases. CONCLUSIONS. Previous studies have suggested that the LMA takes a 'perfect' position at the laryngeal side when a clinically patent airway is recognized. In contrast, our results demonstrated that a central position of the LMA is achieved in only 59% of the cases. Our results indicate that epiglottic downfolding or left/right side or anterior/posterior misplacement are common but generally provide a satisfactory patent airway. This is consistent with fibreoptic findings in children and radiological observations in adults. The LMA is an essential enrichment to conventional airway management. It provides a better seal than the face mask, especially in bearded or in old patients where the facial contours are often not suited to the mask. Ideal indications seem to be elective operations of intermediate duration (1-2 h). The LMA does not protect against aspiration. For patients who are at risk of regurgitation of gastric contents, use of the LMA is absolutely contraindicated. Relative contraindications are local pathology of the pharynx and situations with low pulmonary compliance and/or high airway resistance (massive obesity, asthma, etc.), especially during controlled ventilation. Further studies are necessary to establish definite indications for the application of the LMA.

Adolescent↗
PubMedDate not supplied

Nitrous oxide concentrations in the posterior nasopharynx during administration by nasal mask.

PURPOSE: Nitrous oxide (N2O) administration with nasal mask produces variable outcomes in dental patients. This study describes a novel sampling method to measure actual inspired/expired N2O concentrations ([N2O]). METHODS: Fifteen adult volunteers (32.5 +/- 8.5 years) underwent placement of a nasopharyngeal probe. With a nasal mask, 100% oxygen (O2) was administered for 2 minutes. N2O was introduced incrementally every 2 minutes for a final flowmeter [N2O] of 50% and subsequently decreased in the same manner. Anesthesia gas monitors analyzed inspired/expired [N2O], [O2], and PETCO2 from the nasopharynx and end-inspired/expired [N2O] in the mask. Data were measured every 20 seconds and analyzed. Inspired/expired nasopharyngeal and nasal mask [N2O] and [O2] were expressed as the median value at each time point for all subjects and plotted against flowmeter settings. RESULTS: Average inspired nasal mask [N2O] was 31% lower than flowmeter settings and decreased by another 19% on the way to the nasopharyngeal sampling site. During the phase of increasing N2O, average expired nasopharyngeal [N2O] was 22% lower than inspired [N2O]. When N2O was decreased, the effect was reversed and average expired [N2O] was 18% higher than inspired. Expired [N2O] was on average 51% lower than flowmeter settings. Mean PETCO2 was 39.7 +/- 1.4 mm Hg. CONCLUSIONS: Nasopharyngeal end-expired [N2O] varied markedly from flowmeter settings. Correlation of PETCO2 with expected physiologic values validates sampling methodology. This method allows accurate, continuous, and actual measurements of inhaled/exhaled gases in awake patients as well as decision-making/analysis of effectiveness of mask type to determine average [N2O] during administration by nasal mask.

Adult↗
PubMed1993

Do adaptive frequency response (AFR) hearing aids reduce 'upward spread' of masking?

Speech recognition scores in noise are improved for some subjects who wear hearing aids that reduce low-frequency noise with an adjustable high-pass filter circuit. To evaluate whether these improvements were related to a reduction in upward spread of masking, pure-tone masking patterns for a low-frequency band-pass noise were measured in normal and hearing-impaired subjects. The filter skirt of the noise masker was very steep, with attenuation above the 1000 Hz cutoff greater than 120 dB per octave. Masking patterns for the same noise were also obtained in the presence of a high-pass filter that simulated the effects of an adaptive frequency response (AFR) hearing aid. Differences in the masking patterns were considered a measure of upward spread of masking. On average, subjects with high-frequency hearing loss demonstrated greater amounts of upward spread of masking than did normal-hearing listeners. Further, monosyllabic speech recognition in noise testing indicated improvements in performance of the hearing-impaired subjects related to the decrease of upward spread of masking in the high-pass filtering conditions.

Adult↗
PubMed1993

Masking and visual field effects on a lateralized rod-and-frame test.

The rod-and-frame test (RFT) has been widely used in the study of sex differences in spatial abilities. However, laterality studies involving this test are very scarce. An experiment was conducted to investigate whether laterality effects would be affected by post-stimulus masking. Ninety-six subjects participated in the experiment. For half the subjects, stimuli were followed by a blank screen, while for the other half, stimuli were followed by a mask. An overall left visual field advantage (LVFA) was found in the task. An interaction of sex of subjects, masking conditions, and frame tilt was also found. Further analyses showed that the sex by angle of frame interaction was significant when a mask was presented after the stimuli, but not when no mask followed the stimuli. Data tended to confirm the hypothesis that the LVFA was only significant when a mask was presented after the stimuli. These findings demonstrate the usefulness of a masking procedure in visual field studies, whereas the right hemisphere advantage found on the RFT is consistent with previous findings with visuo-spatial tasks.

Adolescent↗
PubMed1998

[Sore throat after use of the laryngeal mask and intubation].

The laryngeal mask was developed by Brain in 1981 and described for the first time in 1983. It has been applied a few million times worldwide since 1988. One of the main complication is soreness of the throat. Two hundred unselected patients who had gynaecological procedures under general anaesthesia--100 under laryngeal mask airway and 100 under intubation--were surveyed to ascertain the incidence of sore throats under laryngeal mask airway. Each patient was asked about soreness of the throat during the next two days. The incidence and duration of sore throats were recorded using a pain scale (0-100). After narcoses with the laryngeal mask, 63 patients had no complaints. Thirty-seven had sore throats with an average pain score of 8.1 +/- 13.8 on the day of operation. The average pain scores showed a decreasing tendency (4.2 +/- 9.5 and 0.4 +/- 2.6) for the first and second postoperative day. After intubation narcoses, we recorded sore throats significantly more frequently (p < 0.05) and the average pain score on the day of operation was significantly higher (13.2 +/- 17.5; p < 0.05) than after narcoses with the laryngeal mask. Also after narcoses with the laryngeal mask, the average pain scores decreased quickly on the first and second postoperative days (5.1 +/- 9.0 and 0.2 +/- 1.4). There were no differences regarding sore throats between narcoses with the laryngeal mask or intubation on these two postoperative days. Using both anaesthesiological methods, sore throat was not related to duration of anaesthesia or the experience of the anaesthetist.

Adolescent↗
PubMed1994

Native and sialic acid masked Lewis(a) antigen reactivity in medullary thyroid carcinoma. Distinct tumour-associated and prognostic relevant antigens.

Forty-six medullary thyroid carcinomas (MTC) were subjected to a qualitative and quantitative characterization of native and sialic acid masked Lewis(a) (Le(a)) antigens. Immunohistochemical investigations included monoclonal antibodies (MABs) directed against alpha(2,3)-sialyl-Le(a), i.e. CA19-9 (MAB 19-9), native Le(a) (MAB anti Le(a)) and alpha(2,3)sialyl type 1 structure, i.e. CA 50 (MAB C50). To detect sialic acid masked Le(a) reactivity, MAB anti-Le(a) was also applied to native and enzymatically desialylated tissue sections with and without masking of sialic acid residues by sialic acid and sequence specific lectins. Only 7 MTC (15%) displayed a weak expression of CA19-9, while 16 (33%) showed moderate positive staining for native Le(a). Twenty-seven tumours exhibited a strong staining by the N'ase MAB anti Le(a) staining sequence. The latter could most effectively be inhibited by the simultaneous masking of alpha(2,3)-and alpha-(2,6)-linked sialic acid residues due to the competitive binding of sialic acid and sequence specific lectins: Maackia amurensis agglutinin (specific alpha(2,3)-linked sialic acid) and Sambucus nigra agglutinin (specific alpha(2,6)-linked sialic acid). Thus, in MTC the major portion of sialic acid masked Le(a) antigen reactivity is different from that detected by the MAB 19-9. The antigen reactivity is probably due to Le(a) structures containing both alpha(2,3) and alpha(2,6)-linked sialic acid residues. A highly significant correlation between the expression of CA50 and that detected by the N'ase MAB anti-Le(a) staining sequence indicates that the alpha(2,3)-sialyl type 1 chain represents a common intermediate structure within the pathway of the biosynthesis of sialylated Le(a) antigens, excluding the formation of CA19-9 via the formation of the disialyl type 1 structure. This is subsequently fucosylated to the corresponding sialic acid masked Le(a). Preliminary clinicopathological studies indicate that the sialic acid masked Le(a) antigens detected by the N'ase MAB anti-Le(a) staining sequence are related to biologically aggressive MTC.

Antibodies, Monoclonal↗
PubMed1993

Masking of physicians in the Growth Failure in Children with Renal Diseases Clinical Trial.

Masking--hiding identities of treatments from the patient, physician and/or statistician--is a critical element in clinical trials. Wherever possible, masking is implemented to eliminate observational bias or systematic error. In this paper, general concepts of masking in clinical trials are examined. Specific masking procedures used in the "Growth Failure in Children with Renal Diseases" (GFRD) Clinical Trial are described. A method to evaluate the "success" of this masking procedure for physicians is introduced. For each randomized patient at each clinical center, the clinic director was asked to predict which treatment (1,25-dihydroxyvitamin D3 or dihydrotachysterol) was assigned. Results showed that 72% of responses initially indicated "absolutely no idea" of treatment. Additional analyses revealed that the number and percentage of "correct" guesses were essentially equal for the two treatment groups and that a patient's time on treatment did not affect the mask. We conclude that the mask of physicians in the GFRD Clinical Trial was well maintained.

Bias↗
PubMed1989

Receptive field properties of human motion detector units inferred from spatial frequency masking.

This study was designed to investigate the spatial frequency selectivity and spatial structure of receptive fields of motion sensitive mechanisms in human vision. Spatial frequency selectivity was inferred from masking measurements, using dynamic test and mask stimuli. For test frequencies between 0.025 and 15.0 c/deg, maximal masking occurred when the mask frequency matched that of the test, suggesting that the test was detected by mechanisms tuned to (or near to) that frequency. For tests below 0.025 c/deg or above 15.0 c/deg, maximal masking occurred at 0.025 and 15.0 c/deg, respectively, suggesting that there exist no mechanisms selective to frequencies outside these limits. A masking model, suitable for interpreting results obtained with drifting test stimuli, was developed and used to calculate spatial frequency selectivity functions from masking data. Assuming small signal linearity, and a constant phase spectrum, the selectivity functions were inverse-Fourier transformed to yield estimates of the extent and structure of receptive fields. Field width was found to vary with test spatial frequency from 5.8 deg at 0.03 c/deg to 0.05 deg at 10.0 c/deg. These estimates were compared with width estimates previously obtained by a summation technique (Anderson & Burr, 1987), and found to be similar over a wide range of spatial frequencies (2.5 log units). Gabor functions provided a reasonable fit to the calculated field profiles at high spatial frequencies (above 1.0 c/deg), but not at low frequencies.

Fourier Analysis↗
PubMed2006

Masked hypertension and target organ damage in treated hypertensive patients.

BACKGROUND: Recent studies have shown that an elevated ambulatory or home blood pressure (BP) in the absence of office BP-a phenomenon called masked hypertension-is associated with poor cardiovascular prognosis. However, it remains to be elucidated how masked hypertension modifies target organ damage in treated hypertensive patients. METHODS: A total of 332 outpatients with chronically treated essential hypertension were enrolled in the present study. Patients were classified into four groups according to office (<140/90 or >or=140/90 mm Hg) and daytime ambulatory (<135/85 or >or=135/85 mm Hg) BP levels; ie, controlled hypertension (low office and ambulatory BP), white-coat hypertension (high office but low ambulatory BP), masked hypertension (low office but high ambulatory BP), and sustained hypertension (high office and ambulatory BP). Left ventricular mass index, carotid maximal intima-media thickness, and urinary albumin levels were determined in all subjects. RESULTS: Of the patients, 51 (15%), 65 (20%), 74 (22%), and 142 (43%) were identified as having controlled hypertension, white-coat hypertension, masked hypertension, and sustained hypertension, respectively. Left ventricular mass index, maximal intima-media thickness, and urinary albumin level in masked hypertension were significantly higher than in controlled hypertension and white-coat hypertension, and were similar to those in sustained hypertension. Multivariate regression analyses revealed that the presence of masked hypertension was one of the independent determinants of left ventricular hypertrophy, carotid atherosclerosis, and albuminuria. CONCLUSIONS: Our findings indicate that masked hypertension is associated with advanced target organ damage in treated hypertensive patients, comparable to that in cases of sustained hypertension.

Aged↗
PubMed2001

Some effects of repeated handling and the use of a mask on stress responses in zebu cattle during restraint.

The objective of this investigation was to evaluate the effect of repeated handling and the use of a mask on the order of entry, temperament, cortisol concentration and heart and respiratory rates of Brahman cattle during restraint in a squeeze chute. In the first experiment, 18 cows were restrained in the chute for 10min on 19 test-days and blood samples were collected during five of the trials. Habituation to handling was reflected by a decrease in cortisol concentration as the study advanced (P<0.01). In the second experiment, conducted 6 months later, animals were randomly allotted to two groups, alternating the use of a mask over test-days while restraining the cows in the chute for 3min. Respiratory and heart rates were measured at the beginning and end of each 3min trial. A blood sample was also taken at the end of each trial. Respiratory rates decreased while the animals were restrained and this decrease tended to be greater (P=0.09) when the animals were wearing masks (3.06) than when not (2.2breaths/min). Heart rates also decreased and more so for masked animals (10.6beats/min) than for non-masked (5.0, P<0.01). Cortisol values tended to be higher (9.9 versus 4.7ng/ml, P=0.08) when animals were restrained without a mask. Temperament scores were lower (P>0.01) when cows were masked and have a relative high correlation (r=0.58) with flight distance values, (P<0.05). Finally, the order of entrance was found consistent over test-days, (P<0.01). It is concluded that Brahman cattle: (a) habituate to repeat handling in a squeeze chute; (b) are less emotionally reactive when their eyes were covered during this process and (c) establish a repeatable order of entrance to the chute.

Journal Article↗
PubMed2004

Practitioners' impressions of patients with Parkinson's disease: the social ecology of the expressive mask.

The expressive mask of Parkinson's disease, a reduced spontaneity, intensity, and fluidity of facial, bodily, and vocal expression, jeopardizes interpersonal interaction and quality of life. Observers have difficulty perceiving the "real" person behind the mask, leading to failed communication and misunderstanding. A social ecological explanation of this difficulty is that observers have learned in their daily social lives, and quite appropriately so, that expressive behavior reveals meaningful information about character. The premise of this study was that health practitioners, especially novices, would bring into the clinic their everyday perceptual tendencies related to deciphering character. The study examined novice and expert practitioners' impressions of the personality of patients with Parkinson's disease who were videotaped during a healthcare interview. It was found that practitioners, especially novices, appeared to be overly sensitive to expressive masking when forming impressions about patient extraversion. They incorrectly perceived patients with more masking to be less extraverted than patients with less masking. Novice practitioners were particularly inaccurate in their impressions of neuroticism compared to experts. Novices incorrectly perceived patients with more masking as being more neurotic, whereas experts tended to be sensitive to valid cues of neuroticism. Practitioners' impressions of patient conscientiousness were not sensitive to masking and were highly accurate.

Attitude of Health Personnel↗