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PubMed1981

Masking of foveal and parafoveal vision during eye fixations in reading.

A window or visual mask as moved across text in synchrony with the reader's eye movements. The size of the window or mask was varied so that either information in foveal or parafoveal vision was masked on each fixation. In another experiment, the onset of the mask was delayed for a certain amount of time following the end of the saccade. The results of the experiments point out the relative importance of foveal and parafoveal vision for reading and further indicate that most of the visual information necessary for reading can be acquired during the first 50 msec that information is available during an eye fixation.

Adult↗
PubMed1998

Emotional conditioning to masked stimuli: expectancies for aversive outcomes following nonrecognized fear-relevant stimuli.

The role of conscious awareness in human Pavlovian conditioning was examined in 2 experiments using masked fear-relevant (snakes and spiders; Experiments 1 and 2) and fear-irrelevant (flowers and mushrooms; Experiment 1) pictures as conditioned stimuli, a mild electric shock as the unconditioned stimulus, and skin conductance responses as the primary dependent variable. The conditioned stimuli were presented briefly (30 ms) and were effectively masked by an immediately following masking stimulus. Experiment 1 demonstrated nonconscious conditioning to fear-relevant but not to fear-irrelevant stimuli. Even though the participants could not recognize the stimuli in Experiment 2, they differentiated between masked stimuli predicting and not predicting shocks in expectancy ratings. However, expectancy ratings were not related to the conditioned autonomic response.

Adult↗
PubMed1983

Backward masking, the suffix effect, and preperceptual storage.

This article considers the use of auditory backward recognition masking (ABRM) and stimulus suffix experiments as indexes of preperceptual auditory storage. In the first part of the article, two ABRM experiments that failed to demonstrate a mask disinhibition effect found previously in stimulus suffix experiments are reported. The failure to demonstrate mask disinhibition is inconsistent with an explanation of ABRM in terms of lateral inhibition. In the second part of the article, evidence is presented to support the conclusion that the suffix effect involves the contributions of later processing stages and does not provide an uncontaminated index of preperceptual storage. In contrast, it is claimed that ABRM experiments provide the most direct index of the temporal course of perceptual recognition. Partial-report tasks and other paradigms are also evaluated in terms of their contributions to an understanding of preperceptual auditory storage. Differences between interruption and integration masking are discussed along with the role of preperceptual auditory storage in speech perception.

Humans↗
PubMed1999

An event-related potential examination of masked and unmasked repetition priming in Alzheimer's disease: implications for theories of implicit memory.

Fifteen patients diagnosed with Alzheimer's disease (AD) and 26 matched older controls engaged in a lexical-decision task with a list of words and nonwords while event-related brain potentials (ERPs) were recorded. Two repetition conditions were embedded in the list: words repeated at relatively long lags or words repeated shortly after a brief masked presentation. Although older controls displayed behavioral and ERP repetition priming for words repeated at long lags, consistent with previous studies, AD patients displayed neither. In contrast, both controls and AD patients displayed an ERP repetition priming effect for words repeated shortly after a brief masked presentation. ERP priming effects for masked and unmasked repetition differed in older controls, and additionally, the ERP masked priming effect differed between controls and AD patients. Results are discussed in the context of studies that have examined memory performance in brain-damaged populations using an impaired-intact dichotomy.

Acoustic Stimulation↗
PubMed2006

How much like a target can a mask be? Geometric, spatial, and temporal similarity in priming: a reply to Schlaghecken and Eimer (2006).

The authors make 3 points in response to F. Schlaghecken and M. Eimer's proposal of self-inhibition as an explanatory factor in the negative compatibility effect: (a) The self-inhibition hypothesis lacks empirical support for its main tenets; (b) considering the roles of geometric, spatial, and temporal similarity of primes and masks makes self-inhibition unnecessary; and (c) the negative compatibility effect occurs even when the main tenets of self-inhibition are violated. The authors propose that understanding what is "relevant" in a masked-priming task applies not only to geometric features that are shared with the target but to spatial and temporal ones as well. Briefly, target-mask similarity determines how motor preparation is accumulated during the prime-mask sequence.

Adult↗
PubMed1989

Early interference in a priming task with brief masked targets.

Priming effects were examined in two experiments using either a pronunciation or lexical decision task. The prime, either a strong associate of the target, an unrelated word, or a neutral prime, was presented for 200 ms. After an SOA of 200, 400, or 800 ms, a masked target was presented for 33.3, 50, or 66.7 ms. Attention was manipulated by varying the probability that prime and target would be strongly associated. Both experiments showed significant interference in the low attention condition and at the 200-ms SOA, presumably before the onset of consciously directed processing. Two subsequent experiments using a short SOA and the low attention condition attempted to determine the conditions under which this interference will occur by varying the interstimulus interval, target duration, and the mask. It was found that interference occurred only when targets were brief and masked. These results are discussed in terms of a model involving lateral inhibition between nodes in semantic memory. It is suggested that when the target is brief and masked, the node in memory corresponding to the target is much less strongly activated and therefore more susceptible to the inhibitory effects of other activated nodes.

Attention↗
PubMed1993

Excimer laser sclerostomy: the in vitro development of a modified open mask delivery system.

The argon fluoride (ArF) excimer laser at 193 nm ablates the ocular tissues with a new order of precision and virtually no adjacent damage. A glaucoma filtration operation has been designed in which small-bore sclerostomies are created using the ArF excimer laser delivered through an open mask. The mask plicates the conjunctiva at the limbus prior to ablation. Removing the mask at the end of the procedure allows the conjunctiva to relax back to its original position, separating the conjunctival and scleral wounds. Formal conjunctival dissection is thus avoided. Feasibility studies in cadaver pig eyes, using a fluence per pulse of 400 mJ/cm2 and a pulse repetition rate of 20 Hz, indicate that sclerostomies of 300 microns diameter can be reliably formed if an en-face air jet is built into the mask to raise the pressure in the target area, preventing aqueous flooding.

Animals↗
PubMed1991

Effect of respiratory training with a mouth-nose-mask in tetraplegics.

Ten tetraplegics, 8 males and 2 females, with a median age of 32 years participated in a scheduled 6 weeks training programme with a respiratory muscle training mouth-nose-mask (RMT-mask) with a fixed expiratory and an increasing inspiratory resistance set by the tetraplegic in accordance to his/her increasing ability during the training period. During the 6 weeks the tetraplegics required to use the RMT-mask for 15 minutes three times a day. Before and after each training session they measured peak flow (PEF). Lung volumes, ventilatory and diffusion capacity were measured before and after the 6 weeks training period. The training resulted only in a significant change in the PEF, which increased with 11% from 371 l/min before to 412 l/min in average after the 6 weeks of training (p less than 0.025). This statistically significant increase was confirmed by the measurements of PEF performed by the tetraplegics themselves during the training period. In addition there was an increase in PEF from before to immediately after each 15 minutes training session, this trend reached statistically significance (p less than 0.025) in the third '2 weeks period'. These results might indicate a possibility of improving the tetraplegics ability to cough by use of a simple RMT-mask, which in turn might prevent certain lung complications including pneumonia, and atelectasia.

Adult↗
PubMed2006

Hood versus mask nebulization in infants with evolving bronchopulmonary dysplasia in the neonatal intensive care unit.

OBJECTIVE: To compare infants' discomfort, nursing-time and caregiver preference, and assess the clinical efficiency (as a secondary outcome) of hood versus facemask nebulization in infants with evolving bronchopulmonary dysplasia (BPD) in the neonatal intensive care unit. STUDY DESIGN: A prospective, open, randomized, controlled crossover clinical trial. In total, 10 infants with BPD who were on inhaled beta-agonist bronchodilators and corticosteroids were randomly assigned to receive their nebulized treatments either by a facemask, or by a hood for 2-3 days, and then crossover to receive the same treatments with the other technique for another 2-3 days. Infants' discomfort, nursing-time, caregiver preference and clinical efficiency were compared. RESULTS: At baseline there was no significant clinical difference between the groups. Nurse-time required for administering the hood nebulization (mean+/-s.e.m.: 1.9+/-0.1 min) was significantly shorter than the time for mask nebulization (12.0+/-0.6 min, P<0.0001). Infants' discomfort score was significantly lower (0.1+/-0.04) for hood versus mask nebulization (2.5+/-0.2, P<0.0001). Nurses and parents unequivocally preferred the hood treatment. During both mask and hood nebulization therapies (2-3 days) clinical efficiency was comparable. While both methods caused an immediate (20 min post) clinical improvement, the immediate respiratory assessment change score was significantly greater for the hood versus the mask nebulization (0.62+/-0.27 versus 0.13+/-0.14, P<0.05). CONCLUSIONS: Nebulization of aerosolized medications in infants with evolving BPD by hood was less time-consuming for caregivers and was much better tolerated by the infants while being at least as effective as the conventional facemask nebulization.

Administration, Inhalation↗
PubMed2005

Sensory processing of backward-masking signals in children with language-learning impairment as assessed with the auditory brainstem response.

The purpose of this study was to examine the possible contribution of sensory mechanisms to an auditory processing deficit shown by some children with language-learning impairment (LLI). Auditory brainstem responses (ABRs) were measured from 2 groups of school-aged (8-10 years) children. One group consisted of 10 children with LLI, and the other group (control) consisted of 10 children with normally developing language. The ABR was elicited with a brief tone burst presented either alone (no-masking condition) or immediately followed by a longer duration noise burst (backward-masking condition). The primary dependent variable was the latency of wave V of the ABR. The mean latencies were not significantly different for the 2 groups in the no-masking condition. However, in the backward-masking condition, the mean latency for the LLI group was significantly increased relative to the mean latency for the control group. Thus, the presence of successive sounds delay the neural response in children with LLI. The explanation for this delay at the level of the brainstem is not known, but it may be due to disruption of synchrony, activation of alternate (less direct) pathways, increased inhibition, or some combination of these (or other) factors.

Child↗
PubMed1977

Loudness perception for short-duration tones in masking noise.

The effect of masking noise on the temporal summation of loudness is investigated here by performing loudness balances between a standard 500-msec tone burst (1000 Hz at either 20-, 50-, or 80-dB SPL) and either masked or unmasked comparison tone bursts (1000 Hz with durations between 10 and 640 msec). In all but two instances, the obtained functions relating SPL for equal loudness to stimulus duration could be plotted as two line segments that met to form a knee. The slopes of the line segments at durations less than the kneepoints are altered by the masking noise, becoming less steep with increased masking. The rate of the slope decrease is related to the standard sound pressure level (SPL) and is greatest using the 80-dB SPL standard and least with the 20-dB SPL standard. Temporal summation of loudness continues at durations above the kneepoints. However, the obtained slopes are less than those found below the knee, and are independent of the test conditions. The slope changes are found to be related to the noise producing a power transformation on the operating characteristics of the auditory system. These latter findings are discussed in relation to Zwislocki's quantitative theory of the temporal summation of loudness.

Acoustic Stimulation↗
PubMed1982

Masking of pure tones by broad-band noise in cochlear-impaired listeners.

We measured masked thresholds for pulsed pure tone (5, 1.0, 2.0, and 4.0 kHz) in the presence of different levels of broad-band noise (nominally 0, 20, 40, and 60 dB/Hz). Several of the 16 cochlear-impaired listeners displayed masked thresholds that were considerably higher than those obtained from 10 normal listeners. At the 60 dB/hz noise level the correlation coefficients between thresholds in noise and thresholds in quiet were r = 36, .44, .63 and .64 for signal frequencies of .5, 1.0, 2.0, and 4.0 kHz, respectively. The growth of masking, as masker level was increased, was linear for the normal listeners but was disproportionate and nonlinear in some cochlear-impaired listeners. In these data and data from others studies, it is clear that thresholds in noise cannot be predicted from thresholds in quiet. Masked thresholds are related to other measures of frequency resolution and to speech intelligibility in noise, but it is argued that psychoacoustic tuning curves provide more direct measures of the auditory-filter characteristics.

Adult↗
PubMed1982

Use of contralateral masking in the measurement of the auditory brainstem response.

In the first portion of this study, the effects of two levels of contralateral masking on the auditory brainstem response (ABR) were investigated in 10 normal-hearing subjects. No significant changes were observed in the mean latency-intensity functions or the mean amplitude-intensity functions of this group of subjects when noise of various levels was added to the nontest ear. In the second portion of this study, ABRs were also recorded from the poorer ear of four subjects with a profound unilateral sensorineural hearing loss. Results from the latter group revealed a crossed-over wave V in all cases when the stimulus was delivered to the poorer ear and the nontest (better) ear was not masked. Contralateral masking obliterated this "crossed ABR" in all four unilaterally impaired subjects. These results provide support for the use of contralateral masking when recording from the poorer ear of subjects having asymmetrical hearing loss.

Adult↗
PubMed1989

The perception of rhythm and word boundaries in noise-masked speech.

The present experiment tested the suggestion that human listeners may exploit durational information in speech to parse continuous utterances into words. Listeners were presented with six-syllable unpredictable utterances under noise-masking, and were required to judge between alternative word strings as to which best matched the rhythm of the masked utterances. For each utterance there were four alternative strings: (a) an exact rhythmic and word boundary match, (b) a rhythmic mismatch, and (c) two utterances with the same rhythm as the masked utterance, but different word boundary locations. Listeners were clearly able to perceive the rhythm of the masked utterances: The rhythmic mismatch was chosen significantly less often than any other alternative. Within the three rhythmically matched alternatives, the exact match was chosen significantly more often than either word boundary mismatch. Thus, listeners both perceived speech rhythm and used durational cues effectively to locate the position of word boundaries.

Cues↗
PubMed1990

Frequency selectivity and comodulation masking release in adults and in 6-year-old children.

Frequency selectivity and comodulation masking release (CMR) for a 1000-Hz signal frequency were examined in 6-year-old children and adults. An abbreviated measure of frequency selectivity was also conducted for a 500-Hz signal. Frequency selectivity was measured using a notched-noise masking method, and CMR was measured using narrow bands of noise whose amplitude envelopes were either uncorrelated or correlated. There were 6 listeners in each age group. No differences were observed between the adults and children for either auditory measure. Similarly, no differences were observed in the ability to detect a pure-tone signal in a relatively wideband noise masker. When the masking noise was narrowband, however, the masked thresholds of the children were higher than those of the adults. Two characteristics that distinguish narrowband noise from wideband noise are: (1) narrowband noise has a pitch quality corresponding to its center frequency, whereas wideband noise does not have definite pitch; (2) the intensity fluctuations are relatively greater in narrowband noise than in wideband noise. This may suggest that 6-year-old children have a reduced ability to detect signals in noise backgrounds where the signal has perceptual qualities similar to the noise, or in noise backgrounds having a high degree of fluctuation.

Acoustics↗
PubMed1994

Electropalatographic data collected with and without a face mask.

This study investigates the extent to which the use of a face mask conveys linguopalatal contact changes during speech production. Electropalatographic data from five Catalan speakers were collected for different consonants, i.e., the alveolar stop [n], the alveolopalatal stop [n] and the palatal approximant [j], in the sequences [iCi] and [aCe]. Results for [n] indicate more closure retraction in the mask versus nonmask condition occurring presumably when the mask is pressed forcefully against the face in front of the mouth. The use of the mask for [n] and [j] causes an increase in dorsopalatal contact, which reflects most likely a strategy of articulatory and/or perceptual compensation.

Electric Stimulation↗
PubMed1999

The effects of decreased audibility produced by high-pass noise masking on N1 and the mismatch negativity to speech sounds /ba/and/da.

This study investigated the effects of decreased audibility produced by high-pass noise masking on the cortical event-related potentials (ERPs) N1 and mismatch negativity (MMN) to the speech sounds /ba/ and /da/, presented at 65 dB SPL. ERPs were recorded while normal listeners (N = 11) ignored the stimuli and read a book. Broadband masking noise was simultaneously presented at an intensity sufficient to mask the response to the speech sounds, and subsequently high-pass filtered. The conditions were QUIET (no noise); high-pass cutoff frequencies of 4000, 2000, 1000, 500, and 250 Hz; and broadband noise. Behavioral measures of discrimination of the speech sounds (d' and reaction time) were obtained separately from the ERPs for each listener and condition. As the cutoff frequency of the high-pass masker was lowered, ERP latencies increased and amplitudes decreased. The cutoff frequency where changes first occurred differed for N1 and MMN. N1 showed small systematic changes across frequency beginning with the 4000-Hz high-pass noise. MMN and behavioral measures showed large changes that occurred at approximately 1000 Hz. These results indicate that decreased audibility, resulting from the masking, affects N1 and the MMN in a differential manner. N1 reflects the presence of audible stimulus energy, being present in all conditions where stimuli were audible, whether or not they were discriminable. The MMN is present only for those conditions where stimuli were behaviorally discriminable. These studies of cortical ERPs in high-pass noise studies provide insight into the changes in brain processes and behavioral performance that occur when audibility is reduced, as in hearing loss.

Adult↗
PubMed2000

Age-related improvements in auditory backward and simultaneous masking in 6- to 10-year-old children.

This study investigated the development of auditory frequency and temporal resolution using simultaneous and backward masking of a tone by a noise. The participants were 6- to 10-year-old children and adults. On the measure of frequency resolution (the difference in the detection threshold for a tone presented either in a bandpass noise or in a spectrally notched noise), 6-year-old children performed as well as adults. However, for the backward masking task, 6-year-olds had, on average, 34 dB higher thresholds than adults. A negative exponential decay function fitted to the backward masking data for subjects of all ages indicated that adult-like temporal resolution may not be reached until about 11 years of age. These results show that, measured by masking, frequency resolution has reached adult-like performance by 6 years of age, whereas temporal resolution develops beyond 10 years of age. Six-year-old children were also assessed with tests of cognitive ability. Improvements in both frequency and temporal resolution were found with increasing IQ score.

Adult↗