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Frequency-to-electrode allocation and speech perception with cochlear implants.

The hypothesis was investigated that selectively increasing the discrimination of low-frequency information (below 2600 Hz) by altering the frequency-to-electrode allocation would improve speech perception by cochlear implantees. Two experimental conditions were compared, both utilizing ten electrode positions selected based on maximal discrimination. A fixed frequency range (200-10513 Hz) was allocated either relatively evenly across the ten electrodes, or so that nine of the ten positions were allocated to the frequencies up to 2600 Hz. Two additional conditions utilizing all available electrode positions (15-18 electrodes) were assessed: one with each subject's usual frequency-to-electrode allocation; and the other using the same analysis filters as the other experimental conditions. Seven users of the Nucleus CI22 implant wore processors mapped with each experimental condition for 2-week periods away from the laboratory, followed by assessment of perception of words in quiet and sentences in noise. Performance with both ten-electrode maps was significantly poorer than with both full-electrode maps on at least one measure. Performance with the map allocating nine out of ten electrodes to low frequencies was equivalent to that with the full-electrode maps for vowel perception and sentences in noise, but was worse for consonant perception. Performance with the evenly allocated ten-electrode map was equivalent to that with the full-electrode maps for consonant perception, but worse for vowel perception and sentences in noise. Comparison of the two full-electrode maps showed that subjects could fully adapt to frequency shifts up to ratio changes of 1.3, given 2 weeks' experience. Future research is needed to investigate whether speech perception may be improved by the manipulation of frequency-to-electrode allocation in maps which have a full complement of electrodes in Nucleus implants.

Adult↗

Static, dynamic, and relational properties in vowel perception.

The present work reviews theories and empirical findings, including results from two new experiments, that bear on the perception of English vowels, with an emphasis on the comparison of data analytic "machine recognition" approaches with results from speech perception experiments. Two major sources of variability (viz., speaker differences and consonantal context effects) are addressed from the classical perspective of overlap between vowel categories in F1 x F2 space. Various approaches to the reduction of this overlap are evaluated. Two types of speaker normalization are considered. "Intrinsic" methods based on relationships among the steady-state properties (F0, F1, F2, and F3) within individual vowel tokens are contrasted with "extrinsic" methods, involving the relationships among the formant frequencies of the entire vowel system of a single speaker. Evidence from a new experiment supports Ainsworth's (1975) conclusion [W. Ainsworth, Auditory Analysis and Perception of Speech (Academic, London, 1975)] that both types of information have a role to play in perception. The effects of consonantal context on formant overlap are also considered. A new experiment is presented that extends Lindblom and Studdert-Kennedy's finding [B. Lindblom and M. Studdert-Kennedy, J. Acoust. Soc. Am. 43, 840-843 (1967)] of perceptual effects of consonantal context on vowel perception to /dVd/ and /bVb/ contexts. Finally, the role of vowel-inherent dynamic properties, including duration and diphthongization, is briefly reviewed. All of the above factors are shown to have reliable influences on vowel perception, although the relative weight of such effects and the circumstances that alter these weights remain far from clear. It is suggested that the design of more complex perceptual experiments, together with the development of quantitative pattern recognition models of human vowel perception, will be necessary to resolve these issues.

Humans↗

Perception of and adaptation to rectal isobaric distension in patients with faecal incontinence.

BACKGROUND: Perception of, and adaptation of the rectum to, distension probably play an important role in the maintenance of continence, but perception studies in faecal incontinence provide controversial conclusions possibly related to methodological biases. In order to better understand perception disorders, the aim of this study was to analyse anorectal adaptation to rectal isobaric distension in subjects with incontinence. PATIENTS/METHODS: Between June 95 and December 97, 97 consecutive patients (nine men and 88 women, mean (SEM) age 55 (1) years) suffering from incontinence were evaluated and compared with 15 healthy volunteers (four men and 11 women, mean age 48 (3) years). The patients were classified into three groups according to their perception status to rectal isobaric distensions (impaired, 22; normal, 61; enhanced, 14). Anal and rectal adaptations to increasing rectal pressure were analysed using a model of rectal isobaric distension. RESULTS: The four groups did not differ with respect to age, parity, or sex ratio. Magnitude of incontinence, prevalence of pelvic disorders, and sphincter defects were similar in the incontinent groups. When compared with healthy controls, anal pressure and rectal adaptation to distension were decreased in incontinent patients. When compared with incontinent patients with normal perception, patients with enhanced perception experienced similar rectal adaptation but had reduced anal pressure. In contrast, patients with impaired perception showed considerably decreased rectal adaptation but had similar anal pressure. CONCLUSION: Abnormal sensations during rectal distension are observed in one third of subjects suffering from incontinence. These abnormalities may reflect hyperreactivity or neuropathological damage of the rectal wall.

Adaptation, Physiological↗

Perception of airflow obstruction and associated breathlessness in normal and asthmatic subjects: correlation with anxiety and bronchodilator needs.

BACKGROUND: Perception of bronchoconstriction varies between individuals and its determinants remain to be identified. The perception of airflow obstruction and breathlessness during induced bronchoconstriction was studied, and the effects of anxiety, repetition of the stimulus, and bronchodilator needs on these measurements were examined in normal and asthmatic subjects. METHODS: Fifteen normal (control) and 25 asthmatic subjects had two consecutive methacholine inhalation tests to induce a 20-50% fall in FEV1. Evaluation of the perceived magnitude of airflow obstruction, breathlessness, level of anxiety generated, and bronchodilator needs was obtained before each FEV1 measurement on a modified Borg scale from 0 to 10. RESULTS: Mean (SE) maximal fall in FEV1 in asthmatic and control subjects was of similar magnitude: test 1, 37.6 (1.4)% and 38.7 (3.1)%, and test 2, 36.0 (1.6)% and 27.7 (2.4)% respectively. There was a large interindividual variation in perception of airflow obstruction and breathlessness but, although they were well correlated in asthmatic subjects, they were perceived differently by the control subjects. Perception of airflow obstruction was greater in asthmatic subjects. The level of anxiety and the bronchodilator use were low and did not influence perception. CONCLUSIONS: During induced bronchoconstriction, the overall perception of airflow obstruction and breathlessness were similar among asthmatic subjects but controls showed a higher perception of airflow obstruction for any given level of breathlessness. Asthmatic subjects perceived airflow obstruction and breathlessness to a greater degree than did controls but anxiety and bronchodilator need were not correlated with respiratory sensation. The variability of bronchodilator use for similar degrees of bronchoconstriction suggests that it may be misleading to assess the severity of asthma control using only this indirect measure.

Adult↗

Neural mechanisms of tactual form and texture perception.

In the last decade or so, there has been rapid movement toward the use of more complex stimuli in the study of perceptual function related to the hand. This review has focused on the neural mechanisms of form and texture perception. Evidence from neurophysiological and psychophysical studies in which static touch, scanning touch, and the Optacon were used indicate that the spatial acuity of the RA system may be as much as three times poorer than the SAI system, evidence that suggests that form perception is dominated by the SAI system. Pattern recognition behavior in a tactual letter recognition task appears to be directly related to the response properties of SAI afferent fibers. Psychophysical studies of roughness perception show that roughness magnitude is related to surface structure in an orderly manner. Because roughness varies along an intensive continuum, mean impulse rate in one or more of the afferent systems is the most obvious coding possibility. No satisfactory relationship between mean impulse rate and roughness has been observed, however. The strongest hypothesis is that tactual roughness perception is based on spatial variation in the SAI population response. The combined evidence from studies reviewed here suggests complementary roles for each of the afferent systems, which are presented as working hypotheses: The SAI system is the primary spatial system and is responsible for tactual form and roughness perception when the fingers contact a surface directly and for the perception of external events through the distribution of forces across the skin surface. The PC system is responsible for the perception of external events that are manifested through transmitted high-frequency vibrations of the kind that are critical in the use of objects as tools. The RA system is responsible for the detection and representation of localized movement between skin and a surface as well as for surface form and texture when surface variation is too small to activate the SAI afferents effectively.

Animals↗

Gut perception in humans is modulated by interacting gut stimuli.

Digestive symptoms depend on multiple interacting gut stimuli, but integration of visceral afferent traffic is poorly understood. Our aim was to elucidate the contribution of simultaneous intestinal stimuli to conscious perception. In 17 healthy subjects, we performed stimulus-response trials of jejunal distensions (1-min duration at 5-min intervals in 8-ml increments) either alone or with a background electrical stimulus, and stimulus-response trials of electrical stimuli (1-min duration at 5-min intervals in 6-mA steps) either alone or with a background intestinal distension. The four stimulus-response trials were performed concomitantly applying the different types of stimuli in random order. Perception was measured on a scale of 0 to 6. Background stimulation markedly increased perception of test stimuli, reducing tolerance from 44 +/- 3 to 32 +/- 3 ml and from 67 +/- 6 to 33 +/- 4 mA (P < 0.05 for both). However, whereas jejunal distensions below the perception threshold did not modify perception of the background stimulus (4 +/- 1% change; not significant), unperceived electrical stimuli exerted a sensitizing effect and increased perception of the background distension up to uncomfortable levels (111 +/- 40% increment; P < 0.05). In conclusion, activation of different pools of jejunal afferents produces summative effects on perception, and this sensitizing effect can be exerted by unperceived stimulation of mechanoinsensitive jejunal afferents.

Adult↗

Multiple sensory cues underlying the perception of translation and path.

The translational linear vestibuloocular reflex compensates most accurately for high frequencies of head translation, with response magnitude decreasing with declining stimulus frequency. However, studies of the perception of translation typically report robust responses even at low frequencies or during prolonged motion. This inconsistency may reflect the incorporation of nondirectional sensory information associated with the vibration and noise that typically accompany translation, into motion perception. We investigated the perception of passive translation in humans while dissociating nondirectional cues from actual head motion. In a cue-dissociation experiment, interaural (IA) motion was generated using either a linear sled, the mechanics of which generated noise and vibration cues that were correlated with the motion profile, or a multiaxis technique that dissociated these cues from actual motion. In a trajectory-shift experiment, IA motion was interrupted by a sudden change in direction (+/-30 degrees diagonal) that produced a change in linear acceleration while maintaining sled speed and therefore mechanical (nondirectional) cues. During multi-axis cue-dissociation trials, subjects reported erroneous translation perceptions that strongly reflected the pattern of nondirectional cues, as opposed to nearly veridical percepts when motion and nondirectional cues coincided. During trajectory-shift trials, subjects' percepts were initially accurate, but erroneous following the direction change. Results suggest that nondirectional cues strongly influence the perception of linear motion, while the utility of cues directly related to translational acceleration is limited. One key implication is that "path integration" likely involves complex mechanisms that depend on nondirectional and contextual self-motion cues in support of limited and transient otolith-dependent acceleration input.

Acceleration↗

Role of extraocular muscle proprioception in the development of depth perception in cats.

1. The ophthalmic branch of the trigeminal nerve (V1), which carries extraocular proprioceptive afferents, was sectioned unilaterally or bilaterally in kittens and adult cats. Depth perception was measured behaviorally in these sectioned cats, as well as in control cats. 2. For kittens that underwent unilateral V1 sections at 6-11 wk of age, postsurgical values of binocular depth perception--measured 1.5-3 mo later--were 2-3 times worse than in normal control animals. Cats that underwent unilateral V1 sections as adults, however, showed no postsurgical deficits in binocular depth perception. 3. For kittens that underwent bilateral V1 sections at 6.5-7.5 wk of age, similar longterm impairments were found in binocular depth perception. No impairment was found in two kittens bilaterally sectioned at 11.5 wk of age. A cat that underwent bilateral sections as an adult also showed no binocular depth perception deficits. 4. Although these behavioral effects were observed only when unilateral and bilateral V1 sections were performed up to a certain age in development, they differed in two ways. 1) Imbalance of extraocular proprioceptive inflow produced by unilateral section had a deleterious effect at an age when the final adult level had been reached. At that stage, complete suppression of inflow produced by the bilateral section failed to impair the final level of binocular performance. 2) Short-term effects observed during the week following the section appeared in bilaterally operated animals as a transient freezing of the presurgical binocular performance whatever the age of the section during the sensitive period. In contrast, short-term effects produced by unilateral section were found to be age dependent: a progressive slowing down in the normal rate of improvement of binocular thresholds was observed following a section performed at 5 wk of age; an arrest in development was found when surgery was done at 6-7 wk of age. A significant impairment appeared within 2 days when the section was performed at 11 wk of age. 5. In all experimental kittens, monocular depth perception thresholds were unaffected or impaired only to a minor extent (less than 15% change) following the unilateral or bilateral section. In unilaterally operated kittens, there were no consistent differences associated with the side of the section. 6. A sham-operated kitten, in which the V1 was visualized but not cut, showed no impairments in binocular or monocular depth perception.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗

Distributions of alternation rates in various forms of bistable perception.

Studying the temporal dynamics of bistable perception can be useful for understanding neural mechanisms underlying the phenomenon. We take a closer look at those temporal dynamics, using data from four different ambiguous stimuli. We focus our analyses on two recurrent themes in bistable perception literature. First, we address the question whether percept durations follow a gamma distribution, as is commonly assumed. We conclude that this assumption is not justified by the gamma distribution's approximate resemblance to distributions of percept durations. We instead present two straightforward distributions of reciprocal percept durations (i.e., rates) that both easily surpass the classic gamma distribution in terms of resemblance to empirical data. Second, we compare the distributions arising from binocular rivalry with those from other forms of bistable perception. Parallels in temporal dynamics between those classes of stimuli are often mentioned as an indication of a similar neural basis, but have never been studied in detail. Our results demonstrate that the distributions arising from binocular rivalry and other forms of bistable perception are indeed similar up to a high level of detail.

Attention↗

Temporal dynamics in bistable perception.

Bistable perception is fundamentally a dynamic process: Our perceptual experience continuously alternates when an ambiguous or rivalrous stimulus is observed. Here we present a method to analyze instantaneous measures of dominance and transition between percepts. The analysis extracts three time-varying probabilities. First, the transient preference represents the probability of perceiving one interpretation at one instant. Second, the reversal probability is the probability that the current percept will change at the next evaluation. Finally, the survival probabilities are the probability that at one instant the current percept will not switch to the alternative interpretation. We derive the relationships between these probabilities and offer a test of independence between consecutive percepts. We also introduce a simple technique to sample the observer's perception at regular intervals. The analyzing method is illustrated with the example of binocular rivalry. We demonstrate Levelt's second proposition with the survival probability measure and show that the consecutive rivalrous percepts are not independent.

Dominance, Ocular↗

Perceptibility curve test for digital radiographs before and after correction for attenuation and correction for attenuation and visual response.

OBJECTIVE: Two digital image processing methods, correction for X-ray attenuation and correction for attenuation and visual response, have been developed. The aim of the present study was to compare digital radiographs before and after correction for attenuation and correction for attenuation and visual response by means of a perceptibility curve test. MATERIAL AND METHODS: Radiographs were exposed of an aluminium test object containing holes ranging from 0.03 mm to 0.30 mm with increments of 0.03 mm. Fourteen radiographs were exposed with the Dixi system (Planmeca Oy, Helsinki, Finland) and twelve radiographs were exposed with the F1 iOX system (Fimet Oy, Monninkylä, Finland) from low to high exposures covering the full exposure ranges of the systems. Radiographs obtained from the Dixi and F1 iOX systems were 12 bit and 8 bit images, respectively. Original radiographs were then processed for correction for attenuation and correction for attenuation and visual response. Thus, two series of radiographs were created. Ten viewers evaluated all the radiographs in the same random order under the same viewing conditions. The object detail having the lowest perceptible contrast was recorded for each observer. Perceptibility curves were plotted according to the mean of observer data. RESULTS: The perceptibility curves for processed radiographs obtained with the F1 iOX system are higher than those for originals in the exposure range up to the peak, where the curves are basically the same. For radiographs exposed with the Dixi system, perceptibility curves for processed radiographs are higher than those for originals for all exposures. Perceptibility curves show that for 8 bit radiographs obtained from the F1 iOX system, the contrast threshold was increased in processed radiographs up to the peak, while for 12 bit radiographs obtained with the Dixi system, the contrast threshold was increased in processed radiographs for all exposures. When comparisons were made between radiographs corrected for attenuation and corrected for attenuation and visual response, basically no differences were found. CONCLUSION: Radiographs processed for correction for attenuation and correction for attenuation and visual response may improve perception, especially for 12 bit originals.

Humans↗

Paranoia and emotion perception across the continuum.

OBJECTIVES: Persons with high levels of paranoid ideation may be more sensitive to emotional stimuli, particularly negative emotions, reflecting the operation of a paranoid schema. However, this finding has not been consistently supported and needs further study. This study examined the effect of paranoia, as measured on a continuum, on emotion perception. It was predicted that higher levels of paranoia would be associated with improved emotion perception scores with better recognition for negative emotions than positive. DESIGN: A four-group ANOVA design was used to compare participants with clinical and sub-clinical paranoia to reflect the continuum view of paranoia. METHODS: A group with persecutory delusions (N=30) was compared with three sub-clinical groups (N=88) on two posed emotion perception tasks. The sub-clinical participants were divided into high, moderate, and low groups based on scores from the Paranoia Scale, a widely used measure of sub-clinical paranoia. RESULTS: Persons with persecutory delusions had lower overall emotion perception scores than all of the sub-clinical groups. For negative emotions, persons with persecutory delusions had lower identification scores than the moderate and low sub-clinical groups, but were no different than the high sub-clinical group. Anger was especially problematic for clinical participants. There were no differences for positive emotions. CONCLUSIONS: Instead of an enhanced sensitivity for the recognition of emotional states, higher levels of paranoia were linked to a performance deficit on emotion perception tasks. The deficits in emotion perception may reflect the increased skepticism and scrutiny associated with posed emotion tasks (Davis & Gibson, 2000). Research should begin to focus on the underlying mechanisms of emotion perception deficits in paranoia.

Adult↗

Parental perceptions of their preschool-aged children's oral health.

BACKGROUND: Parents have an important role in making decisions about their children's oral health. The purpose of the authors' study was to determine parental perceptions of their children's oral health status and factors correlated with these perceptions of health. METHODS: The authors analyzed data for 3,424 children (2-5 years of age) from the Third National Health and Nutrition Examination Survey. They based the dependent variable on a question asked of primary caregivers: "How would you describe the condition of [child's name]'s natural teeth?" Explanatory variables included demographic variables, dental visits, perception of child's general health, need for dental care and presence of tooth caries. RESULTS: Eighty-nine percent of parents rated their child's oral health as excellent, very good or good, and 11 percent rated it as fair or poor (mean = 2.7 on a five-point scale, with 1 being excellent and 5 being poor). Tooth caries, perceived need for dental cleaning and treatment, lower income and poorer general health perceptions were associated with poorer parental ratings. CONCLUSIONS: Actual disease and perceived need are associated significantly with parents' perceptions of their children's oral health. PRACTICE IMPLICATIONS: Understanding parents' perceptions of their children's oral health and factors that motivate these perceptions can help dentistry overcome barriers that parents encounter in accessing dental care for their children.

Child, Preschool↗

Determinants of women's perceptions of risk in battering relationships.

Two studies have recently identified battered women's perceptions as a substantial predictor of reassault by their batterers. Only a few exploratory studies examine how women make these useful perceptions. We attempted to identify determinants of battered women's perceptions of reassault and safety using the 15-month follow-up of a multisite evaluation of batterer intervention. The regression analyses indicate that the perceived likelihood of reassault increased with men who were divorced or separated, heavy drinkers, and severely abusive in the past. The strongest determinant for perceptions of safety was the perceived likelihood of reassault. Also, the women's professed reasons for their perceptions corresponded to the actual determinants. The women's perceptions appear, therefore, to be grounded in practical circumstances and correspond to establish predictors of reassault. Further research is needed to identify the additional cues, processes, or intuitions that make women's perceptions such a strong predictor of reassault.

Adolescent↗

Assessing the image quality of a CCD-based digital intraoral radiography system: application of perceptibility curve test.

The perceptibility curve test is a method for evaluating the psychophysical properties of radiographic systems. The concept of the perceptibility curve is based on the minimum perceptible exposure differences that are recorded by a particular imaging system. The perceptibility curve test was applied to a Charge-Coupled Device (CCD)-based digital intraoral radiography system in this study. A test object was made of a square aluminum block, 28 mm in both height and length and 10 mm in thickness. The test object had ten contrast details in the form of round holes with diameters of 1.5 mm. The depths of the holes ranged from 0.05 mm to 0.5 mm in steps of 0.05 +/- 0.01 mm. An X-ray unit was used that operated in the range of 60 to 90 kVp. Test radiographs were shown to observers in random order. Six observers were asked to rate them regarding the number of spots representing holes that they could perceive. The smallest perceptible difference in gray level on the computer monitor, a 15-inch cathode-ray tube (CRT), was then found. The minimum difference in gray level between a perceptible detail and the background was determined. Dose response functions were employed to determine exposures corresponding to these gray levels. For each case, delta logE as a function of the number of object details was calculated. Finally the reciprocal of all values of (delta logE)min were calculated. The number of details which the observers perceived decreased linearly with decreasing delta logE values. The maximum number of details that observers perceived was eight or nine. The perceptibility curves showed that their peaks shifted slightly with a change of the kVp but that their shapes were similar at different kVp settings.

Color↗

Phoneme perception via hearing aids with and without compression and the role of temporal resolution.

Hearing impairment is more than a sensitivity loss. The causes of reduced discrimination can be found also in deteriorations in loudness perception (recruitment), frequency resolution and temporal resolution. Only recruitment can be compensated for by modern hearing aids, namely by the reduction of the dynamic range by means of compression. However, the introduction of compression introduces temporal distortions, which may deteriorate the temporal cues of speech. In this study the perception of nonsense consonant-vowel-consonant-words presented through hearing aids was studied in a group of 12 hearing-impaired listeners. Phoneme perception in conditions with and without compression was analyzed and related to temporal parameters of the listeners' hearing. A detailed analysis of the patterns of confusions revealed clear qualitative differences in the perception of phonemes with and without compression. These differences can be related to an improved perception of temporal cues like the preburst silent interval of plosives and to spectral changes induced by the activation of the compression circuit. A reduced temporal resolution is disadvantageous for the perception of temporal cues like plosive detection, but our data do not suggest that the perception of temporal cues is hampered excessively by temporal distortions from the compression circuit itself.

Adolescent↗

Characterizing the influence of native language experience on adult speech perception.

Previous cross-language research has indicated that some speech contrasts present greater perceptual difficulty for adult non-native listeners than others do. It has been hypothesized that phonemic, phonetic, and acoustic factors contribute to this variability. Two experiments were conducted to evaluate systematically the role of phonemic status and phonetic familiarity in the perception of non-native speech contrasts and to test predictions derived from a model proposed by Best, McRoberts, and Sithole (1988). Experiment 1 showed that perception of an unfamiliar phonetic contrast was not less difficult for subjects who had experience with an analogous phonemic distinction in their native language than for subjects without such analogous experience. These results suggest that substantive phonetic experience influences the perception of non-native contrasts, and thus should contribute to a conceptualization of native language-processing skills. In Experiment 2, English listeners' perception of two related nonphonemic place contrasts was not consistently different as had been expected on the basis of phonetic familiarity. A clear order effect in the perceptual data suggests that interactions between different perceptual assimilation patterns or acoustic properties of the two contrasts, or interactions involving both of these factors, underlie the perception of the two contrasts in this experiment. It was concluded that both phonetic familiarity and acoustic factors are potentially important to the explanation of variability in perception of nonphonemic contrasts. The explanation of how linguistic experience shapes speech perception will require characterizing the relative contribution of these factors, as well as other factors, including individual differences and variables that influence a listener's orientation to speech stimuli.

Adolescent↗

Contraceptive characteristics: the perceptions and priorities of men and women.

CONTEXT: Despite the fact that choosing a contraceptive method is often a decision made by couples, little is known about how men and women differ in their perceptions of the characteristics of various method types, and in the importance that they attach to those characteristics when choosing a contraceptive method. METHODS: The data analyzed here are subsets from two companion surveys conducted in 1991--1,189 men aged 20-27 who were surveyed in the National Survey of Men and 740 women aged 20-27 who were surveyed in the National Survey of Women. Multivariate ordered logit analysis is used to examine how gender is related to both the importance that individuals assign to seven specific contraceptive characteristics when choosing a method, and to perceptions about the extent to which five common method types possess each of these characteristics. RESULTS: Women rank pregnancy prevention as the single most important contraceptive characteristic when choosing a method, with 90% citing it as "very important." The health risks associated with particular methods and protection from sexually transmitted diseases (STDs) are rated as the second most important characteristics by women (each mentioned as "very important" by 77%). In contrast, men consider STD prevention for themselves and their partner to be just as important as pregnancy protection (each mentioned as "very important" by 84-86%), and they rank STD prevention as more important than other health risks (by 72%). Women, but not men, rank both ease of use and the need to plan ahead as being more important characteristics than a method's interference with sexual pleasure. Both men and women have an accurate understanding of the strengths and weaknesses of particular methods, but differ enough in their perceptions to alter the relative attractiveness of each method. In particular, women have more favorable perceptions than men about the pill, being somewhat more likely than men to believe that the pill is "very good" at preventing pregnancy (75% vs. 67%) and to say that it is very good at not interfering with sexual pleasure (82% vs. 76%). In contrast, women have generally less favorable perceptions than men about other reversible methods, including the condom: Women were less likely than men to consider the condom very good at pregnancy prevention (29% vs. 46%) or at having no need for advance planning (22% vs. 38%). Gender differences in perceptions about the specific characteristics of contraceptive methods often vary by marital status. CONCLUSIONS: Men and women have somewhat different priorities when choosing a contraceptive method. Despite many similarities between women and men in their perceptions about the characteristics of each method type, numerous differences between them may have an important influence on how couples make their method choices.

Adult↗