Locomotion of the Blind Controlled by Natural Sound Cues

Strelow, Edward R.; Brabyn, John A.

doi:10.1068/p110635

Cited by 79 publications

(33 citation statements)

References 13 publications

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“…Moreover, this perceptual ability is manifested in functionally important behavior, such as goal-directed locomotion and awareness of the positions of objects in nearby space. This emphasis on nonvisual obstacle perception as a useful skill has received little attention in the experimental literature on adults (Strelow & Brabyn, 1982), yet an appreciation of the functional context of the ability may be necessary not only as a pragmatic basis for devising workable dependent variables but also as a theoretical rationale for exploring developmental influences.…”

Section: Discussionmentioning

confidence: 99%

“…The present experiments were not designed to isolate the specific nonvisual information mediating the children's detection of objects, but they were conducted under the assumption that auditory information would be the most pseful. This assumption was based on clinical practice in orientation and mobility training (Welsh & Blasch, 1980), on experimental reports that nonvisual obstacle perception is at chance level when people are deprived of hearing (Ammons et al, 1953;Cotzin & Dallenbach, 1950;Strelow & Brabyn, 1982;Worchel & Dallenbach, 1947), and on numerous reports that obstacle perception is enhanced by auditory sensory aids such as directional noise generators (e.g., Clarke, Pick, & Wilson, 1975;Juurmaa, 1970). Efforts were made to minimize the potential contributions of nonauditory information such as wind (obstacles were downwind from the path of locomotion), heat and light shadows (the path was in full sunlight with the sun to the children's backs), and smell (the obstacles were placed downwind and did not have a strong odor).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have typically involved overt verbal or gestural reports of the perception of obstacles. Although such measures are well suited for investigations of the informational basis for obstacle perception, they do not indicate how the information is utilized for functional goals such as moving from one place to another (Strelow & Brabyn, 1982).…”

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confidence: 99%

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Obstacle perception by ongenitally blind children

Ashmead

Hill

Talor

1989

Perception & Psychophysics

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The ability to perceive objects from a distance and navigate without vision depends principally on auditory information. Two experiments were conducted in order to assess this ability in congenitally blind children aged 4 to 12 years who had negligible amounts of visual experience or formal mobility training. In Experiment 1, children walked along a sidewalk toward a target location to get some candy. A box was placed along the path on some trials, and the children were instructed to avoid the box if it was present. The children spent more time in the region just in front of the box than in the region just behind it, indicating that they perceived the box and acted 80 as to navigate around it. In Experiment 2, children attempted to discriminate whether a nearby disk was on their left or on their right. The children performed at above-chance levels, again indicating distal perception of objects. fie results of both experiments suggest that blind children with little or no visual experience or formal training utilize-nonvisual information, presumably auditory, to perceive objects. The specific nature of this auditory information requires further investigation, but these findings imply that the underlying perceptual ability does not require experience in spatial vision or deliberate training and intervention.Navigation through cluttered environments depends on perception of the locations of objects and surfaces so that obstacles can be avoided and clear pathways can be used. Although vision is ideally suited for this task, both blind observers and blindfolded sighted observers can locomote without collisions through spaces containing large objects (Supa, Cotzin, & Dallenbach, 1944; Worchel, Mauny, & Andrew, 1950). Various explanatory processes for this ability to navigate without vision have been proposed over the years, including "facial vision" resulting from sensitivity to changes in air pressure near surfaces, a "sixth sense" unique to blind persons, and echolocation based on reflected sounds. The ability is mediated by sensitivity to auditory information, probably in the form of reflected sounds or sound shadows. For example, Supa et al. (1944) found that both blind observers and blindfolded sighted observers who could otherwise stop I-2m in front of a large panel collided with it if their hearing was strongly attenuated. Attenuation of other potential sensory information, such as tactile or thermal stimulation, did not adversely affect performance, so it was concluded that auditory information was necessary and sufficient.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Obstacle perception by ongenitally blind children

Ashmead

Hill

Talor

1989

Perception & Psychophysics

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“…Navigational tasks are one instance where this seems to be clear. Strelow & Brabyn (1982) performed an experiment where subjects were to walk a constant distance from a simple straight barrier, being a wall or series of poles at 2 m intervals (diameter 15 cm or 5 cm), without any physical contact to the barrier. Footfall noise and finger snaps were the only information.…”

Section: Advances In Sound Localizationmentioning

confidence: 99%

Spatial Audio Applied to Research with the Blind

Katz¹,

Picinali²

2011

Advances in Sound Localization

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Advances in Sound Localizationwww.intechopen.com interesting result was found by Ohuchi et al. (2006) in testing angular and distance localization for azimuthally located sources with and without head movement. Overall, blind subjects outperformed sighted control for all positions. For distance estimations, in addition to being more accurate, errors by blind subjects tended to be overestimations, while sighted control subject errors were underestimations, in accordance with numerous other studies. These studies indicate that one must take a second look at many of the accepted conclusions of auditory perception, especially spatial auditory perception, when considering the blind, who do not necessarily have the same error typologies due to different learning sensory conditions. A number of studies, such as Weeks et al. (2000), have focused on neural plasticity, or changes in brain functioning, evaluated for auditory tasks between blind and sighted subjects. Results by both Elbert et al. (2002) and Poirier et al. (2006) have shown increased activity in typically visual areas of the brain for blind subjects. While localization, spectral analysis, and other basic tasks are of significant importance in understanding basic auditory perception and differences that may exist in performance ability between sighted and blind individuals, these performance differences are inherently limited by the capacity of the auditory system. Rather, it is in the exploitation of this acoustic and auditory information, requiring higher level cognitive processing, where blind individuals are able to excel relative to the sighted population. Navigational tasks are one instance where this seems to be clear. Strelow & Brabyn (1982) performed an experiment where subjects were to walk a constant distance from a simple straight barrier, being a wall or series of poles at 2 m intervals (diameter 15 cm or 5 cm), without any physical contact to the barrier. Footfall noise and finger snaps were the only information. With 8 blind and 14 blindfolded sighted control subjects, blind subjects clearly outperformed sighed subjects, some of whom claimed the task to be impossible. The results showed that blindfolded subjects performed overall as well in the wall condition as blind subject in the two pole conditions. Morrongiello et al. (1995) tested spatial navigation with blind and sighted children (ages 4.5 to 9 years). Within a carpeted room (3.7 m × 4.9 m), four tactile landmarks were placed at the center of each wall. Subjects, blind or blindfolded, were guided around the room to the different landmarks in order to build a spatial cognitive map. The same paths were used for all subjects, and not all connecting paths were presented. This learning stage was performed with or without an auditory landmark condition, a single metronome placed at the starting position. Subjects were then asked to move from a given landmark to another, with both known and novel paths being tested. Different trajectory parameters were evaluated. Results for sighted subjects in...

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“…68 Echolocation involves a process for locating objects by means of sound waves produced by the emitter, such as clicks, chirps, cane taps, etc being reflected back to the emitter from objects in the environment. 69 Detection of variations in naturally occurring sounds in the ambient sound field due to reflections by objects such as walls, 68,70 locating sound sources, and locating the direction, distance and direction of moving sound sources are also very important to the visually impaired listener. 71 A person with vision impairment but normal hearing is more dependent on auditory cues for navigation, locating a desired sound source and separating it from competing sounds, and for identifying alerting signals than a person with normal vision and hearing.…”

Section: Auditory and Visual Localizationmentioning

confidence: 99%

Effect of Dual Sensory Loss on Auditory Localization: Implications for Intervention

Simon

Levitt

2007

Trends in Amplification

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Our sensory systems are remarkable in several respects. They are extremely sensitive, they each perform more than one function, and they interact in a complementary way, thereby providing a high degree of redundancy that is particularly helpful should one or more sensory systems be impaired. In this article, the problem of dual hearing and vision loss is addressed. A brief description is provided on the use of auditory cues in vision loss, the use of visual cues in hearing loss, and the additional difficulties encountered when both sensory systems are impaired. A major focus of this article is the use of sound localization by normal hearing, hearing impaired, and blind individuals and the special problem of sound localization in people with dual sensory loss.

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Locomotion of the Blind Controlled by Natural Sound Cues

Cited by 79 publications

References 13 publications

Obstacle perception by ongenitally blind children

Obstacle perception by ongenitally blind children

Spatial Audio Applied to Research with the Blind

Effect of Dual Sensory Loss on Auditory Localization: Implications for Intervention

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