代写代考 Dual Sensory Loss: Facts, Rehabilitation, and Research

Dual Sensory Loss: Facts, Rehabilitation, and Research
Ying- 2022.10.20
Perceptual Issues in Visual Impairment

Interactions between Vision and Hearing
• Think about how our senses work independently/interactively in our daily life.
An Introduction to Dual Sensory Loss Rehabilitation for Dual Sensory Loss

Sight, smell, hearing, taste and touch

Spatial Processing

Spatial Localization: Vision
Retinotopic mapping

Spatial Localization: Hearing
132 Neuropsychology of Space
Horizontal localization
Interaural time difference Interaural sound level difference
Vertical localization
outer ear.
Figure 4.3 (Left) A sound that is presented from the left of the head arrives sligh earlier at the left than the right ear, and its intensity is higher for the left ear than the right ear. (Center) A sound that is presented from right in front of the body m line arrives at both ears simultaneously at the same intensity. (Right) A sound tha presented from the right of the head arrives earlier to and has a higher intensity the right relative to the left ear.
in horizontal space are interaural time and sound level differences (I
Monaural spectral cues generated by the modification of a
sound by the torso, head, and the
and ILD; Middlebrooks & Green, 1991). The way our ears are position
on our head causes a difference in arrival time of a sound at the left a
the right ear depending on the position of a sound source relative to t
head. Whenever a sound source is located on the right side of the head sound wave first arrives at the right ear, and a few microseconds later
the left ear. In contrast, when a sound source is located to the left of t head, a sound wave first arrives at the left ear, and a few milliseconds la to the right ear. Depending on the position of the sound source on t horizontal meridian, the ITD changes, allowing the brain to calculate t lateral position of a sound source in space (Fig. 4.3). Sounds located the median plane will arrive at the same time at the left and right when no objects are in the way.
Another cue to a sound source’s position in lateral space is the interau
r level difference (ILD). When a sound is located to the right of the head, th

Spatial Processing: Vision Dominates Hearing
Ventriloquist Illusion
Ventriloquist effect in multisensory research
Question: Can you think of any real-life examples when vision and hearing are from different locations?

Speech Perception

Speech Perception
I’d love you
I love you Olive juice ✓ I have two

Speech Perception
Bucket Podcast

Speech Perception
Fight you Factual Value Vacuum

Speech Perception: Audiovisual Integration
McGurk Effect (McGurk & McDonald, 1976)

Perception of Time
Unlike spatial processing, hearing outperforms vision in temporal processing.
An auditory stimulus takes only 8–10 ms to reach the brain, but a visual stimulus takes 20-40 ms.

Perception of Time: Hearing Dominates Vision

Vision and Hearing
Why do we need redundant information from vision and hearing?
– Sound and visual images we encounter in daily life may not be ideal.

Vision and Hearing
Vision is “noisy”. Vision is “gone”.
Both vision and hearing are noisy.

Vision and Hearing
Why do we need redundant information from vision and hearing?
– Sound and visual images we encounter in daily life may not be ideal.
– Vision and/or hearing may be impaired.

Interactions between Vision and Hearing
• Think about how our senses work independently/interactively in our daily life.
An Introduction to Dual Sensory Loss
• Dual Sensory Loss > Vision Loss + Hearing Loss Rehabilitation for Dual Sensory Loss

Vision Loss
Consequences of an eye disease or disorder on a measure of visual function such as acuity, contrast sensitivity or visual field.
Causes of vision impairment:
• Macular degeneration
• Glaucoma
• Cataract
• Diabetic retinopathy

Hearing Loss
Complete or partial loss of the ability to hear from one or both ears.
Causes of hearing impairment:
• Medication
• Ear infection

Hearing Loss
Complete or partial loss of the ability to hear from one or both ears.
Criteria: pure tone thresholds measured by audiometer.

Dual Sensory Loss – Prevalence
Dual Sensory Loss concerns a large population.
Worldwide there are 0.2% population with severe Dual Sensory Loss (deafblind), and 2% with its mild form (World Federation for the deafblind, 2018).
When we hear the term deaf-blind, we often imagine a person who is unable to hear or see anything; however, this is typically not the case.

Dual Sensory Loss – Prevalence
The prevalence of Dual Sensory Loss increase with age.
Age-related DSL contributes to approximately 80% of the total DSL case.
Table1. Characteristics among Individuals 45 Years of Age and Older in the US.
Age Range (yrs)
Vision Impairment Alone (%)
2.21 (2.20-2.23)
3.06 (3.03-3.09)
5.67 (5.60-5.74)
Hearing Impairment Alone (%)
2.82 (2.80-2.84)
8.95 (8.90-9.00)
20.59 (20.48-20.71)
Dual Sensory Impairment (%)
0.70 (0.69-0.71)
1.83 (1.81-1.86)
7.62 (7.54-7.70)
Adapted from Fuller et al., 2018

Dual Sensory Loss > Vision Loss + Hearing Loss
1. Persons with Dual Sensory Loss often have additional disabilities.
(World Federation for the deafblind, 2018)

Dual Sensory Loss > Vision Loss + Hearing Loss
2. Persons with Dual Sensory Loss may experience poorer levels of health and barriers to accessing health services.
Common challenges to accessing both general health and rehabilitation services :
• a lack of accommodations in health facilities, particularly in terms of
accessible information and alternative forms of communication;
• costs of accessing care, as insurance often does not always cover all
• concentration of services in cities, with little available in rural areas;
• a lack of knowledge of and training on Dual Sensory Loss among
health professionals
(World Federation for the deafblind, 2018)

Dual Sensory Loss > Vision Loss + Hearing Loss
Vision and Hearing Loss Simulator

Dual Sensory Loss > Vision Loss + Hearing Loss
“Blindness separates people from things; deafness separates people from people.”
3. People with Dual Sensory Loss show increased
functional, social and psychological difficulties.
• Developmental issues such as behavior disorders.
• Reduced activities
• More likely to show depression symptoms.
Brennan et al. (2005), Brennan et al. (2006), Dargent-Molina et al. (1996), Grue et al. (2009), Reuben et al. (1999), World Federation for the deafblind, (2018)

Dual Sensory Loss > Vision Loss + Hearing Loss
Sensory Loss and Cognitive Decline
• Two theories underlying the association between sensory loss and dementia
– Cascade theory
– Common cause theory
4. Dual Sensory Loss increases the risk for cognitive decline than single sensory loss
• Social engagement as a mediating factor: Dual Sensory Loss was not associated with a greater cognitive decline among socially engaged individuals, while it was associated among socially disengaged individuals (Yamada et al., 2016).

Rehabilitation for Dual Sensory Loss
The special rehabilitation needs by people with Dual Sensory Loss have received very little attention.
• Assistive devices for visually impaired persons usually assume good hearing and vice versa (Wittich et al., 2016; St-Amour et al., 2018).
• Dual Sensory Loss related topics were mostly absent in occupational therapy curriculum (Wittich et al., 2017).
Question: Can you think of an assistive device that is not “friendly” to persons with Dual Sensory Loss?

Access to Information
Hearing Compensation
Audio books

Access to Information
Vision compensation

Orientation & Mobility Training
Orientation & Mobility Training
A story about getting a new guide dog.

Orientation & Mobility Training
Blindfold Training?
Two arguments about blindfold training
“… they are still trying to rely only on their vision to navigate, and are not paying attention to their other senses that may enhance their mobility. In these cases, I suggest a student wear a blindfold when training to use a white cane.”
“someone who has low vision and who meets the legal criteria for blindness may not need or want to be blindfolded or employ the methods of blindness during the rehabilitative process or in daily life unless they are unequivocally more efficient and comfortable methods. “

Orientation & Mobility Training
Spatial Localization Survey [35 real-life scenarios]. Examples:
• You are walking along a city sidewalk. A police vehicle is approaching with a siren sound and flashing lights. You need to determine which direction the police car is coming from.
• You are sitting with two friends at a table in a busy restaurant. Your friends are in a discussion and are talking back and forth. You want to keep track of who is talking.
• You are waiting for elevators in a building. There are three running elevators that make a beeping sound when they open up. You need to determine which elevator has opened.

Orientation & Mobility Training
How much do people rely on vision?
Dual Sensory Loss Vision Loss Only
When primarily relying on
100 Normal Vision 75
hearing, do they ignore 25 their vision?
20/20 20/63 20/200 20/632 20/20 Visual Acuity (Snellen)
20/20 20/63 20/200 20/632 20/2000 Visual Acuity (Snellen)
20/20 20/63 20/200 20/632 20/2000 Visual Acuity (Snellen)
Vision Dominance Index (%)
Proportion of Discarding Vision (%)
Vision Dominance Index (%)
Proportion of Discarding Vision (%)

Hearing Aids
Hearing Aids
There are 30 million of people with hearing loss in the US. Only 1/5 use hearing aids.
People with Dual Sensory Loss are less likely to use hearing aids.
• Small batteries
• Directionality of sound
• Accessibility of user interface
• Frequent updating
• Lack of knowledge of vision loss by Audiologists

Rehabilitation for Dual Sensory Loss
There is a need for an integrated vision and hearing rehabilitation approach that incorporate both vision and hearing impairment in the assessment and intervention, and outcome evaluation for patients.

Take Home Message
Vision and hearing have many shared functions. They compensate each other in people with single sensory impairment.
Dual Sensory Loss concerns a large population with heterogeneous nature of diagnoses, severity, and onset.
Despite the efforts in the rehabilitation for vision or hearing loss individually, the special needs of people with Dual Sensory Loss have received very little attention.

Take Home Message
Dual Sensory Loss needs more rehabilitation and research efforts.
Assistive Technology
Environmental Modification
Sensory Skills Training
Disorder Assessment Impairment Rehabilitation Disability Societal Handicap Support
Colenbrander & Fletcher, 1995

Thank you!

程序代写 CS代考加微信: powcoder QQ: 1823890830 Email: powcoder@163.com

Related Posts