Visual Impairment Lecture Handout PDF

Visual impairment and blindness in childhood Development, assessment and compensatory skills Dr Val Tadić [email protected] 1 Today…. What is visual impairment (VI)? What are developmental imp...

Visual impairment and blindness in childhood Development, assessment and compensatory skills Dr Val Tadić [email protected] 1 Today…. What is visual impairment (VI)? What are developmental implications of visual impairment in childhood? Social-emotional, cognitive and behavioural manifestations What are the implications of visual impairment for cognitive and behavioural assessment and diagnosis in children? Can lack of vision be compensated for in the context of development and how? 2 What is visual impairment (VI) and/or blindness? Severe or total reduction in vision that cannot be corrected with standard glasses or contact lenses. 3 1  World Health Organisation (WHO) classification of visual impairment (VI) 1. normal vision 2. visual impairment 3. severe visual 4. blindness (VI) impairment (VI) 1. Finger counting at 3 m 2. Hand movement 3. Light perception 4. No light perception 4 Epidemiology of VI and blindness in childhood Globally, 19 million children are visually impaired, of which 1.4 million are blind (Solebo and Rahi, 2014) In UK (Rahi and Cable, 2001) About 2 in 1000 Most from birth 5 Epidemiology of VI and blindness in childhood In UK (Rahi & Cable, 2001; Theo et al., 2021) 75% neither preventable or treatable Increased in children born preterm, children with brain damage and children born with brain anomalies or some genetic syndromes that may predispose to eye abnormalities. Often associated with additional impairments or chronic disease (over 75%) Increased risk of developmental delay in isolated VI Salt, A., & Sargent, J. (2014). Common visual problems in children with disability. Archives of disease in childhood, 99(12), 1163-1168 6 2  Role of vision Vision guides the co-ordination and understanding of relations between objects in the environment and self-position in space (Rieser & Rider, 1991) Innate visual bias e.g. 30 min old babies show preference for face like stimuli (Johnson et al., 1991) 2-5 day old infants detect and preferentially look at faces and make eye contact (Farroni, Csibra, Simion, & Johnson, 2002). 7 Role of vision – key developmental milestones Object permanence Understanding that objects (and people) exist even when we can’t see them Out of sight, out of mind! Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 8 Role of vision – key developmental milestones Joint attention Triadic co-ordination of attention between the child, another person and an object (or an event) Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 9 3  Role of vision – key developmental milestones Imitation Copying observed behaviour Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 10 Role of vision – key developmental milestones Pretend play Make-believe play involving representational ability (you can represent one thing with another) Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 11 Role of vision – key developmental milestones Language and communication Object labeling/vocabulary, conversation, pragmatic (social) language Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 12 4  Role of vision – key developmental milestones Theory of Mind Understanding that other people have thoughts, feelings and beliefs that differ from our own and that those mental states influence how people act and behave Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 13 What does this mean for development of a visually impaired child? Theory of mind (incl. Pretend play pragmatic Imitation language) Joint attention Object permanence Recommended revision on key developmental milestones: Any Developmental Psychology textbook e.g. Gillibrand et al (2016) 14 Role of vision and developmental milestones Object permanence and joint attention delayed (Bigelow, 1986, 2003; Fazzi et al., 2011, Dale & Salt, 2008, Urquet Alfaro et al., 2018, 2021) Absence or delay of imaginative play in young blind children (e.g. pretending a block is a car); limited once it emerges (Fraiberg, 1997; Bishop, Hobson & Lee, 2005; Hughes et al, 1998; Troster & Brambring, 1994) Language relatively spared but ‘unusual’ (e.g. repetitive, stereotypical), with particular difficulties in pragmatic language (McConachie and Moore, 1994: McConachie, 1990; Andersen, Dunlea at Kekelis, 1984; Fraiberg, 1977) Difficulties with Theory of Mind tasks in blind children, which are typically expected to be mastered by sighted children of similar mental ability and at the same age (McAlpine & Moore, 1995, Minter et al. 1998) BUT: Significant variation! General picture of delay rather than ’deficit’ Although some children have more pervasive difficulties, some are comparable to sighted children! 15 5  - Personal pronoun reversal - Frequent use of repetitive, imitative speech/echolalia - Frequent use of stereotyped speech, routines and formulaic speech - Egocentric speech - Difficulties in communicative conversation and pragmatic language (e.g. not initiating conversations) Difficulties in language and communication Behavioural manifestations of blindness in Autism children Restricted interests Difficulties with social and imagination interaction - Delayed or restricted pretend, non-functional play - Difficulties in social interaction and prelinguistic communication - Mannerisms and stereotyped behaviours e.g. hand- - Difficulties with perspective taking flapping and rocking - Limited joint attention 16 - Personal pronoun reversal - Frequent use of repetitive, imitative speech/echolalia - Frequent use of stereotyped speech, routines and formulaic speech - Egocentric speech - Difficulties in communicative conversation and pragmatic language (e.g. not initiating conversations) Difficulties in language and communication Behavioural manifestations of blindness in Autism children Restricted interests Difficulties with social and imagination interaction - Delayed or restricted pretend, non-functional play - Difficulties in social interaction and prelinguistic communication - Mannerisms and stereotyped behaviours e.g. hand- - Difficulties with perspective taking flapping and rocking - Limited joint attention 17 - Personal pronoun reversal - Frequent use of repetitive, imitative speech/echolalia - Frequent use of stereotyped speech, routines and formulaic speech - Egocentric speech - Difficulties in communicative conversation and pragmatic language (e.g. not initiating conversations) Difficulties in language and communication Behavioural manifestations of blindness in Autism children Restricted interests Difficulties with social and imagination interaction - Delayed or restricted pretend, non-functional play - Difficulties in social interaction and prelinguistic communication - Mannerisms and stereotyped behaviours e.g. hand- - Difficulties with perspective taking flapping and rocking - Limited joint attention 18 6  Autism - overview Autism Spectrum Disorders (ASD) Often used to refer to a set of conditions listed under the term Pervasive Developmental Disorders in the DSM - IV Autistic Disorder, Asperger’s Disorder, Childhood Disintegrative Disorder (CDD) and Pervasive Developmental Disorders Not Otherwise Specified (PPD-NOS). DSM-V – broader diagnosis capturing a continuum of severity, rather than distinct disorders Diagnosis based on 2 core areas: Impairments in social communication and interaction Restricted, repetitive patterns of behaviours, interests and activities 19 ASD - Diagnostic criteria I Impairments in social communication and impairments in social interaction: 1. Deficits in social-emotional reciprocity (e.g., failure to go back and forth in conversations, failure to respond to or initiate social interactions). 2. Deficits in nonverbal communication (e.g., eye contact or body language). 3. Deficits in developing, maintaining and understanding relationships (e.g., difficulties in adjusting behaviour to social context or in showing an interest in peers). Meet all 3 for diagnosis. 20 ASD - Diagnostic criteria II Restricted, repetitive patterns of behaviours, interests or activities: 1. Stereotyped or repetitive motor movements, use of objects or speech (e.g., lining up toys, echolalia). 2. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., need to eat same food, extreme distress to small changes). 3. Insistence on sameness, inflexible adherence to routines or ritualized patterns of verbal or nonverbal behaviour (e.g. have the same routine everyday). 4. Hyper or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment (e.g., extreme sensitivity/insensitivity to noises or temperatures). Meet at least 2 for diagnosis. 21 7  ASD - Diagnostic Criteria III Symptoms must be present in the early developmental period. Symptoms cause clinically significant impairment in social, occupational or other important area of current functioning. The disturbances are not better explained by intellectual disability or global developmental delay. 22 Autistic presentation in visually impaired and blind children History of autism in blind children E.g. Keeler (1958) – 5 blind children with retinopathy of prematurity – ROP Also Wing (1969) – 5 children with rubella Rogers and Newhart Larson (1989) – 5 children with Leber’s amaurosis Ek et al (1998) – bilateral optic nerve hypoplasia and ROP More recent estimates: Mukaddes et al (2007) – 12% 7-18y-olds met the diagnosis for autistic disorder Jure et al (2016) – Prevalence of ASD as high as 50% and 30 times more frequent in children who are blind than in the sighted population Kiani et al (2019) – blind adults with intellectual disabilities more likely to have ASD than sighted controls Key risk factors: severity of VI, brain damage, developmental delay 23 Autistic presentation in visually impaired and blind children Brown, Hobson, Lee and Stevenson (1997) Compared 24 congenitally blind children of diverse aetiology with matched groups of sighted children with and without autism (on CARS checklist) Both autism diagnosis and ‘autistic features’ (not meeting diagnostic criteria for autism) strikingly prevalent 9 blind children met DSM criteria for autism Hobson, Lee and Brown (1997) Compared the 9 blind ‘autistic’ children with a new group of sighted children with autism (CA and VIQ matched) Is autism in blind children the same as autism in sighted children? Mostly similar in clinical features but less severe in blind children 24 8  Autistic presentation Tadić, Pring and Dale (2010) Parental reports of pragmatic language and stereotypical behaviour in visually impaired differentiating VI and sighted children and blind children 9 of 15 VI children of intelligence in the typical range showed a socio- communicative profile consistent with the broader ASD 25 Implications Does the behavioural overlap in visual impairment and autism point to the common underlying cause? OR Is the overlapping behavioural presentation in visual impairment and autism just a surface similarity? 26 Visual Impairment and Autism Hobson and Lee (2010) 10 years later, followed up the 9 blind ‘autistic’ children and 7 (of 9) sighted autistic children from the original study (Hobson et al., 1997) At follow up: 8 of 9 blind children failed DSM criteria for autism, whereas all 7 out of 7 sighted children with autism still within the criteria Improvements in most areas for blind children, although some behavioural patterns persisted Some blind children seem to outgrow autism later on (whilst autism in sighted is fairly stable) Replicated more recently by Jure et al., (2015) 27 9  Visual Impairment and Autism Likely difference in natural history of the development of autistic ‘disorder’ between blind and sighted children. For blind children, lack of vision is a risk factor Visual impairment may coincide with underlying neurological factors in some children making them more likely to receive diagnosis of ASD. Autistic-presentation in blind children as part of the broader autistic spectrum. But – specific implication for ASD diagnosis and intervention in blind children Need to differentiate what is typical for blind children but not seen in sighted children with or without autism (i.e. the ‘blindisms) from ‘true’ ASD (difficulties common to both blind and sighted children with autism). 28 Assessment and diagnostic considerations Lack of tests suitable for use with visually impaired and blind children Tests developed for and with sighted children frequently used for diagnosing ASD in visually impaired and blind children Reliance on visual stimuli and visual behaviours Most existing tests don’t have norms for visually impaired and blind children Testing procedure may not take sensory impairment into account Test adjustments are often made ad hoc, but either not validated or inappropriate Diagnostic considerations: Assessment and diagnostic procedures should be performed by professionals with expertise in both blind children’s development and ASD. Accurate diagnosis informs appropriate educational provision and interventions Interventions need to be tailored to take into account the child’s complex needs 29 Heterogeneity and qualitative difference There is a significant variation in developmental outcomes in bind children. When comparing blind and sighted children, are we comparing like with like? Lived experience and interaction with the environment ‘qualitatively’ different More recent studies, using adapted developmental tests showing no differences in ToM and pragmatic language (Pijnacker et al., 2012, Bartoli et al., 2019) The impact of visual loss on developmental outcome in research studies to date is mediated by other factors and behaviours (Veldhorst et al., 2022) Vision is important, but is it essential for normal development? 30 10  Brain plasticity Sadato, Pascal-Leone et al (1996) – Activation of visual cortical areas during tactile tasks in blind participants Bedney, Richardson and Saxe (2015) - Occipital (“visual”) brain regions respond to sound and spoken language in blind children and young people Lane et al (2017) - the frontotemporal language network was less left-lateralized in congenitally blind than in sighted individuals and a positive correlation between the lateralization of frontotemporal cortex and that of language-responsive occipital areas in blind individuals. In absence of visual experience, visual cortex can take over other functions 31 Role of language Language as a compensatory mechanism (Webster and Roe, 1998) Language output: Superior expressive and receptive language performance (especially verbal memory) in blind vs. sighted school aged children on standardised language tests (Tadić et al, 2010) Superior verbal working memory (Greenaway et al., 2018; Dekker et al. 1993) Verbal ability distinguishes blind children with better Theory of Mind task performance from those who fail the tasks (Green et al., 2004) Language input: Mothers of blind children adapt input - speak more and provide more descriptions to their children during interactions (Perez-Pereira and Conti-Ramsden, 1999; Tadić et al., 2013) 32 Auditory advantage Echolocation Ability to detect objects in environment by sensing echoes from those objects, by actively creating sounds Originally called ‘obstacle sense’, but enables also detection of size, distance, shape, even texture Found in both sighted and blind individuals although most echolocators are blind Blind individuals better echolocators (see Thaler and Goodale, 2016 for an overview) 33 11  Auditory advantage Echolocation Blind people found to be more sensitive to acoustic reverberations than sighted people (Theng et al., 2011) Better echo discrimination by blind non-echolocators when compared to sighted (Nilsson and Schenkman, 2016) Traditional visual brain recruited during echolocation in blind echolocators (Thaler et al., 2011) Early blind participant show superior echolocation ability compared to late blind participant (Thaler et al., 2011) Fulfils the function of vision/visual perception for blind people? Implications for mobility training and independent living. 34 Auditory advantage Absolute Pitch (AP) (also known as ‘perfect’ pitch) Ability to recognize, label and remember a specific tone without reference to an external standard Rare - 1 in 10,000 Not a prerequisite for musical ability or talent 35 Auditory advantage Absolute Pitch (AP) (also known as ‘perfect’ pitch) Increased prevalence of absolute pitch in blind individuals (Ockelford, 1988; Welch, 1988) Superior ‘pitch’ discrimination in blind vs. sighted adults (Voss & Zatorre, 2012) and children (Dimatati et al., 2012) Present in c.40% of congenitally blind children and typically first manifests around 2 years (Ockelford & Matawa, 2009) Hamilton et al (2004) – more exaggerated enlargement in the left temporal lobe area planum temporale associated with AP in blind vs. sighted musicians 36 12  Auditory advantage Music is an important in blind children’s education (Ockelford and Markou, 2012) Blindness frequently associated with musical abilities And occasionally with extraordinary talents! 37 Savant syndrome First described by Langdon Down – Idiot Savant (1887) Savant = saviour (‘to know’) in French ‘persons with developmental disabilities, including but not limited to autism, or other CNS disorders or disease have some spectacular “islands of genius” that stand in jarring juxtaposition to overall limitations’ (Treffert, 2010). 38 Savant syndrome General population prevalence: 1 in 20, 000 (Rimland 1988) 1 in 2000 in population with learning difficulties (Pring et al 1995) 9.8% of individuals with autism show savant skills (Happe, 1999) 4-6 times more prevalent in males (Treffert 2014) Typically, exceptional skills seen in 5 general areas: music, art, calendar calculating, mathematics or mechanical/visual-spatial skills. Fewer than 100 reported cases of prodigious savants in the world A common triad of musical genius, blindness and autism (Miller 1989; Treffert 1989, 2007) 39 13  Summary Visual impairment from early childhood impacts on all areas of child’s development and functioning Many important milestones compromised due to reduced access to visual modes of communication early in development Risk factor for ASD diagnosis But significant heterogeneity in developmental outcomes A picture of a delay or differential pathway, rather than deficit A model for understanding the role of vision in child development Evidence that vision is important but not essential for successful development Evidence for brain plasticity and flexibility of the cognitive system Language and auditory advantage as compensatory mechanism Platform for emergence of compensatory skills and sometimes unique, extraordinary gifts 40 Some interesting programmes and podcasts ‘In the key of genius’ – TED talk by Prof Adam Ockelford and Derek Paravicini https://www.ted.com/talks/derek_paravicini_and_adam_ockelford_in_the_key_of_genius ‘How I use sonar to navigate the world’ – TED talk by Daniel Kish https://www.ted.com/talks/daniel_kish_how_i_use_sonar_to_navigate_the_world ‘How To Become Batman’ – ‘Invisibilia’ podcast featuring Daniel Kish https://www.npr.org/programs/invisibilia/378577902/how-to-become-batman ‘Seeing world without sight’ (BBC Travel Show with Tony Giles) https://www.bbc.co.uk/programmes/n3ct5t7s 41 References Bedny, M., Richardson, H., & Saxe, R. 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