CH 12. Visual perception 연세대학교작업치료학과김정란 1 성장과발달 7

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1 CH 12. Visual perception 연세대학교작업치료학과김정란 1

2 Contents } Definitions } The visual system } Anatomy of the eye } Visual-receptive functions } Visual-cognitive functions } Developmental sequence } Visual-perceptual problems } Evaluation methods 2

3 Definition } Visual perception ( 시지각기술 ) } Recognition and identification of shapes, objects, colors and other qualities } 물체의크기, 형태, 공간적관계에대한정확한판단 } 시각적자극에대해감각을통해수용하고, 특정인지활동을통해 인식하는모든과정 } Visual receptive component ( 시각적수용요소 ) Process of extracting and organizing information } Visual cognitive component ( 시각적인지요소 ) Ability to interpret and use what in seen 3

4 The visual system } 감각기관들의주요기능 : to receive information } Sensory receptor 의약 70%: vision } 관련된된해부학적구조 } Eye, oculomotor muscles, and pathways, optic nerve, optic tract, occipital cortex, and associative areas of the cerebral cortex(parietal and temporal lobes) 4

5 1. Anatomy of the Eye 안구의구조 기능 3 개의층 Sclera( 공막 ) 안구를보호하고지지함 (white) Choroid( 맥락막 ) Retina( 망막 ) Fovea centralis ( 중심와 ) 산란한빛을흡수하여암실을만드는역할을함 (black) Receptor nerve cells로구성 ( 막대세포,( 빛 ) 원뿔세포 ( 색 )( 그물모양 ) 물체의상이가장선명하게맺히는곳임 Corea( 각막 ) 빛광선을굴절시킴 ( 투명 ) Aqueous humor( 수양액 ) Iris( 홍채 ), pupil( 동공 ) 빛광선을굴절시킴 동공크기조절을통해빛의양조절 Crystalline lens( 수정체 ) Vitreous humor( 초자액 ) Optic nerve 5 빛을굴절시키고초점을맞춤빛광선을굴절시킴뇌신경 II

6 Figure cross-section of the eye 시각체계와관련된뇌영역 Parietal lobe 공간지각 Occipital lobe: 시각피질 Inferior temporal lobe; 물체지각 6

7 2. Visual-receptive functions : oculomotor system (CN Components III, IV, VI) 설명 Visual fixation Visual tracking Saccadic eye movement Acuity ( 시력 ) Accommodation Binocular fusion Stereopsis Convergence and divergence 일정시간동안물체를쳐다보고집중할수있는능력 머리고정상태에서눈의부드러운움직임 / 느림 보는지점을시야안의한곳에서다른곳으로변화시키는순서적이고빠른눈의움직임 시야범위내에서물체의세밀한특징을구별하는능력 다양한거리에위치한물체에초점을맞추는과정원근조절 - 수정체두께변화 ( 굴절각도변화 ) 두눈으로바라본하나의지각대상을합체시키는능력 à 두개의상을하나로융합하는과정 깊이지각또는 3 차원적시각 두안구를안쪽과바깥쪽으로움직이는능력 à 물체의거리에따라 7

8 2. Visual-cognitive functions 1) Visual attention: 시각적입력을선택하는능력 } Alertness 자연스러운각성상태 } Selective attention 방해자극을막아내면서중요한자극이나생각에초점을유지하는능력 } Visual vigilance=sustained attention Visual task 에지속적으로집중하는능력 } Divided(shared) attention 두가지이상의과제에대해동시에반응하는것 예 > 음악 + 학습.. 8

9 2) Visual memory : 과거의경험 ( 기억 ) 에시각적정보를통합하 는것 } 기억의기간에따른분류 long-term memory : 영구적저장 short-term memory : 약 30 초가량정보의일부를유지하는능력 9

10 3) Visual discrimination: 자극의특성을탐지하는능력 } Recognition : 저장을위해자극의주요특성을알아채는능력 } Matching: 시각자극사이의유사성을알아채는능력 } Categorization: 본것을비슥한것과다른것으로범주화하는능력 } Distinction of object vision and spatial vision 물체지각 (object (form) perception); what things are(temporal lobe) Form constancy Visual closure Figure ground 공간지각 (spatial perception) ; where things are (inferior parietal lobe) Position in space Depth perception Topographical orientation 10

11 1 Object perception Form constancy ( 형태항상성 ) 다양한환경, 위치, 크기에서물체와형태의동일성을인지하는능력 Visual closure ( 시각폐쇄 or 시각적연속성 ) 미완성의표상으로부터물체나형태를인식하는능력 Figure ground ( 전경 - 배경구분 ) 물체의전경과배경을구분해주위의정보로부터핵심적중요한자료에집중하는능력 11

12 2 Spatial perception Position in space/ visual spatial orientation ( 공간내위치 ) 물체또는다른물체와의공간적관계성을인식하는것 위, 아래, 사이, 오른쪽 / 왼쪽같은방향성용어이해에중요함 Depth perception 물체사이의상대적거리와지표면의변화를인식하는것 예 > 계단내려가기, 컵에물붓기 Topographic orientation 위치의경로를이해는것 물체가있는장소와장소까지의환경과경로를인식하는것 12

13 4) Visual imagery: visualization } 물리적으로존재하지않는사물일지라도마음의눈으로사람, 생각, 그리고물체를그리는능력 } 예 > 글로쓰여진설명에기초해서책에있는캐릭터를형상화 할수있음 13

14 Developmental framework for intervention } Hierarchy of visual perceptual skills development (Warren, 1993) : 시각적발달과관련된대표적모델!! Primary visual skills: 모든시각기능의기본 } Oculomotor control / Visual field/ Visual acuity Visual attention Scanning : 훑어보기 Pattern recognition } 패턴을발견하고인식하기 ( 전체적인윤곽 à 세밀한특성 ( 명암, 질감등 )) Visual memory : 이후인출을위해정보를저장하는능력 Visual cognition } 문체해결, 계획설정, 의사결정을위해정신적으로시각정보를 조작하고다른감각정보와통합하는능력

15 } Bottom-up approach : Evaluation and treatment 15

16 Developmental sequence 1. Visual-receptive functions } 태내기 } 임신 24 주 : gross anatomical structure, visual pathway } 임신 주 : retina, visual cortex 의광범위한성장 } 임신 5 개월 : eye movement } 생후 } 신생아 : visual fixation ability, reflexive tracking ability } 생후 2 개월 : accommodation, convergence, oculomotor subsystem } Controlled tracking skills horizontal Vertical diagonal circular 16

17 2. Visual-cognitive functions Table 12-1.Developmental ages for emergence of visual perceptual skills Visual perception Developmental age Object(form) Figure-ground Improves between 3 and 5 years of age Stabilized growth at 6 to 7 years of age 17 Form constancy Dramatic improvement between 6 and 7 years of age With less improvement from 8 to 9 years of age Spatial Position in space Development complete at 7 to 9 years of age Spatial relationship Improves to approximately 10 years of age

18 } Object (form) vision } Development Tactile, kinesthetic, vestibular inputà vision, audition 6-7 세아동의선호도 Kinesthetic, tactile, visual and auditory learning } Spatial vision } 공간조직화과정 Verticalàhorizontalà oblique and diagonal dimensions } Laterality and directionality 자신의오른쪽과왼쪽을구별하는 internal awareness: 6-7 세확립 Outside laterality 개념이넓혀지는것 8 세에시작 Reading 과 writing 을위한 visual discrimination 에서중요한역할 18

19 Visual-perceptual problems 1. Visual-receptive functions } Checklist of observable clues to classroom vision problems(figure 12-3) 1 Appearance of eyes 눈의충혈, 눈물의과다분비, 덮힌눈꺼풀, 잦은눈다래끼 2 Complaints when using eyes at desk 이마또는관자놀이의두통, 눈이가렵거나따가움, 현기증등 3 Behavioral signs of visual problems 19

20 Visual-perceptual problems 1. Visual-receptive functions 20 } Checklist of observable clues to classroom vision problems(figure 12-3) 1 Behavioral signs of visual problems Eye movement abilities : 책을읽을때줄을반복해서읽거나단어을생략해서읽기도하며, 눈동자를돌려읽기보다는고개를돌려읽음 Eye teaming abilities: 두개로보이거나단어에문자를반복해서쓰고숫자의위치를잘배치하지못함 Eye hand coordination abilities: 선을바로긋지못하고숫자의수직, 수평배열이어려우며읽은줄을표시하기위해손을이용하기도함 Visual-form perception : 비슷한단어구별을위해손으로쓰는행동이자주나타남 Refractive status ( 굴절상태- 근시, 원시, 난시 ) 눈을자주문지르고곁눈질을하거나책을너무가까이또는너무멀리두고읽는등의행동

21 } Individuals with functional vision problems (Seiderman, 1984) } Difficulty completing school tasks in a timely manner } Avoidance of reading work } visual fatigue } Adaptation through the development of a refractive error to perform near-centered visual task demands } Impairment of oculomotor control à 응시를조절하고방향조정하는능력을제한함 } Disruption of cranial nerve function } Disruption of central neural control 21

$} Refractive errors } 근시, 원시, 난시 } Binocular dysfunction Strabismus (Crossed or wandering eye) : 근육의불균형으 로인함 Double vision Effects$

22 } Refractive errors } 근시, 원시, 난시 } Binocular dysfunction Strabismus (Crossed or wandering eye) : 근육의불균형으 로인함 Double vision Effects on the development of visual perception Phoria ( 안구사시 ) Tendency for one eye to go slightly in, out, up, or down 22 두눈의명확한비정상적배열은없음

23 2. Visual-cognitive functions 1) Attention } Arousal state } Behaviors of overattentiveness, underattentiveness, or poor sustained attention } Selective attention } Reduced ability to focus in a visual targetà easily confused } Not obtain the specific information needed for the task } Vigilance } Reduced persistence on an visual task } Shared (divided) attention } Can only focus well on one task at a time } Easily confused or distracted if required to share visual attention between two tasks 23

24 2) Memory } Poor or reduced ability to recognize or retrieve visual information } Reduced to store visual information in short- or long-term memory } Inability to recognize or match visual stimuli presented previously } Not stored this information in memory or may not be able to retrieve in from memory } Inconsistent recall abilities } Poor ability to use mnemonic strategies for storage : 기억력증진을위한전략을사용하는능력저하 24

25 3) Visual discrimination } Poor discrimination abilities } Inadequate ability to recognize, match, and categorize } Poor matching skills } Difficulty matching the same shape presented in a different spatial orientation or may confuse similar shape } Difficulty in recognizing form within a complex field } Object (form) vision } Spatial vision 25

26 1) Object (form) vision } Form constancy problem } Different sizes or different orientations in spaceà difficulty recognizing forms and objects } Visual closure deficit } Unable to identify a form or object if an incomplete presentation is made } Figure-ground problem } Not be able to pick out a specific toy from a shelf } Difficulty with sorting and organizing personal belongings } 숨은그림찾기 or 책에서중요한정보찾기어려움 26

27 2) Spatial vision } Position in space difficulty } Difficulty planning their actions in relation to objects around them } 종이에글자간격을맞춰쓰기어려워함 } Difficulty in understanding directional language such as in, out, on, under, next to, up, down, and in front of } Decreased depth perception } 공간사이걷기, catch a ballà 어려움 } Unable to visually determine } Surface plane 이변하는경우 : 계단, 연석 } Diminished topographic orientation } Easily lost / 다음에갈위치를찾지못함 } Difficulty determining the location of objects and settings 27

28 3. Diagnoses with problems in visual perception 1) Prematurity } Retinopathy( 망막변성 ) à blindness } Cortical visual impairment } 굴절에러 : 저시력, 두꺼운수정체, 난시, 사시등 2) Developmental disabilities } blindness or other visual impairment 의진단중복됨 3) Cerebral palsy } Strabismus, ocular motor problems, convergence insufficiencies, nystagmus } Spasticity > athetosis: Group with spastic quadriplegia greatest problems in visual perception 28

29 4) Language delay } Visual perception 발달 - 언어발달과관련됨 } Every animal with four legsà dog } Visually discriminate between dog and lion } Visual spatial perception deficits à difficulty in understanding directional language such in, on, under, and next to 5) Learning disabilities } Visual-perceptual problems 가있는경우가많음 29 } 지능검사에서언어점수보다수행점수가낮은아동에서더높은 빈도보임

30 6) Psychiatric disorders } 발생빈도 : Visual motor skills > visual perception skills } Some children with autism } Poor oculomotor function 30

31 4. Effects of visual-perceptual problems on performance skills and occupations } bilateral manipulative skills are affected } Difficulty with activities of daily living } Community mobility may be difficult } Work and productive activities problems } Home management } Classroom assignment } Educational activities problems 31

32 } Educational problems in the school-age child 1 Problems in reading } Reading : requires visual attention, visual memory, and visual discrimination } Severe dysfunction: recognition of wordsà impaired } Memory deficiencies } Unable to remember the visual shape of letters and words } Visual discrimination deficit } Not be able to recognize symbols } Slow to master the alphabet and number : 예 > p, q, g, b & d } Visual spatial deficits } Difficulty with map reading / interpretation of instructional graphics( 예 > charts, diagrams) 32

33 2 Problems in spelling } Impaired processing of simultaneous visual stimulià difficulty with spelling } Sound-symbol association : 예 > 받아쓰기 3 Problems in handwriting and Visual-motor integration } Visual attention problem } Difficulty with the correct letter formation, spelling, mechanics of grammar, punctuation, and capitalization : 글자형성, 철자, 문장구성, 대문자사용등의어려움 } Visual discrimination } Unable to recognize letters or words and copying } Unable to discriminate a letterà poor letter formation } Visual spatial problem } Reversals of letters or numbers } Best predictor of handwriting (VIM) 33

34 4 Problems in mathematics } Difficulty correctly aligning columns for calculationà answer incorrect } Figure-ground problems } 혼란요소 : Worksheets with many rows and columns of math problems } Visual spatial perception problems } Geometry present difficulty 34

35 Evaluation methods } Consideration } Entire process of vision } Relationship of visual function to behavior and performance } interdisciplinary team approach } Reading specialist } Psychologist } Speech-language pathologist } Classroom teacher } Vision specialist: ophthalmologist, optometrist 35

36 1. Evaluation of visual-receptive functions } Including visual fields, visual acuity, and oculomotor control } Visual-receptive problemsà visual-cognitive deficits (Warren, 1990) } Occupational therapist: familiar with visual screening } Basic tests administered to select children who are at risk for inadequate visual functions } Perimetry, confrontation, and careful observation as performs daily activities : 시야측정, 대면검사, 관찰 } Missing and misreading the beginning or ends of words or numbers 36

37 } Refractive status } 굴절상태확인 : 근시, 원시, 난시 } Snellen test at 20 feet(6m) } Telebinocula } Contrast sensitivity test } Occupational therapist ; oculomotor dysfunction 관찰 } Screening test: several questions 1 Do the eyes work together? How well? 2 Where is visual control the most efficient? The least efficient? 3 정확하고빠른안구움직임의종류는? 4 글을읽을때머리를과도하게움직이나? 건너뛰나? 37

38 정상시력가진사람이볼수있는거리 (0.1) 38

39 2. Evaluation of visual-cognitive assessment } observation } Difficulty in selecting, storing, retrieving, or classifying visual information } Visual search strategies used during visual perceptual tasks } How the child approaches the task } How the child processes and interprets visual information } Methods used for storage and retrieval of visual information } Amount of stress associated with visual activities } Clinical evaluation } Typically administered by occupational therapists 39

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