Mandy DD Part 1 Flashcards
Prevalence and background of dd
From delayed mental/physical development. Can be physical or mental. Around 13% students are SEN, 4% severe. SEN 4x more likely to have anxiety disorders. More m than f. 7.4% dld
What is the medical model
Measures indv against norm, deficit view to provide treatment and support. Legitimises conditions, builds knowledge. W: limits understanding by looking at individual, view as deficit, can made diagnosis in masking adults diff and focus on cure is problematic- common underlying neurodevelopmental continuum
Social model
1975- way to change systems in society but had an impact on research. Diff between impairment and disability (disability due to society so looks at removing barriers). New ways of describing and understanding conditions
Diff in neurodiversity
Singer 98 (sociologist) developed neurodivergent as opposed to neurotypical. Focuses on diffs and strengths not deficits but can be problematic (ppl don’t Id with strengths)
Wolff: white matter and development
measured white matter tract by seeing how water passes through the brain. 92 infants test at 6,12 and 24 months. At 6 months, later diagnosed with autism had higher white matter integrity, 12 months no diffs then reversed at 24 months
Development timing
Nuerodiv. Have atypical timings which can alter their environmental input and misaligns growth across domains
Estes 2015: infants that had autism had motor impairments at 6 months which led to communication deficits (gesture use..)
Example of how brains differ massand
Massand 2013: adults with and without autism learnt words the same but EEG showed occurred within diff areas of the brain
Different research methods
Cross sectional (quick and cheap but can’t show change, usually age/skill matched). Longitudinal, intervention studies/randomised control trials (measure ability, intervention, measure change and placebo). -example Reynolds 2003: intervention to improve cerebral function Improved dyslexia but didn’t randomly allocate so one group better and no placebo
Causal models
Morton and frith 1995: behavioural level is the actions observed, cognitive level can only be inferred, biological level is brain, genes and functioning and all are affected by the environment
Comorbidity definition
When two or more disorders occur at the same time at a greater rate than chance
DLD background
Used to be specific language impairment, language skills below peers (1-2sd). Typical oral motor function, no hearing loss or nuero damage or psych problems but may have cog delay. 7% preschoolers. Poor vocab, phonology (distinguish/repeat), poor grammar in inflection morphology. Behaviouraldisplay (grammar representation deficit)
Causal model/theoretical framework (Morton and frith, hulme and snowling
Behavioural first (what is observed), then cognitive, then biological and each stage interacts with environment. Can lead to hypotheses but no developmental change/comorbidity
Phonology and morphology definition
Phonology is the pattern of speech sounds (phonemes) within language. Morphology is the smallest meaningful unit in grammar of language e.g unladylike has 3
Grammar and syntax definition
Grammar is a system of rules by which words are properly formed/combined in a language. Syntax is a more general set of rules about combinations of words and phrases that can be used for sentences
Inflection morphology
Where a morpheme is added to a grammatical category (noun, verb, adjective) to assign a property (tense, number, possession)
Symptoms of dld using the model
Behavioural- specific deficit in grammatical representations. At cognitive- information processing limitations , auditory processing deficits and phonological deficits. Biological-procedural deficit hypothesis
Procedural deficit hypothesis PDH
Systems in LTM: procedural (skill learning in basal ganglia and cerebellum) and declarative (hippocampus learning word difficulties). Deficit in procedural causes language deficits and nonverbal like sequence learning. Have spared declarative memory (vocab learning not affected so compensatory)contradicts symptoms
Language network
Involved: inferior frontal gyrus, superior and middle temp gyri, brocas and wernickes area. Mixed evidence for diffs: Mayes 2015 studies have found atypical inferior frontal gyrus and striatum, some say increased vol, some decreased and activation. BOLD mri supports diffs in striatum and left frontal fury is w decreased myelination
Lateralisation and atypical lateralisation
Experience creates localisation, functions localised to hemi, language L. Perisylvian cortex in lang network, vol bigger in left but dld have smaller in L or no diff plante 91 but 2015 found limited evidence and structure not always correlated with lateralisation
Functional transcranial doppler ultrasound
Records direction of blood flow in anterior, middle and posterior cerebral arteries. Some evidence for weaker lateralisation in left hemi in word generation tasks bishop 2p13 but recent found no group diffs and more R activation in control
Cortical processing of language
EEG measure AP during tasks, more temporal than spatial, diff wave forms indicate diff processes (N100 for unexpected stim, P100 important stim, ELAN is an early waveform linked to fast, automatic processing of grammar in an incorrect phrase, p600 is later processing of incorrect.
Mismatch - response to incongruent.
EEG diffs for DLD
Mcarthur 2009: DLD show a flatter N1-P1 region
Uwer 2002 and bishop 2007 DLD show reduced amplitude for consonant vowel stimuli
Webber fox 205 found diff elan response and p600 for dld
Dld dsm
Defines as persistent difficulties in the acquisition and use of language across modalities and may involve comprehension or production deficits in vocab, sentence structure, discourse
Vocab and grammar impairment examples
Children are slow to acquire words and have limited vocabs- mcgregor 2013
Rely on non specific words like thingy and can’t do words with abstract meaning
Difficulty retrieving words they know. Slow to produce first word combinations. Typical is 18-24 months but ld are 2 to 4 years old
Have shorter utterances
Difficulty with morphologies like tenses, possessions, subject verb agreement, pronouns
Preschool assessment of dld
Some standardised measures are used but also, spontaneous speech, play interaction, allowing the child to talk for a puppet
At school age: standardised test to see the impact on education, test scores
Dld differential diagnosis
Language difficulties may have nonverbal reasoning deficits which may reduce intervention. Acquired epileptic aphasia-need sleep eeg. Specific learning disorders: many have reading impairments, low educational attainment, maths probs and coordination. Selective mutism (ssris help), 1.5x more likely to meet adhd, language disorder strong predictor of psych outcome, hard to delay gratification/predict others
Dld linked to auditory and memory
Difficulty perceiving sounds, some W auditory deficits don’t have language difficulties and improving auditory skills doesn’t improve literacy. Linked to poor stm
Environmental factors and dld-mothers
Twin studies show quality of early mother interactions predict language abilities at 36motnhs old Thorpe 2003. Maternal education and socioeconomic status linked as poor children have less language competence letts 2013. Decoding diffs more common in deprived areas
Social pragmatic communication disorder
How children infer meaning, randomised control trials suggest interventions that target auditory processing not effective but those that target semantic skills /grammatical forms are
Types of dyslexia
acquired (developed typically, from illness or head injury) or developmental (genetic and impacts development)
Lexicon, semantics, pragmatics definitions
Lexicon is our ltm store of words, semantics is meaning behind language, pragmatics studies the same words and meanings but emphasis on context (physical, epistemic, linguistic)
Skills in learning to read
Foundation or oral language and for inferences need word meaning. Goal is to understand written text by building mental representations. Gough 85: broken into decoding and comprehension. Dyslexia have difficulties decoding, others are poor comprehenders
Dyslexia definition and prevalence
Pattern of learning difficulties with accurate or fluent word recognition, poor decoding and spelling. Occurs despite general cognitive ability in the normal range and adequate instruction
Life time persistence, 3-6% of pop, called specific learning disorder. Symptoms varied so diff theories
Dyslexia sensory theories
Rapid auditory processing theory: talla: deficit in perception of short, varying, rapid sounds. Rise time theory goswami: deficit in tracking amplitude rise times cues in auditory-time taken from onset to max amplitude. Visual/magnocellular theories Livingston: system responds to rapid changes in visual stim so have reduced sensitivity. Nicolson: dysfunctional cerebellum, motor control&automisation
Weaknesses of sensory theories
Ramus 2003, vellutino 2004: little evidence that core deficit in dyslexia: rapid auditory, signal tracking, visual or cerebellar
Do show difficulties but not the core difficulty
Phonological deficit hyp PDH
Phon core variable deficit hypothesis is stanovich 1994, phon deficit hyp is snowling 1987. Deficit in phonological coding but semantic syntactic and pragmatic lang unaffected. Variable deficits outside core
How to measure phonology
The sound structure of lang split into unconscious/implicit (process lang info fast when talking and listening, measured W non word repetition, naming, stm, paired association)or conscious/explicit. (Activity manipulating sound structure of speech, knowledge from reading like phonics, measured W phoneme isolation and deletion, oddity task, spoonerisms)
Phoneme testing experiments
Phoneme deletion bice- b is ice snowling 2001. Reading age matched controls, dyslexics did worse than reading age and chronological age. Non word repetition Hatcher 2002: dyslexics did worse than reading age matched
Why known as a reading diff, predictors of word reading
Ppl first noticed those who struggled to read in absence of other diff, need decoding for reading. Phonetic awareness, letter knowledge/alphabetic principle from rapid automatised naming wolf. Caravolas measures all 3 predicted reading ability 10m later. Bu: phoneme awareness&letter knowledge predicts word reading later. Stress after long periods of reading
Dyslexia profile
Poor reading and spelling-phonological diffs neuro diffs (model). Less impaired at reading prose but at words in isolation as no context, persist to adulthood, deficits in paired association, mapping between letters and sounds but visual unimpaired. Some poor decoders have good reading comprehension (spectrum). Poor working memory
Neurobiology-reading network
Focus in L hemi. Richlan: L inferior gyrus has phonological output, reciprocal connections to left OT, L parietal lobule has general attentional mechanisms and Top down connection to left OT. left IFG and occipito temp cortex has phonological decoding of famil/unfam letters. Richlan meta analysis found under activity in temporoparietal regions and occipito temp regions. Over activity in frontal gyrus (compen). In children, anterior system overactive, posterior under
Fmri diffs
Measures blood o2 levels (bold), measure of neuronal activity, good spatial, poor temporal. Van der mark dyslexics and normal did continuous reading task with phon and orthographic processing. Connection between L occipital temp cortex and L inferior gyrus in normal but diff in dyslexics in - same results found in non English speakers
Comorbidity W dld
Reading builds on verbal lang, both have diff with phon as key part of lang. dld problem w comprehension . Snowling found dyslexic vocab most similar to controls (dld and comorbid diff), for decoding, dyslexia and comorbid diff to controls but dld similar. For reading comp: dyslexics did better than dld and comorbid, suggests separate conditions W diff causes
What makes up specific learning disorder also language learning impairment
Dyslexia, dyscalculia, dysgraphia. Lli have varied problems with literacy but not traditional traditional criteria
How to improve children’s literacy
Boosting oral language at school entry had + effects on reading comp later. Children W adhd learnt o read so not about attention. Home literacy background improves as seek out more literary experience. Poor readers come from large families where later born face delays. Schooling makes big diff. In Germany/Finland , found by slow rates of reading but in England poor accuracy main marker
