LINGUIST List 15.1302
Sun Apr 25 2004
Review: Lang Acquisition: Verhoeven & van Balkom (2004)
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Leah R. Paltiel-Gedalyovich, Classification of Developmental Language Disorders
Message 1: Classification of Developmental Language Disorders
Date: Sat, 24 Apr 2004 23:31:04 +0200
From: Leah R. Paltiel-Gedalyovich <glh33zahav.net.il>
Subject: Classification of Developmental Language Disorders
EDITOR: Verhoeven, Ludo; van Balkom, Hans
TITLE: Classification of Developmental Language Disorders
SUBTITLE: Theoretical issues and clinical implications
PUBLISHER: Lawrence Erlbaum Associates
YEAR: 2004
Announced at: http://linguistlist.org/issues/15/15-177.html
Leah R. Paltiel-Gedalyovich, Ben-Gurion University of the Negev
SUMMARY
This volume is an edited collection of papers evolving from a workshop
at the Max Planck Institute for Psycholinguistics. A short
introduction precedes the main body of the book which is divided into
three parts of roughly equal length: etiology, typology and assessment
and intervention. The editors state the purpose of the book as 'the
classification of subtypes of developmental language disorders' (DLDs,
p. 6). This classification is examined with an eye towards assessment
and intervention.
In the introduction, the editors briefly review the various
descriptions of DLD and the implications of the difficulties for
schooling. They then highlight theoretical and practical difficulties
in assessment and differential diagnosis, making practical if brief
recommendations for what may be involved in the assessment
process. Classification of the type of DLD is seen as a primary goal
of assessment, however, limitations in diagnostic tools limit the
ability to reach such a classification at a clinical level.
Thus, this volume aims to contribute towards remediating this
situation. Multi-faceted approaches of this collection is emphasized
by the very different research orientations and methodologies of the
participants. It brings a range of theoretical orientations,
concentrating on translating theory into clinical practice.
The stated target population is anyone interested in SLI. It is also
recommended as an introduction to SLI for undergraduate and graduate
students.
PART 1 ETIOLOGY
In the opening chapter, Chapter 1 'Characteristics of children with
specific language impairment (SLI)', Nicola Botting and Gina
Conti-Ramsden describe the difficulty in reaching a positive criterion
for SLI and review the negative criteria (what to rule out). They then
describe their research project, a survey of 50% of the children
attending special language educational environments in England. They
thus have a large sample size (233 children) at one age group (7
years) assessed twice at a one year interval. Note that their group
included many children (58) whose standardized language test scores
fell within normal limits yet were significantly lower than their
non-verbal abilities.
Their research results in a classification of these children into 6
groups which they compare to the classification of Rapin and Allen,
although, they prefer to characterize their groups by description of
the pattern of performance on a a number of clinical tasks rather than
a label. They report the changes which occur in the surveyed
population over the year - interestingly, children may change their
classification but new classifications were not found. The authors
compensate for limited discussion, probably due to length limitations,
by references to detailed published accounts for more in depth
discussion.
In my opinion this chapter deals with typology and not etiology and
would have been more appropriately placed as an opening for the second
section of the book.
Chapter 2 ' Neuroplasticity and development: 'The acquisition of
morphosyntax in children with early focal lesions and children with
specific language impairment' by Judy Reilly, Jill Weckerly and
Beverly Wulfeck follows. This chapter compares the patterns of
behavior of children with focal brain lesions and SLI with their
normally developing peers. Here the emphasis is on the differential
patterns shown by different etiologies. The authors conclude that the
populations are differentiated in terms of patterns of recovery rather
that patterns of disability. As in the previous chapter, the research
brought was carried out on an impressively large population. Children
with focal brain lesions are found to recover and reach normal levels
of language behavior by age 7-8 while children with SLI retain
impaired behavior until older ages. The results are related to the
question of neuroplasticity. The recovery of the children with focal
lesions shows the plasticity of the brain with healthy areas
compensating for damaged areas. This is unavailable for children with
SLI due to the postulated diffuse nature of the brain impairment.
Chapter 3 is 'Language disorders across modalities: The case of
developmental dyslexia' by Pieter H. Been and Frans Zwarts. The
authors describe a model of auditory perception, the combined
ARTPHONE-SWEEP model. They use this model to simulate behavioral and
brain study results of phonological awareness in Finnish and Dutch
normal controls, adult dyslexics and in infants at risk for
dyslexia. The model shows that dyslexic behavior may results from a
deficit in auditory areas which is similar to a visual deficit, based
on general perceptual deficits affecting auditory and/or visual
areas. This is supported by the modelling of the SWEEP component on
models of the visual cortex. However, similar results can be found
based on the ARTPHONE model which models an auditory, language
specific capacity.
The model has the advantage of making predictions (and
recommendations) regarding treatment options, both pharmaceutical and
behavioral. It provides a theory of the neural structural deficits
underlying dyslexia, specifically, reduced local neural density. Thus
deals directly with the question of etiology for this population. The
chapter is quite technical as a fair bit of familiarity with neural
anatomy and phyiology, as well as modeling is assumed.
Chapter 4 'Neuroimaging measures in the study of specific language
impairment' by Paavo H. T. Leppanen, Heikki Lyytinen, Naseem Choudhury
and April A. Benasich gives a review of the results of a variety of
neuroimaging techniques for children with SLI and related
deficits. The accuracy and benefits of such techniques in studying
adults is stressed along with the parallel expectation regarding
children in general and particularly in clinical populations. Each
technique is introduced with a brief description assuming no or little
prior knowledge. References to detailed reviews of a variety of
techniques are given.
No definitive correlation between anatomical anomaly or neural
function and behavioral pattern (subgroup of SLI ) has been found but
some trends are evident, particularly in the auditory pathway and in
auditory processing. Inconsistencies in techniques, populations and
results between studies make drawing conclusions difficult. It is not
always clear which behavioral pattern is being examined for a
neuro-substrate due to lack of a unified definition of SLI.
The authors conclude that a potential for neuroimaging as a technique
for identification and prognosis of children at risk for langauge and
language related disorders exists but it is not yet well enough
developed to be used for differential diagnosis or definitive
prediction.
Chapter 5 'Information processing in children with specific language
impairment' by Ronald B. Gillam and LaVae M. Hoffman deals with
etiologies of SLI, accompanying symptomatology which may or may not be
causal: attention deficits, auditory discrimination and processing
deficits, phonological representation limitations.
After considering research into working memory, specifically for
auditory speech information, Gillam and Hoffman conclude that the main
difficulty is in creating, retaining and using 'verbal
codes'. Alternatively, recoding phonological information may cause
system overload for these children.
Along with a survey of the relevant research, the authors report two
experiments of their own. The first (published) study deals with the
question of working memory for verbal codes. The second (in press)
study deals with the role of central executive function. they found
that children with SLI could not take advantage of the multi-modal
clues. Rather than being integrated, the separate visual and auditory
clues served to detract from each other. Limitations in verbal storage
capacity account for poor performance. They suggest that children
with SLI show problems in general memory and response time relative to
age-matched peers, concluding that there is a problem with general
capacity.
Clinical implications are discussed, specifically, they suggest a
"dynamic assessment" process to assess both language skills and
"psychological functions that support language development" (p. 150).
These psychological functions include: attention, perception, memory,
and central executive functions. The testing process involves:
pretest, teaching (1-2 sessions), posttest. The posttest assesses the
degree and type of change resulting from the teaching phase in order
to evaluate the child's information processing abilities. A specific
example of the assessment process using the example of narrative
skills is given.
Intervention strategies are based on the results of the
assessment. Although general treatment may be highly oriented towards
ecological validity and pragmatic appropriateness for the social and
academic environment, 'mini-lessons' focussing on particular skill
areas are sometimes needed. Intervention techniques suggested include:
promoting attention, reducing speech rate and improving clarity,
promoting phonological coding by drawing attention to various aspects
of phonology, choosing treatment topics based on what is familiar to
the child, organizing new information and provide memory aids.
Chapter 6, 'Environmental factors in developmental language disorders'
by Sienke Goorhuis-Brouwer, Francien Coster, Han Nakken and Henk Lutje
Spelberg discusses the role of social communication in the development
of language disorders and the converse influence of a language
disorder on socio-emotional development.
Three pilot studies are reported: Study 1 examined the behavior of
pre-school (1-3 years) children with SLI. Based on a behavior and
language questionnaire the only difference between the normally
developing preschoolers and those with SLI was in the adaptation (less
open in contact with peers). The parent interview however showed
behavior problems, again in the area of socialization. Study 2
examined the behavior of kindergarten (3-6 years) children with SLI.
Observations assessed by the CBCL (Achenbach, 1991) did not show
significant differences between the groups, but again, the parent
interview did. Three quarters of the parents reported problems. Study
3 examined the behavior of school children (6-15 years) with
SLI. Teachers reported socio-emotional problems which were supported
by their observations reported by the teachers version (TRF) of the
CBCL.
>From the pilot studies the authors hypothesized that there is a
gradual increase in the correlation between reported and observed
aberrant behavior with increased age. The combination of behavioral
problems and language deficit increasingly interferes with social
interactions and communications with adults and peers. This hypothesis
was examined in a large study (over 150 participants). The methodology
involved the CBCL teacher and parent observation forms. Around one
third of the children were found to be within the clinical range for
socio-emotional development based on parental ratings, the percentage
of children rated by teachers to be within this range was slightly
higher. When the ratings were taken together almost half the children
were considered to be within the clinical range. Note that there was
poor parent-teacher agreement. This is interpreted as indicative of
the children's differential behavior depending on the communicative
situation and partner. Discrepancy between early perceived behavior
and actual behavior was found to affect development of deviant
behavior.
Part II Typology
Chapter 7 'Speech output disorders' by Ben Maassen opens this
section. Using Levelt's (1989) model of speech output, Maasen aims to
arrive at clinical diagnosis. He compares developmental apraxia of
speech (DAS) with dysarthria, phonological delay , other
(non-specific) articulation disorders and normal speech. As such the
symptoms of DAS reflect difficulty 'somewhere between word form
retrieval and articulation' (p. 177) in Levelt's model. He follows
Bishop (1992) as defining the disorder as a deficit in converting from
phonology to motor execution. Five procedures for evaluating
intelligibility both quantitatively and qualitatively are described:
1. producing phonetic contrasts, 2. phonological process analysis of
a spontaneous sample, 3. word identification, 4. Percentage
consonants correct (PCC, Shriberg and Kiawtkowski, 1982), and
5. scales of speech qualities. In addition Maasen demands of a speech
evaluation that it should aid in determining etiology and allow
differential diagnosis.
An empirical study is reported. Criteria for selecting participants as
DAS, dysarthric, SLI or otherwise are described in
detail. Experimental tasks include real and nonsense word production
as well as rapid syllable string production. Results show that on the
word production task, children with DAS produce more errors than
children with SLI or dysarthria who produce more errors than their
normally developing peers. Dysarthria results in a high percentage of
distortions while DAS results in a high percentage of place
substitutions. All groups show similar patterns regarding other
aspects of sound production. On the maximum repetition task children
with dysarthria are slower than children with DAS and SLI who are
slower than children with normal development.
Similarities between the SLI and DAS effects leads to a closer
analysis which suggests that about half of the children with SLI show
dyspraxic symptoms, suggesting a possible shared underlying
deficit. This deficit is thought to be a deficit at the level of
speech segments and articulatory movement. These are parallel to
Levelt's 'segmental spellout' and 'phonetic spellout'. Note that DAS
rarely occurs in isolation. Although the chapter is clearly written, I
would have benefited from a more detailed (and graphic?) explanation
of Levelt's model.
Chapter 8 'Central auditory processing' (CAP) by Jack Katz and Kim
Tillery first gives statistics on the prevalence of CAP disorders
(CAPD) in the normal population (thought to be 5% -10%); similar or
higher percentages may exist in clinical populations. A disorder in
CAP is defined as a disorder in what is done with auditory input. CAPD
has been associated with learning difficulties, primarily reading but
also other language and communicative areas. Its symptoms may be
confused with attentional disorders. However, many children with ADHD
also suffer from CAPD.
A behavioral CAP assessment battery is described which includes:
1. Staggered spondaic word test (SSW), this yields a quantitative
score as well as therapeutically useful qualitative error analysis. ,
2. Phonemic synthesis test (PS) which provides quantitative and
qualitative information on sound blending skills. , and 3. Speech in
noise test.
CAP behavioral studies, together with neural lesion information, have
resulted in classification of four subtypes : 1. 'Decoding category'
(DEC), 2. 'Tolerance-fading memory' (TFM) category, 3. 'Organization
category' , and 4. 'Integration'. The categories are summarized in a
clear table. For each category a clear description of the symptoms,
the anatomical areas affected and the relation between these is given.
The authors follow with a sample case study which relates assessment
results to intervention recommendations. Finally intervention
strategies are suggested for each of the categories.
Chapter 9 ''Lexical deficits in specific language impairment' by
Laurence B. Leonard and Patricia Deevy looks at children with lexical
rather than grammatical disorders (cf. work by van der Lely on a
lexical subtype of SLI). They describe the lexicon and its importance,
as well as problems deriving directly from lack of word knowledge,
secondary effects on grammar and morpho-grammar learning.
Although early symptoms of SLI include late first words, smaller
vocabulary, limited comprehension, and decreased lexical diversity,
the general pattern of vocabulary composition and use is similar to
younger normally developing children. The authors survey some
assumptions regarding lexical processing. Each word entry includes:
"lexical concepts" (meanings are formed for words and links are made
with related meanings), "lemma" (grammatical properties and links to
other entries with similar grammatical properties), and "lexeme"
(phonological information including links with entries with shared or
similar information). Comprehension progresses from lexeme to lemma to
lexical concept. For production the process is reversed.
A review of research into lexical skills of children with SLI shows
evidence for relatively normal learning of novel words for
comprehension but reduced learning for production. An explanation of
these results in the context of the given model suggests that this is
indicative of the formation of a reduced lexeme. There appear to be
two groups of impairment, for one, semantic information is more
distorted and for the other, it is phonological information which is
primarily affected. Specific difficulty with verbs may also be
explained within this model although the authors note that some 'pure'
syntactic difficulties remain.
Chapter 10 is 'Morphological disorders' by Dorit Ravid, Ronit Levie
and Galit Avivi Ben-Zvi. These authors choose Hebrew derivational
morphology as a diagnostic tool in comparison of school children with
SLI and NLA. Thus, they aim to contribute to the delay versus deviance
debate.
Language in school children is characterized by continued development
alongside the interaction of language with growing literacy
skills. Children with SLI show problems with: 1. lexicon
2. morphological processing, 3. metalinguistic skills. Children tend
to learn the morphology of morphologically rich languages relatively
easily, including SLI children. On the other hand, studies of
derivational morphology in English have shown that SLI children have
difficulty with this area. Previous study by these authors has shown
children with SLI have difficulty in production of novel derived nouns
and in semantic noun classification.
Adjectives are a unique content word class semantically, pragmatically
and syntactically. Adjectives characterize nouns and as such have a
morphology which reflects the characteristics of the noun in
morphologically rich languages. As background to their study, the
authors give a short and clear description of Hebrew verbal, nominal
and adjectival morphology.
Counter to predictions children with SLI perform more poorly on
comprehension task than age and language matched controls. On
production tasks, children with SLI differ from both
groups. Resultative adjectives are found to be significantly easier
than attributive and denominal. Children with SLI differ from both
groups on resultative adjectives but do not differ from language
matched controls on attributive and denominal adjective derivation.
The difficulty with comprehension is interpreted as resulting from
difficulty in analysis of morphology. However, the experimental task
requires production as well, such that it is not clear what causes of
the poor performance. The authors note non-language factors which may
have confounded results but do not consider expressive language
difficulty.
The results are interpreted as supporting a deviance (as opposed to
delay) explanation. This is based on a qualitative analysis of errors
(quantitative analysis does not shown consistent difference from
language matched controls): children with SLI use analytic expressions
and semantic responses more often than their LA matched peers as well
as one strategy (unconventional adjective). They conclude that this is
an appropriate area of study for distinguishing SLI.
In Chapter 11 'Grammatical impairment: An overview and a sketch of
Dutch' by Jan de Jong examines theories of the morpho-grammatical
deficit which is present in most children with SLI. De Jong reviews
theories of grammatical symptoms of SLI. 1. Non-salience of
inflectional markings - "surface" hypothesis. Leonard (1989) accounts
for cross-linguistic differences where differences in surface saliency
of inflections account for whether or not they are affected by SLI.
2. Decreased control of subject-verb agreement. 3. Prolonged optional
infinitive stage. 4. Decreased knowledge of abstract features.
Part of the author's doctoral dissertation is reported which
investigates the nature of tense and agreement in Dutch SLI and what
(if any) of these SLI theories are supported? Results show error
patterns in children with Dutch SLI as compared with controls
including inconsistent marking of past tense. Errors include
omissions, substitution (present tense affixes), infinitive forms. In
addition - omissions of inflectional markers (regarding 3rd person),
misrepresentation of number (singular instead of plural), form
position concordance.
De Jong explains the data as compatible with all but the extended
optional infinitive stage hypothesis for omissions, substitutions
cause difficulty for the surface theory as well. Adapting the optional
infinitive stage to Dutch is difficult since this follows (in the
proposed stages) a finite stage. The children use an auxiliary plus
infinitive. The optional infinitive account does not predict the
agreement (person, number) errors. The agreement hypothesis does not
predict the past tense errors. Overgeneralizations argue against a
theory that SLI children have no linguistic rules. Research into
non-English SLI leads to the need to account for substitutions not
just omissions, and to consider phenomena of verb second languages.
In Chapter 12 'Pragmatic disability in children with specific language
impairments' by Hans van Balkom and Ludo Verhoeven pragmatic
disability is defined as a deficit in communicative use of
language. Specifically "an inability to select and match a suitable
linguistic form to the most appropriate and effective communicative
function. ' (p. 283)
Two approaches modular and functional are described and illustrated in
clear figures. I found it interesting that the population studied was
very young and that the entire SLI group reached age appropriate
behavior as measured by formal tests within two years. Is this
representative of children with SLI?
Results of the empirical study show that SLI and NLA are not
differentiated by the appropriateness and variety of communicative
functions. Rather, the SLI population uses inappropriate linguistic
forms for these functions. The authors note the reciprocal
relationship between the children's language performance and the
parental language behaviors resulting in a poorer linguistic
environment. The children have difficulty with discourse processes
because of weaker representation of linguistic knowledge, even when
this knowledge reaches normal levels. Within the SLI group, higher
functioning children perform better than lower functioning children
with regard to form-function mapping as measured by discourse
coherence. Parent interactions with children with SLI are less
involved and less equally distributed than with children with
NLA. This linguistic environment provides for the child with SLI only
limited opportunities to develop discourse strategies.
PART III Assessment and Intervention
In Chapter 13 'Specific language impairment: Diagnostic dilemmas' by
Dorothy V. M. Bishop, the author begins with arguing for the different
demands of a classification system for research and clinical
purposes. She makes use of the World Health Organization
classification to suggest that research deals with impairment, while
clinical work deals with disability arising form such an impairment
and aims to minimize handicap resulting from such disability.
The aim of clinical assessment is to determine which children will
benefit from which specific forms of intervention and educational
placement. Traditional criteria like IQ discrepancy scores need to be
used discriminantly, again depending on the goal of
classification. The type of assessment used is influenced by the
model. Qualitative assessment strategies result from a model which
views SLI behavior as atypical, eg. Rice's (2000) extended optional
infinitive test or non-word repetition. Standardized tests may not be
geared to distinguish impaired and non-impaired populations.
Children with a really specific disorder are unusual; usually we find
co-morbidity. The search for a very specific diagnosis may result in a
too narrow evaluation of the child. She notes that various
professionals will diagnose the same symptoms differently. A
multidimensional model (instead of labels) allows us to relate to the
child's function in a variety of critical areas. However, we need
labels to allow appropriate educational placement. Bishop emphasizes,
the pure cases are NOT representative of the SLI population. For
research purposes co-morbidity raises issues of the relationship
between the various impairments. Clinical approaches are more
successful in describing underlying processes. Bishop ends by
describing some different types of SLI which do have consensus.
In Chapter 14 'A dynamic systems approach to diagnostic measurement of
SLI' Paul van Geert defines a dynamic system as "a structure of
interacting forces" (p. 327) which undergoes 'self-organization;'
becoming increasingly more ordered and structured.
As opposed to the classical Chomskyan nativist view and the "poverty
of the stimulus" argument for language innateness, the dynamic systems
approach allows rich linguistic competence to develop from poor
linguistic input by not assuming the axiom of entropy. According to
the Chomskyan view, deficient language development should first of all
reflect a deficit in the innate substrate; according to the dynamic
systems approach, every step in the self-organization process causes
the following step.
This system is iterative; thus the input to the next stage is the
preceding stage plus environmental input. Finding the cause of
impairment requires reconstructing the developmental process. The
system may reach an "attractor state" where the output stage is
similar to input stage which will be semi-stable unless external
factors are changed (e. g. an individual is given a hearing aid).
The model adopted of development is a linear increase model: Each
successive state depends on the current state plus input. If increase
and decreasing factors are of statistically equal magnitude the result
is a 'random walk' showing random fluctuations. The use of the model
to explain fluctuations (loss and recovery) is exemplified by
Landau-Kleffner syndrome.
Since more than one skill area competes for the resources (such as
attention) the amount of competition influences the outcome. The model
predicts a bi-modal pattern of development for two competing
factors. The possibility of innate language disorder or innate
language knowledge is compatible with the model. An innate disordered
state influences the amount of resources which must be allocated.
A dynamic model predicts (as is found) changes in the pattern across
time. An impaired genotype may have different manifestations as
resources are competed for - resulting in different patterns of
strengths and weaknesses.
Psychological properties cannot be accurately measured by tests
because they are the interaction of the individual with the context
and environment. Therefore, assessment involves describing a range of
characteristic performances for a skill area (e.g. morphosyntax) for a
child under different contexts (e.g. test performance, normal
communication, stress, etc. ) . Thus, one part of the description of
the child's ability addresses the variability of his/her
performance. In this view, test-retest variability is expected. Rather
than giving a child a specific label, van Geert suggests stating that
a diagnostic label is "characteristic of a specific person to a degree
of approximately. . . . (x). " (p. 345)
I found the detailed explanation of the model and the use of figures
and examples extremely helpful in understanding a view of language
acquisition and disorder which was totally new to me.
In Chapter 15 'Early detection of developmental language disorders'
Hanneke de Ridder and Heleen van der Stege discuss a screening
instrument for language impairment introduced as part of a national
health center protocol for infants/toddlers. The screening instrument
(VTO)is based on early precursors of communication evident in
parent-child interactions in children 0-3 years. The instrument
schedule follows regular check-up schedule for health centers:
1,2,3,6,9,12,15,18, and 24 mos. Here results of the last 4 visits
where measurements occurred are reported. Note that the time allowed
is less than 5 minutes for administration of a parent interview with
standardized questions.
The areas covered are: production, comprehension,
conversation/play. Close to 900 children participated in
standardization. For the majority of questions, 90% or more of the
children had acquired the surveyed skills, but many questions did
not. A look at the detailed chart of the results of this survey shows
that for almost all items over 80% of the children performed as
expected.
As assessed by this screening instrument, underlying structure emerges
at 9 months for comprehension and at 12 months for production - by age
24-30 months production versus comprehension problems can be
distinguished. No structure for interaction is shown. The cut off
score for normal language behavior is determined by the estimated
incidence of language disorders in the country.
Predictive validity is shown in a follow up study, as a correlation
was found between failing the screening test and language performance
1 and 3 years later. There were 10% false negatives, information on
false negatives is not yet available. The authors note that despite
the success of the screening instrument a major problem remains in
parents refusing to follow up recommendations for further testing.
Chapter 16 'Early intervention for children with language impairments'
by Steve F. Warren and Paul J. Yoder discusses the basis of
intervention as the notion that the quality of the input influences
development. The authors present three different models of
intervention: responsive interaction, milieu, and didactic
teaching. They describe how each works and then argue that children at
different stages of cognitive and language development can best
benefit from different types of therapy. Responsive interaction is
found to be the best option for children at the stage of development
above MLU 2. 5, milieu for children under MLU 2. 0 and didactic
teaching for children with MLUs over 2. 5 and mild cognitive deficits.
Also, the therapeutic goal affects method, e.g. milieu teaching has
been found to be effective for vocabulary teaching. The message is to
choose the therapy method of best-fit to the specific child at the
specific stage of the child as opposed to opting for one type of
therapy throughout. Recommendations which a clinician can take and
apply to his/her clinical work are made.
Chapter 17 'Benefits of speech manipulation for children with language
disorders' by Ludo Verhoeven and Eliane Segers discusses intervention
based on compensation for assumed limitations in temporal processing
at the basis of language disorders. Specifically, they look at
research showing the effect of lengthening of formant transitions for
individuals with SLI , as well as research on related intervention
programs. This research has involved phonemic (between phoneme
boundaries) or phonetic (allophonic variation)
discrimination. Individuals with language disorders have been found to
have more difficulty than controls in discriminating between CVs with
a stop consonant. Studies using a speech continuum find differences
between 'slow learners' and normal controls but differences overall
tend to be smaller. Overall lengthening formant transition was found
to improve discrimination for language disordered children (but not
adult aphasics).
Intervention programs following this research includes computer
assisted training: one example is the fairly intensive Fast ForWord
program. In this program computer training is adapted to the child's
progress, the program includes syntax and morphology as well as
auditory training. Research evaluating this and similar problems is
methodologically problematic. Furthermore, the intervention programs
do not closely follow the techniques researched.
Although a clear pattern of auditory perceptual difficulty is shown,
the authors question the causal relationship between this difficulty
and the language disorder.
The closing chapter, Chapter 18 'The close association between
classification and intervention of children with primary language
impairments. ' by James Law examines classification as related to the
existence of differential intervention strategies. He recommends
distinguishing transient from persistent language disability by
diagnostic therapy designed to child's individual needs, matched to a
specific set of behaviors. He reviews research into the effectiveness
of intervention, summarizing 22 group studies. Conclusions include:
parent-directed treatment is as effective as direct clinician
treatment, there is transfer from intervention in syntax to
phonological skills and vice versa, positive intervention outcomes are
found for articulation/phonology, expressive language, and receptive
language, and finally, auditory training did not improve
articulation/phonology. Usually intervention moved children into the
normal range of language performance.
Law notes that further research is needed to evaluate whether the
effects of intervention are only short terms or are real long term
changes in the child's psycholinguistic abilities.
Working backwards, behavioral patterns which respond to intervention
can be considered classification categories, e. g. if work on
articulation improves performance we can identify a category of
children with articulatory impairment. Consequently, the less we know
about intervention with a certain pattern of behavior (such as
pragmatics), the further we are from a useful classification.
EVALUATION
I found the volume interesting reading throughout. Although a wide
range of theoretical points of view are represented and within the
topic, a wide range of sub-topics, continuity is maintained by the
progression from the theoretical to the practical. Dorothy Bishop's
paper at the beginning of Part III aids this transition in her
discussion of the differences between research and clinical needs
regarding classification. The fact that many chapters include
references to other chapters in the book, either for theoretical
basis/practical application or for a contrasting view, adds to the
coherence of the volume as a whole. I found some chapters to assume
more previous knowledge or familiarity with the topic than others,
something which may need to be considered when recommending the book
to students. However, all chapters are clearly written and well
referenced, pointing the reader in the appropriate direction for
filling in any missing background.
REFERENCES
Bishop, D. V. M. (1992) 'The underlying nature of specific language
impairment', Journal of Child Psychology and Psychiatry and Allied
Disciplines, 33, 3-66.
Leonard, L. B. (1989) 'Language learnability and specific language
impairment in children', Applied Psycholinguistics, 10, 179-202.
Levelt, W. J. M. (1989) Speaking: From intention to articulation.
Cambridge, MA: MIT Press.
Rice, M. L. (2000) 'Grammatical symptoms of specific language
impairment', in D. V. M. Bishop & L. B. Leonard, eds., Speech and
language impairments in children: Causes, characteristics,
intervention and outcome, pp. 17-34. Hove, UK: Psychology Press.
Shriberg, L. D. and Kiawtkowski, J. (1982) 'Phonological disorders
III: A procedure for assessing severityof involvement', Journal of
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ABOUT THE REVIEWER
Leah Gedalyovich is currently assisting in research into Hebrew G-SLI
at the Department of Foreign Literatures and Linguistics, Ben-Gurion
University of the Negev. She combines research with part-time work as
a speech-language pathologist in pre-school and school settings.
Research interests include normative first language acquisition
(primarily of Hebrew), language disorders, the interaction of
semantics and pragmatics and the clinical application of linguistic
theory.