Discourse—sentence interaction in the speech of language-disordered and normal children

The effects of linguistic complexity were examined on children's story discourse. Four groups of 15 subjects each were used: (a) language-disordered; (b) chronologically age matched with normal language abilities; (c) language-age matched; and (d) language-age matched with articulatory errors. The experimental task was sentence production in a story context. Phonological complexity (syllable length of words) was varied. Errors simplified phonological, syntactic and story structures. Older normals exhibited the fewest phonological errors and the greatest mean-length complexity for the sentences produced. The language-disordered children made more phonological errors than the younger normals, although they did not differ from the younger normals in the mean-length sentence complexity. No differences occurred in the number of phonological errors or mean-length sentence complexity between the language-age-matched groups, ones with and without articulatory errors. All four groups exhibited similar story structure. The consistent effects of phonological complexity during story production lends support for a limited processing capacity explanation of children's language disorders.     

The role of the left mesial frontal cortex in fluent speech: Evidence from a case of left supplementary motor area hemorrhage

This study reports on a woman who suffered left anterior cerebral artery hemorrhage with a focal lesion undercutting the left supplementary motor area. After almost complete recovery of language the patient was left with dysfluent, halting speech. In a series of four experiments we examined the major factors influencing the patient's articulation. There was a significant effect of lexicality and syllabic length on repetition and articulatory learning (Experiments 1 and 2). The number of syllables was also found to influence, in a simple reaction task, onset latencies, but not inter-response times (Experiment 3). On the contrary, articulatory intricacy had no particular effect on either repetition or vocal reaction (Experiments 1 and 3). While repetition of real words was preserved, single word production in word generation tasks was impaired. Rhyme generation and alliteration. both of which rely on phonological processing, were particularly involved, whereas semantic word generation tasks like verb generation and generation of category members were relatively spared (Experiment 4). Control tasks revealed that the observed phonological processing deficit was confined to the condition of generating spoken language output. These experimental findings suggest that the patient's dysfluent speech could neither be attributed to a deficit of linguistic processing proper, nor to one of motor execution. Her speech disorder rather resulted from an impairment of initiating sequential articulations, particularly in association with the process of downloading temporarily stored multisyllabic strings from an articulatory buffer. This deficit could obviously be overcome in real word repetition through the use of a semantic lexical route.     

Effects of syntactic and semantic argument structure on sentence repetition in agrammatism: Things we can learn from particles and prepositions

Background: Sentence production impairment in aphasia has been attributed to several possible sources that are not mutually exclusive. Linguistic accounts often attribute the difficulty to the complexity of a verb's syntactic and/or semantic argument structure. Cognitive processing accounts emphasise the reduced processing capacity observed in agrammatic aphasia, which in turn has been attributed to reduced semantic short-term memory (STM) or slowed processing.

Aims: In this study we used verb particles and prepositions to investigate effects of differences in syntactic and semantic argument structure on sentence repetition in aphasia. We predicted that verb particles and sentences containing verb-particle constructions would be easier to repeat than prepositions and prepositional transitive sentences, as the former have a less-complex semantic and syntactic argument structure than the latter. Also, semantic and phonological spans were assessed to determine if a reduction in either capacity correlates with repetition ability.

Methods & Procedures: Participants were eight individuals with chronic aphasia. The experimental task was repetition of transitive sentences balanced for length and lexical content containing either verb particles or prepositional object structures. Accuracy of sentence repetition and repetition of verb particles and prepositions within sentences was examined. We calculated the effect of structural complexity on the sentence repetition task as the difference between proportion correct of verb-particle constructions and prepositional transitives. Semantic and phonological STM spans and word spans were also assessed and correlated with this measure of the structural complexity effect on sentence repetition.

Outcomes & Results: Verb-particle sentences were repeated correctly significantly more often than prepositional transitive sentences, and within those sentences verbal particles were repeated correctly significantly more often than prepositions. The effect was strongly associated with fluency scores: it was present in participants with low fluency scores, but not in those with high fluency scores. The phonological, but not the semantic, STM probe span measure correlated with both the difference in accurate repetition of verb-particle and prepositional transitive sentences and the particles and prepositions within those sentences.

Conclusions: Results indicate that differences in argument structure of particle and preposition constructions influence sentence repetition in agrammatic aphasia. The finding that lower fluency scores are associated with poorer performance on more complex structures suggests that this effect is associated with agrammatism. The impact of these structural distinctions between particles and prepositions should be taken into account during development of treatment stimuli for those with agrammatism.     

A case for the involvement of phonological loop in sentence comprehension

The specific role of the phonological loop in sentence comprehension is still a matter of debate.We tested the behavioural consequences of activity disruption in left BA40 and BA44, key regions of the phonological loop, on language comprehension using 1 Hz rTMS. Comprehension was assessed by means of two tasks: a sentence-to-picture matching task, with sentences varying in length and syntactic complexity (Experiment 1), and a sentence verification task (Experiment 2). rTMS over left BA40 significantly reduced accuracy for syntactically complex sentences and long, but syntactically simpler sentences, while rTMS over left BA44 significantly reduced accuracy only for syntactically complex sentences. rTMS applied over left BA40 also impaired performance on sentences in which word order was crucial.We suggest that the neural correlates of the phonological loop, left BA40 and BA44, are both involved in the comprehension of syntactically complex sentences, while only left BA40, corresponding to the short-term store, is recruited for the comprehension of long but syntactically simple sentences. Therefore, in contrast with the dominant view, we showed that sentence comprehension is a function of the phonological loop.     

Lesion analysis of cortical regions associated with the comprehension of Nonreversible and Reversible yes/no questions

We investigated the association between yes/no sentence comprehension and dysfunction in anterior and posterior left-hemisphere cortical regions in acute stroke patients. More specifically, we manipulated whether questions were Nonreversible (e.g., Are limes sour?) or Reversible (e.g., Is a horse larger than a dog?) to investigate the regions associated with semantic and syntactic processing. In addition, we administered lexical tasks (i.e., Picture-Word Verification, Picture Naming) to help determine the extent to which deficits in sentence processing were related to deficits in lexical processing. We found that errors on the lexical tasks were associated with ischemia in posterior-temporal Brodmann Areas (BA 21, 22, 37) and inferior parietal regions (BA 39, 40). Nonreversible question comprehension was associated with volume of tissue dysfunction, while Reversible question comprehension was associated with posterior regions (BA 39, 40) as well as one anterior region (BA 6). We conclude that deficits in Nonreversible questions required extensive dysfunction that affected language processing across multiple levels, while Reversible question comprehension was associated with regions involved in semantics as well as working memory that indirectly influenced syntactic processing. Overall, this suggests that yes/no question comprehension relies on multiple regions and that the importance of certain regions increases in relation to semantic, phonological, and syntactic complexity.     

The representation of lexical-syntactic information: evidence from syntactic and lexical retrieval impairments in aphasia

This study explored lexical-syntactic information - syntactic information that is stored in the lexicon - and its relation to syntactic and lexical impairments in aphasia. We focused on two types of lexical-syntactic information: predicate argument structure (PAS) of verbs (the number and types of arguments the verb selects) and grammatical gender of nouns. The participants were 17 Hebrew-speaking individuals with aphasia who had a syntactic deficit (agrammatism) or a lexical retrieval deficit (anomia) located at the semantic lexicon, the phonological output lexicon, or the phonological output buffer. After testing the participants' syntactic and lexical retrieval abilities and establishing the functional loci of their deficits, we assessed their PAS and grammatical gender knowledge. This assessment included sentence completion, sentence production, sentence repetition, and grammaticality judgment tasks. The participants' performance on these tests yielded several important dissociations. Three agrammatic participants had impaired syntax but unimpaired PAS knowledge. Three agrammatic participants had impaired syntax but unimpaired grammatical gender knowledge. This indicates that lexical-syntactic information is represented separately from syntax, and can be spared even when syntax at the sentence level, such as embedding and movement are impaired. All 5 individuals with phonological output buffer impairment and all 3 individuals with phonological output lexicon impairment had preserved lexical-syntactic knowledge. These selective impairments indicate that lexical-syntactic information is represented at a lexical stage prior to the phonological lexicon and the phonological buffer. Three participants with impaired PAS (aPASia) and impaired grammatical gender who showed intact lexical-semantic knowledge indicate that the lexical-syntactic information is represented separately from the semantic lexicon. This led us to conclude that lexical-syntactic information is stored in a separate syntactic lexicon. A double dissociation between PAS and grammatical gender impairments indicated that different types of lexical-syntactic information are represented separately in this syntactic lexicon.     

Non-word repetition and non-word discrimination in Swedish preschool children

By looking at data on expressive phonology, non-word repetition, non-word discrimination and phonological sensitivity in two groups of Swedish children, the common basis for tasks tapping into different levels of phonological processing is discussed. Two studies were performed, one including children with language impairment (LI) and one including children with normal language development (NL). A discrimination task consisting of non-word pairs differing in one phoneme was developed. In both groups there was a significant correlation between non-word repetition and phoneme identification. In children with LI phoneme identification was significantly correlated with expressive phonology. In children with NL non-word repetition correlated significantly with non-word discrimination, which was linked both to rhyme recognition and phoneme identification. Non-word discrimination might be equally useful as non-word repetition as an early screening tool and would circumvent the confounding factor of an expressive phonological impairment as well as decrease the amount of complicating factors involved in scoring procedures.     

Sentence production in Parkinson’s disease

While growing evidence reports changes in language use in non-demented individuals with Parkinson’s disease (PD), the presence and nature of the deficits remain largely unclear. Researchers have proposed that dysfunctioning fronto-basal ganglia circuit results in impaired grammatical processes, predicting qualitatively similar language impairments between individuals with PD and agrammatic Broca’s aphasia, whereas others suggest that PD is not associated with language-specific grammatical impairment. In addition, there is a paucity of research examining syntactic production in PD at the sentence-level. This study examined sentence production of individuals with PD, healthy older adults, and individuals with agrammatic Broca’s aphasia. In Experiment 1, using a Cinderella story-telling task, proportion of grammatical sentences, number of embedded clauses and production of verb arguments in sentences were examined. In Experiment 2, a structured sentence elicitation task was used in which syntactic complexity of sentences (canonical vs. non-canonical word order) was systematically manipulated while minimizing demands for non-syntactic processing. Only the participants with agrammatic Broca’s aphasia showed significantly impaired syntactic production in both experiments. Participants with PD did not show impaired syntactic production in either task, despite impairments in lexical retrieval, repetition of words and sentences, and speech production. These findings suggest that impaired syntactic processing may not be a core deficit underlying the changes in language use in non-demented PD. Changes in language use in PD are qualitatively different from language deficits in aphasia.     

Non‐word repetition and non‐word discrimination in Swedish preschool children

By looking at data on expressive phonology, non‐word repetition, non‐word discrimination and phonological sensitivity in two groups of Swedish children, the common basis for tasks tapping into different levels of phonological processing is discussed. Two studies were performed, one including children with language impairment (LI) and one including children with normal language development (NL). A discrimination task consisting of non‐word pairs differing in one phoneme was developed. In both groups there was a significant correlation between non‐word repetition and phoneme identification. In children with LI phoneme identification was significantly correlated with expressive phonology. In children with NL non‐word repetition correlated significantly with non‐word discrimination, which was linked both to rhyme recognition and phoneme identification. Non‐word discrimination might be equally useful as non‐word repetition as an early screening tool and would circumvent the confounding factor of an expressive phonological impairment as well as decrease the amount of complicating factors involved in scoring procedures.     

Remediation of language processing in aphasia: Improving activation and maintenance of linguistic representations in (verbal) short-term memory

BACKGROUND: Verbal short-term memory (STM) impairments are invariably present in aphasia. Word processing involves a minimal form of verbal STM, i.e., the time course over which semantic and phonological representations are activated and maintained until they are comprehended, produced, or repeated. Thus it is reasonable that impairments of word processing and verbal STM may co-occur. The co-occurrence of language and STM impairments in aphasia has motivated an active area of research that has revealed much about the relationship of these two systems and the effect of their impairment on language function and verbal learning (Freedman & Martin, 2001; Martin & Saffran, 1999; Trojano & Grossi, 1995). In keeping with this view a number of researchers have developed treatment protocols to improve verbal STM in order to improve language function (e.g., Koenig-Bruhin & Studer-Eichenberger, 2007). This account of aphasia predicts that treatment of a fundamental ability, such as STM, which supports language function, should lead to improvements that generalise to content and tasks beyond those implemented in treatment. AIMS: We investigated the efficacy of a treatment for language impairment that targets two language support processes: verbal short-term memory (STM) and executive processing, in the context of a language task (repetition). We hypothesised that treatment of these abilities would improve repetition abilities and performance on other language tasks that require STM. METHOD: A single-participant, multiple-baseline, multiple-probe design across behaviours was used with a participant with conduction aphasia. The treatment involved repetition of words and nonwords under three "interval" conditions, which varied the time between hearing and repeating the stimulus. Measures of treatment effects included acquisition, maintenance, and follow-up data, effect sizes, and pre- and post-treatment performance on a test battery that varies the STM and executive function demands of language tasks. OUTCOMES #ENTITYSTARTX00026; RESULTS: Improvement of repetition was mostly specific to treated stimuli. Post-treatment measures of language ability indicated improvements in single and multiple word processing tasks, verbal working memory tasks, and verbal span. CONCLUSIONS: Treatment of STM and executive processes in the context of a word repetition task resulted in improvements in other non-treated language tasks. The approach used in this study can be incorporated into other language-processing tasks typically used in treatment of language disorders (e.g., sentence processing).     

Phonological,lexical, and semantic errors produced by impairment at the output buffer in a Spanish aphasic patient

We present a single case of a right-handed female patient, RH, who was categorized as suffering from conduction aphasia. She presented no articulatory problems during spontaneous speech but made a significant number of phonological paraphasias in naming and repetition tasks. The number of errors increased for long words and pseudowords. This pattern of results points to damage in the “Phonological Output Buffer” (POB) as the basis of this disorder. However, this patient did not make mistakes when reading words and pseudowords aloud, even when we introduced a delay between the presentation of the word and its production to test the working memory resources of the phonological buffer. Furthermore, the patient’s ability to name objects, repeat words, and write to dictation improved with her degree of familiarity with the items. The damage could be situated at the point where phonemes are selected and ordered to produce words. We posit that the deficits observed in this patient, and the differences encountered between her performance and that of others described in the literature, in particular in reading tasks, can be explained by considering POB damage to be gradual in nature. According to this explanation, the performance of patients with damage to the POB will depend on the amount of information provided by the stimulus (word/nonword), the language particularities (regular/irregular), and the nature of the task demands (repetition, writing, naming, or reading).     

Language processing modulated by literacy: a network analysis of verbal repetition in literate and illiterate subjects

Previous behavioral and functional neuroimaging data indicate that certain aspects of phonological processing may not be acquired spontaneously, but are modulated by learning an alphabetic written language, that is, learning to read and write. It appears that learning an alphabetic written language modifies the auditory-verbal (spoken) language processing competence in a nontrivial way. We have previously suggested, based on behavioral and functional neuroimaging data, that auditory-verbal and written language interact not only during certain language tasks, but that learning and developing alphabetic written language capacities significantly modulates the spoken language system. Specifically, the acquisition of alphabetic orthographic knowledge has a modulatory influence on sublexical phonological processing and the awareness of sublexical phonological structure. We have suggested that developing an orthographic representation system for an alphabetic written language, and integrating a phoneme-grapheme correspondence with an existing infrastructure for auditory-verbal language processing, will result in a modified language network. Specifically, we suggest that the parallel interactive processing characteristics of the underlying language-processing brain network differ in literate and illiterate subjects. Therefore, the pattern of interactions between the regions of a suitably defined large-scale functional-anatomical network for language processing will differ between literate and illiterate subjects during certain language tasks. In order to investigate this hypothesis further, we analyzed the observed covariance structure in a PET data set from a simple auditory-verbal repetition paradigm in literate and illiterate subjects, with a network approach based on structural equation modeling (SEM). Based on a simple network model for language processing, the results of the present network analysis indicate that the network interactions during word and pseudoword repetition in the illiterate group differ, while there were no significant differences in the literate group. The differences between the two tasks in the illiterate group may reflect differences in attentional modulation of the language network, executive aspects of verbal working memory and the articulatory organization of verbal output. There were no significant differences between the literate and illiterate group during word repetition. In contrast, the network interactions differed between the literate and illiterate group during pseudoword repetition. In addition to differences similar to those observed in the illiterate group between word and pseudoword repetition, there were differences related to the interactions of the phonological loop between the groups. In particular, these differences related to the interaction between Broca's area and the inferior parietal cortex as well as the posterior-midinsula bridge between Wernicke's and Broca's area. In conclusion, the results of this network analysis are consistent with our previously presented results and support the hypothesis that learning to read and write during childhood influences the functional architecture of the adult human brain. In particular, the basic auditory-verbal language network in the human brain is modified as a consequence of acquiring orthographic language skills.     

Patterns of syntactic development in children with Williams syndrome and Down's syndrome: evidence from passives and wh-questions

This study investigates the syntactic abilities of ten individuals with Williams syndrome (WS) (mean chronological age: 8;9 years; mean mental age: 4;8 years) and Down's syndrome (DS) (mean chronological age: 8;7 years; mean mental age: 4;6 years), matched individually on chronological age, mental age and performance IQ. The syntactic components investigated include the comprehension of passives and the production, comprehension and repetition of wh-questions. Performance is compared to ten younger typically developing (TD) controls matched individually to both experimental groups on mental age (mean chronological age: 4;4 years; mean mental age: 5;0 years). Participants were given a standardized measure of grammatical ability and non-standardized tasks exploring the comprehension of active and passive sentences, and the production, comprehension and repetition of a range of wh-question types: wh-subject, wh-object, which NP-subject and which NP-object. Participants with WS and DS performed similarly on the standardized measure of grammatical ability, as well as on the experimental tasks that tapped comprehension of passives, and production and comprehension of wh-questions. Participants with DS performed significantly more poorly than both the WS cohort and TD controls on the repetition of wh-questions. Both the WS and DS cohorts performed significantly more poorly on most of the syntactic tasks compared to the younger TD controls. Individuals with WS and DS experienced significant difficulties in tasks measuring aspects of syntactic ability and performed more poorly than mental age-matched TD controls. Implications of these findings, with regards to the debates around language "intactness" in WS, as well as the similarities and differences in language abilities in WS and DS, dependent on age and developmental stages studied, are explored.     

Sequential processing deficit as a shared persisting biomarker in dyslexia and childhood apraxia of speech

The purpose of this study was to investigate the hypothesis that individuals with dyslexia and individuals with childhood apraxia of speech share an underlying persisting deficit in processing sequential information. Levels of impairment (sensory encoding, memory, retrieval, and motor planning/programming) were also investigated. Participants were 22 adults with dyslexia, 10 adults with a probable history of childhood apraxia of speech (phCAS), and 22 typical controls. All participants completed nonword repetition, multisyllabic real word repetition, and nonword decoding tasks. Using phonological process analysis, errors were classified as sequence or substitution errors. Adults with dyslexia and adults with phCAS showed evidence of persisting nonword repetition deficits. In all three tasks, the adults in the two disorder groups produced more errors of both classes than the controls, but disproportionally more sequencing than substitution errors during the nonword repetition task. During the real word repetition task, the phCAS produced the most sequencing errors, whereas during the nonword decoding task, the dyslexia group produced the most sequencing errors. Performance during multisyllabic motor speech tasks, relative to monosyllabic conditions, was correlated with the sequencing error component during nonword repetition. The results provide evidence for a shared persisting sequential processing deficit in the dyslexia and phCAS groups during linguistic and motor speech tasks. Evidence for impairments in sensory encoding, short-term memory, and motor planning/programming was found in both disorder groups. Future studies should investigate clinical applications regarding preventative and targeted interventions towards cross-modal treatment effects.     

Is the word-length effect linked to subvocal rehearsal?

Models of phonological short-term memory (pSTM) generally distinguish between two components: a phonological buffer and a subvocal rehearsal. Evidence for these two components comes, respectively, from the phonological similarity effect and the word-length effect which disappears under articulatory suppression. But alternative theories posit that subvocal rehearsal is only an optional component of the pSTM. According to them, the depletion of the length effect under articulatory suppression results from the interference of the self-produced speech rather than the disruption of subvocal rehearsal.In order to disentangle these two theories, we tested two patients with a short-term memory deficit. FA, who presents a pseudoword repetition deficit, and FL, who does not. FA’s deficit allowed for the observance of an ecological case of subvocal rehearsal disruption without any articulatory suppression task. FA’s performance in pSTM tasks reveals as controls a phonological similarity effect, and contrary to controls no word-length effect. In contrast, the second patient, FL, exhibits the same effects as control subjects. This result is in accordance with models of pSTM in which the word-length effect emerges from subvocal rehearsal and disappears when this latter is disrupted.     

Kinematic analysis of lingual movements during consonant productions in dysarthric speakers with Friedreich's ataxia: A case-by-case analysis

Articulatory kinematics were investigated using electromagnetic articulography (EMA) in four dysarthric speakers with Friedreich's ataxia (FRDA). Specifically, tongue-tip and tongue-back movements were recorded by the AG-200 EMA system during production of the consonants /t/ and /k/ as produced within a sentence utterance and during a rapid syllable repetition task. The results obtained for each of the participants with FRDA were individually compared to those obtained by a control group (n = 10). Results revealed significantly greater movement durations and increased articulatory distances, most predominantly during the approach phase of consonant production. A task difference was observed with lingual kinematics more disturbed during the syllable repetition task than during the sentence utterance. Despite expectations of slowed articulatory movements in FRDA dysarthria, the EMA data indicated that the observed prolongation of consonant phase durations was generally associated with greater articulatory distances, rather than slowed movement execution.     

Syntax and Morphology in Danish-Speaking Children with Autism Spectrum Disorder

The current study examined delays in syntax and morphology, and vocabulary, in autism spectrum disorder (ASD). Children ages 4–6 years with ASD (n?=?21) and typical development (n?=?21), matched on nonverbal mental age, completed five language tasks. The ASD group had significant delays in both syntax and morphology, and vocabulary measures, with significant within-group heterogeneity; furthermore, syntactic and morphological measures were impaired even for subgroups matched on vocabulary. Children in the ASD group without early language delay showed syntactic and morphological impairment, with intact performance on vocabulary and sentence repetition. Findings indicate that syntactic and morphological impairments are a significant concern for high-functioning children with ASD, and may be overlooked if language evaluation focuses exclusively on vocabulary.     

Dichotic listening and sentence repetition performance in children with reading difficulties

Numerous investigations have identified weaknesses in speech processing and language skills in children with dyslexia; however, little is known about these abilities in children with reading difficulties (RD). The primary objective of this investigation was to determine the utility of auditory speech processing tasks in differentiating children with RD from those with typical reading skills. It was hypothesized that children, who perform below grade level in reading, would also show poorer performance on both dichotic listening and sentence repetition tasks because of the reciprocal influences of deficient auditory speech processing and language abilities. A total of 180 Hungarian-speaking, monolingual 8-, 9- and 10-year-old children, with and without RD, participated in dichotic listening and sentence repetition (modified by noise and morphosyntactic complexity) tasks. Performances were compared across ability groups, age and gender. Children with RD evidenced significantly poorer performance than controls on both tasks. Effects for age and gender were more noticeable in students with RD. Our findings support the notion that reading deficiencies are also associated with poor auditory speech processing and language abilities in cases where dyslexia is not diagnosed. We suggest that these tasks may be used as easy and fast screening tests in the identification of RD.     

Higher-order semantic processing in formal thought disorder in schizophrenia

Higher-order semantic impairments and lack of sensitivity to linguistic context have both been implicated in formal thought disorder (FTD) in schizophrenia. Most investigations have focused on comprehension. We investigated the processing of higher-order semantic relations and the role of emotional arousal in FTD patients? linguistic comprehension and production. We compared FTD schizophrenia patients (n=14) with non-FTD schizophrenia patients (n=18) and healthy controls (n=15) on sense-judgment and repetition tasks, in emotionally negative and neutral conditions. We predicted that the FTD group would display poor sensitivity compared to the other two groups in comprehension and production, and that this would be exacerbated by sentence complexity and negative emotional arousal. The emotional manipulation was not robustly successful, and did not affect task performance in the patient groups. FTD patients made significantly more errors on sense-judgments and repetition than the other two groups. Complexity affected all groups to a similar extent in sense-judgments, but affected FTD patients disproportionately in the repetition task. These results support the view that a lack of sensitivity to context underlies FTD in comprehension and production stages of processing. Patients fail to utilise linguistic context to integrate lexical forms into a global whole and guide their access to lexical targets.     

Reading ability and phonological awareness in Japanese children with dyslexia

In alphabetic languages, the deficit of the phonological awareness is considered as the core deficit in developmental dyslexia. However, the role of phonological awareness in the acquisition of reading Japanese kana, the transparent, mora-based phonogram, has not been understood completely. We examine the abilities of Japanese dyslexic children on different types of Japanese phonological tasks, and discussed which tasks significantly account for each aspect of reading ability. METHODS: Fifteen dyslexic children (9.53+/-1.52 years old), and 15 children with normal reading ability (9.17+/-0.90 years old) participated in this study. They performed three types of phonological awareness tasks. The mora counting task and the mora reversal task of words require phonological awareness at the mora level. The letter rhyming task, which resembles the task in English language, requires phonological awareness at the phoneme level. We evaluated the reading ability by the reading speed, the reading errors, and the number of pauses while reading sentences aloud. RESULTS: The task performances of the dyslexic group on all three phonological awareness tasks were significantly lower than those of the control group. Stepwise multiple regression analysis revealed that the mora counting task and the rhyming letter task most significantly explained the reading speed and number of reading pauses. The mora reversal task of words, together with the antegraded digit span, significantly explained the reading errors. CONCLUSIONS: Japanese dyslexics showed deficits of phonological awareness both at the mora and the phoneme levels. Phonological awareness must be crucial for acquiring the ability of decoding phonograms, including Japanese kana.