Is nonword repetition a test of phonological memory or long-term knowledge? It all depends on the nonwords

The extent to which children's performance on tests of nonword repetition is constrained by phonological working memory and long-term lexical knowledge was investigated in a longitudinal study of 70 children tested at 4 and 5 years of age. At each time of testing, measures of nonword repetition, memory span, and vocabulary knowledge were obtained. Reading ability was also assessed at 5 years. At both ages, repetition accuracy was greater for nonwords of high- rather than low-rated wordlikeness, and memory-span measures were more closely related to repetition accuracy for the low-wordlike than for the high-wordlike stimuli. It is argued that these findings indicate that nonword repetition for unwordlike stimuli is largely dependent on phonological memory, whereas repetition for wordlike items is also mediated by long-term lexical knowledge and is therefore less sensitive to phonological memory constraints. Reading achievement was selectively linked with earlier repetition scores for low-wordlike nonwords, suggesting a phonological memory contribution in the early stages of reading development. Vocabulary knowledge was associated with repetition accuracy for both low- and high-wordlike nonwords, consistent with the notion that lexical knowledge and nonword repetition share a reciprocal developmental relationship.     

Interaction between verbal and gestural language in progressive aphasia: a longitudinal case study.

The objective of this longitudinal study is to investigate the on-line interaction between praxis and linguistic abilities in a progressive aphasia case. During 3 years of evolution, procedural discourse of a progressive aphasic patient was videotaped five times, allowing us to analyze the progression of both language and gestural production as well as the interaction between these two. We anticipated that, in the absence of apraxia, the patient would compensate for her speech deficit by producing progressively more and more meaningful gestures. Our compensatory hypothesis was confirmed but the compensation was not as efficient as one would expect given the absence of apraxia. With the progression of the speech deficit, the patient could not replace some verbs by pantomimes that were otherwise accompanying her discourse in the preceding testing sessions. We suggest that such a compensatory ability may constitute one important characteristic of the progressive aphasia syndrome.     

Phonological dyslexia: a test case for reading models

Following brain damage, skilled readers may encounter more severe problems in reading nonwords than familiar words, a type of deficit referred to as phonological dyslexia. We report on 2 individuals with Alzheimer's disease who show phonological dyslexia. Although highly accurate in reading familiar words aloud (even those with irregular spelling, such as sew), they were quite impaired in nonword reading. Both patients performed well in phonological tasks involving the repetition, identification, and manipulation of phonemes of orally presented words and nonwords. These results challenge the idea, proposed in the context of connectionist and evolutionary theories, that phonological dyslexia originates from a phonological deficit. However, the results are consistent with reading models, such as the dual-route model, that attribute phonological dyslexia to a deficit that selectively affects the reading mechanisms responsible for deriving the sounds of nonwords. According to these models, such a deficit is not necessarily accompanied by a more general phonological impairment.     

Voice onset time in aphasia: Thai II. Production

The aim of this study was to investigate voice onset time (VOT) production in homorganic word-initial stops in Thai in order to explore the nature of speech production deficits across clinical varieties of aphasia. Thai exhibits a three-category distinction in bilabial (/b,p,ph/) and alveolar (/d,t,t,h/) stops, and a two-category distinction in velar (/k,kh/) stops. Subjects included three Broca asphasics, one transcortical motor asphasic, two global asphasics, one conduction aphasic, one Wernicke aphasic, one nonaphasic dysarthric patient, one right-brain-damaged patient, and five normal controls. Test stimuli consisted of eight monosyllabic real words. The results of VOT measurements indicated that Broca and global asphasics exhibited a more severe production disorder than Wernicke, conduction, or transcortical motor asphasics. The right-brain-damaged patient showed no impairment in VOT production. Comparisons are drawn to earlier studies of VOT production in aphasia in two-category languages. Issues concerning the underlying basis of the production deficit for nonfluent aphasics, fluent aphasics, and nonaphasic dysarthrics as well as the relation between perception and production of VOT are discussed.     

Can “words” be processed as integrated units?

Three experiments examined the information processing of letters embedded within one-syllable words and similar unpronounceable sequences. A speeded discrimination task was used to detect processing differences between words and nonwords in a situation where both the identity and position of critical display information was known to subjects before stimulus presentation. Results indicated that word pairs differing by two letters were more quickly discriminated than two words differing in a single letter, while nonword pairs differing in two letters were discriminated no faster than two nonwords differing in a single letter. A further comparison showed a performance advantage for words over nonwords in a condensation task that forced a scan of stimulus letters for correct responding. These results suggest that familiarity affects information processing at a perceptual level, and are incompatible with theories suggesting that familiarity effects are due to inferential factors following letter feature analysis.     

Confrontation naming impairment in dementia

In tone languages pitch variations (tones) serve to distinguish the lexical meanings of words. This study was conducted to examine the extent and nature of impairment in the perception of tones by aphasic patients who were monolingual speakers of Thai, a tone language which has five contrastive tones (mid, low, falling, high, rising). Six subjects participated in the study: two Broca aphasics, one transcortical motor aphasic, one conduction aphasic, one right brain-damaged nonaphasic, and one normal control. Three sets of stimuli (two real-speech, one synthetic-speech) were presented for identification, each set containing five Thai words minimally distinguished by tone. Results of the perception tests indicated that the performance of all four left brain-damaged aphasics differed significantly from that of the normal control, while the performance of the right brain-damaged nonaphasic did not. The normal performance of the right brain-damaged nonaphasic patient on this tone identification task suggests that deficits in the perception of tone exhibited by left brain-damaged patients can be attributed specifically to pathology in the language dominant hemisphere rather than to a general brain-damage effect. No difference in performance among the left brain-damaged patients could be attributed to a specific type of aphasic syndrome. The pattern of tonal confusions of the aphasics in comparison to that of normals suggests that their deficit is primarily quantitative rather than qualitative. Although two (mid, low) of the five tones accounted for a large percentage of the aphasics' errors, no uniform rank order of tones in terms of identifiability could be established across aphasic subjects, which suggests that their deficit is general to all five tones rather than selective to individual tones.     

Sensitivity to sub-syllabic constituents in brain-damaged patients: evidence from word games

Two experiments were conducted to examine whether left- (LHD) and right-hemisphere-damaged (RHD) patients exhibit sensitivity to sub-syllabic constituents (i.e., onsets and codas) in the generation of nonwords, using a word games paradigm adapted from. Four groups of individuals (including LHD fluent and nonfluent aphasic patients, RHD patients and normal controls) were trained to add syllables to monosyllabic CVC nonwords either after the initial consonant (Experiment 1) or prior to the final consonant (Experiment 2) to create bisyllabic nonwords. Experimental stimuli consisting of CCVC or CVCC nonwords tested whether participants would preserve or split the onset and coda constituents in producing the novel bisyllabic nonwords. Results revealed that the majority of subjects demonstrated sensitivity to the sub-syllabic constituents, preserving the onsets and codas. The fluent aphasic patients exhibited a greater than normal tendency to split the onset and coda constituents; however, the small number of individuals in that group whose data met inclusion criteria limits the conclusions that may be drawn from these findings. The results are discussed in relation to theories of phonological deficits in aphasia.     

Evidence of syntactic deficits in a fluent aphasic

The syntactic abilities of a mild Wernicke's aphasic were examined in production and comprehension tasks. The patient made few errors involving the omission or substitution of substantives or grammatical markers, especially after the first few weeks of testing. Despite his good ability to produce sentences with acceptable surface form, he continued to make role reversal errors and to produce a restricted range of syntactic forms. In comprehension, he also demonstrated an impairment in his ability to use the syntactic information in a sentence to assign role relations. These syntactic impairments could not be attributed to a short-term memory deficit as the patient showed only a slightly reduced short-term memory span, and showed evidence of having a normal phonological store. Implications for theories of aphasic deficits as well as for theories of normal language processing are discussed.     

A mechanism of implicit lexicalized phonological recoding used concurrently with underdeveloped explicit letter-sound skills in both precocious and normal reading development

These are findings of theoretical interest from: (i) follow-up of a case study of a precocious reader; and (ii) normally developing readers who served as comparison groups. The precocious reader was first reported when 2–3 years of age (Cognition 74 (2000) 177). From 3 to 7 years of age her precocious reading development continued, her word reading accuracy increasing from the 8- to the 16-year-level, although her phonemic awareness skills remained underdeveloped relative to word reading. Nonword reading continued to develop rapidly. Her word reading, however, was more than phonological recoding. At 5 years of age, in comparison with reading-level matched normal 11-year-olds she exhibited strong effects of semantic characteristics of words and evidence of well-specified lexical orthographic representations. In common with normal comparison 11-year-olds, who had not received instruction in explicit phonics, her explicit letter-sound skills were underdeveloped but she possessed high speed and accuracy in nonword reading, a result most theories of the acquisition of reading fail to explain. Her responses to irregularly spelt nonwords indicated higher proficiency than the 11-year-olds in acquiring lexical orthographic representations not predictable from prior phonological recoding knowledge. It is considered that this proficiency contributes to an explanation of her precocious reading development. A mechanism of implicit lexicalized phonological recoding is involved which explains the dissociation of skills in both the precocious reader and normally developing readers.     

Lexical and buffer effects in reading and in writing Noun-Noun compound nouns

Reading and writing Noun-Noun compound nouns was investigated in two Italian aphasic patients: one with phonological dyslexia and the other with phonological dysgraphia. The patients were required to read, write and repeat a list of Noun-Noun compounds and length-matched non-compound nouns. The dyslexic patient RF read compounds better than non-compounds, and his repetition was flawless for both categories. The dysgraphic patient DA wrote non-compounds better than compounds because of a deficit in keeping separate entries at the lemma level. Differential performance when processing compounds and non-compounds is the result of a deficit in different components within the mental lexicon architecture.     

A comparison of the performance of Persian speaking children who do and do not stutter on three nonwords repetition tasks

PurposeThe purpose of the study was to examine the performance of Persian speaking children who stutter (CWS) and children who do not stutter (CWNS) on three nonword repetition tasks, while also focusing on which task and scoring method best differentiates the two groups of children.MethodThirty CWS and 30 CWNS between the ages of 5;0 to 6;6 completed three nonword repetition tasks that varied in complexity. Each task was scored using two methods: nonwords correct and phonemes correct. Between-group differences in performance on each task were examined, along with disfluencies for CWS and the task and scoring method that best differentiated the CWS and CWNS.ResultsThe findings revealed that, across all three nonword repetition tasks, the CWS consistently produced fewer nonwords correct and phonemes correct than the CWNS group at virtually all syllable lengths. The CWS produced more disfluencies on longer nonwords than shorter nonwords in all three nonword repetition tasks. The nonword repetition task with lower wordlikeness and more phonologically complex items best differentiated the two groups of children. Findings further revealed that discriminative accuracy was highest for scoring based on the number of phonemes produced correctly.ConclusionFindings provide further evidence to suggest that CWS may have difficulty with phonological working memory and/or phonological processing.     

Reading without phonology: Evidence from aphasia

This study of an aphasic dyslexic supports the view that there are separate visual and phonological pathways in reading. The patient retained a reading vocabulary of at least 16 500 words although she was unable to perform operations that critically depend on grapheme-to-phoneme conversion; these included reading nonsense words, recognizing rhymes and homophones, and accessing lexical entries from homophonic spellings such as “kote”. Typographical variation, such as mixed case presentation, did not interfere with her reading performance, which suggests that it is mediated by letter identification rather than by a wholistic method of word recognition. The total performance pattern strongly suggests that this patient identifies words by matching particular letter-strings with their corresponding meanings.     

Selective Deficit of One Language in a Bilingual Patient Following Surgery in the Left Perisylvian Area

We report on a right-handed bilingual patient with a left perisylvian arteriovenous malformation that caused a mild naming deficit evident only on formal language testing in both languages. Sodium amytal injected in the left carotid artery (Wada test) before surgery resulted in speech arrest for both languages. Following surgery for removal of the lesion she developed additional deficits in her native language without alteration in her second language. Selective impairment in one language after surgery demonstrates that each language has different anatomical representation within the perisylvian dominant area.     

Rapid recovery from aphasia: a detailed language analysis

The paper presents a daily analysis of the language recovery of a patient who was globally aphasic at the time of her first observation and who had recovered language, as measured by the Western Aphasia Battery, at the time of her discharge 14 days later. The paper emphasizes the relatively regular growth of normal syntactic, lexical, and pragmatic features coupled with similar regular decreases in aphasic features. Observations of both phenomena are necessary to describe language recovery.     

When "macrocefalo (macrocephalous)" is read "minicervello (minibrain)": evidence from a single case study

We report the case of a patient who showed a marked deficit in compound reading after almost complete recovery from his aphasic disturbances. Omission of one of the two compound components was his most frequent type of error. The patient also produced many paraphasias, which always respected the compound structure of the target. Similar errors were found on tasks of naming and writing to dictation. A deficit in retrieving the verb component of verb-noun compounds was also observed, consistent with the patient's residual agrammatism, and with decomposition at some point in processing. We suggest that this pattern of performance is compatible with a dual route model that hypothesises two stages of compound retrieval, a whole word stage followed by a decomposition into two constituent morphemes.     

A study of repetition in aphasic patients

The ability of the aphasic patient to repeat a message is a capacity of considerable diagnostic value. While it is well known that certain aphasic groups (e.g., transcortical aphasics) repeat better than other groups (e.g., conduction aphasics), possible qualitative differences among the groups have not been subjected to analysis. To secure information on repetition profiles in various aphasic subgroups, a test consisting of 11 types of items, presented under conditions of both immediate and delayed recall, was administered to eight groups of aphasic patients. The results documented a significant difference across aphasic groups, one related to site of lesion but not to severity of comprehension defect. Performance proved to be a joint product of the length and the meaningfulness of the stimulus items. The delayed condition aided Broca's aphasics and impeded anomic aphasics; in addition, nonsense syllables proved to be easier on immediate recall, while meaningful stimuli, particularly those which were number related, were relatively easier on delayed recall. Finally, sound errors were more likely to be made by Broca's and “mixed anterior” aphasics, while meaning errors were particularly prominent among conduction aphasics. These results are discussed in terms of the mechanisms which may mediate repetition in aphasic patients.     

Acquired dyslexia in Spanish: a review and some observations on a new case of deep dyslexia

Readers and writers of Spanish use an orthography that is highly transparent. It has been proposed that readers of Spanish can rely on grapheme-phoneme correspondences, alone, to access meaning or phonology from print. In recent years, a number of case studies have yielded evidence inconsistent with this idea. We review these studies with particular focus on those that report evidence for reading based on direct lexical mappings between print, orthographic representations, and meaning or phonology. We report a new case of acquired literacy impairment in Spanish, MJ, who presents a pattern of preserved abilities and deficits symptomatic of deep dyslexia. The patient is unable to read nonwords, but can read a substantial number of words. Her reading is characterized by the production of semantic, visual, and derivational errors. We argue that MJ has a deficit in her lexical selection ability, common to both her reading and her naming problems. We propose that MJ, and the other cases we review, demonstrate that lexical reading is adopted by skilled readers even in a transparent language.     

Phonological and semantic information in word and nonword reading in a deep dyslexic patient

Deep dyslexia is diagnosed when brain-injured, previously literate adults make reading errors that include hallmark semantic paralexias (e.g., reading HEART as BLOOD) and are also impaired at reading nonwords (e.g., FRIP). The diversity of these symptoms have led most researchers to conclude that there are multiple sources of impairment in this syndrome and that one of the most critical is a failure to process phonological information at a sublexical level. The patient (SD) reported in this study fits the deep dyslexia profile to the extent that she makes several semantically related reading errors. She also shows the classic frequency and image ability effects of the syndrome. However, as we report, she does read some nonwords correctly and she shows a strong advantage for naming when phonemic cues are presented. We discuss the performance of SD, on these preliminary tasks, in terms of a phonological selection impairment.     

Preserved and Impaired Detection of Structure From Motion by a 'Motion-blind" Patient

Following bilateral extrastriate damage to areas that include the suspected human homologue of V5/MT, the patient LM has a specific deficit in processing moving stimuli. She has difficulty detecting the movement or coding the velocity of single moving dots. Nevertheless, we find that she can report human actions in Johansson “biological motion ”; displays. This requires the accurate coding of the direction and velocity of many moving dots. The implication is that structure can be extracted from motion in regions of visual cortex other than those traditionally associated with motion processing. However, she cannot report the spatial disposition of the actors whose actions she has recognized, not their movement in depth relative to her. A possible interpretation is that coding in these additional regions is primarily object-centred. Adding a small number of random stationary “noise” dots to the display prevents her from identifying the actions, suggesting that segregation by motion is implemented within the traditional movement areas.