The selective impairment of phonological processing: A case study

A case study is reported of an aphasic patient with fluent speech and markedly superior comprehension of written vs. spoken words. Results of extensive testing supported the hypothesis that the patient suffers from a phonological processing deficit that affects performance in all tasks that require the generation of a phonological code. This selective deficit is interpreted as the underlying cause of diverse symptoms such as asyntactic comprehension of written sentences, the commission of spelling errors in writing, and the production of literal paraphasias and neologisms in spontaneous speech. Alternative possibilities for the classification of this patient are discussed.     

Articulatory coding and phonological judgements on written words and pictures: The role of the phonological output buffer

Abstract

The ability of Italian subjects to make phonological judgements was investigated in three experiments. The judgements comprised initial sound similarity and stress assignment on pain of both written words and pictures. Stress assignment on both words and pictures as well as initial sound similarity on pictures required the activation of phonological lexical representations, but this was not necessarily the case for initial sound similarity judgements on word pairs. The first study assessed the effects of concurrent articulatory suppression on the judgements. Experiment 2 used a concomitant task (chewing), which shares with suppression the use of articulatory components but does not involve speech programming and production. The third experiment investigated the effects of unattended speech on the phonological judgements. The results of these three experiments showed that articulatory suppression had a significant disrupting effect on accuracy in all four conditions, while neither articulatory non-speech (chewing) or unattended auditory speech had any effect on the subjects' performance. The results suggest that these phonological judgements involve the operation of an articulatory speech output component, which is not implemented peripherally and does not require the involvement of a non-articulatory input system.     

The selective impairment of phonological processing in speech production

We report the naming performance of a patient (DM) with a fluent progressive aphasia who made phonological errors in all language production tasks. The pattern of errors in naming was strikingly clear: DM made very many phonological errors that resulted almost always in nonword responses. The complete absence of semantic errors and the very low ratio of formal errors relative to nonword errors (1.6:30.3) in DM's performance are discussed in the context of recent claims about the nature of naming deficits in fluent aphasics. We argue that DM's performance makes highly improbable the claim that fluent aphasia results from global lesions affecting all levels of the lexical access system equally.     

Orthographic and phonological facilitation in speech production: new evidence from picture naming in Chinese

Picture naming is facilitated when a target picture (e.g. of a cat) is accompanied by a form-related context word (e.g. CAP) relative to an unrelated word (e.g. PEN). Because in alphabetic languages phonological and orthographic similarity are confounded, Chinese, a logographic language, has been employed to study these two effects in isolation. The results obtained suggest that the orthographic facilitation effect is localized at an earlier processing level than the phonological facilitation effect. In the present study we examine this issue again, using an experimental design in which the context words in the related and unrelated conditions are optimally matched. In contrast to the earlier studies Experiments 1 and 2 fail to show differences in the time course of the two context effects. Moreover, Experiment 3 provides direct evidence against an early, conceptual locus of orthographic facilitation. Our findings indicate that in Chinese language production both orthographically and phonologically related context words have their effect at the rather late level of word-form encoding.     

Depersonalization: a selective impairment of self-awareness

Depersonalization is characterised by a profound disruption of self-awareness mainly characterised by feelings of disembodiment and subjective emotional numbing. It has been proposed that depersonalization is caused by a fronto-limbic (particularly anterior insula) suppressive mechanism--presumably mediated via attention--which manifests subjectively as emotional numbing, and disables the process by which perception and cognition normally become emotionally coloured, giving rise to a subjective feeling of 'unreality'. Our functional neuroimaging and psychophysiological studies support the above model and indicate that, compared with normal and clinical controls, DPD patients show increased prefrontal activation as well as reduced activation in insula/limbic-related areas to aversive, arousing emotional stimuli. Although a putative inhibitory mechanism on emotional processing might account for the emotional numbing and characteristic perceptual detachment, it is likely, as suggested by some studies, that parietal mechanisms underpin feelings of disembodiment and lack of agency feelings.     

Use of phonological codes for Chinese characters: evidence from processing of parafoveal preview when reading sentences

The role of phonological coding for character identification was examined with the benefit of processing parafoveal characters in eye fixations while reading Chinese sentences. In Experiment 1, the orthogonal manipulation of phonological and orthographic similarity can separate two types of phonological benefits for homophonic previews, according to whether these previews share the same phonetic radical with the targets or not. The significant phonological benefits indicate that phonological coding is activated early when the character is in the parafovea. Experiment 2 manipulated the character's consistency value and found that the phonological preview benefits are reliable only when the targets are high consistency characters. The results of two experiments suggest that phonological computation is rapid and early at both character and radical levels for Chinese character identification.     

Visual word recognition in bilinguals: evidence from masked phonological priming

Bilingual written language representation was investigated with the masked phonological priming paradigm. Pseudohomophonic and control primes of French target words were used to show that Dutch-French bilinguals exhibit the same pattern of phonological and orthographic priming as native French speakers, which suggests that the same processes underlie first-and second-language processing. It was also found that for bilinguals, but not monolinguals, it is possible to prime a target word of the second language with a homophonic stimulus (either word or nonword) of the first language. This interlingual phonological priming effect was of the same size as the intralingual priming effect. Implications for theories of bilingual written language representation and for the interpretation of the masked phonological priming paradigm are discussed.     

The activation of phonological representations by bilinguals while reading silently: evidence from interlingual homophones

These experiments investigated whether bilinguals activate phonological representations from both of their languages when reading silently in one. The critical stimuli were interlingual homophones (e.g., sank in English and cinq in French). French-English and English-French bilinguals completed an English lexical decision task. Decisions made by French-English bilinguals were significantly faster and more accurate for interlingual homophones than for matched English control words. In subsequent experiments, the homophone facilitation effect in the latency data disappeared when distractors were changed to pseudohomophones, when cognates and interlingual homographs were added to the experiment, and when the proportion of critical stimuli was decreased. However, the homophone effect in the error data remained. In contrast, English-French bilinguals revealed little evidence of an interlingual homophone effect. Several attempts were made to increase the saliency of the nontarget language, however these manipulations produced only a small effect in the error data. These results indicate that the activation of phonological representations can appear to be both language-specific and nonspecific depending on the proficiency of the bilinguals and whether they are reading in their weaker or stronger language.     

The effect of sonority on word segmentation: evidence for the use of a phonological universal

It has been well documented how language-specific cues may be used for word segmentation. Here, we investigate what role a language-independent phonological universal, the sonority sequencing principle (SSP), may also play. Participants were presented with an unsegmented speech stream with non-English word onsets that juxtaposed adherence to the SSP with transitional probabilities. Participants favored using the SSP in assessing word-hood, suggesting that the SSP represents a potentially powerful cue for word segmentation. To ensure the SSP influenced the segmentation process (i.e., during learning), we presented two additional groups of participants with either (a) no exposure to the stimuli prior to testing or (b) the same stimuli with pauses marking word breaks. The SSP did not influence test performance in either case, suggesting that the SSP is important for word segmentation during the learning process itself. Moreover, the fact that SSP-independent segmentation of the stimulus occurred (in the latter control condition) suggests that universals are best understood as biases rather than immutable constraints on learning.     

Selective impairment of the graphemic buffer in acquired dysgraphia: a case study

The case of an Italian dysgraphic patient (S.E.), who showed a deficit of both written and oral spelling capacities, without significant differences between words and nonwords, is reported. The pattern of the patient's performance was identical on writing to dictation, delayed copying, and written naming. The most common category of errors was single-letter deletions, and errors were predominantly made in medial positions. Stimulus length appeared to be the single factor that most affected performance. This pattern is consistent with the hypothesis that S.E.'s spelling disorder results from selective damage of the Graphemic Buffer. The case is discussed in relation to current functional models of writing and is compared with similar cases reported previously.     

A dynamic phonological model derived from the intonational analysis of a jargon aphasic patient

This study is a detailed phonological and intonational analysis of one subject's jargon productions. The cohesiveness and complexity of the intonation patterns and appropriateness of the gestures lead to the hypothesis that the jargon productions are due to phonological problems as opposed to semantic or syntactic problems. A psycholinguistic model containing a dynamic phonological component is hypothesized to account for this subject's jargon.     

The link between speech perception and production is phonological and abstract: evidence from the shadowing task

This study reports a shadowing experiment, in which one has to repeat a speech stimulus as fast as possible. We tested claims about a direct link between perception and production based on speech gestures, and obtained two types of counterevidence. First, shadowing is not slowed down by a gestural mismatch between stimulus and response. Second, phonetic detail is more likely to be imitated in a shadowing task if it is phonologically relevant. This is consistent with the idea that speech perception and speech production are only loosely coupled, on an abstract phonological level.     

The selective impairment of semantic memory

The selective impairment of semantic memory is described in three patients with diffuse cerebrallesions. These patients, selected on the basis of a failure to recognize or identify common objects (agnosia for objects), were investigated in detail. In particular, their perceptual, language and memory functions were assessed, and the limits and properties of their recognition difficulties explored.

It was found that knowledge of pictorial representations of objects, and of words, was impaired or impoverished, and in both instances knowledge of subordinate categories was more vulnerable than superordinate categories. Evidence is presented that this impairment of semantic memory cannot be accounted for by intellectual impairment, sensory or perceptual deficits, or expressive language disorder. The implications of damage to the semantic memory system for the operation of other cognitive systems, in particular short and long-term memory functions, are considered. Some tentative evidence for the structural basis for a hierarchically organized modality-specific semantic memory system is discussed.     

Visual and phonological pathways to the lexicon: Evidence from Chinese readers

In this study, we investigated the role of visual and phonological information in lexical access of Chinese characters. Homophonic English words have been the main source of stimuli for word recognition research. However, since these stimuli also often look alike, visual and phonological information may be confounded in reported experiments. In contrast, many homophonic Chinese characters are visually distinct. In addition, visually similar characters often have very different pronunciations. These characteristics allow a more controlled investigation of the roles of visual and phonological information in activation of meaning. In the present study, two types of Chinese characters were used in a semantic categorization paradigm: integrated characters, which contain strokes that are not separable; and compound characters, which contain at least two clearly identifiable components. The results show that the recognition of a Chinese integrated character depends primarily on visual information, whereas the recognition of a Chinese compound character relies on visual, phonological, and semantic information. It is concluded that visual information plays a greater role in Chinese character recognition than has previously been documented.     

The effect of phonological realization of inflectional morphology on verbal agreement in French: evidence from ERPs

The present study examined the impact of the phonological realization of morphosyntactic agreement within the inflectional phrase (IP) in written French, as revealed by ERPs. In two independent experiments, we varied the presence vs. absence of phonological cues to morphological variation. Of interest was whether a graded ERP response to these different conditions could be found in native speakers (Experiment 1), and whether non-native learners would benefit from the presence of phonological cues (Experiment 2). The results for native French speakers showed that compared to grammatically correct instances, phonologically realized inflectional errors produced a significant P600 response, which was statistically larger than that produced by errors that were silent. German L1-French L2 learners showed similar benefits of the phonological realization of morphemes. Phonologically realized errors produced a robust P600 response whereas silent errors produced no robust effects. Implications of these results are discussed in reference to previous studies of L2 acquisition of morphosyntax.     

Nonword repetition in specific language impairment: More than a phonological short-term memory deficit

The possible role of phonological short-term memory in the nonword repetition deficit of children with specific language impairment (SLI) was investigated in a study comparing serial recall and nonword repetition of sequences of auditorily presented CV syllables. The SLI group showed impairments in both serial recall and nonword repetition relative to typically developing children of the same age, however the SLI deficit in nonword repetition was greater and persisted even when differences on an independent measure of short-term memory were taken into account. These findings cannot be readily explained in terms of a sole deficit in short-term memory, and point instead to differences between the serial recall and nonword repetition paradigms as potential factors contributing to this disorder of learning.     

Phonology and syntax in specific language impairment: evidence from a connectionist model

Difficulties in resolving pronominal anaphora have been taken as evidence that Specific Language Impairment (SLI) involves a grammar-specific impairment. The present study explores an alternative view, that grammatical deficits in SLI are sequelae of impaired speech perception. This perceptual deficit specifically affects the use of phonological information in working memory, which in turn leads to poorer than expected syntactic comprehension. This hypothesis was explored using a connectionist model of sentence processing that learned to map sequences of words to their meanings. Anaphoric resolution was represented in this model by recognizing the semantics of the correct antecedent when a bound pronoun was input. When the model was trained on distorted phonological inputs-simulating a perceptual deficit-it exhibited marked difficulty resolving bound anaphors. However, many other aspects of sentence comprehension were intact; most importantly, the model could still resolve pronouns using gender information. In addition, the model's deficit was graded rather than categorical, as it was able to resolve pronouns in some sentences, but not in others. These results are consistent with behavioral data concerning syntactic deficits in SLI. The model provides a causal demonstration of how a perceptual deficit could give rise to grammatical deficits in SLI.     

Activation of phonological codes during reading: evidence from errors detection and eye movements

This experiment explored the role of phonology in the activation of word meanings when homophonic and nonhomophonic errors were embedded in meaningful texts. The resulting data supported the position that phonological codes are activated very early in eye fixation and are compatible with the verification model of Van Orden (1987).