The syntax of single words: Evidence from a patient with a selective function word reading deficit

We describe the reading performance of a patient who has selective deficits for reading nonwords, function words, and morphologically complex words in isolation. His reading of highly abstract nouns and verbs, however, is relatively well preserved. He can recognise and comprehend the meaning of written function words, of derivational morphology, and of most inflectional morphology. We suggest that his deficit in reading grammatical morphemes is unrelated to his problems in reading nonwords and cannot be explained by their low semanticity and imageability. The patient's speech is ungrammatical but is not devoid of grammatical morphemes and his reading of functional elements improves when these are presented within the context of sentences. We argue that syntactic information relevant to individual lexical items including information about how the word may potentially be used within a phrase must be accessed during single word reading tasks (e.g., Levelt, 1989). This is particularly difficult for function words due to their linguistic specification, which is different from that of lexical categories (Chomsky, 1995). Both linguistic theory and Garrett's (e.g., 1982) model of sentence processing account for the patient's improved reading of function words in the context of sentences.     

Foveal crowding in posterior cortical atrophy: a specific early-visual-processing deficit affecting word reading

Visual crowding is a form of masking in which single-letter identification is compromised by the presence of additional letters or other simple visual forms in close proximity. This behavioural phenomenon has been studied most frequently in the context of amblyopic and normal peripheral vision. In the current study, we investigate this phenomenon in the context of two patients with peripheral dyslexia and a third with visual disorientation consequent to bilateral posterior cortical atrophy. In one case, reading showed the effects of word length typical of letter-by-letter reading, whereas the second case was unable to read any whole words. In a series of letter identification tasks, recognition accuracy was shown to decrease significantly in the presence of a range of flanking stimuli (e.g., letters, digits, letter fragments). Compatible with previous reports of the crowding phenomenon, the flanking effect was strengthened by increasing flanker proximity but was unaffected by target or flank size, flank contrast, target-flank lexicality, or flank category. One patient also showed amelioration of the flanking effect when the target and flankers were of opposite contrast polarity. To the best of our knowledge, this is the first demonstration of visual crowding in individuals with posterior cortical atrophy. We consider the relevance of these empirical findings to accounts of the letter-by-letter reading form of peripheral dyslexia. In particular, we suggest that crowding constitutes one specific form of early-visual-processing deficit, which impairs the reading process.     

Length effect in word naming in reading: role of reading experience and reading deficit in italian readers

Vocal reaction times (RTs) in naming 3- to 8-letter words were measured in proficient and dyslexic readers (Study 1). In proficient readers, RTs were independent of word length up to 5-letter words, indicating parallel processing. In the 5- to 8-letter range, RTs increased linearly, indicating sequential processing. Reading experience was associated with both faster discrimination of individual elements and parallel processing of increasingly large word parts. In dyslexics, RTs increased linearly with increasing length indicating reliance on sequential decoding. Individual analysis indicated 2 profiles of RTs (Types A and B). In Study 2, the distinction between A and B dyslexics was not associated with the use of different reading procedures. However, a more marked speed deficit characterized Type B dyslexics.     

Foveal crowding in posterior cortical atrophy: A specific early-visual-processing deficit affecting word reading

Visual crowding is a form of masking in which single-letter identification is compromised by the presence of additional letters or other simple visual forms in close proximity. This behavioural phenomenon has been studied most frequently in the context of amblyopic and normal peripheral vision. In the current study, we investigate this phenomenon in the context of two patients with peripheral dyslexia and a third with visual disorientation consequent to bilateral posterior cortical atrophy. In one case, reading showed the effects of word length typical of letter-by-letter reading, whereas the second case was unable to read any whole words. In a series of letter identification tasks, recognition accuracy was shown to decrease significantly in the presence of a range of flanking stimuli (e.g., letters, digits, letter fragments). Compatible with previous reports of the crowding phenomenon, the flanking effect was strengthened by increasing flanker proximity but was unaffected by target or flank size, flank contrast, target–flank lexicality, or flank category. One patient also showed amelioration of the flanking effect when the target and flankers were of opposite contrast polarity. To the best of our knowledge, this is the first demonstration of visual crowding in individuals with posterior cortical atrophy. We consider the relevance of these empirical findings to accounts of the letter-by-letter reading form of peripheral dyslexia. In particular, we suggest that crowding constitutes one specific form of early-visual-processing deficit, which impairs the reading process.     

Memory for single items, word pairs, and temporal order of different kinds in a patient with selective hippocampal lesions

One kind of between-list and two kinds of within-list temporal order memory were examined in a patient with selective bilateral hippocampal lesions. This damage disrupted memory for all three kinds of temporal order memory, but left item and word pair recognition relatively intact. These findings are inconsistent with claims that (1) hippocampal lesions, like those of the medial temporal lobe (MTL) cortex, disrupt item and word pair recognition, and that (2) hippocampal lesions disrupt temporal order memory and item recognition to the same degree. Not only was word pair recognition intact in the patient, but further evidence indicates that her recognition of other associations between items of the same kind is also spared so retrieval of such associations cannot be sufficient to support within-list temporal order recognition. Rather, as other evidence indicates that the patient is impaired at recognition of associations between different kinds of information, within-list (and possibly between-list) temporal order memory may be impaired by hippocampal lesions because it critically depends on retrieving associations between different kinds of information.     

Memory for single items,word pairs,and temporal order of different kinds in a patient with selective hippocampal lesions

One kind of between-list and two kinds of within-list temporal order memory were examined in a patient with selective bilateral hippocampal lesions. This damage disrupted memory for all three kinds of temporal order memory, but left item and word pair recognition relatively intact. These findings are inconsistent with claims that (1) hippocampal lesions, like those of the medial temporal lobe (MTL) cortex, disrupt item and word pair recognition, and that (2) hippocampal lesions disrupt temporal order memory and item recognition to the same degree. Not only was word pair recognition intact in the patient, but further evidence indicates that her recognition of other associations between items of the same kind is also spared so retrieval of such associations cannot be sufficient to support within-list temporal order recognition. Rather, as other evidence indicates that the patient is impaired at recognition of associations between different kinds of information, within-list (and possibly between-list) temporal order memory may be impaired by hippocampal lesions because it critically depends on retrieving associations between different kinds of information.     

Consequences of an inhibition deficit for word production and comprehension: Evidence from the semantic blocking paradigm

We investigated the semantic blocking effect in picture naming and word–picture matching for two nonfluent aphasic patients who show evidence of a deficit in inhibiting verbal representations (M.L. and B.Q.), one fluent aphasic patient (K.V.), and neurologically intact control participants. In two picture-naming tasks (Experiments 1A and 1B), M.L. and B.Q., relative to controls, showed a greatly exaggerated semantic blocking effect in naming latencies that increased dramatically across repeated presentations. On two corresponding word–picture matching tasks (Experiments 2A and 2B), both also showed an increasing semantic blocking effect, though the effects were not as large nor as consistent as those in naming. The fluent patient, K.V., showed a pattern like controls on both tasks. On an associated word–picture matching task, both M.L. and B.Q. showed results paralleling those of controls. The contrast between the production and comprehension patterns for M.L. and B.Q. supports the conclusion that their exaggerated blocking effect in production arises during lexical rather than semantic selection. We postulate that M.L.'s (and potentially B.Q.'s) production effect is due to difficulties in postselection inhibition, which results in overactivation of lexical representations. This overactivation is likely to be one source of their nonfluency in spontaneous speech.     

The neurocognitive basis of reading single words as seen through early latency ERPs: a model of converging pathways

This paper first provides a brief review of the functional neuroanatomy of reading single words, focusing on the lexical and phonological routes. Next, early (defined as peaking prior to 350 ms) reading event-related potential components are summarized. A comprehensive effort is made to organize existing observations into a coherent scheme and commentary is made on terminology. Proposals are made regarding the cognitive function reflected by each ERP component and the associated generator sites. The overall framework constitutes a neurocognitive model of reading and demonstrates how the high temporal resolution of event-related potentials can provide additional insights into the reading process beyond those available from behavioral and neuroimaging studies, with a special focus on how the two pathways implied in reading are coordinated. The present model suggests that there are two such coordinating operations, convergence processes during an initial information burst and resonance processes during an extended harmonization process that follows.     

Closed-class words in sentence production: Evidence from a modality-specific dissociation

Classic observations in the field of the neuropsychology of language have established that brain injury can result in the specific disruption of the ability to use words from the closed class (e.g., determiners, auxiliary verbs, prepositions, etc.) while the production of words from the open class is preserved (e.g., nouns, verbs, etc.). In this study, we report the case of a French native speaker who, following a cerebral-vascular accident, presents a dissociation between open- and closed-class words. Importantly, this dissociation is only observed in the written modality of output while oral speech production is by and large normal. Furthermore, the difficulties in writing closed-class words were only observed during sentence production--in spontaneous production or in writing to dictation tasks--but not during single word production. The origin of this deficit is discussed in the context of previously proposed models of sentence production.     

Closed-class words in sentence production: Evidence from a modality-specific dissociation

Classic observations in the field of the neuropsychology of language have established that brain injury can result in the specific disruption of the ability to use words from the closed class (e.g., determiners, auxiliary verbs, prepositions, etc.) while the production of words from the open class is preserved (e.g., nouns, verbs, etc.). In this study, we report the case of a French native speaker who, following a cerebral-vascular accident, presents a dissociation between open- and closed-class words. Importantly, this dissociation is only observed in the written modality of output while oral speech production is by and large normal. Furthermore, the difficulties in writing closed-class words were only observed during sentence production--in spontaneous production or in writing to dictation tasks--but not during single word production. The origin of this deficit is discussed in the context of previously proposed models of sentence production.     

Direct priming effects beyond words: a case of word pairs

One important issue in direct priming research is whether or not priming effects are restricted to single words. Four series of experiments were conducted with word pairs. The reading time was measured for physically inverted word pairs written in katakana characters. The results indicated that the direct priming effect was obtained with word pairs regardless of the task condition, perceptual or semantic. The important thing is whether the task is processed in an integrated manner or not.     

Cognitive processes in spatial mapping: Evidence from a developmental spatial deficit

We report a case study of an adolescent girl (N.K.Y.) with a developmental deficit affecting spatial processing. In a simple spatial mapping task, N.K.Y. shows a striking dissociation: She succeeds in one variant of the experiment in which the stimuli are objects, but struggles in a structurally identical task with people as stimuli. We present evidence that this dissociation stems from a tendency to automatically adopt the spatial perspective of other people, but not objects—a phenomenon also observed in neurotypical individuals. When adopting another person’s perspective, N.K.Y. imagines herself in the other’s position, representing the other’s left and right as if it were her own. N.K.Y.’s deficit in relating left–right information to her own body then disrupts her performance. Our results shed light on the nature of N.K.Y.’s deficit as well as the cognitive operations involved in spatial perspective taking.     

The functional architecture of the cognitive numerical-processing system: Evidence from a patient with multiple impairments

Abstract

RH, a brain-damaged patient with multiple impairments in numerical processing, was tested extensively on a set of transcoding tasks in which numerals were converted from one form to another (e.g. 94 → ninety-four). The pattern of error rates across tasks, and the patterns of error types within tasks, support the assumption that numerical processing is mediated by multiple independent numeral comprehension and numeral production processes that communicate via central semantic representations of numbers (McCloskey, Caramazza, & Basili, 1985).     

The orthographic buffer in writing Chinese characters: Evidence from a dysgraphic patient

We investigated the postlexical processes in writing Chinese characters by studying the delayed copying performance of a Chinese dysgraphic patient, W.L.Z. His delayed copying difficulty could not be attributed to peripheral motor deficit and could not be readily explained by lexical or semantic factors. Instead, the copying performance was sensitive to a word length variable (number of logographemes), and the most prevalent errors were logographeme substitutions. Furthermore, in the substitution errors, the target logographemes and responses tended to share visual/motoric attributes. We propose that the delayed copying difficulty reflects a deficit to the buffering component in writing (coined “logographeme output buffer”), and the universality and language-specific features of the output buffer in writing are discussed.     

Pure alexia and covert reading: Evidence from Stroop tasks

Patients with pure alexia (also referred to as letter-by-letter readers) show a marked word-length effect when naming visually presented words, evidenced by a monotonic increase in response time (or decrease in accuracy) as a function of the number of letters in the string. Interestingly, despite the difficulty in overtly reporting the identity of some words, many patients exhibit fast and above-chance access to lexical and/or semantic information for the same words. To explore the extent of this covert reading, we examined the degree of interference afforded by the inconsistent (word identity and colour label do not match) versus neutral condition in a Stroop task in a pure alexic patient, EL. EL shows evidence of covert reading on a semantic categorisation task and a lexical decision task. She also demonstrates covert reading by exhibiting Stroop interference of the same magnitude as a matched control subject, when naming the colour of the ink in which a word is printed. When the word shares some but not all letters with the colour name (BLOW instead of BLUE), neither subject shows interference. In contrast with the control subject, EL does not show Stroop interference when various orthographic changes (degraded visual input, cursive font) or phonological or semantic changes are made to the word. These findings indicate that although some implicit processing of words may be possible, this processing is rather rudimentary. Not surprising, this implicit activation may be insufficient to support overt word identification. We explain these findings in the context of a single, integrated account of pure alexia.     

Neural mechanisms of Korean word reading: a functional magnetic resonance imaging study

The use of functional magnetic resonance imaging permits the collection of brain activation patterns when native Korean speakers (12 persons as subjects) read Korean words and Chinese characters. The Korean language uses both alphabetic Korean words and logographic Chinese characters in its writing system. Our experimental results show that the activation patterns obtained for reading Chinese characters by Korean native speakers involve neural mechanisms that are similar to Chinese native speakers; i.e. strong left-lateralized middle frontal cortex activation. For the case of Korean word reading, the activation pattern in the bilateral fusiform gyrus, left middle frontal gyrus, left superior temporal gyrus, right mid temporal gyrus, precentral gyrus, and insula was observed. This suggests that the activation pattern for Korean word reading appears to corroborate with that of alphabetic words at the general level. A further noteworthy finding of our study is the strong activation of the posterior part of the right dorsolateral prefrontal cortex (BA 8). The right hemispheric BA 8 belongs to the visual higher order control area and we propose that this area should be responsible for processing of visuospatial (surface form) information of Korean words.     

Pure alexia and covert reading: Evidence from Stroop tasks

Abstract

Patients with pure alexia (also referred to as letter-by-letter readers) show a marked word-length effect when naming visually presented words, evidenced by a monotonic increase in response time (or decrease in accuracy) as a function of the number of letters in the string. Interestingly, despite the difficulty in overtly reporting the identity of some words, many patients exhibit fast and above-chance access to lexical and/or semantic information for the same words. To explore the extent of this covert reading, we examined the degree of interference afforded by the inconsistent (word identity and colour label do not match) versus neutral condition in a Stroop task in a pure alexic patient, EL. EL shows evidence of covert reading on a semantic categorisation task and a lexical decision task. She also demonstrates covert reading by exhibiting Stroop interference of the same magnitude as a matched control subject, when naming the colour of the ink in which a word is printed. When the word shares some but not all letters with the colour name (BLOW instead of BLUE), neither subject shows interference. In contrast with the control subject, EL does not show Stroop interference when various orthographic changes (degraded visual input, cursive font) or phonological or semantic changes are made to the word. These findings indicate that although some implicit processing of words may be possible, this processing is rather rudimentary. Not surprising, this implicit activation may be insufficient to support overt word identification. We explain these findings in the context of a single, integrated account of pure alexia.     

Lexical processing in the absence of explicit word identification: Evidence from a letter-by-letter Reader

Abstract

The lexical decision performance of a letter-by-letter reader, ML, was analysed for words presented for too short an exposure duration for him to identify or name them. His level of performance was surprisingly good by comparison with that of previously reported patients. In addition he gave a very similar pattern of responses to inappropriately affixed words as to appropriately affixed ones. His performance on these tasks could not be attributed to neglect or to the use of letter sequential dependencies. In addition, with the same exposure duration, ML showed “semantic access” characteristics in word categorisation tasks. This evidence for lexical processing in the absence of explicit identification is discussed in relation to alternative accounts of letter-by-letter reading.