Pronounceable Pseudowords Research Articles

EEG lexicality effect predicts clinical outcome in disorders of consciousness.

This study aimed at probing covert language processing in patients with disorders of consciousness. An auditory paradigm contrasting words to pronounceable pseudowords was designed, while recording bedside electroencephalogram and computing the two main correlates of lexicality: N400 and late positive component (LPC). Healthy volunteers and 19 patients, 10 in a minimally conscious state and 9 in a vegetative state (also coined unresponsive wakefulness syndrome), were recorded. N400 was present in all groups, whereas LPC was only present in the healthy volunteers and minimally conscious state groups. At the individual level, an unprecedented detection rate of N400 and LPC was reached, and LPC predicted overt cognitive improvement at 6 months. ANN NEUROL 2023;93:762-767.

Letter processing in Russian: Does orthography matter?

Prior research has suggested that the identification and encoding of letter positions within letter strings might be influenced by orthography. Letters in transparent languages (e.g., Greek) with regular grapheme-to-phoneme correspondences are processed sequentially, whereas letters in deep languages (e.g., English) are processed in parallel. In three experiments, we used a visual search paradigm to test this hypothesis on Russian—a relatively transparent language. In Experiment 1, we measured the identification speed of Cyrillic letters at each position in the five-element real words or pronounceable pseudowords. In Experiment 2, the performance was compared to random letter strings, and in Experiment 3, to non-linguistic symbol strings. Our results reveal a search pattern similar to English, excluding strictly serial letter computation, which is inconsistent with the orthography hypothesis. Moreover, we showed that the lexical status and the nature of the string (linguistic/non-linguistic) affect response times for Russian and therefore must be accounted for in models of visual word recognition.

Electrophysiological analysis of stimulus variables in equivalence relations.

Recently, electrophysiological measures have been used to evaluate the functional overlap between semantic relations and laboratory-defined equivalence relations with abstract stimuli. Several studies using semantic judgment procedures have shown that accompanying EEG-measured neural activity for stimulus pairs from equivalence classes is very similar to that of word pairs from participants' native language. However, those studies often included pronounceable elements (e.g., written nonsense syllables) as at least one member of the experimentally defined classes. The present study conducted EEG studies that contrasted classes with and without such elements. Two groups of undergraduate students completed a matching-to-sample procedure to establish 3 4-member equivalence classes. For Group 1, samples and comparisons were pronounceable pseudowords and abstract figures. For Group 2, the matching-to-sample stimuli were abstract figures only. EEG data recorded during the semantic judgment tasks showed waveform patterns compatible with prior studies of semantic relations in Group 1 but not in Group 2.

The neural substrates of natural reading: a comparison of normal and nonword text using eyetracking and fMRI.

Most previous studies investigating the neural correlates of reading have presented text using serial visual presentation (SVP), which may not fully reflect the underlying processes of natural reading. In the present study, eye movements and BOLD data were collected while subjects either read normal paragraphs naturally or moved their eyes through “paragraphs” of pseudo-text (pronounceable pseudowords or consonant letter strings) in two pseudo-reading conditions. Eye movement data established that subjects were reading and scanning the stimuli normally. A conjunction fMRI analysis across natural- and pseudo-reading showed that a common eye-movement network including frontal eye fields (FEF), supplementary eye fields (SEF), and intraparietal sulci was activated, consistent with previous studies using simpler eye movement tasks. In addition, natural reading versus pseudo-reading showed different patterns of brain activation: normal reading produced activation in a well-established language network that included superior temporal gyrus/sulcus, middle temporal gyrus (MTG), angular gyrus (AG), inferior frontal gyrus, and middle frontal gyrus, whereas pseudo-reading produced activation in an attentional network that included anterior/posterior cingulate and parietal cortex. These results are consistent with results found in previous single-saccade eye movement tasks and SVP reading studies, suggesting that component processes of eye-movement control and language processing observed in past fMRI research generalize to natural reading. The results also suggest that combining eyetracking and fMRI is a suitable method for investigating the component processes of natural reading in fMRI research.

Does pronounceability modulate the letter string deficit of children with dyslexia? A study with the rate and amount model

The locus of the deficit of children with dyslexia in dealing with strings of letters may be a deficit at a pre-lexical graphemic level or an inability to bind orthographic and phonological information. We evaluate these alternative hypotheses in two experiments by examining the role of stimulus pronounceability in a lexical decision task (LDT) and in a forced-choice letter discrimination task (Reicher–Wheeler paradigm). Seventeen fourth grade children with dyslexia and 24 peer control readers participated to two experiments. In the LDT children were presented with high-, low-frequency words, pronounceable pseudowords (such as DASU) and unpronounceable non-words (such as RNGM) of 4-, 5-, or 6- letters. No sign of group by pronounceability interaction was found when over-additivity was taken into account. Children with dyslexia were impaired when they had to process strings, not only of pronounceable stimuli but also of unpronounceable stimuli, a deficit well accounted for by a single global factor. Complementary results were obtained with the Reicher–Wheeler paradigm: both groups of children gained in accuracy in letter discrimination in the context of pronounceable primes (words and pseudowords) compared to unpronounceable primes (non-words). No global factor was detected in this task which requires the discrimination between a target letter and a competitor but does not involve simultaneous letter string processing. Overall, children with dyslexia show a selective difficulty in simultaneously processing a letter string as a whole, independent of its pronounceability; however, when the task involves isolated letter processing, also these children can make use of the ortho-phono-tactic information derived from a previously seen letter string. This pattern of findings is in keeping with the idea that an impairment in pre-lexical graphemic analysis may be a core deficit in developmental dyslexia.

Segregation of Lexical and Sub-Lexical Reading Processes in the Left Perisylvian Cortex

A fundamental issue in cognitive neuroscience is the existence of two major, sub-lexical and lexical, reading processes and their possible segregation in the left posterior perisylvian cortex. Using cortical electrostimulation mapping, we identified the cortical areas involved on reading either orthographically irregular words (lexical, “direct” process) or pronounceable pseudowords (sublexical, “indirect” process) in 14 right-handed neurosurgical patients while video-recording behavioral effects. Intraoperative neuronavigation system and Montreal Neurological Institute (MNI) stereotactic coordinates were used to identify the localization of stimulation sites. Fifty-one reading interference areas were found that affected either words (14 areas), or pseudo-words (11 areas), or both (26 areas). Forty-one (80%) corresponded to the impairment of the phonological level of reading processes. Reading processes involved discrete, highly localized perisylvian cortical areas with individual variability. MNI coordinates throughout the group exhibited a clear segregation according to the tested reading route; specific pseudo-word reading interferences were concentrated in a restricted inferior and anterior subpart of the left supramarginal gyrus (barycentre x = −68.1; y = −25.9; z = 30.2; Brodmann’s area 40) while specific word reading areas were located almost exclusively alongside the left superior temporal gyrus. Although half of the reading interferences found were nonspecific, the finding of specific lexical or sublexical interferences is new evidence that lexical and sublexical processes of reading could be partially supported by distinct cortical sub-regions despite their anatomical proximity. These data are in line with many brain activation studies that showed that left superior temporal and inferior parietal regions had a crucial role respectively in word and pseudoword reading and were core regions for dyslexia.

Phonological awareness predicts activation patterns for print and speech

Using fMRI, we explored the relationship between phonological awareness (PA), a measure of metaphonological knowledge of the segmental structure of speech, and brain activation patterns during processing of print and speech in young readers from 6 to 10 years of age. Behavioral measures of PA were positively correlated with activation levels for print relative to speech tokens in superior temporal and occipito-temporal regions. Differences between print-elicited activation levels in superior temporal and inferior frontal sites were also correlated with PA measures with the direction of the correlation depending on stimulus type: positive for pronounceable pseudowords and negative for consonant strings. These results support and extend the many indications in the behavioral and neurocognitive literature that PA is a major component of skill in beginning readers and point to a developmental trajectory by which written language engages areas originally shaped by speech for learners on the path toward successful literacy acquisition.

Incidental learning of abstract rules for non-dominant word orders

One way in which adult second language learners may acquire a word order that differs from their native language word order is through exposure-based incidental learning, but little is known about that process and what constrains it. The current studies examine whether a non-dominant word order can be learned incidentally, and if so, whether the rule can be generalized to new words not previously seen in the non-dominant order. Two studies examined the incidental learning of rules underlying the order of nouns and verbs in three-word strings. The self-timed reading speeds of native English speakers decreased as a result of practice with a non-dominant rule (words ordered either as "verb noun noun" or "noun noun verb"). The same pattern of results was also found for new words ordered according to the previously encountered rule, suggesting learning generalized beyond the specific instances encountered. A second experiment showed such rule learning could also occur when the nouns were replaced with pronounceable pseudowords. Learning was therefore possible in the absence of any pre-existing relationships between the items. Theoretical and educational implications are discussed.

Reading in a deep orthography: neuromagnetic evidence for dual-mechanisms

Despite substantial efforts to connect cognitive-linguistic models with appropriate anatomical correlates, the question of which cognitive model best accounts for the neuropsychological and functional neuroimaging evidence remains open. The two most popular models are grounded in conceptually different bases and thus make quasi-distinct predictions in regard to the patterns of activation that should be observed in imaging investigations of linguistic processing. Dual-mechanism models propose that high-frequency regular and irregular words are processed through a lexicon-based word code, which facilitates their processing and pronunciation latencies relative to pseudowords. In contrast, single-mechanism models suggest the same behavioral effects can be explained through semantic mediation without the existence of a lexicon. In most previous studies, words and pronounceable pseudowords were presented in lexical-decision or word reading paradigms, and hemodynamic techniques were utilized to distinguish involved anatomical areas. The results typically indicated that both word classes activated largely congruent tissues, with a magnitude advantage for pseudowords in most or all activated regions. However, since the dual-mechanism model predicts both word types utilize the entire linguistic network, but that certain operations are merely obligatorily involved, these results do not sharply refute nor clearly support the model's main tenets. In the current study, we approach the dual- versus single-mechanism question differently by focusing on the temporal dynamics of MEG imaged neuronal activity, during performance of an oddball version of continuous lexical-decision, to determine whether the onset latency of any cortical language region shows effects of word class that are indicative of preferential versus obligatory processing pathways. The most remarkable aspect of our results indicated that both words and pseudowords initially activate the left posterior fusiform region, but that the spatiotemporal dynamics clearly distinguish the two word classes thereafter. For words, this left fusiform activation was followed by engagement of the left posterior inferior temporal, and subsequently activation reached the left posterior superior temporal region. For pseudowords, this sequential order of left temporal area activations was reversed, as activity proceeded from the left fusiform to the left superior temporal and then the left inferior temporal region. For both classes, this dynamic sequential spread manifested within the first 300 ms of stimulus processing. We contend these results provide strong support for the existence of dual-mechanisms underlying reading in a deep orthographic language (i.e., English).

Differential Use of Orthographic and Phonological Coding Strategies by Students with Symmetrical and Asymmetrical Reading and Spelling Skills

This study investigated the orthographic and phonological coding strategies of students with symmetrical and asymmetrical reading and spelling achievement. Based on performance on a standardized achievement test, fourth-and fifth-grade students (N = 50) were classified as having no difficulties with reading and spelling, difficulties with both reading and spelling, or difficulties with spelling but not with reading. Students were administered the following tasks to assess their use of orthographic and phonological strategies: 1) rhyme judgment, 2) orthographic and phonological similarity in memory, 3) reading pronounceable pseudowords, and 4) deciding which pseudoword looked most like a real word. Compared to the poor readers and spellers, the results indicated a greater use of phonological coding strategies by the good readers regardless of spelling skill. Additionally, students who were poor readers and spellers demonstrated greater use of orthographic than phonological coding strategies. However, students with asymmetrical good reading but poor spelling skills recalled fewer orthographically distinct words than the good or poor readers and spellers, thereby, showing some differential use of an orthographic coding strategy. The results highlight the importance of considering students' orthographic in addition to phonological processing strategies when assessing and identifying specific learning disabilities. The results also provide evidence for the differential use of these strategies by students with either symmetrically poor or asymmetrically good reading but poor spelling skills.

Pseudoword and Real Word Memory in Unilateral Temporal Lobe Epilepsy

Recognition memory for pronounceable pseudowords (PWs), real words, and degraded photographs of unfamiliar faces, was examined in 45 patients with unilateral temporal lobe epilepsy (TLE), before and after Anterior Temporal Lobectomy, to test predictions from two accounts of hemispheric differences in memory functioning: (1) The ‘material-specific’ account predicts that left TLE (LTLE) patients would be impaired in memory for both familiar (real words) and unfamiliar (PWs) verbal stimuli, while memory for novel complex visual stimuli (unfamiliar faces) would be impaired in right TLE (RTLE) patients. (2) The ‘familiarity’ account predicts that memory for familiar stimuli (such as words) will be impaired in LTLE patients, while memory for both linguistic and nonlinguistic unfamiliar stimuli should be disrupted in RTLE patients. Results were consistent with the ‘material-specific’ hypothesis suggesting that both familiar and unfamiliar linguistic stimuli are processed for memory in the left medial temporal lobe (MTL), whereas unfamiliar nonverbal stimuli are processed for memory in the right MTL.

The visual word form area: a prelexical representation of visual words in the fusiform gyrus.

Event-related fMRI was used to test the hypothesis that the visual word form area in the left fusiform gyrus holds a modality-specific and prelexical representation of visual words. Subjects were engaged in a repetition-detection task on pairs of words or pronounceable pseudo-words that could be written or spoken. The visual word form area responded only to written stimuli, not to spoken stimuli, independently of their semantic content. We propose that the occasional activation of the fusiform gyrus when listening to spoken words is due to the topdown recruitment of visual orthographic or object representations.

Implicit perception in patients with visual neglect: Lexical specificity in repetition priming

Twelve patients with left-sided neglect, five patients with left-sided hemianopia, and 16 matched controls performed lexical decisions for foveally presented target words or pseudowords. Target words or pseudowords could be preceded by the same stimuli, presented for 150 ms as primes in either the left (LVF) or the right (RVF) visual hemifield. Primes in the RVF caused similar levels of priming across the three groups. In contrast, whereas primes in the affected LVF did not cause priming in hemianopic patients, patients with neglect showed highly significant priming from LVF primes, and the level of priming from these neglected primes was increased relative to normal control levels. This priming effect was attributed to lexical access, because no repetition priming was observed for pronounceable pseudowords. In striking contrast to the priming results, neglect patients' explicit recognition performance for these prime stimuli was at chance for the left hemifield, although it was near perfect for the right hemifield. This demonstrates that the observed priming effects in the left hemifield were indeed caused by stimuli that were not explicitly perceived.

Dissociation of Pure Korean Words and Chinese-Derivative Words in Phonological Dysgraphia

Phonological dysgraphia is a writing impairment, characterized by marked disability to spell pronounceable pseudo-words as opposed to relatively mild reduction in ability to spell real words. Within the realm of Korean vocabulary, there are two categories of real words: pure Korean words and Chinese-derivative words. We present a patient with a history of CVA, resulting in phonological dysgraphia and, further, a dissociated performance in the aforementioned two categories of real words. It is suggested that the lexicon for pure Korean words is segregated from that for Chinese-derivative words.

Word order effects in German sentences and German pseudo-word sentences

Summary: German belongs to those languages that allow a free permutation of subject, direct object and indirect object in verb final sentences. Five linear precedence (LP) principles have been postulated to describe preference patterns for the different word orders ( Uszkoreit, 1986 ). The present study tested if these rules are valid for meaningful German sentences only or also hold for pseudo-word sentences, i.e., if they are independent of semantic language aspects. Twelve students saw sentences in six different but legal word orders and in one illegal word order, either with normal German words or pronounceable pseudo-words. They had to answer a question focussing on the thematic role of one or more complements. In addition, they rated the acceptability of a subset of sentences in all experimental conditions. The canonical word order was processed fastest and processing times increased the more LP-principles were violated, both for normal and pseudo-word sentences. Moreover, acceptability ratings decreased monotonously with an increasing deviation of the sentences from its canonical word order, again irrespective of the stimulus material. The ungrammatical permutation received the lowest acceptability ruting. These results imply that the LP-principles describe syntactical preferences independent of meaning, at least in isolated sentences.

Impaired spelling in Alzheimers disease: a linguisticdeficit?

Different kinds of real words and pronounceable pseudowords (PWs) were presentedfor writing to dictation to patients with the diagnosis of probable Alzheimers disease (AD) and toage- and education-matched healthy controls. Though spelling less accurately on all tasks, ADpatients responded in a manner generally qualitatively similar to controls. Except for a slightlyenhanced effect of spelling regularity in real word writing accuracy, AD patients showed thesame sensitivity to various lexical, orthographic and phonological variables as controls. Bothgroups showed no difference in spelling accuracy for words and PWs with regular vs ambiguousspelling patterns, and groups also showed similar orthographic preferences when spelling PWshaving several different acceptable pronunciations. Finally, AD patients and controls producedsimilar types of errors when spelling real words. Dementia severity was related to the overallaccuracy, but not to the pattern, of spelling responses. It is suggested that the decline in responseaccuracy in cognitively demanding writing tasks in patients with more advanced dementia ismost likely due to semantic impairment and impairments of nonlinguistic functions of attention,executive control and praxis, rather than to a disturbance within language specific processes.

Lexical effects and lexical properties associated with National Adult Reading Test (NART) stimuli in healthy young adults and healthy elderly adults

Fifty healthy younger adults and 45 healthy elderly adults performed a speeded lexical decision task (LDT). Stimuli consisted of 57 National Adult Reading Test (NART) words (the NART consists of “irregular” words that violate standard spelling-to-sound correspondence rules) and 57 pronounceable pseudowords (e.g., blant). Both groups displayed statistically equivalent lexicality (PW-W) effects, and error rates were lower in elderly adults. With groups equated on vocabulary ability, lexicality effects remained the same and error rates did not differ across either group. Correlational analyses confirmed the role played by word frequency and word familiarity in latencies to NART stimuli. Results are discussed regarding the importance of obtaining speeded latency measures for age-related word recognition comparisons. © 1998 John Wiley & Sons, Inc. J Clin Psychol 54: 577–584, 1998.

Lexical effects and lexical properties associated with National Adult Reading Test (NART) stimuli in healthy young adults and healthy elderly adults.

Fifty healthy younger adults and 45 healthy elderly adults performed a speeded lexical decision task (LDT). Stimuli consisted of 57 National Adult Reading Test (NART) words (the NART consists of "irregular" words that violate standard spelling-to-sound correspondence rules) and 57 pronounceable pseudowords (e.g., blant). Both groups displayed statistically equivalent lexicality (PW-W) effects, and error rates were lower in elderly adults. With groups equated on vocabulary ability, lexicality effects remained the same and error rates did not differ across either group. Correlational analyses confirmed the role played by word frequency and word familiarity in latencies to NART stimuli. Results are discussed regarding the importance of obtaining speeded latency measures for age-related word recognition comparisons.

Preserved Semantic Priming Effect in Alexia

BH, a left-handed patient with alexia and nonfluent aphasia, was presented with a lexical-decision task in which words and pronounceable pseudowords were preceded by semantically related or unrelated picture primes (Experiment 1). In Experiment 2, BH was given an explicit reading task using the word lists from Experiment 1. Performance on Experiment 2 disclosed severe reading deficits in both oral reading and semantic matching of the words to pictures. However, in Experiment 1, BH demonstrated a significant semantic priming effect, responding more accurately and more quickly to words preceded by related primes than by unrelated primes. The present results suggest that even in a patient with severe alexia, implicit access to semantic information can be preserved in the absence of explicit identification. The possibility of categorical gradient in implicit activation (living vs. nonliving) in BH was also discussed, which, however, needs to be clarified in the further investigation.

Spectral responses in the gamma-band: physiological signs of higher cognitive processes?

It has recently been proposed that brain responses in the gamma-range (> 20 Hz) include information about specific cognitive processes in the human brain. Empirical data substantiating this assumption come from EEG and MEG recordings during visual and language processing. For example, 30 Hz activity has been found to be stronger during processing of words than during processing of meaningless but pronounceable pseudo-words. However, it has been reported that power changes in the gamma-band are sometimes artefacts of changes taking place in other frequencies, such as the alpha-band. In this study, we investigated power changes in frequency bands outside the gamma-range and found no evidence that such changes are related to the dynamics in gamma-power distinguishing between words and pseudowords. These results are consistent with the view that gamma-band responses are an indicator of lexical processing and other cognitive processes related to binding of stimulus features into a whole (Gestalt), as proposed by Singer.