Letter Matching Research Articles

Disrupted neural responses to phonological and orthographic processing in dyslexic children: an fMRI study.

Developmental dyslexia, characterized by difficulty in reading, has been associated with phonological and orthographic processing deficits. fMRI was performed on dyslexic and normal-reading children (8-12 years old) during phonological and orthographic tasks of rhyming and matching visually presented letter pairs. During letter rhyming, both normal and dyslexic reading children had activity in left frontal brain regions, whereas only normal-reading children had activity in left temporo-parietal cortex. During letter matching, normal-reading children showed activity throughout extrastriate cortex, especially in occipito-parietal regions, whereas dyslexic children had little activity in extrastriate cortex during this task. These results indicate dyslexia may be characterized in childhood by disruptions in the neural bases of both phonological and orthographic processes important for reading.

Normal Development of Bilateral Field Advantage and Evoked Potential Interhemispheric Transmission Time

Implications of the developmental progression of myelination of the corpus callosum were studied using evoked potential interhemispheric transmission time (EP-IHTT) and the bilateral field advantage (BFA) in letter matching. Forty-two normal children aged 7 to 17 years were asked to respond regarding whether 2 letters matched when presented either unilaterally (both in the same visual field) or bilaterally (1 letter in each field). Evoked potentials were recorded with bilateral midparietal electrodes during unilateral presentations of the letter-matching task. Age-related changes were found for both EP-IHTT and BFA. BFA in reaction time in the visual letter-matching task increased significantly with age. Decreasing EP-IHTT with age was also evident (although only in a statistical trend). These findings lend support to the hypothesis that increased callosal myelination during late childhood has functional significance. Callosal maturation appears to result in faster interhemispheric transfer and increasing ability to integrate information across the midline.

All the King's Horses and All the King's Men: Putting the Brain Back Together Again

Finding two mixed-case letters that share the same name is easier to do when the letters are presented in opposite visual fields than when they are both in the same field. By contrast, finding a match between two same-case letters is easier when they are in the same field. These visual field effects have been attributed to the ability of the corpus callosum to coordinate the work of the cerebral hemispheres [Banich, M. T. (1998). The missing link: The role of interhemispheric interaction in attentional processing. Brain and Cognition, 36, 128–157; Weissman, D. H., & Banich, M. T. (2000). The cerebral hemispheres cooperate to perform complex but not simple tasks. Neuropsychology, 14, 41–59]. The present study considers the alternative hypothesis that attentional scanning biases may be at work. Experiment 1 examined the effects of explicit instructions to scan items in a specific order; Experiment 2 examined influences of implicit location biasing; Experiment 3 considered the possibility that same-case letter matching is different because a perceptual grouping mechanism can be used in that task. In each experiment, we first interpreted the results within the hemispheric framework before considering the alternative accounts. We concluded that two scanning biases may be in effect: (1) an automatic bias favoring items in locations relatively distant from the current focus of attention and (2) a learned bias to scan letters in a left-to-right direction.

Bilateral field advantage and evoked potential interhemispheric transmission in commissurotomy and callosal agenesis

The role of the corpus callosum versus other cerebral commissures in the interhemispheric integration of visual information was studied in four individuals with complete agenesis of the corpus callosum, two individuals with partial agenesis, one total commissurotomy patient, and normal individuals. Evoked potential (EP) indices of interhemispheric transmission of visual sensory responses were observed during matching of unilateral and bilateral visual field letters and patterns. Neither the commissurotomy nor any of the acallosal patients had ipsilateral hemisphere visual EPs (P1 and N1), demonstrating that the posterior callosum is necessary for interhemispheric transmission of these components of visual evoked potentials. While the commissurotomy patient could not compare bilaterally presented letters, the anterior commissure of the acallosal patients appeared to be sufficient for interhemispheric comparison of single letters. However, bilateral comparison of more complex visual patterns resulted in considerable difficulty for complete agenesis patients, while comparison of patterns was more nearly normal when anterior callosal fibers were present (partial agenesis).

Improving perception of letters and visual structure of language.

Information about letters and the physical structure of language printed in Roman characters was given to children beginning to read. Experimental investigations coupled three alternative graphic modes of printing upper- and lower-case letters with an instructional intervention termed "Alpha-Beta" which provides practice in letter sorting, matching of letters, associative matching, and memory matching. In respect to graphics, Mode A letters were in standard alphabet form. Mode B provided standard letters with each backed by a unique half-tone (Visually Stippled Alphabet); Mode C provided standard letters with each backed by a unique visual texture (Visually Patterned Alphabet). Pre-posttest change in reading readiness was measured using the Metropolitan Readiness Test. In the first study 224 English-speaking 5- to 6-yr.-old children were tested. In the second there were 158 Spanish-speaking girls and boys 6 to 7 years old. It was predicted that Alpha-Beta intervention involving visually patterned alphabet would lead to the greatest increases in readiness scores. This is confirmed in both studies for children low in reading readiness preexperiment. Children high in reading readiness are less affected. The second experiment involved Spanish-speaking children and investigated intervention by Alpha-Beta against a no-intervention control. This confirms the value of Alpha-Beta per se. Possible explanations for the improvements are identified.

Alcohol induced changes in regional cerebral glucose metabolic rate during divided attention

Under conditions of moderate alcohol intoxication (0.75 ml/kg) and an alcohol-disguised placebo, eight non-alcoholic male volunteers performed a divided attention task after injection of 18-F-2-fluoro-2-deoxyglucose (FDG) for a Positron Emission Tomography (PET) study. The administration of alcohol or placebo followed a random order double-blind protocol. During 32 min of divided attention, the subject performed a letter matching task or a spatial orientation task presented simultaneously on a computer-generated split display. The task to be performed was indicated by an arrow on the display that changed randomly every few trials. Alcohol intoxication was associated with a trend toward generally reduced performance. Task performance differences between the alcohol and placebo conditions were significantly correlated with cortical glucose metabolic rates (GMR) in the superior, inferior, and middle parietal lobes. Impaired performance was associated with GMR decreases. GMR in several subcortical and medial cortical areas were also correlated with performance changes, including areas of the putamen and cingulate. The major finding is that individual differences in GMR change from placebo to alcohol in parietal cortex are related to individual differences in attention performance. The application of PET with selective information processing paradigms provides a useful method for isolating and in identifying the effects of alcohol intoxication on the function of the central nervous system.

126 Psychometric intelligence and event-related desynchronisation during performance of a letter matching task

126 Psychometric intelligence and event-related desynchronisation during performance of a letter matching task

Visual and phonological processes in poor readers' word recognition

ABSTRACTIn two experiments, poor and normal Dutch readers, matched for reading age, were presented with visual matching tasks on a computer screen. In Experiment 1, word and pseudoword letter strings were used. The strings consisted of either uppercase/lowercase congruent (e.g., o/O) or uppercase/lowercase incongruent letters (e.g., a/A). Poor readers needed significantly more time to decode uppercase/lowercase incongruent pairs, especially when the pairs consisted of pseudowords. Experiment 2 investigated whether this effect was phonologically or visually mediated. Strings of letters, digit strings, and abstract figure symbols were used. Letter strings included words, pseudowords, and nonwords. Poor readers needed more time to match incongruent letter case pairs, consistent with Experiment 1. Poor readers performed more poorly on letter and digit string matching but not on the figure–symbol matching task. No evidence was found for the differential use of orthographic information in terms of multiletter constraints. The combined data on the letter, digit, and graphic symbol matching experiments suggest that an inadequate command of grapheme–phoneme associations is a critical factor in reading disability. Evidence for poor visual processing as an independent source of reading disability could not be established.

Three paper-and-pencil tests for speed of information processing: Psychometric properties and correlations with intelligence

After more than 15 years of research efforts there is strong empirical evidence for an association of high psychometric intelligence with a high speed of information processing in Elementary Cognitive Tasks (ECTs). A wider application of this mental speed approach to human intelligence, also to other areas of basic and applied psychology, could be largely facilitated through the availability of paper-and-pencil (PP) tests for mental speed. This paper describes the development and empirical investigation of two new PP ECTs based on rationales of Sternberg's short term memory scanning and Posner's letter matching, as well as findings for the already established PP test for mental speed, the so-called Coding Test. In three empirical studies the PP ECTs proved reliable, they are substantially correlated with diverse measures of psychometric intelligence (up to -.70) and they displayed convergent validity with respect to other PP tests of mental speed but showed only medium relationships with computerized ECTs. We conclude that these PP tests allow an economical assessment of elementary speed of information processing as an important basis of individual differences in psychometric intelligence.

The psychological refractory period: evidence for age differences in attentional time-sharing.

The authors report 2 psychological refractory period (PRP) experiments in which the stimulus onset asynchrony (SOA) between Task 1 and Task 2 was 150 ms, 250 ms, 600 ms, and 1,100 ms for both younger and older adults. H. Pashler's (1994a) response-selection bottleneck theory predicts that SOA manipulations should not affect Task 1 performance, but that reaction time (RT) for Task 2 should increase as the SOA between the 2 tasks decreases (i.e., the classical PRP effect). In Experiment 1 (Task 1 = tone discrimination, Task 2 = dot location), older adults showed a larger PRP effect than younger adults did, although Task 1 RT was affected by SOA, suggesting that participants were grouping their responses on some trials. That is, participants were holding their response for Task 1 until they had completed processing Task 2, and then they responded to both tasks almost simultaneously. However, a subset of participants (11 younger adults and 11 older adults) who showed no evidence of response grouping on Task 1 continued to show a larger PRP effect for older adults on Task 2. In Experiment 2 (Task 1 = dot location, Task 2 = simultaneous letter matching), older adults continued to show a larger PRP effect than younger adults for Task 2, and Task 1 performance was unaffected by SOA. Consequently, these experiments provide evidence that older adults (relative to younger adults) exhibit a decrement in time-sharing at the response-selection stage of processing. These results suggest that attentional time-sharing needs to be added to the list of topics examined in aging research on varieties of attention.

The “Poffenberger” and “Dimond” Paradigms: Interrelated Approaches to the Study of Interhemispheric Dynamics?

Brown and Jeeves (1993) found that an evoked potential estimate of interhemispheric transfer time, from the left to the right hemisphere, correlated negatively with a bilateral field advantage (BFA) in a response-choice letter matching task. We implemented a go no-go dot size matching task to determine whether the crossed-uncrossed difference (CUD) in reaction time, commission errors and omission errors (estimates of the “cost” of interhemispheric transfer) would correlate with BFAs in data from the same experiment and whether the type of decision (“same” versus “different”) would modulate the CUDs and/or BFAs. Sixteen normal right-handed subjects were tested. The CUDs were negatively correlated with the BFAs. Canonical correlation analysis of this set of relations was highly significant (r= .95). Estimates of left-to-right relay were far more strongly related to BFA (p= .0001) than were estimates of right-to-left relay (p= .03). “Same” decisions yielded a unilateral field advantage and “different” decisions a bilateral field advantage in omission error data, this crossed interaction reaching significance. More efficient interhemispheric relay favored BFAs, i.e., strongly suggesting in such cases an advantage of interhemispheric over intrahemispheric integration. This effect appeared to be markedly asymmetric. Furthermore, resource sharing within and between the hemispheres was a function of the “same” versus “different” dimensions of the decision to be made, especially in omission errors. The opposite dissociation occurred less markedly in the reaction times, this double dissociation reaching significance, revealing presence of a subtle speed–accuracy trade-off in interhemispheric dynamics.

Intelligence and reaction times in the Hick, Sternberg and Posner paradigms

The relationship between psychometric intelligence and reaction times (RTs) in three well-known elementary cognitive tasks (Hick simple and choice reaction time task, Sternberg's short-term memory scanning, Posner's letter matching) was studied in a sample of 116 participants. In conformity with other studies mean RTs and intraindividual variabilities (SDs) of RT were correlated significantly with Raven's Advanced Progressive Matrices (APM). On the basis of the mental speed theory the processing measures or component scores (like slopes in the Hick and Sternberg paradigm and the NI-PI measure in the Posner task) should give the most substantial relationships with intelligence. However, as in other previous studies these measures displayed rather low, albeit significant, relationships with intelligence, which was probably due to the low reliability of these parameters. For the Posner paradigm, we proposed alternative approaches to compute an indicator for long-term memory (LTM) access that gave substantial correlations with intelligence. We conclude that LTM access is significantly associated with psychometric intelligence, whereas up to now there has been no unequivocal evidence for a substantial relationship between short-term memory access in the Sternberg task and intelligence.

Unilateral and Bilateral Brain Hemispheric Advantage on Visual Matching Tasks and Their Relationship to Styles of Religiosity

Eighty-five undergraduate students were tested in two studies using a computer-based tachistoscopic-type letter- and dot-matching task under various conditions. This task was used to determine the extent to which they displayed unilateral and bilateral brain-hemisphere advantages in the speed and accuracy of their responses. For the letter-matching task in both studies, the intellectual religiosity group displayed a stronger unilateral advantage favoring the right-visual field (RVF) (left brain) than the affective group. Generally, the participants with a more affective style of religiosity had faster reaction times on the matching tasks, especially for correct non-matching responses and on the dot-matching (right-brain) stimulus presentations. The affective groups also tended to have a stronger bilateral advantage for both dots and letter matching compared to the intellectual group. In the second study, the Myers-Briggs personality typology inventory (MBTI) was included in the assessment and was significantly related to the religiosity intellectual/affective dimension. With percent errors as the dependent variable, MBTI feeling-dominant participants displayed a stronger bilateral advantage for dots presentations but not letters, while thinking-dominant respondents on this dimension had a stronger unilateral advantage for letters but not dots. The major implication of these preliminary findings is that enduring religious traits may be anchored in basic brain behavior tendencies that can be measured using neuropsychological laboratory-based tasks.

The relationship between speed of information processing and cognitive ability

Speed of information processing as measured by various reaction time and inspection tasks has been shown to correlate with psychometric intelligence, and it has been suggested that general intelligence ( g) is determined to some degree by the speed that information is processed. If this is so, then various measures of speed of information processing should correlate substantially with each other, and each should also correlate with a wide range of psychometric tests that load on g. Alternatively, intelligence may be considered to be a multi-faceted complex of partially related abilities with specific abilities being dependent upon specific cognitive processes. If this is the case, it should be possible to discover independent cognitive processes, some of which correlate with one facet or broad ability and some with another. This paper presents three experiments in which the relationship between intellectual ability and four speed of information processing measures was examined. These were rate of memory scanning, rate of retrieval of information from long term memory, speed of stimulus-response mapping and inspection time (IT). Results showed that correlations between IT and most reaction time measures of speed of information processing were low, and that correlations between different versions of IT were negligible. In addition, some cognitive tasks with verbal material (memory scanning rate for digits and Posner letter matching IT) correlated most substantially with Verbal Reasoning whereas non-verbal (two-line) IT consistently correlated with tests loading on g. It was thus suggested that while non-verbal IT may be a measure of a perceptual speed attribute that contributes to mental functioning, other “speed of information processing” parameters may be more specific to a subset of abilities.

ERP changes in alcoholics with and without alcohol psychosis

The present study compared alterations of event-related brain potentials (ERPs) in subgroups of chronic alcoholics with different complications during alcohol withdrawal. Twenty alcoholics with only mild to moderate alcohol withdrawal symptoms, two groups of alcoholics with histories of either delirium tremens (n = 9) or alcohol hallucinosis (n = 13), and a control group of 38 nonalcoholics were examined. Patients were tested in unmedicated state and not earlier than 14 days after drinking cessation. An auditory Oddball paradigm and a visual Letter Matching paradigm were used as cognitive tasks. In the auditory task, all alcoholic groups exhibited delayed N200 and P300 latencies and a reduced P300 amplitude as compared to nonalcoholics. In the visual task, only P300 amplitude was significantly diminished. Patients having suffered from delirium tremens or alcohol hallucinosis showed greater Oddball P300 amplitudes than alcoholics with uncomplicated withdrawal syndrome. Furthermore, delirium and hallucinosis patients differed in their ERPs, with hallucinosis patients showing an earlier P300 peak in both the auditory Oddball and the Letter Matching task. It is concluded that changes in ERPs during abstinence might reflect specific neurophysiological dysfunctions in alcoholics prone to different alcohol-related psychoses.

Identifying Simple Numerical Stimuli: Processing Inefficiencies Exhibited by Arithmetic Learning Disabled Children

Children with arithmetic learning disabilities (ALD) and normally achieving (NA) controls were administered a battery of computerised tasks, including numerical and letter matching, naming latency, and memory span. The letter spans as well as the digit spans of the ALD children were smaller than those of their NA peers, arguing against the hypothesis of a specific deficit in working memory for numerical information. Although the ALD children were no slower than their NA peers in accessing either numerical or letter codes, their pattern of correlations between numerical and letter judgements both within and between the matching and naming-latency tasks differed from that of the NA group, suggesting a difference in the means by which these children access numerical representations. Another particularly intriguing result was that the ALD children failed to use the most efficient procedure when judging name identity for physically same numerical stimuli. Additional evidence indicated that this may have been due to dysfunctional subitizing. These and other findings confirm that ALD children display several processing inefficiencies when judging simple numerical stimuli.

Cerebral specialisation for receptive language in individuals with down syndrome

Abstract Two experiments examined cerebral specialisation for linguistic material in adults with Down syndrome (DS). For a dihaptic letter matching task, a left hand/right hemisphere advantage was observed for the DS group. For a visual field letter identification task, the DS data were suggestive of a left field/right hemisphere superiority. Thus, as predicted by our model (Elliott, Weeks, & Elliott, 1987), atypical cerebral organisation of speech perception is evident in persons with DS. Moreover, the functional disconnection of neural systems subserving the control of complex movement and those responsible for speech perception can be generalised to include the haptic and visual processing of linguistic material.

Altered Visual-Field Asymmetries for Letter Naming and Letter Matching as a Result of Concurrent Presentation of Threatening and Nonthreatening Words

Thirty-two right-handed subjects (16 male and 16 female students) were administered a unilateral letter-naming task and two unilateral letter-matching tasks: physical-identity letter matching (shape task) and nominal-identity letter matching (name task). Each task contained three conditions. In control conditions, no concurrent task was given. In threat and nonthreat conditions, each unilateral stimulus was preceded by a centrally presented threatening or nonthreatening word. Subjects were instructed to recall this word after their response to the lateral stimulus. With letter naming, each trial consisted of three consonants presented horizontally to the left or right visual field. Across conditions, subjects identified more letters correctly in the right visual field than in the left visual field. The concurrent presentation of threatening words resulted in a selective enhancement of left visual-field performance. In the control condition of the shape task, same letter pairs were identified faster than different pairs when they were presented to the right visual held. The concurrent presentation of threatening words resulted in a selective shortening of left visual-held latencies to same pairs. In the name task, the concurrent presentation of threatening words resulted in improved accuracy on left visual field trials. No sex differences in perceptual asymmetries and in emotional priming effects were found. The results demonstrate that threatening stimuli can activate the right hemisphere and alter the laterality patterns for several tasks.

Reading Direction and Attention - Effects on Lateralized Ignoring

The effects of the scan for the first element in reading (leftmost in English, rightmost in Hebrew) on the ability of subjects to ignore irrelevant stimuli in one visual field more than in the other were investigated. The hypothesis tested was that English readers would have a harder time ignoring irrelevant stimuli in the left visual held than in the right Visual field, with the opposite pattern predicted for readers of Hebrew. The paradigm employed by Banich (Banich & Belger, 1990) was used with two letter matching tasks. The results showed that when an irrelevant letter was present, English readers responded more slowly in the right than in the left visual field, and Hebrew readers showed the opposite pattern (Experiment 1). This interaction did not occur when the irrelevant letter was deleted (Experiment 2). These findings are discussed in terms of their relation to eye movements and covert attention and to the use of bilateral displays in neuropsychological experiments.

Event-related desynchronization

Preface. Acknowledgements, List of contributors. I. General Introduction: Brain Oscillations and Event-related Dynamics. 1. Basic concepts on EEG synchronization and desynchronization (F.H. Lopes da Silva, G. Pfurtscheller). 2. EEG synchronization in cat, monkey and human during attentive states. A brief survey (P. Buser, A. Rougeul-Buser). 3. Functional patterns and their physiological origins in the waking EEG: a theoretical integration with implications for event-related EEG responses (M.B. Sterman). 4. Functional meaning of event-related desynchronization (ERD) and synchronization (ERS) (G. Pfurtscheller, F.H. Lopes da Silva). 5. Event-related dynamics of alpha band rhythms: a neuronal network model of focal ERD/surround ERS (P. Suffczynski, J.P.M. Pijn, G. Pfurtscheller, F.H. Lopes da Silva). II. Temporal and Spatial Quantification of ERD/ERS. 6. Quantification of ERD and ERS in the time domain (G. Pfurtscheller). 7. Spatial mapping of ERD/ERS (M. Van Burik, G. Edlinger, G. Pfurtscheller). 8. Quantification of event-related coherence (ERCoh) (C. Andrew). 9. Methodological advances in the analysis of event-related desynchronization data: reliability and robust analysis (A.P. Burgess, J.H. Gruzelier). III. Cognitive Processing and ERD/ERS. 10. Event-related band power changes and memory performance (W. Klimesch). 11. Event-related desynchronization in the functional exploration of cognitive processes (K. Dujardin, P. Derambure, J.-L. Bourriez, J.-D. Guieu). 12. Event-related EEG changes during auditory processing (C.M. Krause). 13. ERD as an index of anticipatory behavior (M.C.M. Bastiaansen, C.H.M. Brunia, K.B.E. Bocker). 14. Psychometric intelligence and event-related desynchronization during performance of a letter matching task (A.C. Neubauer, G. Sange, G. Pfurtscheller). 15. Event-related EEG response correlates of task difficulty, sleep deprivation, and sensory distraction (M.B. Sterman). IV. Movement and ERD/ERS. 16. ERD and ERS in voluntary movement of different limbs (G. Pfurtscheller, K. Pichler-Zalaudek, C. Neuper). 17. Effects of handedness and type of movement on event-related desynchronization within the alpha and beta bands (A. Staneak Jr., G. Pfurtscheller). 18. Temporal and spatial aspects of event-related desynchronization and movement-related cortical potentials (J.-D. Guieu, J.-L. Bourriez, P. Derambure, L. Defebvre, F. Cassim). 19. Event-related desynchronization during execution, imagination and withholding of movement (L. Leocani, G. Magnani, G. Comi). 20. Motor imagery and ERD (C. Neuper, G. Pfurtscheller). 21. ERD and coherence of sequential movements and motor learning (C. Gerloff, M. Hallett). 22. Movement-related changes of rhythmic versus slow activities in the human motor cortices. Review of the magnetoencephalographic studies (T. Nagamine, H. Shibasaki). V. Clinical Applications of ERD/ERS. 23. ERD in brain ischemia (G. Pfurtscheller). 24. Event-related desynchronization of mu rhythm in Parkinson's disease (L. Defebvre, J.L. Bourriez, P. Derambure, J-D. Guieu, A. Destee). 25. ERD of the mu rhythm in self-paced and externally triggered movements in idiopathic Parkinson's disease and effect of a single dose of L-DOPA on self-paced movement (G. Magnani, L. Leocani, M. Cursi, G. Corni). 26. Event-related synchronization of beta rhythms in idiopathic Parkinson's disease (G. Pfurtscheller, B. Ortmayr, K. Pichler-Zalaudek, J. Dietz, F. Reisecker). 27. Reactivity of central cortical rhythms in epileptic patients with focal motor seizures (P Derambure, J.-L. Bourriez, L. Defebvre, F. Cassim, J.-D. Guieu). Subject index.