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At least 19 recordsLinked to original sources
PubMed2005

Using errorless learning to treat letter-by-letter reading: contrasting word versus letter-based therapy.

Some pure alexic readers have been shown to activate lexical and semantic knowledge under brief presentation conditions. This ability is not seen when letter-by-letter reading accuracy is high or the reading impairment is very severe. It is also unlikely to occur under normal untimed presentation because the pure alexic will make deliberate use of their letter-by-letter strategy. This paper presents data from a moderately severe letter-by-letter reader, FD, who had visual processing problems affecting reading. He also had other mild aphasic characteristics. FD showed implicit reading abilities under brief presentation conditions, being able to make lexical decisions and semantic categorisations well above chance. FD was given two therapy programmes, the first, whole word therapy to exploit this implicit ability and the second to improve letter-by-letter accuracy and speed. FD showed some improvement in reading ability after both therapy programmes, particularly for words of personal interest to him. His letter naming accuracy and reading of visually similar words were the most resistant to change. A striking effect of therapy was the cessation of FD's letter-by-letter reading and the emergence of some of the characteristics of deep dyslexia. Even when therapy concentrated on letter accuracy, FD did not revert back to his original letter-by-letter reading strategy. The results are discussed with reference to the two theories of pure alexia. Some conclusions are drawn about the need for therapists to examine and exploit all residual reading skills when devising therapeutic programmes.

Acoustic Stimulation↗
PubMed1996

Letter dyslexia in a letter-by-letter reader.

We describe a letter-by-letter patient who produced misreading errors in both letters in isolation and in words. All errors were visual in nature. We hypothesized an access deficit to the abstract visual representation of letters that prevents letter identification. This deficit could account for the patient's letter-by-letter behavior, since each letter constituted a potential identification problem. An access deficit, moreover, could also explain the patient's letter visual errors. In access processing, in fact, the letters sharing common structural features in their abstract representations were the ones more frequently mismatched.

Aged↗
PubMed1990

From letters to words: procedures for word recognition in letter-by-letter reading.

There are two alternative interpretations of how word recognition is accomplished in letter-by-letter reading. One postulates that it relies on the spelling system operating "in reverse," whereas the other claims that it is mediated by the reading system. Because of the close association between patterns of reading and spelling in previously reported cases of letter-by-letter reading, both hypotheses may be considered equally plausible. We now report a patient with letter-by-letter reading who demonstrated a striking dissociation between reading and spelling. Our observations in this patient argue against the concept of "reading via spelling" and suggest that word recognition in letter-by-letter reading is mediated by the orthographic input lexicon used in normal reading.

Agraphia↗
PubMed1995

Perceiving exterior letters of words: differential influences of letter-fragment and non-letter-fragment masks.

Previous research shows letter-fragment masks and non-letter-fragment fields have different effects on performance with briefly presented alphabetic targets. However, popular accounts of these differences ignore mask configuration. Over a series of experiments, configurational effects of letter-fragment (LF) and non-letter-fragment (NLF) masks were compared. When the configuration of LF masks matched word boundaries, performance with exterior letter pairs from words improved, whereas performance with illegal exterior-letter pairs and single letters was unaffected. When the same changes were made to NLF masks, only an overall drop in performance occurred, with no selective effect on target type. Thus, although LF mask configuration selectively affected lexical processing, NLF mask configuration produced substantially different effects, indicating problems with contemporary accounts of masking differences that ignore influences of mask configuration.

Attention↗
PubMed2001

The slope of the psychometric function for Bailey-Lovie letter charts: defocus effects and implications for modeling letter-by-letter scores.

BACKGROUND: Visual acuity measurement often results in an imprecise endpoint because subjects correctly identify some but not all of the letters on one or more size levels on a letter chart. The extent of this transition zone from seeing to nonseeing can be described by probit size, which is calculated by performing Probit Analysis on letter chart data. There has been no previous research into the effects of optical defocus on letter chart probit size. METHODS: We tested 18 young visually normal subjects monocularly during three different defocus conditions: best spectacle correction (zero defocus) and +1.00 D and +2.00 D additions. Stimuli were Bailey-Lovie-style logarithm of the minimum angle of resolution (log MAR) letter charts constructed with a 0.05 logMAR size progression between size levels. Frequency of seeing data from these charts were used to calculate probit size. RESULTS: There were statistically significant effects of optical defocus on mean probit size. After Monte Carlo correction for bias, we believe that true mean values for probit size are about 0.07 logMAR for well-corrected subjects and up to 0.12 logMAR with optical defocus. CONCLUSION: The smaller probit size for well-corrected subjects should correspond to a sharper logMAR visual acuity endpoint and less intrasubject variability in logMAR acuity than for subjects with a larger probit size (optical defocus). Our modeling shows that these different probit sizes can also significantly affect letter-by-letter visual acuity scoring.

Adult↗
PubMed2005

Letter-by-letter acquired dyslexia is due to the serial encoding of letters.

Letter-by-letter acquired dyslexia (pure alexia) is assumed to be related to the serial encoding of letters, but the evidence for this assumption is somewhat indirect. Here, we demonstrate that the deficit is indeed due to serial encoding by comparing the performance of a letter-by-letter dyslexic reader with the performance of normal readers who were forced to read letter by letter; the data patterns are remarkably similar.

Dyslexia, Acquired↗
PubMed2005

Letter form as a constraint for errors in neglect dyslexia and letter position dyslexia.

Does letter-form constrain errors in peripheral dyslexia? In Hebrew, 5 of the 22 letters have two different letter forms, one is used only when the letter occurs in word-final position, the other form is used in initial and middle positions. Is the information on final-forms encoded in the letter identity information and used for word identification, or is it discarded? The current research explored this question through the effect of final vs. non final letter form on the error pattern in neglect dyslexia (neglexia) and letter position dyslexia (LPD). Left word-based neglexia results in errors of omission, substitution and addition of letters in the left side of words, which in Hebrew is the end of the word. We examined whether final letter form blocks the addition of letters to the end of the word and whether omissions of letters after letters in non-final form are avoided. The predominant error type in LPD is migration of letters within words. We tested whether migrations also occur when they cause form change of either final-form letters that move to middle position or middle-form letters that move to final position. These questions were assessed in both acquired and developmental neglexia and LPD. The results indicated a strong effect of final letter-form on acquired neglexia and on acquired and developmental LPD, which almost completely prevented form-changing errors. This effect was not found in developmental neglexia, where words that end in final-form letters were actually more impaired than other words, probably because final-form letters appear only on the neglected side of the word for Hebrew-reading children with left developmental neglexia. These data show that early visuo-orthographic analysis is sensitive to final letter form and that final letter form constrains errors in peripheral dyslexia.

Adult↗
PubMed1997

Age, gender and the effectiveness of high-threat letters: an analysis of Oregon's driver improvement advisory letters.

The Oregon Driver Improvement Program monitors driver records and takes corrective action at each of four levels. The advisory letter is the first level. An automated quality control system randomly withholds actions from five percent of drivers, producing a control group. Records of 27,026 advisory letter recipients and 1453 control subjects were analyzed. Of the 27,026 letter recipients, 13,623 received a randomly assigned, experimental soft-sell letter and the rest a standard letter. Records were monitored for 24 subsequent months. Overall, those receiving either advisory letter had fewer traffic accidents than the control group, and the standard letter is significantly more effective than the soft-sell letter. However there are several apparent differences in effectiveness by age and by gender. The standard letter is clearly more effective for younger drivers but the soft-sell letter appears to be most effective for drivers over age 45. Considering gender, both letters reduce collisions but the standard letter is more effective for men. For women, the standard letter is more effective than the soft-sell letter, but not more effective than no letter. In fact, accident-free survival for women receiving no letter was nominally but not significantly higher than for women receiving either letter. There are no significant differences in moving violations. However, with regard to major traffic violations, those receiving letters had significantly higher violation free survival, although there were also notable differences in effectiveness, by age.

Accidents, Traffic↗
PubMed1989

[Effects of size of letters on selective identification of letters].

An experiment was performed to examine the effects of the size of target and noise letters on selective identification of a target letter. Twelve undergraduate students were required to identify a target letter on a visual display which presents a target letter alone or a target letter flanked by two noise letters. The reaction time of pressing buttons to the target letter was measured under combined conditions of size of target and noise letters. The large target letter was identified faster than the small one whether it was accompanied by noise letters or not. The large noise letters exerted stronger effects on the identification of a target letter than the small one. The results agreed with the prediction based on the assertion by Eriksen and Schultz (1979). Further, it was found that the effects of size of letters varied according to the relation between target letters and noise letters and to the similarity of a target letter to noise letters.

Attention↗
PubMed2004

Knowing letter names and learning letter sounds: a causal connection.

Two experiments tested the common assumption that knowing the letter names helps children learn basic letter-sound (grapheme-phoneme) relation because most names contain the relevant sounds. In Experiment 1 (n=45), children in an experimental group learned English letter names for letter-like symbols. Some of these names contained the corresponding letter sounds, whereas others did not. Following training, children were taught the sounds of these same "letters." Control children learned the same six letters, but with meaningful real-word labels unrelated to the sounds learned in the criterion letter-sound phase. Differences between children in the experimental and control groups indicated that letter-name knowledge had a significant impact on letter-sound learning. Furthermore, letters with names containing the relevant sound facilitated letter-sound learning, but not letters with unrelated names. The benefit of letter-name knowledge was found to depend, in part, on skill at isolating phonemes in spoken syllables. A second experiment (n=20) replicated the name-to-sound facilitation effect with a new sample of kindergarteners who participated in a fully within-subject design in which all children learned meaningless pseudoword names for letters and with phoneme class equated across related and unrelated conditions.

Child↗
PubMed2007

Temporal processing deficits in letter-by-letter reading.

Theories of the cognitive impairment underlying letter-by-letter reading vary widely, including prelexical and lexical level deficits. One prominent prelexical account proposes that the disorder results from difficulty in processing multiple letters simultaneously. We investigated whether this deficit extends to letters presented in rapid temporal succession. A letter-by-letter reader, G.M., was administered a rapid serial visual presentation task that has been used widely to study the temporal processing characteristics of the normal visual system. Comparisons were made to a control group of 6 brain-damaged individuals without reading deficits. Two target letters were embedded at varying temporal positions in a stream of rapidly presented single digits. After each stream, the identities of the two letters were reported. G.M. required an extended period of time after he had processed one letter before he was able to reliably identify a second letter, relative to the controls. In addition, G.M.'s report of the second letter was most impaired when it immediately followed the first letter, a pattern not seen in the controls, indicating that G.M. had difficulty processing the two items together. These data suggest that a letter-by-letter reading strategy may be adopted to help compensate for a deficit in the temporal processing of letters.

Adult↗
PubMed1997

[Letter-by-letter alexia after left hemispheral lesion without hemianopsia nor callosal involvement. 2 cases].

We describe two patients suffering from a letter-by-letter reading following an infarct in the left posterior cerebral artery's territory. Unlike most of the verbal alexics, this strategy was particularly fast and effective. Two other features distinguished these patients from verbal alexics: the absence of hemianopia and the sparing of the corpus callosum. A study of the reading of letters and words by each hemisphere was performed. In the first case, the left hemisphere was unable to identify any letter or word. The visual stimuli did not activate the visual word form, not the system which normally recognize letters. However, this latter could be activated by the information transmitted by the right hemisphere via the corpus callosum. In the second case, the left hemisphere could, as well as the right one, identify all the letters. On the other hand, identification of words was impaired, and did not improve when the duration of the visual presentation increased. The left hemisphere, unable to access to the visual word form, could not decipher letter-by-letter. One hypothesis is that the left visual working memory was reduced, and could not store more than one letter. The right hemisphere deciphered the words sequentially, and transmitted the information to the left systems which recognize the letter. These two observations confirm that letter-by-letter alexia could result exclusively from the destruction, of the inaccessibility of the visual word-form. A lesion of the left ventral occipito-temporal structures is sufficient, and a left hemianopia, or a splenial lesion is not absolutely necessary. The sparing of the corpus callosum allows a fast transmission to the left phonological processing, if the left systems recognizing letters are efficient.

Aged↗
PubMed2006

An attempt to simulate letter-by-letter dyslexia in normal readers.

We attempted to simulate the main features of letter-by-letter (LBL) dyslexia in normal readers through stimulus degradation (i.e. contrast reduction and removal of high spatial frequencies). The results showed the word length and the letter confusability effects characteristic of LBL dyslexia. However, the interaction of letter confusability and N size (i.e. a facilitatory effect only for low confusability targets) previously observed in LBL dyslexics [Arguin, M., Fiset, S., & Bub, D. (2002). Sequential and parallel letter processing in letter-by-letter reading. Cognitive Neuropsychology, 19, 535-555; Arguin, M., & Bub, D. (2006). Parallel processing blocked by letter similarity in letter dyslexia: a replication. Cognitive Neuropsychology, 22, 589-602; Fiset, D., Arguin, M. & McCabe, E. (2005a). The breakdown of parallel letter processing in letter-by-letter dyslexia. Cognitive Neuropsychology, 22, 1-22] was not found. Our results suggest that the type of visual degradation employed here may only partially correspond to the visual deficit present in LBL dyslexia and that this degradation may have prevented the normal readers from accessing visual information available to LBL dyslexics when they use the compensatory strategy of serial letter processing.

Adult↗
PubMed2006

Inducing letter-by-letter dyslexia in normal readers.

Letter-by-letter (LBL) dyslexia is an acquired reading disorder characterized by very slow reading and a large linear word length effect. This suggests the use of a sequential LBL strategy, in sharp contrast with the parallel letter processing used by normal subjects. Recently, we have proposed that the reading difficulty of LBL dyslexics is due to a deficit in discriminating visually similar letters based on parallel letter processing [Arguin, M., Fiset, S., & Bub, D. Sequential and parallel letter processing in letter-by-letter dyslexia. Cognitive Neuropsychology, 19, 535-555, 2002]. The visual mechanisms underlying this deficit and the LBL strategy, however, are still unknown. In this article, we propose that LBL dyslexic patients have lost the ability to use, for parallel letter processing, the optimal spatial frequency band for letter and word recognition. We claim that, instead, they rely on lower spatial frequencies for parallel processing, that these lower spatial frequencies produce confusions between visually similar letters, and that the LBL compensatory strategy allows them to extract higher spatial frequencies. The LBL strategy would thus increase the spatial resolution of the visual system, effectively resolving the issue pertaining to between-letter similarity. In Experiments 1 and 2, we succeeded in replicating the main features characterizing LBL dyslexia by having normal individuals read low-contrast, high-pass-filtered words. Experiment 3, conducted in LBL dyslexic L.H., shows that, indeed, the letter confusability effect is based on low spatial frequencies, whereas this effect was not supported by high spatial frequencies.

Adult↗
PubMed2004

The pathophysiology of letter-by-letter reading.

Pure alexia is a frequent and incapacitating consequence of left occipitotemporal lesions. It is thought to result from the disruption or the disconnection of the visual word form area (VWFA), a region reproducibly located within the left occipito-temporal sulcus, and encoding the abstract identity of strings of visual letters. Alexic patients often retain effective single letter recognition abilities, and develop an effortful letter-by-letter reading strategy which is the basis of most rehabilitation techniques. We study a patient who developed letter-by-letter reading following the surgical removal of left occipito-temporal regions. Using anatomical and functional MRI in the patient and in normal controls, we show that alexia resulted from the deafferentation of left fusiform cortex, and we analyze the network of brain regions subtending letter-by-letter reading. We propose that during letter-by-letter reading (1) letters are identified in the intact right-hemispheric visual system, with a central role for the region symetrical to the VWFA; (2) letters are serially transferred to the left hemisphere through the intact segment of the corpus callosum; (3) word identity is eventually recovered in the left hemisphere through verbal working memory processes involving inferior frontal and supramarginal cortex.

Adult↗
PubMed2002

Does the spelling dyslexic read by recognizing orally spelled words? An investigation of a letter-by-letter reader.

In this single case report we describe our further observations of a patient (ROC) with a classical spelling dyslexia. A word length effect and a script effect were demonstrated. No evidence of semantic processing was obtained with brief tachistoscopic presentations. Single letter identification was unimpaired. In a series of experiments it was shown that her letter-by-letter reading strategy was mediated by explicit letter naming. In particular, it was observed that with successive presentation of the individual letters there was a stepwise function relating her whole word reading to the single letter presentation times. These durations permitted explicit letter naming. When explicit letter naming was prevented by a simultaneous articulatory suppression task, her letter-by-letter reading was significantly impaired. Her performance was compared with a second patient (MRF) who could read but could not spell. His reading was unaffected by articulatory suppression and significantly impaired by a successive presentation of the individual letters of a word. It is argued that explicit letter naming provides an input to the spelling system and thus can be recognized as orally spelled words. We conclude that in the reading-impaired patient there was a lexical deficit compensated for by the operation of a component of her intact spelling system.

Dyslexia, Acquired↗
PubMed1990

A letter-by-letter reader who could not read nonwords.

Letter-by-letter reading is a neuropsychological syndrome characterized by oral reading which seems to be mediated by explicit naming of constituent letters of the printed string. Thus reading time rises abnormally as a function of the length of the items to-be-read. This syndrome is generally interpreted as indicating a disconnection within the normal reading system prior to the activation of the visual and phonological lexical access routes. The patient retains a subsidiary strategy of spelling words by naming their constituent letters and uses this strategy for planning their pronunciation. If this interpretation is correct then reading aloud in letter-by-letter reading should not be affected by the features of the letter string which are stored lexically as the functional disconnection is postulated to occur prior to this stage. In this paper we report the case of a letter-by-letter reader who shows some signs which are puzzling in terms of current interpretations of the syndrome. They can be summarized as follows: (1) The patient reads words better than he reads nonwords; (2) Concrete words are processed more holistically while abstract words are processed more letter-by-letter; (3) Lexical decisions can be made far more rapidly than words can be read aloud. These three signs are very difficult to account for if reading is accomplished solely through a non-lexical reversed spelling strategy. Our experimental investigations of this patient are reported and alternative models assuming strategic control over the reading mechanism are discussed.

Adult↗
PubMed2002

Referral letters in oral medicine: standard versus non-standard letters.

Usually referral letters are the only means of communication between general practitioners and specialists in the health area. However, they are inadequate if important basic data are omitted. The aim of this study was to compare the content of standard and non-standard letters. A total of 1956 files from the Oral Medicine Service were consecutively evaluated (March 1996 to September 2000). Key items were considered for analysis and the results were stored in a database using the Epinfo 6.04 program. The chi2 test (alpha=0.05) was applied to the results. Of the 1956 files examined, 34% (662) had a referral letter, 31% of them being standard letters and 69% non-standard letters. Most standard letters (87%) were from professionals of public health institutions. Most percent discrepancies between standard and non-standard letters were observed for patient address (14.90 vs 1.32%), patient age (54.81 vs 9.47%), chief complaint (32.21 vs 8.37%), fundamental lesion (29.33 vs 13.66%), and symptoms (27.81 vs 15.42%). Statistically significant differences were observed for patient age, professional referring the patient, chief complaint, and site of the lesion. The quality and quantity of the information differed significantly between the two types of letters. The standard letters were more complete and contained information commonly absent in the non-standard letters. We suggest the use of standard letters for improving the quality of communication among professionals.

Chi-Square Distribution↗