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1.  Recombinative generalization of within-syllable units in prereading children. 
This study demonstrates recombinative generalization of within-syllable units in prereading children. Three kindergarten children learned to select printed consonant-vowel-consonant words upon hearing the corresponding spoken words. The words were taught in sets; there were six sets, presented consecutively. Within sets, the four words that were taught had overlapping letters, for example, sat, mat, sop, and sug. Tests for recombinative generalization determined whether the children selected novel words with the same components as the trained words (e.g., mop and mug). Two children demonstrated recombinative generalization after one training set, and the 3rd demonstrated it after two training sets. In contrast, 2 other children, who received tests but no training, showed low accuracy across six sets. The 3 experimental children then demonstrated highly accurate printed-word-to-picture matching, and named the majority of the printed words. These findings are a promising step in the development of a computerized instructional technology for reading.
PMCID: PMC1284276  PMID: 11214028
2.  Neural Correlates of Visual versus Abstract Letter Processing in Roman and Arabic Scripts 
Journal of cognitive neuroscience  2013;25(11):10.1162/jocn_a_00438.
In alphabetic orthographies, letter identification is a critical process during the recognition of visually presented words. In the present experiment, we examined whether and when visual form influences letter processing in two very distinct alphabets (Roman and Arabic). Disentangling visual versus abstract letter representations was possible because letters in the Roman alphabet may look visually similar/dissimilar in lowercase and uppercase forms (e.g., c-C vs. r-R) and letters in the Arabic alphabet may look visually similar/dissimilar, depending on their position within a word (e.g., vs. -). We employed a masked priming same–different matching task while ERPs were measured from individuals who had learned the two alphabets at an early age. Results revealed a prime–target relatedness effect dependent on visual form in early components (P/N150) and a more abstract relatedness effect in a later component (P300). Importantly, the pattern of data was remarkably similar in the two alphabets. Thus, these data offer empirical support for a universal (i.e., across alphabets) hierarchical account of letter processing in which the time course of letter processing in different scripts follows a similar trajectory from visual features to visual form independent of abstract representations.
PMCID: PMC3837287  PMID: 23806176
3.  Which Children Benefit from Letter Names in Learning Letter Sounds? 
Cognition  2007;106(3):1322-1338.
Typical U.S. children use their knowledge of letters' names to help learn the letters' sounds. They perform better on letter sound tests with letters that have their sounds at the beginnings of their names, such as v, than with letters that have their sounds at the ends of their names, such as m, and letters that do not have their sounds in their names, such as h. We found this same pattern among children with speech sound disorders, children with language impairments as well as speech sound disorders, and children who later developed serious reading problems. Even children who scored at chance on rhyming and sound matching tasks performed better on the letter sound task with letters such as v than with letters such as m and h. Our results suggest that a wide range of children use the names of letters to help learn the sounds and that phonological awareness, as conventionally measured, is not required in order to do so.
PMCID: PMC2267370  PMID: 17692304
4.  Instruction Matters: Spelling of Vowels by Children in England and the US 
Reading and writing  2012;26(3):473-487.
Letter names are stressed in informal and formal literacy instruction with young children in the US, whereas letters sounds are stressed in England. We examined the impact of these differences on English children of about 5 and 6 years of age (in reception year and Year 1, respectively) and US 6 year olds (in kindergarten). Children in both countries spelled short vowels, as in bag, more accurately than long vowels, as in gate. The superiority for short vowels was larger for children from England, consistent with the instructional emphasis on letter sounds. Errors such as gat for words with long vowels such as gate were more common among US children, reflecting these children’s use of vowels’ names as a guide to spelling. The English children’s performance on a letter knowledge task was influenced by the fact that they are often taught letter sounds with reference to lowercase letters and letter names with reference to uppercase letters, and their spellings showed some effects of this practice. Although emphasis on letter sounds as opposed to letter names influences children’s patterns of performance and types of errors, it does not make the difficult English writing system markedly easier to master.
PMCID: PMC3607663  PMID: 23543866
spelling; vowels; letter names; letter sounds; letter knowledge; literacy instruction
5.  Learning Letter Names and Sounds: Effects of Instruction, Letter Type, and Phonological Processing Skill 
Preschool-aged children (n = 58) were randomly assigned to receive instruction in letter names and sounds, letter sounds only, or numbers (control). Multilevel modeling was used to examine letter name and sound learning as a function of instructional condition and characteristics of both letters and children. Specifically, learning was examined in light of letter name structure, whether letter names included cues to their respective sounds, and children’s phonological processing skills. Consistent with past research, children receiving letter name and sound instruction were most likely to learn the sounds of letters whose names included cues to their sounds, regardless of phonological processing skills. Only children with higher phonological skills showed a similar effect in the control condition. Practical implications are discussed.
PMCID: PMC2978809  PMID: 20097352
emergent literacy; alphabet; letter names; letter sounds; phonological processing
6.  Contributions of Emergent Literacy Skills to Name Writing, Letter Writing, and Spelling in Preschool Children 
The purpose of this study was to examine which emergent literacy skills contribute to preschool children’s emergent writing (name-writing, letter-writing, and spelling) skills. Emergent reading and writing tasks were administered to 296 preschool children aged 4–5 years. Print knowledge and letter-writing skills made positive contributions to name writing; whereas alphabet knowledge, print knowledge, and name writing made positive contributions to letter writing. Both name-writing and letter-writing skills made significant contributions to the prediction of spelling after controlling for age, parental education, print knowledge, phonological awareness, and letter-name and letter-sound knowledge; however, only letter-writing abilities made a significant unique contribution to the prediction of spelling when both letter-writing and name-writing skills were considered together. Name writing reflects knowledge of some letters rather than a broader knowledge of letters that may be needed to support early spelling. Children’s letter-writing skills may be a better indicator of children’s emergent literacy and developing spelling skills than are their name-writing skills at the end of the preschool year. Spelling is a developmentally complex skill beginning in preschool and includes letter writing and blending skills, print knowledge, and letter-name and letter-sound knowledge.
PMCID: PMC3172137  PMID: 21927537
alphabet knowledge; emergent literacy; letter writing; name-writing; spelling
7.  Learning to Label Letters by Sounds or Names: A Comparison of England and the United States 
Learning about letters is an important foundation for literacy development. Should children be taught to label letters by conventional names, such as /bi/ for b, or by sounds, such as /bə/? We queried parents and teachers, finding those in the U.S. stress letter names with young children whereas those in England begin with sounds. Looking at 5- to 7-year-old children in the two countries, we found that U.S. children were better at providing the names of letters than English children. English children outperformed U.S. children on letter-sound tasks, and differences between children in the two countries declined with age. We further found that children use the first-learned set of labels to inform the learning of the second set. As a result, English and U.S. children made different types of errors in letter-name and letter-sound tasks. The children’s invented spellings also differed in ways reflecting the labels they used for letters.
PMCID: PMC2671388  PMID: 18675428
8.  Prereading Deficits in Children in Foster Care 
School psychology review  2011;40(1):140-148.
Reading skills are core competencies in children's readiness to learn and may be particularly important for children in foster care, who are at risk for academic difficulties and higher rates of special education placement. In this study, prereading skills (phonological awareness, alphabetic knowledge, and oral language ability) and kindergarten performance of 63 children in foster care were examined just prior to and during the fall of kindergarten. The children exhibited prereading deficits with average prereading scores that fell at the 30th to 40th percentile. Variations in prereading skills (particularly phonological awareness) predicted kindergarten teacher ratings of early literacy skills in a multivariate path analysis. These findings highlight the need for interventions focused on prereading skills for children in foster care.
PMCID: PMC3159895  PMID: 21869854
foster care; reading; early literacy; school readiness; kindergarten
9.  Linking the shapes of alphabet letters to their sounds: the case of Hebrew 
Reading and writing  2012;25(2):569-585.
Learning the sounds of letters is an important part of learning a writing system. Most previous studies of this process have examined English, focusing on variations in the phonetic iconicity of letter names as a reason why some letter sounds (such as that of b, where the sound is at the beginning of the letter’s name) are easier to learn than others (such as that of w, where the sound is not in the name). The present study examined Hebrew, where variations in the phonetic iconicity of letter names are minimal. In a study of 391 Israeli children with a mean age of 5 years, 10 months, we used multilevel models to examine the factors that are associated with knowledge of letter sounds. One set of factors involved letter names: Children sometimes attributed to a letter a consonant–vowel sound consisting of the first phonemes of the letter’s name. A second set of factors involved contrast: Children had difficulty when there was relatively little contrast in shape between one letter and others. Frequency was also important, encompassing both child-specific effects, such as a benefit for the first letter of a child’s forename, and effects that held true across children, such as a benefit for the first letters of the alphabet. These factors reflect general properties of human learning.
PMCID: PMC3278080  PMID: 22345901
Alphabet; Hebrew; Letter names; Letter sounds
10.  Structured Printed Referral Letter (Form Letter); Saves Time and Improves Communication 
Referral of patients to hospitals, specialists and other institutions is an essential part of primary health care. Patients are referred to specialists when investigation or therapeutic options are exhausted in primary care or when opinion or advice is needed from them. Referral has considerable implications for patients, health care system and health care costs. Good communication between primary and secondary care is essential for the smooth running of any health care system. Referral and reply letters are the sole means of communication between doctors most of the time and breakdown in communication could lead to poor continuity of care, delayed diagnoses, polypharmacy, increased litigation risk and unnecessary testing. A referral letter also helps to avoid patient dissatisfaction and loss of confidence in family physician. Studies of referral letters have reported that specialists are dissatisfied with their quality and content. Inclusion of letter writing skills in the medical curriculum, peer assessment and feedback have shown to improve the quality of referral letters. Form letters have shown to enhance information content and communication in referral process. In Sri Lanka referral letters are usually hand written and frequent complaints are that these letters do not contain adequate information and retrieval of information is a problem due to poor legibility and clarity. Sometimes Primary care doctors refer patients to hospitals and specialists with only verbal instructions. To address these short comings this form letter was introduced. Based on the guidelines and systematic review of published articles, items of information to be included were decided. Printed forms of the letter are kept in the practice and the doctor has to just fill up relevant information under each heading. The objectives of introducing this structured referral letter was to improve the quality and standard of referral letters and save time for both general practitioners and specialists.
PMCID: PMC3894031  PMID: 24479068
Referral letters; communications between GP and specialist; structured referral forms; general practice
11.  IRTs of the ABCs: Children's Letter Name Acquisition 
Journal of school psychology  2012;50(4):461-481.
We examined the developmental sequence of letter name knowledge acquisition by children from 2 to five years of age. Data from 2 samples representing diverse regions, ethnicity, and socioeconomic backgrounds (ns = 1074 & 500) were analyzed using item response theory (IRT) and differential item functioning techniques. Results from factor analyses indicated that letter name knowledge represented a unidimensional skill; IRT results yielded significant differences between letters in both difficulty and discrimination. Results also indicated an approximate developmental sequence in letter name learning for the simplest and most challenging to learn letters -- but with no clear sequence between these extremes. Findings also suggested that children were most likely to first learn their first initial. We discuss implications for assessment and instruction.
PMCID: PMC4322910  PMID: 22710016
alphabet; preschool; literacy; assessment; instruction
12.  An fMRI study of semantic processing in men with schizophrenia 
NeuroImage  2003;20(4):1923-1933.
As a means toward understanding the neural bases of schizophrenic thought disturbance, we examined brain activation patterns in response to semantically and superficially encoded words in patients with schizophrenia. Nine male schizophrenic and 9 male control subjects were tested in a visual levels of processing (LOP) task first outside the magnet and then during the fMRI scanning procedures (using a different set of words). During the experiments visual words were presented under two conditions. Under the deep, semantic encoding condition, subjects made semantic judgments as to whether the words were abstract or concrete. Under the shallow, nonsemantic encoding condition, subjects made perceptual judgments of the font size (uppercase/lowercase) of the presented words. After performance of the behavioral task, a recognition test was used to assess the depth of processing effect, defined as better performance for semantically encoded words than for perceptually encoded words. For the scanned version only, the words for both conditions were repeated in order to assess repetition-priming effects. Reaction times were assessed in both testing scenarios. Both groups showed the expected depth of processing effect for recognition, and control subjects showed the expected increased activation of the left inferior prefrontal cortex (LIPC) under semantic encoding relative to perceptual encoding conditions as well as repetition priming for semantic conditions only. In contrast, schizophrenics showed similar patterns of fMRI activation regardless of condition. Most striking in relation to controls, patients showed decreased LIFC activation concurrent with increased left superior temporal gyrus activation for semantic encoding versus shallow encoding. Furthermore, schizophrenia subjects did not show the repetition priming effect, either behaviorally or as a decrease in LIPC activity. In patients with schizophrenia, LIFC underactivation and left superior temporal gyrus overactivation for semantically encoded words may reflect a disease-related disruption of a distributed frontal temporal network that is engaged in the representation and processing of meaning of words, text, and discourse and which may underlie schizophrenic thought disturbance.
PMCID: PMC2806220  PMID: 14683698
13.  Repetition of letter strings leads to activation of and connectivity with word-related regions 
Neuroimage  2011;59(3):2839-2849.
Individuals learn to read by gradually recognizing repeated letter combinations. However, it is unclear how or when neural mechanisms associated with repetition of basic stimuli (i.e., strings of letters) shift to involvement of higher-order language networks. The present study investigated this question by repeatedly presenting unfamiliar letter strings in a one-back matching task during an hour-long period. Activation patterns indicated that only brain areas associated with visual processing were activated during the early period, but additional regions that are usually associated with semantic and phonological processing in inferior frontal gyrus were recruited after stimuli became more familiar. Changes in activation were also observed in bilateral superior temporal cortex, also suggestive of a shift toward a more language-based processing strategy. Connectivity analyses reveal two distinct networks that correspond to phonological and visual processing, which may reflect the indirect and direct routes of reading. The phonological route maintained a similar degree of connectivity throughout the experiment, whereas visual areas increased connectivity with language areas as stimuli became more familiar, suggesting early recruitment of the direct route. This study provides insight about plasticity of the brain as individuals become familiar with unfamiliar combinations of letters (i.e., words in a new language, new acronyms) and has implications for engaging these linguistic networks during development of language remediation therapies.
PMCID: PMC3254793  PMID: 21982931
letter strings; fMRI; connectivity; reading; learning; plasticity
14.  Transferring control demands across incidental learning tasks – stronger sequence usage in serial reaction task after shortcut option in letter string checking 
Frontiers in Psychology  2014;5:1388.
After incidentally learning about a hidden regularity, participants can either continue to solve the task as instructed or, alternatively, apply a shortcut. Past research suggests that the amount of conflict implied by adopting a shortcut seems to bias the decision for vs. against continuing instruction-coherent task processing. We explored whether this decision might transfer from one incidental learning task to the next. Theories that conceptualize strategy change in incidental learning as a learning-plus-decision phenomenon suggest that high demands to adhere to instruction-coherent task processing in Task 1 will impede shortcut usage in Task 2, whereas low control demands will foster it. We sequentially applied two established incidental learning tasks differing in stimuli, responses and hidden regularity (the alphabet verification task followed by the serial reaction task, SRT). While some participants experienced a complete redundancy in the task material of the alphabet verification task (low demands to adhere to instructions), for others the redundancy was only partial. Thus, shortcut application would have led to errors (high demands to follow instructions). The low control demand condition showed the strongest usage of the fixed and repeating sequence of responses in the SRT. The transfer results are in line with the learning-plus-decision view of strategy change in incidental learning, rather than with resource theories of self-control.
PMCID: PMC4246662  PMID: 25506336
incidental learning; information reduction; serial reaction task; transfer; cognitive conflict; instruction following; pliance
15.  Reduced Neural Integration of Letters and Speech Sounds in Dyslexic Children Scales with Individual Differences in Reading Fluency 
PLoS ONE  2014;9(10):e110337.
The acquisition of letter-speech sound associations is one of the basic requirements for fluent reading acquisition and its failure may contribute to reading difficulties in developmental dyslexia. Here we investigated event-related potential (ERP) measures of letter-speech sound integration in 9-year-old typical and dyslexic readers and specifically test their relation to individual differences in reading fluency. We employed an audiovisual oddball paradigm in typical readers (n = 20), dysfluent (n = 18) and severely dysfluent (n = 18) dyslexic children. In one auditory and two audiovisual conditions the Dutch spoken vowels/a/and/o/were presented as standard and deviant stimuli. In audiovisual blocks, the letter ‘a’ was presented either simultaneously (AV0), or 200 ms before (AV200) vowel sound onset. Across the three children groups, vowel deviancy in auditory blocks elicited comparable mismatch negativity (MMN) and late negativity (LN) responses. In typical readers, both audiovisual conditions (AV0 and AV200) led to enhanced MMN and LN amplitudes. In both dyslexic groups, the audiovisual LN effects were mildly reduced. Most interestingly, individual differences in reading fluency were correlated with MMN latency in the AV0 condition. A further analysis revealed that this effect was driven by a short-lived MMN effect encompassing only the N1 window in severely dysfluent dyslexics versus a longer MMN effect encompassing both the N1 and P2 windows in the other two groups. Our results confirm and extend previous findings in dyslexic children by demonstrating a deficient pattern of letter-speech sound integration depending on the level of reading dysfluency. These findings underscore the importance of considering individual differences across the entire spectrum of reading skills in addition to group differences between typical and dyslexic readers.
PMCID: PMC4199667  PMID: 25329388
16.  Teaching computer-based spelling to individuals with developmental and hearing disabilities: transfer of stimulus control to writing tasks. 
Computer-based instruction may yield widely useful handwritten spelling. Illustrative cases involved individuals with mental retardation and hearing impairments. The participant in Study 1 matched computer pictures and printed words to one another but did not spell the words to pictures. Spelling was then taught using a computerized procedure. In general, increases in the accuracy of computer spelling were accompanied by improvements in written spelling to pictures. Study 2 extended these results with a 2nd participant. After initial training, spelling improved in the context of a retrieval task in which the participant (a) wrote a list of the names of objects displayed on a table, (b) selected the objects from a shelf, and (c) returned the objects to the table. Nearly perfect accuracy scores declined on some retrieval trials conducted without a list, suggesting that the list may have served a mediating function during retrieval. Transfer of stimulus control of computer-based teaching to the retrieval task may have been attributable to the existence of stimulus classes involving pictures, objects, and printed words.
PMCID: PMC1279871  PMID: 8881342
17.  Effect of Orthographic Processes on Letter Identity and Letter-Position Encoding in Dyslexic Children 
The ability to identify letters and encode their position is a crucial step of the word recognition process. However and despite their word identification problem, the ability of dyslexic children to encode letter identity and letter-position within strings was not systematically investigated. This study aimed at filling this gap and further explored how letter identity and letter-position encoding is modulated by letter context in developmental dyslexia. For this purpose, a letter-string comparison task was administered to French dyslexic children and two chronological age (CA) and reading age (RA)-matched control groups. Children had to judge whether two successively and briefly presented four-letter strings were identical or different. Letter-position and letter identity were manipulated through the transposition (e.g., RTGM vs. RMGT) or substitution of two letters (e.g., TSHF vs. TGHD). Non-words, pseudo-words, and words were used as stimuli to investigate sub-lexical and lexical effects on letter encoding. Dyslexic children showed both substitution and transposition detection problems relative to CA-controls. A substitution advantage over transpositions was only found for words in dyslexic children whereas it extended to pseudo-words in RA-controls and to all type of items in CA-controls. Letters were better identified in the dyslexic group when belonging to orthographically familiar strings. Letter-position encoding was very impaired in dyslexic children who did not show any word context effect in contrast to CA-controls. Overall, the current findings point to a strong letter identity and letter-position encoding disorder in developmental dyslexia.
PMCID: PMC3356879  PMID: 22661961
letter-string processing; letter-position encoding; letter-identity encoding; letter transposition; letter substitution; reading acquisition; dyslexic children
18.  Attention effects on the processing of task-relevant and task-irrelevant speech sounds and letters 
We used event-related brain potentials (ERPs) to study effects of selective attention on the processing of attended and unattended spoken syllables and letters. Participants were presented with syllables randomly occurring in the left or right ear and spoken by different voices and with a concurrent foveal stream of consonant letters written in darker or lighter fonts. During auditory phonological (AP) and non-phonological tasks, they responded to syllables in a designated ear starting with a vowel and spoken by female voices, respectively. These syllables occurred infrequently among standard syllables starting with a consonant and spoken by male voices. During visual phonological and non-phonological tasks, they responded to consonant letters with names starting with a vowel and to letters written in dark fonts, respectively. These letters occurred infrequently among standard letters with names starting with a consonant and written in light fonts. To examine genuine effects of attention and task on ERPs not overlapped by ERPs associated with target processing or deviance detection, these effects were studied only in ERPs to auditory and visual standards. During selective listening to syllables in a designated ear, ERPs to the attended syllables were negatively displaced during both phonological and non-phonological auditory tasks. Selective attention to letters elicited an early negative displacement and a subsequent positive displacement (Pd) of ERPs to attended letters being larger during the visual phonological than non-phonological task suggesting a higher demand for attention during the visual phonological task. Active suppression of unattended speech during the AP and non-phonological tasks and during the visual phonological tasks was suggested by a rejection positivity (RP) to unattended syllables. We also found evidence for suppression of the processing of task-irrelevant visual stimuli in visual ERPs during auditory tasks involving left-ear syllables.
PMCID: PMC3847663  PMID: 24348324
attention; suppression; event-related potential; EEG; audition; speech
19.  Effects of Letter-Identification Training on Letter Naming in Pre-Reading Children 
Three pre-reading children who named 0 to 3 of 20 targeted letters were taught to select the 20 printed letters upon hearing spoken letter names. For all participants, the letter-identification training resulted in naming for the majority of letters.
PMCID: PMC4164198  PMID: 24130117
letter identification; letter naming; matching-to-sample; pre-reading children; reading
20.  The locus of impairment in English developmental letter position dyslexia 
Many children with reading difficulties display phonological deficits and struggle to acquire non-lexical reading skills. However, not all children with reading difficulties have these problems, such as children with selective letter position dyslexia (LPD), who make excessive migration errors (such as reading slime as “smile”). Previous research has explored three possible loci for the deficit – the phonological output buffer, the orthographic input lexicon, and the orthographic-visual analysis stage of reading. While there is compelling evidence against a phonological output buffer and orthographic input lexicon deficit account of English LPD, the evidence in support of an orthographic-visual analysis deficit is currently limited. In this multiple single-case study with three English-speaking children with developmental LPD, we aimed to both replicate and extend previous findings regarding the locus of impairment in English LPD. First, we ruled out a phonological output buffer and an orthographic input lexicon deficit by administering tasks that directly assess phonological processing and lexical guessing. We then went on to directly assess whether or not children with LPD have an orthographic-visual analysis deficit by modifying two tasks that have previously been used to localize processing at this level: a same-different decision task and a non-word reading task. The results from these tasks indicate that LPD is most likely caused by a deficit specific to the coding of letter positions at the orthographic-visual analysis stage of reading. These findings provide further evidence for the heterogeneity of dyslexia and its underlying causes.
PMCID: PMC4042363  PMID: 24917802
phonological output deficit; orthographic input lexicon deficit; orthographic-visual analysis deficit; migration errors; substitution errors; developmental dyslexia
21.  Probe Microphone Measurements: 20 Years of Progress 
Trends in Amplification  2001;5(2):35-68.
Probe-microphone testing was conducted in the laboratory as early as the 1940s (e.g., the classic work of Wiener and Ross, reported in 1946), however, it was not until the late 1970s that a “dispenser friendly” system was available for testing hearing aids in the real ear. In this case, the term “dispenser friendly,” is used somewhat loosely. The 1970s equipment that I'm referring to was first described in a paper that was presented by Earl Harford, Ph.D. in September of 1979 at the International Ear Clinics' Symposium in Minneapolis. At this meeting, Earl reported on his clinical experiences of testing hearing aids in the real ear using a miniature (by 1979 standards) Knowles microphone. The microphone was coupled to an interfacing impedance matching system (developed by David Preves, Ph.D., who at the time worked at Starkey Laboratories) which could be used with existing hearing aid analyzer systems (see Harford, 1980 for review of this early work). Unlike today's probe tube microphone systems, this early method of clinical real-ear measurement involved putting the entire microphone (about 4mm by 5mm by 2mm) in the ear canal down by the eardrum of the patient. If you think cerumen is a problem with probe-mic measurements today, you should have seen the condition of this microphone after a day's work!
While this early instrumentation was a bit cumbersome, we quickly learned the advantages that probe-microphone measures provided in the fitting of hearing aids. We frequently ran into calibration and equalization problems, not to mention a yelp or two from the patient, but the resulting information was worth the trouble.
Help soon arrived. In the early 1980s, the first computerized probe-tube microphone system, the Rastronics CCI-10 (developed in Denmark by Steen Rasmussen), entered the U.S. market (Nielsen and Rasmussen, 1984). This system had a silicone tube attached to the microphone (the transmission of sound through this tube was part of the calibration process), which eliminated the need to place the microphone itself in the ear canal. By early 1985, three or four different manufactures had introduced this new type of computerized probe-microphone equipment, and this hearing aid verification procedure became part of the standard protocol for many audiology clinics. At his time, the POGO (Prescription Of Gain and Output) and Libby 1/3 prescriptive fitting methods were at the peak of their popularity, and a revised NAL (National Acoustic Laboratories) procedure was just being introduced. All three of these methods were based on functional gain, but insertion gain easily could be substituted, and therefore, manufacturers included calculation of these prescriptive targets as part of the probe-microphone equipment software. Audiologists, frustrated with the tedious and unreliable functional gain procedure they had been using, soon developed a fascination with matching real-ear results to prescriptive targets on a computer monitor.
In some ways, not a lot has changed since those early days of probe-microphone measurements. Most people who use this equipment simply run a gain curve for a couple inputs and see if it's close to prescriptive target—something that could be accomplished using the equipment from 1985. Contrary to the predictions of many, probe-mic measures have not become the “standard hearing aid verification procedure.” (Mueller and Strouse, 1995). There also has been little or no increase in the use of this equipment in recent years. In 1998, I reported on a survey that was conducted by The Hearing Journal regarding the use of probe-microphone measures (Mueller, 1998). We first looked at what percent of people dispensing hearing aids own (or have immediate access to) probe-microphone equipment. Our results showed that 23% of hearing instrument specialists and 75% of audiologists have this equipment. Among audiologists, ownership varied among work settings: 91% for hospitals/clinics, 73% for audiologists working for physicians, and 69% for audiologists in private practice. But more importantly, and a bit puzzling, was the finding that showed that nearly one half of the people who fit hearing aids and have access to this equipment, seldom or never use it.
I doubt that the use rate of probe-microphone equipment has changed much in the last three years, and if anything, I suspect it has gone down. Why do I say that? As programmable hearing aids have become the standard fitting in many clinics, it is tempting to become enamoured with the simulated gain curves on the fitting screen, somehow believing that this is what really is happening in the real ear. Additionally, some dispensers have been told that you can't do reliable probe-mic testing with modern hearing aids—this of course is not true, and we'll address this issue in the Frequently Asked Questions portion of this paper.
The infrequent use of probe-mic testing among dispensers is discouraging, and let's hope that probe-mic equipment does not suffer the fate of the rowing machine stored in your garage. A lot has changed over the years with the equipment itself, and there are also expanded clinical applications and procedures. We have new manufacturers, procedures, acronyms and noises. We have test procedures that allow us to accurately predict the output of a hearing aid in an infant's ear. We now have digital hearing aids, which provide us the opportunity to conduct real-ear measures of the effects of digital noise reduction, speech enhancement, adaptive feedback, expansion, and all the other features. Directional microphone hearing aids have grown in popularity and what better way to assess the real-ear directivity than with probe-mic measures? The array of assistive listening devices has expanded, and so has the role of the real-ear assessment of these products. And finally, with today's PC -based systems, we can program our hearing aids and simultaneously observe the resulting real-ear effects on the same fitting screen, or even conduct an automated target fitting using earcanal monitoring of the output. There have been a lot of changes, and we'll talk about all of them in this issue of Trends.
PMCID: PMC4168927  PMID: 25425897
22.  Evaluating Phonological Processing Skills in Children With Prelingual Deafness Who Use Cochlear Implants 
This study investigated the phonological processing skills of 29 children with prelingual, profound hearing loss with 4 years of cochlear implant experience. Results were group matched with regard to word-reading ability and mother’s educational level with the performance of 29 hearing children. Results revealed that it is possible to obtain a valid measure of phonological processing (PP) skills in children using CIs. They could complete rhyming tasks and were able to complete sound-based tasks using standard test materials provided by a commercial test distributor. The CI children completed tasks measuring PP, but there were performance differences between the CI users and the hearing children. The process of learning phonological awareness (PA) for the children with CIs was characterized by a longer, more protracted learning phase than their counterparts with hearing. Tests of phonological memory skills indicated that when the tasks were controlled for presentation method and response modality, there were no differences between the performance of children with CIs and their counterparts with hearing. Tests of rapid naming revealed that there were no differences between rapid letter and number naming between the two groups. Results yielded a possible PP test battery for children with CI experience.
PMCID: PMC2638700  PMID: 18424771
23.  Dissociating verbal and nonverbal audiovisual object processing 
Brain and Language  2009;108(2):89-96.
This fMRI study investigates how audiovisual integration differs for verbal stimuli that can be matched at a phonological level and nonverbal stimuli that can be matched at a semantic level. Subjects were presented simultaneously with one visual and one auditory stimulus and were instructed to decide whether these stimuli referred to the same object or not. Verbal stimuli were simultaneously presented spoken and written object names, and nonverbal stimuli were photographs of objects simultaneously presented with naturally occurring object sounds. Stimulus differences were controlled by including two further conditions that paired photographs of objects with spoken words and object sounds with written words. Verbal matching, relative to all other conditions, increased activation in a region of the left superior temporal sulcus that has previously been associated with phonological processing. Nonverbal matching, relative to all other conditions, increased activation in a right fusiform region that has previously been associated with structural and conceptual object processing. Thus, we demonstrate how brain activation for audiovisual integration depends on the verbal content of the stimuli, even when stimulus and task processing differences are controlled.
PMCID: PMC2693664  PMID: 19101025
Audiovisual; Integration; Verbal; Nonverbal; Semantic; Conceptual; Phonological; Amodal
24.  Pseudo-Synesthesia through Reading Books with Colored Letters 
PLoS ONE  2012;7(6):e39799.
Synesthesia is a phenomenon where a stimulus produces consistent extraordinary subjective experiences. A relatively common type of synesthesia involves perception of color when viewing letters (e.g. the letter ‘a’ always appears as light blue). In this study, we examine whether traits typically regarded as markers of synesthesia can be acquired by simply reading in color.
Methodology/Principal Findings
Non-synesthetes were given specially prepared colored books to read. A modified Stroop task was administered before and after reading. A perceptual crowding task was administered after reading. Reading one book (>49,000 words) was sufficient to induce effects regarded as behavioral markers for synesthesia. The results of the Stroop tasks indicate that it is possible to learn letter-color associations through reading in color (F(1, 14) = 5.85, p = .030). Furthermore, Stroop effects correlated with subjective reports about experiencing letters in color (r(13) = 0.51, p = .05). The frequency of viewing letters is related to the level of association as seen by the difference in the Stroop effect size between upper- and lower-case letters (t(14) = 2.79, p = .014) and in a subgroup of participants whose Stroop effects increased as they continued to read in color. Readers did not show significant performance advantages on the crowding task compared to controls. Acknowledging the many differences between trainees and synesthetes, results suggest that it may be possible to acquire a subset of synesthetic behavioral traits in adulthood through training.
To our knowledge, this is the first evidence of acquiring letter-color associations through reading in color. Reading in color appears to be a promising avenue in which we may explore the differences and similarities between synesthetes and non-synesthetes. Additionally, reading in color is a plausible method for a long-term ‘synesthetic’ training program.
PMCID: PMC3384588  PMID: 22761905
25.  Predictors of Early Reading Skill in 5-Year-Old Children With Hearing Loss Who Use Spoken Language 
Reading research quarterly  2014;49(1):85-104.
This research investigated the concurrent association between early reading skills and phonological awareness (PA), print knowledge, language, cognitive, and demographic variables in 101 5-year-old children with prelingual hearing losses ranging from mild to profound who communicated primarily using spoken language. All participants were fitted with hearing aids (n = 71) or cochlear implants (n = 30). They completed standardized assessments of PA, receptive vocabulary, letter knowledge, word and non-word reading, passage comprehension, math reasoning, and nonverbal cognitive ability. Multiple regressions revealed that PA (assessed using judgments of similarity based on words’ initial or final sounds) made a significant, independent contribution to children’s early reading ability (for both letters and words/non-words) after controlling for variation in receptive vocabulary, nonverbal cognitive ability, and a range of demographic variables (including gender, degree of hearing loss, communication mode, type of sensory device, age at fitting of sensory devices, and level of maternal education). Importantly, the relationship between PA and reading was specific to reading and did not generalize to another academic ability, math reasoning. Additional multiple regressions showed that letter knowledge (names or sounds) was superior in children whose mothers had undertaken post-secondary education, and that better receptive vocabulary was associated with less severe hearing loss, use of a cochlear implant, and earlier age at implant switch-on. Earlier fitting of hearing aids or cochlear implants was not, however, significantly associated with better PA or reading outcomes in this cohort of children, most of whom were fitted with sensory devices before 3 years of age.
PMCID: PMC3929591  PMID: 24563553

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