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PubMed2005

Emerging neurophysiological specialization for letter strings.

In adult readers, printed words and other letter strings activate specialized visual functions within 200 msec, as evident from neurophysiological recordings of brain activity. These fast, specialized responses to letter strings are thought to develop through plastic changes in the visual system. However, it is unknown whether this specialization emerges only with the onset of word reading, or represents a precursor of literacy. We compared 6-year-old kindergarten children who could not yet read words to adult readers. Both age groups detected immediate repetitions of visually presented words, pseudowords, symbol strings, and pictures during event-related potential (ERP) mapping. Maps from seven corresponding ERP segments in children and adults were analyzed regarding fast (<250 msec) and slow (>300 msec) specialization for letter strings. Adults reliably differentiated words through increased fast (<150 msec) occipito-temporal N1 activity from symbols. Children showed a later, more mid-occipital N1 with marginal word-symbol differences, which were absent in those children with low letter knowledge. Children with high letter knowledge showed some fast sensitivity to letter strings, which was confined to right occipito-temporal sites, unlike the stronger adult N1 specialization. This suggests that a critical degree of early literacy induces some immature, but fast, specialization for letter strings before word reading becomes possible. Children also differentiated words from symbols in later segments through increased right occipito-temporal negativity for words. This slow specialization for letter strings was not modulated by letter knowledge and was absent in adults, possibly reflecting a visual precursor of literacy due to visual familiarity with letter strings.

Adult↗
PubMed2006

Copying letters to patients: the view of patients and health professionals.

OBJECTIVE: Government policies and initiatives in England have promoted the involvement of patients in the management of their own health care. Copying clinical letters to patients may improve patients' understanding of their health and the care they receive. Although the National Health Service (NHS) Plan describes copying letters to patients as a 'right', the process of copying letters to patients remains an example of good practice rather than a requirement. We review the literature to explore whether letters should be copied to patients and in what circumstances. METHODS: Review of published literature and evidence from 12 pilot projects funded by the Department of Health (DH) for and against copying letters to patients from the perspective of patients and health professionals. RESULTS: Patients generally find copies of letters beneficial, and tend to be more satisfied with their consultation and report benefits in terms of involvement in their own health care when letters are copied. Health professionals generally have concerns about the relative benefits to the patient and remain concerned about the resource implications of copying letters. CONCLUSIONS: On balance, the limited evidence on copying clinical letters to patients favours copying letters, or at least offering copies, although health professionals are less keen than patients.

Correspondence as Topic↗
PubMed2005

An audit of the standard of response letters sent by hospital specialists to general dental practitioners following a referred patient's first appointment.

INTRODUCTION: To assess the standard of response letters issued by dental hospital departments according to the requirements of the recipient dentists. PATIENTS AND METHODS: A cross-sectional survey from a UK dental hospital. All response letters issued from hospital departments between 1 January and 1 March 2003 were copied. Fifteen letters were selected for each department on a chronological sampling frame. The hospital response letters were compared to dentists' requirements, as determined in a previous study. RESULTS: Almost all departments achieved a minimum total score of 80%. The scores across all of the departments together achieved over 90% for all items of information except those relating to time. The samples of the three departments to score over 90% were the only ones to include SHO letters. The sample of the department with the highest score contained the most SHO letters and no consultant letters. CONCLUSIONS: The content standard of response letters was consistently high, particularly those letters written by SHOs, and most were written within 18 days of the patient's appointment. The use of a previously conducted questionnaire survey of dentists' opinions provided a valid means of assessing the quality of the response letters from hospital specialists.

Appointments and Schedules↗
PubMed1994

Spatial-frequency characteristics of letter identification.

To investigate the spatial-frequency components that govern letter identification we compared contrast thresholds for three types of visual stimulus (1) standard Sloan letters, (2) Sloan letters that were spatially bandpass filtered by cosine log filters, and (3) D6 patterns (sixth spatial derivatives of Gaussians). Stimuli were presented on a gray-scale display screen of a Macintosh computer-based testing system at temporal frequencies primarily of 2 and 16 Hz. Contrast thresholds were measured in two subjects with normal visual acuity with use of forced-choice staircases. Contrast sensitivity functions for standard Sloan letters and D6 patterns were comparable at a temporal frequency of 16 Hz but differed systematically at a temporal frequency of 2 Hz. The measurement of contrast sensitivity for cosine log filtered letters presented at a temporal frequency of 2 Hz indicated that the object spatial frequency of maximum sensitivity shifted to lower frequencies as letter size decreased, whereas the retinal spatial frequency of maximum sensitivity remained relatively constant. When letters were spatially bandpass filtered at a peak object spatial frequency of 2.5 cycles/letter, then contrast sensitivity functions for letter identification were equivalent to those for D6 patterns at both temporal frequencies. These results suggest that spatially filtered letters may provide a more appropriate test of visual function than do standard letter optotypes.

Adult↗
PubMed2000

Letter legibility and chart equivalence.

INTRODUCTION: We tested the appropriateness of the assumption that charts, which only vary in having different sequences of five letters per line, chosen from the same 10 letter set, can be regarded as equivalent for the purpose of making valid comparisons of visual acuity. METHOD: Visual acuity findings from samples of 400 patients, for each of two nominally equivalent Bailey-Lovie charts, have been used to determine the relative legibility of individual letters and lines, using the percentage incorrect method of analysis. RESULTS: The chance of error for the hardest letter is approximately 13 times greater than for the easiest letter on each chart. Significant between-chart differences in error rates for the hardest letters ('F' and 'H') were found. Some letters that have adjacent ranks on the legibility scale were found to have significantly different legibility. Significant differences in difficulty can occur for the same nominal line on apparently equivalent charts because of chance combinations of easier or harder letters in that line. Uneven line-to-line scale intervals have been confirmed for the charts examined, by showing corresponding differences in the distributions of lines of threshold acuity. CONCLUSIONS: The use of varying examination distances may be inappropriate for Bailey-Lovie (or similar) charts that depart from their nominal interval scaling. When different versions of these charts are assumed to be equivalent, the discrepancy between repeated measurements may be significantly increased. There is the possibility of increasing measurement precision using charts having different sequences of the same 10 letters in each line to achieve equal scaling of line intervals. Equivalent charts can be validly constructed using different sequences of the same 10 letters in each line.

Equipment Design↗
PubMed2004

Referral letters to colorectal surgeons: the impact of peer-mediated feedback.

BACKGROUND: General practitioners (GPs) select few patients for specialist investigation. Having selected a patient, the GP writes a referral letter which serves primarily to convey concerns about the patient and offer background information. Referral letters to specialists sometimes provide an inadequate amount of information. The content of referral letters to colorectal surgeons can now be scored based on the views of GPs about the ideal content of referral letters. AIM: To determine if written feedback about the contents of GP referral letters mediated by local peers was acceptable to GPs and how this feedback influenced the content and variety of their referrals. DESIGN: A non-randomised control trial. SETTING: GPs in North Nottinghamshire. METHOD: In a controlled trial, 26 GPs were offered written feedback about the documented contents of their colorectal referral letters over 1 year. The feedback was designed and mediated by two nominated local GPs. The contents of referral letters were measured in the year before and 6 months after feedback. GPs were asked about the style of the feedback. The contents of referral letters and the proportion of patients with organic pathology were compared for the feedback GPs and other local GPs who could be identified as having used the same hospital for their referrals in the period before and after feedback. RESULTS: All GPs declared the method of feedback to be acceptable but raised concerns about their own performance, and some were upset by the experience. None withdrew from the project. There was a difference of 7.1 points (95% confidence interval = 1.9 to 12.2) in the content scores between the feedback group and the controls after adjusting for baseline differences between the groups. Of the GPs who referred to the same hospital before and after feedback, the feedback GPs referred more patients with organic pathology than other local colleagues. CONCLUSIONS: GPs welcome feedback about the details appearing on their referral letters, although peer comparisons may not always lead to changes in practice. However, in some cases feedback improves the content of GP referral letters and may also impact on the type of patients referred for investigation by specialists.

Attitude of Health Personnel↗
PubMed2004

A study of warning letters issued to clinical investigators by the United States Food and Drug Administration.

PURPOSE: This study explores the ethical issues contained in warning letters issued to clinical researchers by the Food and Drug Administration (FDA) in the USA. METHODS: The online FDA Warning Letter Index was reviewed for letters issued to drug and device researchers in the USA and Canada under the violation subject "Clinical Investigator" for the period February 2002 through February 2004. The resultant letters were evaluated for the presence of 7 research ethics themes: deviation from investigational plan; informed consent; adverse event reporting; study reporting; study supervision; institutional review-board approval; and misconduct. RESULTS: Thirty-six FDA warning letters addressing violations of 58 protocols were issued to researchers during the 25 months studied. Researchers performing pulmonary medicine studies received the most warning letters (12), followed by oncology (10) and cardiology (9) researchers. The most common regulatory violations were deviation from the research plan, a flawed or nonexistent consent process, and failure to report or late reporting of adverse events. Three warning letters (8%) mentioned study misconduct, including data fabrication. CONCLUSIONS: Warning letters are informative about good practice, ethics and participant protection in research. As distressing as the content in an FDA warning letter may be to investigators receiving it, that information can become an educational tool for all members of the research team. These letters are also informative as to what the FDA is looking for when they audit clinical trials.

Biomedical Research↗
PubMed2006

Does flattery work? A comparison of 2 different cover letters for an international survey of orthopedic surgeons.

BACKGROUND: Surveys are an important tool for gaining information about physicians' beliefs, practice patterns and knowledge. However, the validity of surveys among physicians is often threatened by low response rates. We investigated whether response rates to an international survey could be increased using a more personalized cover letter. METHODS: We conducted an international survey of the 442 surgeon-members of the Orthopaedic Trauma Association on the treatment of femoral-neck fractures. We used previous literature, key informants and focus groups in developing the self-administered 8-page questionnaire. Half of the participants received the survey by mail, and half received an e-mail invitation to participate on the Internet. We alternately allocated participants to receive a "standard" or "test" cover letter. RESULTS: We found a higher primary response rate to the test cover letter (47%) than to the standard cover letter (30%) among those who received the questionnaire by mail. There was no difference between the response rates to the test and to the standard cover letters in the Internet group (22% v. 23%). Overall, there was a higher primary response rate for the test cover letter (34%) when both the mail and Internet groups were combined, compared with the standard cover letter (27%). CONCLUSIONS: Our test cover letter to surgeons in our survey resulted in a significantly higher primary response rate than a standard cover letter when the survey was sent by mail. Researchers should consider using a more personalized cover letter with a postal survey to increase response rates.

Adult↗
PubMed1985

Improving patient follow-up in incidental screening through referral letters.

The effects of referral letters on increasing the likelihood of patients obtaining hypertension follow-up assessments are presented. Seventy-four patients with elevated diastolic blood pressure (between 95 and 120 mm Hg), who were administratively ineligible for longitudinal care from the Veterans Administration, were randomized into one of four groups: a patient letter; a physician letter; both patient and physician letters; or no letter (control group). No evidence of interaction between the patient and physician letters was found. Results revealed that nearly twice as many patients (63%) receiving the patient letter returned for a hypertension evaluation as compared with those who did not (33%). No difference was found between the physician letter and no physician letter conditions. These findings suggest that patient-directed referral letters can increase the likelihood of follow-up in both previously detected and newly detected cases.

Adult↗
PubMed1984

Behaviorally anchored ranking scale versus letters of recommendation for evaluating residency candidates.

A behavioral scale and traditional letters of recommendation were compared as tools for evaluating applicants for a hospital pharmacy residency program. In designing the behaviorally anchored ranking scale (BARS), a list of desirable characteristics of hospital pharmacy residents was compiled and descriptions were written of effective, average, and ineffective performance for these characteristics. Twelve characteristics in three categories (professionalism, special skills, and character attributes) were used. Each person who had written a letter of recommendation for the 1983-84 hospital pharmacy residency program at the University of Texas Medical Branch in Galveston was also asked to complete a BARS form. Pharmacy administrators involved in the resident-selection process used the BARS criteria to evaluate all letters of recommendation; responses on the BARS forms were then analyzed. For 18 applicants, 46 letters of recommendation and 39 BARS forms were completed. Many of the BARS characteristics were not addressed in letters of recommendation. None of the letters commented on leadership quality. Ability to work with others was the BARS characteristic most often mentioned in the letters (58.7%). Of characteristics that were mentioned in both the letters and the BARS, 82.4% were ranked equally in both. Of all the letters and scales, 59% were not in agreement with each other. The BARS provided a clearer picture of the characteristics and qualities of a hospital pharmacy residency candidate than did the letters of recommendation.

Education, Pharmacy↗
PubMed1994

Recruitment for breast screening in a rural practice. Trial of a physician's letter of invitation.

OBJECTIVE: To evaluate a systematic effort to recruit women for breast screening. DESIGN AND SETTING: Individually addressed letters, signed by the woman's physician (followed by reminder letters and telephone calls as necessary) were sent to women in a rural family practice, prompting them to make an appointment for breast screening at the Ontario Breast Screening Program-the Kingston Centre. PARTICIPANTS: Women were eligible to receive a letter if they were aged 50 to 69, had not had a mammogram for at least 12 months, and did not have a previous diagnosis of breast cancer or current acute symptoms of breast disease. MAIN OUTCOME MEASURES: Response rates were measured to the initial letter, the reminder letter, and the telephone call. Women who came to the breast screening centre as a result of this recruitment effort were surveyed on their reaction to the letter. RESULTS: The response rate, as measured 9 months after the initial letters were sent, was 57.5%; 38% of respondents to the initial letter and 49% of respondents to the reminder letter said they would not have come to the centre without the letter. Both the breast screening program managers and the family physicians involved considered the project a success. CONCLUSION: Integrating with an organized breast screening program is one way for busy family physicians systematically to involve their patients in an early detection program without unduly burdening physicians or disrupting normal patient care.

Aged↗
PubMed1998

Randomized controlled study of customized preventive medicine reminder letters in a community practice.

OBJECTIVE: To test the effectiveness of customized, family-oriented reminder letters in activating patients to seek appropriate preventive services. DESIGN: Randomized clinical trial. One group received computer-generated, customized letters explaining recommended preventive procedures for each family member. A second group received a form letter listing recommendations for all preventive procedures for all age and sex groups. A third group (control group) received no letters. SETTING: A private medical centre, without university affiliation, in rural Quebec. PARTICIPANTS: From 8770 patients who met study criteria, 719 families were randomly selected. Data were available for 1971 of 1998 patients in these families. MAIN OUTCOME MEASURES: The Family Received Index is the proportion of all procedures for which a family was overdue that they received. The Family End-of-study Up-to-date Index is the proportion of procedures for which the family was eligible and for which they were up-to-date at the end of the study. RESULTS: The Family Received Index for families mailed customized letters was more than double the index for patients not mailed letters (Kruskal-Wallis P = .0139). Comparison of the Family End-of-study Up-to-date indices also demonstrated that families of patients sent customized letters were more likely to be up-to-date than families not sent letters (Kruskal-Wallis P = .0054). No statistically significant difference appeared between the number of preventive measures received by the control group and the form-letter group. CONCLUSIONS: This study demonstrates a clinically small but statistically significant value to customizing reminder letters.

Analysis of Variance↗
PubMed1998

The foundations of literacy: learning the sounds of letters.

Learning the sounds of letters is an important part of learning to read and spell. To explore the factors that make some letter-sound correspondences easier for children to learn than others, we first analyzed knowledge of letters' sounds (and names) by 660 children between 3 1/2 and 7 1/2 years old. A second study examined pre-schoolers' (M age 4 years, 11 months) ability to learn various sound-letter mappings. Together, the results show that an important determinant of letter-sound knowledge is whether the sound occurs in the name of the letter and, if so, whether it is at the beginning or the end. The properties of the sound itself (consonant versus vowel, sonorant versus obstruent, stop versus continuant) appear to have little or no influence on children's learning of basic letter-sound correspondences. The findings show that children use their knowledge of letters' names when learning the letters' sounds rather than memorizing letter-sound correspondences as arbitrary pairings.

Child↗
PubMed2001

Contraindicated medications dispensed with cisapride: temporal trends in relation to the sending of 'Dear Doctor' letters.

PURPOSE: 'Dear Doctor' letters alert the prescribing community of drug labeling changes that contain new contraindications, warnings, adverse reactions, and precautions. There has been little assessment of the impact of these letters. We quantified the impact of two 'Dear Doctor' letters concerning interactions between cisapride and a series of drugs. A letter in 1995 described a risk of prolonged QT intervals and serious ventricular arrhythmia in patients who received macrolide antibiotics and imidazole antifungals in conjunction with cisapride. A June 1998 letter that expanded the list of contraindicated comedications had wider distribution than an earlier one, was accompanied by substantial Internet and media coverage, and was complemented by an effort to inform large pharmacy dispensing information organizations of the warnings against concurrent use of the named drugs. METHODS: Health plan members with one or more outpatient pharmacy claims for cisapride during the period 1 January 1995 through 31 May 1999 were identified among members of a large New England health insurer. A retrospective review of concurrent and nearly concurrent dispensings of cisapride and contraindicated comedications was undertaken in the automated pharmacy claims data using both graphical and statistical time-series analysis. We tabulated by month the fraction of cisapride dispensings that occurred in close temporal relation to dispensings of contraindicated comedications. Codispensings that occurred on the same day were taken as the most direct measure of prescriber responsiveness to the letters. Codispensings that occurred in windows of plus or minus 2 weeks (29 day window) and plus or minus 4 weeks (57 day window) were taken as measures of possible simultaneous consumption. Among overlapping dispensings, we counted the proportion dispensed by the same pharmacy. Time series regression analysis of secular, seasonal, and step-effects was conducted. RESULTS: There was a steady decline in codispensing of cisapride and contraindicated medicines, and a pronounced seasonal effect, arising principally from the seasonal use of macrolide antibiotics. Against this background, the isolated Dear Doctor letter of October 1995 had no discernible effect on prescribing practices. The 1998 letter and surrounding activity, by contrast, were followed by a 66% decline in same-day dispensings and a smaller, but still pronounced decline in dispensings in the wider time windows. For most codispensings of contraindicated medications with cisapride, both medications came from the same pharmacy. CONCLUSIONS: Publicity and direct intervention with dispensing pharmacies may be an important supplement to Dear Doctor letters when the goal is to eliminate the codispensing of drugs that should not be taken together.

Adolescent↗
PubMed1995

Loss of vision during the retinal stabilization of letters.

Upper- and lower-case letters of the alphabet were stabilized until loss of vision occurred. Loss of straight-line visibility was the most frequently reported perceptual event. Occasionally, features of letters separated spatially before their loss of visibility. In both instances, loss of visibility often resulted in the perception of a less complex letter. Confidence ratings for each loss of letter visibility indicated that participants were quite certain about perceived fragmentations. In a control experiment, participants were asked to guess how letters would fragment during stabilization. Again, loss of line visibility was the most frequently reported event. However, spatial separation of features was rarely predicted and complex letters were not predicted to fragment into simpler letter forms. Furthermore, the confidence in predicted fragmentation was quite low. These results are consistent with the view that losses of visibility during retinal stabilization constitute a distinct perceptual experience. Fragmentations appear to be determined by the availability of less complex letter forms and by the loss of subletter information, consisting of letter features and information specifying spatial configurations.

Adult↗
PubMed1991

Object spatial frequencies, retinal spatial frequencies, noise, and the efficiency of letter discrimination.

To determine which spatial frequencies are most effective for letter identification, and whether this is because letters are objectively more discriminable in these frequency bands or because can utilize the information more efficiently, we studied the 26 upper-case letters of English. Six two-octave wide filters were used to produce spatially filtered letters with 2D-mean frequencies ranging from 0.4 to 20 cycles per letter height. Subjects attempted to identify filtered letters in the presence of identically filtered, added Gaussian noise. The percent of correct letter identifications vs s/n (the root-mean-square ratio of signal to noise power) was determined for each band at four viewing distances ranging over 32:1. Object spatial frequency band and s/n determine presence of information in the stimulus; viewing distance determines retinal spatial frequency, and affects only ability to utilize. Viewing distance had no effect upon letter discriminability: object spatial frequency, not retinal spatial frequency, determined discriminability. To determine discrimination efficiency, we compared human discrimination to an ideal discriminator. For our two-octave wide bands, s/n performance of humans and of the ideal detector improved with frequency mainly because linear bandwidth increased as a function of frequency. Relative to the ideal detector, human efficiency was 0 in the lowest frequency bands, reached a maximum of 0.42 at 1.5 cycles per object and dropped to about 0.104 in the highest band. Thus, our subjects best extract upper-case letter information from spatial frequencies of 1.5 cycles per object height, and they can extract it with equal efficiency over a 32:1 range of retinal frequencies, from 0.074 to more than 2.3 cycles per degree of visual angle.

Adult↗
PubMed1995

The effects of random element loss on letter identification: implications for visual acuity loss in patients with retinitis pigmentosa.

The hypothesis that reductions in Snellen acuities in patients with retinitis pigmentosa are due solely to losses of photoreceptors was tested by measuring the effects of random losses of sampling elements on letter identification. Sampling element losses were mimicked by setting the luminance of randomly selected pixels equal to the luminance of the surround. The amount of pixel blanking ranged from 0 to 90%. Letters varying in retinal subtense from 5 to 17 min arc were presented for 500 msec. Although letter identification accuracy decreased with increasing pixel blanking for all letter sizes, performance remained relatively high even when a majority of the pixels was blanked. The data suggest that unless the loss of cone photoreceptors in greater than 80%, loss of sampling elements alone can not account for letter acuities poorer than 20/40. In addition to loss of cone photoreceptors in patients with RP, there are histological reports of photoreceptor abnormalities and psychophysical studies of visual sensory deficits. It is conceivable that these alone, or in combination with losses of photoreceptors, could account for decreased visual acuity. In a series of experiments, stimulus parameters were manipulated in order to mimic the effects of some of these abnormalities and deficits and the effects on letter identification were examined. The results of these experiments demonstrated that sampling element loss interacts with sensory factors (e.g. luminance and contrast sensitivity) and perceptual factors (e.g. set size and letter orientation) to reduce letter identification accuracy. The implication of these results is that decreases in letter acuity observed in patients with retinitis pigmentosa cannot be attributed solely to a random loss of sampling elements in the underlying retina, but may be due to the combination of photoreceptor degeneration and other sensory and perceptual factors.

Adult↗
PubMed1994

Recognition and detection of texture-defined letters.

We quantified texture segregation by measuring psychophysically the percent correct detection scores for a set of 10 texture-defined (TD) letters using two-alternative forced-choice, and at the same time quantified spatial discrimination of TD form by measuring psychophysically the percent correct letter recognition scores for the 10 letters using 10-alternative forced-choice. Ten levels of task difficulty were created by adding noise dots to the texture patterns. Two kinds of letters were used. Static textures had the same letter and the same texture pattern throughout any given 1-sec presentation. Dynamic textures had the same letter, but a different texture pattern for every one of the 70 frames during any given 1-sec presentation. For both static and dynamic textures, letter recognition scores fell to chance level from a lower number of noise dots than did letter detection scores. Both recognition and detection scores were generally better for dynamic than for static texture patterns. We suggest that, for dynamic textures, subjects were able to enhance the signal-to-noise ratios of the noisy letters by signal averaging.

Discrimination, Psychological↗