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This paper discusses the functional relatiohship between the position of the stapedius reflex threshold and the results of the Feldmann test. 25 hearing-impaired patients have been examined in this respect. A positive correlation on a 5% level of significance has been confirmed between these two parameters.
PURPOSE: We investigated whether the blind spot is larger in early "preperimetric" glaucoma with already deeply excavated optic discs than in normal persons. METHODS: We examined eight eyes of five patients with definite glaucomatous optic disc cupping but normal visual fields. Ten eyes of five normal healthy volunteers, with normal central excavation, served as controls. With SLO-perimetry we measured the differential light sensitivity 0.5-1.0 degrees outside the disc margins, "within" the center (Goldmann V stimulus) and along the horizontal meridian of the optic discs. Optic disc topography was documented with the Heidelberg Retina Tomograph (HRT). RESULTS: Differential light sensitivities adjacent to the optic discs did not differ in the two groups (normal 8.3dB, early glaucoma 8.4dB). Goldmann IV stimuli presented on the horizontal meridian of optic discs with glaucomatous cupping were seen up to 0.7 degrees centrally (i.e., towards the center) of the disc margin. In the control group this distance was significantly greater (1.3 degrees). The light differential thresholds with stimulus presentation in the disc center (Goldmann V) were significantly higher in the glaucoma group (0+/-2.8dB) than in the normal controls (6.6+/-1.3dB), though disc size was the same in both groups. CONCLUSIONS: Blind spots of normal discs seem to be smaller than those of deeply excavated discs in eyes with early glaucoma, possibly because there is more light scattering by the normal disc surface towards the adjacent functioning retina.
BACKGROUND: Small cortical strokes may cause predominant weakness restricted to a particular group of fingers. However, clinical, radiologic, and etiopathogenetical studies have rarely been done in these patients. METHOD: The author analyzed clinical and radiologic features of 12 patients with small cortical infarcts who had predominant weakness of particular fingers. RESULTS: The patients were divided into two groups: Eight patients had predominant involvement of ulnar-sided fingers (PIUF), and four had predominant involvement of radial-sided fingers (PIRF). Sensory symptoms were also present in eight patients, and the severity correlated with that of motor impairment. Radiologic-clinical correlation showed that the lesions related to PIUF were located significantly more medially than those associated with PIRF in the presumed hand representation area of the motor cortex. In addition, the PIUF was closely associated with severe proximal vessel stenosis or occlusion, whereas the PIRF was often related to emboligenic stroke. CONCLUSIONS: The results agree with traditionally alleged topography for fingers in the human motor cortex: ulnar fingers-medial and radial fingers-lateral. However, whether this result indicates a point-to-point somatotopical representation or differential threshold of excitability in individual neurons remains unknown. Sensory topography seems to be closely associated with that of motor function in individual subjects. The motor cortex representing ulnar-sided fingers may be a borderzone area between large arteries.
Musicians are typically considered to exhibit exceptional auditory skills. Only few studies, however, have substantiated this in basic psychoacoustic tasks. The purpose of the present investigation was to expand our knowledge on basic auditory abilities of musicians compared to non-musicians. Specific goals were: (1) to compare frequency discrimination thresholds (difference limen for frequency [DLF]) of non-musical pure tones in controlled groups of professional musicians and non-musicians; (2) to relate DLF performance to musical background; and (3) to compare DLF thresholds obtained with two threshold estimation procedures: 2- and 3- interval forced choice procedures (2IFC and 3IFC). Subjects were 16 professional musicians and 14 non-musicians. DLFs were obtained for three frequencies (0.25, 1 and 1.5 kHz) using the 3IFC adaptive procedure, and for one frequency (1 kHz) also using the 2IFC. Three threshold estimates were obtained for each frequency, procedure and subject. The results of the present study support five major findings: (a) mean DLFs for musicians were approximately half the values of the non-musicians; (b) significant learning for both groups during the three threshold estimations; (c) classical musicians performed better than those with contemporary musical background; (d) performance was influenced by years of musical experience; and (e) both groups showed better DLF in a 2IFC paradigm compared to the 3IFC. These data highlight the importance of short-term training on an auditory task, auditory memory and factors related to musical background (such as musical genre and years of experience) on auditory performance.
Difference limen for frequency (DLF) is traditionally tested using a frequency increment detection paradigm in which listeners are requested to distinguish between a reference tone and a series of comparison tones of higher frequency. Sporadic findings indicated that an increment paradigm is not necessarily comparable to a decrement paradigm, in which the comparison tones are lower than the reference tone. The purpose of the present study was to test whether the ability to detect frequency increments is different from that of frequency decrements. DLFs of 16 young women were measured at 200 Hz and 1,000 Hz, using detection of both frequency increment and decrement paradigms. Results indicated that: (1) the frequency increment detection paradigm was significantly smaller (i.e., superior) to the decrement paradigm for the DLF task at 200 Hz, (2) for both frequencies, the number of participants who exhibited better DLF using the frequency increment detection paradigm was significantly larger than the number of those who had better DLFs using the frequency decrement paradigm, and (3) for both frequencies, strong correlations were found between DLFs obtained in the increment versus the decrement paradigms. These results have implications: (1) to studies whose subjects may have reduced sensitivities at frequencies higher than the reference tone (such as the hearing impaired), and (2) to models related to the role of auditory feedback on voice accuracy and to the underlying processes of frequency discrimination.
The main objectives of this study were to characterize the selected variables for a better understanding and diagnosis of infantile autism such as clinical and image findings, diagnostic criteria, frequency of neuropsychiatric disorders in the subjects' families, familial recurrence and occurrence of consangunity between the subjects' parents and between other couples in the family. The sample was composed of 36 subjects of both sexes, in the age group from 1 though 20 years old, members of 35 distinctive families, all of which presenting clinical diagnosis for infantile autism. Mental retardation was clinically observed in all subjects of the sample and convulsion in 27.8%; neuropsychiatric disorders were referred in at least one family member of the subjects (97.14% of the families); recurrent autism in 11.42% grandparents and great-grand-parents (2.86%); abnormal findings in computed tomography scan were observed in three subjects. These results support the suggestion of the multifactorial heredity model with differential threshold fold sex in infantile autism. The clinical evaluation of all infantile autism cases should always appraise the neurological, psychiatric and genetic features.
BACKGROUND: temporal ordering and temporal resolution. AIM: to compare the performance of professional singers with that of well tuned and out of tune amateur singers in the pitch pattern test (PPT) and in the Random Gap Detection Test (RGDT). METHOD: participants were 78 individuals, male and female, with ages ranging from 18 to 55 years. All of the participants were singers with normal hearing - previously assessed using pure tone and speech audiometry--and had no language, speech, voice or hearing complaints. Each individual answered a questionnaire concerning, among other subjects, perception about own voice when singing, number of years of professional singing, difficulties when singing new songs and number of years of music study. For the objective assessment the PPT and the RGDT were used in order to investigate temporal ordering and temporal resolution respectively. RESULTS: regarding the RGDT, there was no statistically significant difference between the groups and variables. As for the PPT, it was observed that professional singers presented a better performance, with statistic significance, when compared to well tuned amateur singers and these a better performance when compared to out of tune amateur singers. The performance in the PPT was related to specialized training and study of music theory. CONCLUSION: the RGDT did not prove to be a sensitive test to distinguish professional and amateur singers. On the other hand, the PPT did. The performance in the PPT reflects the number of years of specialized auditory training and music theory study.
OBJECTIVE: To determine the bioavailability and bioactivity of subcutaneously injected insulin. RESEARCH DESIGN AND METHODS: A randomized block design with six male mongrel dogs as subjects. In protocol 1, purified pork insulin was infused intravenously to simulate the pattern of appearance in the blood that would have been expected from subcutaneous injection. Three intravenous doses (0.05, 0.10, and 0.15 U/kg) were infused on separate days in a pattern (0-300 min) designed to approximately simulate the absorption rate of subcutaneously injected insulin. In protocol 2, interscapular subcutaneous injections of pork insulin at 0.10 U/kg were made. RESULTS: Integrated insulin, decrement in plasma glucose, and maximal glucose clearance for subcutaneous injection experiments were similar to intravenous infusion of equal dose (P greater than 0.10) but significantly different from low-dose infusions (P less than 0.025). Similar results were observed for hepatic glucose output and glucose uptake. Hypoglycemia elicited counterregulatory responses that appeared to be under a threshold differentiated at a plasma glucose of approximately 3 mM. Integrated insulin was plotted against insulin dose to create dose-response curves for intravenous data. The curve was then used to predict the actual appearance rate of insulin in plasma for subcutaneous injection. The estimated bioavailability of subcutaneous insulin was 103.0 +/- 10.5% of the injected dose. CONCLUSIONS: We concluded that, in dogs, insulin delivered subcutaneously in the interscapular area is not significantly degraded before absorption, resulting in metabolic effects equal to intravenous insulin infusion of equivalent dose.
The human auditory sensitivity in detecting linear frequency ramps of a continuous pure tone has been studied. It is shown that for short ramp durations (less than 200 msec) discrimination depends on the difference between base and plateau frequencies, the mean threshold being about 3 Hz at 1 kHz. For longer ramp durations (greater than 200 msec), discrimination was found to be based on detection of the actual frequency sweep. No significant difference was found between thresholds for upward and downward sweeps. Expressed in Hz, the threshold for frequency change was approximately constant for base frequencies up to 1 kHz, above which it increased, reaching approximately 14 Hz at 4 kHz. There was no significant difference in the threshold for frequency change from 40 to 80 dB HL but at 20 dB HL the threshold was significantly higher than at 40 dB HL. Intra-individual variation in thresholds was found to be smaller than inter-individual variation. The results are discussed in relation to previous frequency discrimination data, where either tone pulse pairs, continuous frequency modulation or frequency ramps were used as stimuli.
Auditory brainstem response (ABR) wave latency, interpeak interval and amplitude as a function of intensity were measured in 40 subjects divided into equal groups of postmenopausal females, age-matched males and young adults of both sexes. The results illustrate that age and gender play a significant role in ABR wave latency and amplitude. A larger age effect occurred for the female subjects. While this does not dispute an anatomical explanation for the gender effect in ABR, hormonal changes accompanying menopause may also account for some of the gender differences noted in ABR.
Differential thresholds for tempi (with interonset intervals ranging from 100 to 1,500 msec) were measured using an adaptive 2IFC paradigm for several types of auditory sequences. In Experiment 1, the number of intervals in an isochronous sequence was varied to compare the sensitivity for single intervals with that for sequences of two to six intervals. Mean relative just noticeable differences (JNDs) decreased as the number of intervals increased (single intervals = 6%, two intervals = 4%, four intervals = 3.2%, six intervals = 3%) and were optimal at intermediate tempi for both sequences and single intervals (as low as 1.5% in the range between 300 and 800 msec). In Experiment 2, the sensitivity for different types of irregular sequences was studied. Globally, JNDs for irregular sequences were of an intermediate level between that observed for single intervals and that observed for regular sequences. However, the closer a sequence was to regularity, the lower its relative JND. Experiment 3 demonstrated that musicians were more sensitive than nonmusicians to changes in tempo, and this was true for single intervals and for regular and irregular sequences, demonstrating the role of training on these abilities. The results are discussed in terms of possible underlying mechanisms, in particular those providing a mental representation of the mean and dispersion of successive interval durations.
Three experiments were designed to investigate naive observers' abilities at discriminating the rotational velocities of two simultaneously viewed objects. In Experiment 1, rotations could occur about parallel or orthogonal axes, with initial orientations in phase or out of phase, and (for parallel rotational axes) in the same or opposite direction. Differential thresholds were approximately 10%. In Experiment 2, stimulus objects differed in the number of faces revealed in rotation (three vs. four). Observers' response curves had no greater spread, but their PSEs (points of subjective equality) were shifted such that there was a partial compensation for faces revealed per unit time. In both Experiment 1 and Experiment 2, performance was consistent across rotational axis and directional conditions. In Experiment 3, the effect of object size was examined, in order to determine the extent to which angular velocity judgments are influenced by the tangential velocity of the faces. When the comparison cube's edges were half the length of the standard's, PSEs were elevated 18.5%. Taken together, these data suggest that observers are able to discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.
The purpose of this study was to determine if performances on a 500 Hz MLD task and a word-recognition task in multitalker babble covaried or varied independently for listeners with normal hearing and for listeners with hearing loss. Young listeners with normal hearing (n = 25) and older listeners (25 per decade from 40-80 years, n = 125) with sensorineural hearing loss were studied. Thresholds at 500 and 1000 Hz were < or = 30 dB HL and < or = 40 dB HL, respectively, with thresholds above 1000 Hz < 100 dB HL. There was no systematic relationship between the 500 Hz MLD and word-recognition performance in multitalker babble. Higher SoNo and SpiNo thresholds were observed for the older listeners, but the MLDs were the same for all groups. Word recognition in babble in terms of signal-to-babble ratio was on average 6.5 (40- to 49-year-old group) to 10.8 dB (80- to 89-year-old group) poorer for the older listeners with hearing loss. Neither pure-tone thresholds nor word-recognition abilities in quiet accurately predicted word-recognition performance in multitalker babble.
This study was conducted at the University Teaching Hospital, Benin City, Nigeria to investigate urinary frequency in exclusively breastfed neonates. Amongst exclusively breastfed neonates, 59.0% passed urine eight times or more per day while 14.5% passed urine less than five times a day. The comparative figures in partially breastfed neonates were 55.8% and 12.8% respectively. There was no significant association between the type of breastfeeding and urinary frequency. Sex was also not significantly associated with urinary frequency amongst exclusively breastfed infants. However, birthweight showed significant association with urinary frequency in the analysed sample. It is suggested that birthweight, which correlates with gestational maturity may influence urinary frequency because of its effect on renal functional maturation and possibly differential threshold for intravesical pressures required for initiating the micturition reflex. The observed association is, however, not an indication for supplementary water in low-birthweight infants since all the infants had normal hydration status. It is, therefore, recommended that all neonates should not receive supplementary water irrespective of their birthweights.
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A program evaluation of hemodialysis vascular access monitoring was undertaken to determine the effectiveness of serial, objective measurement, running venous dialysis pressures, in reducing access thrombosis in arterio-venous fistulae, as well as to assess the feasibility of long-term, routine monitoring for clients in a limited-care community hemodialysis unit. In all, 102 of 112 eligible patients participated in the study with a 98% compliance rate. Angiography confirmed stenosis in all eight performed for elevated venous pressures and 16 of 20 performed for clinical suspicion. Venous pressure frequency distributions indicated significantly lower venous pressures in lower arm arterio-venous fistulae than in upper arm arteriovenous fistulae or PTFE grafts. Running venous dialysis pressures are effective and feasible for predicting venous stenoses in arteriovenous fistulae in a limited care community hemodialysis unit. Lower and differentiated threshold pressures would increase the sensitivity of this screening tool; the effect on specificity would have to be evaluated.
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Sensitivity to changes in the interaural time difference (ITD) of 50 msec tones was measured in single units in the inferior colliculus of urethane-anesthetized guinea pigs. ITD functions were measured with 100 repeats and fine spacing (100 points per cycle). The just noticeable difference (jnd) for ITD was determined using receiver operating characteristic (ROC) analysis of the spike-count distribution at each ITD. The jnd became progressively smaller as the signal frequency increased from 50 to 800 Hz but became unmeasurable above 1 kHz. The lowest jnds (30 microsec) were comparable with human jnds, indicating that there is sufficient information in the firings of individual neurons to permit discrimination without obligatory pooling. ROC analysis requires the choice of a reference ITD from which the jnd may be found by stepping the target ITD through the ITD function. For each neuron the reference was chosen to minimize the jnd. The lowest jnd was usually for ipsilateral leading references, near the minimum of the ITD function where the variance was also low, but where the slope was nearing its steepest. This was despite the peak of the ITD function occurring for contralateral leading stimuli. When the reference ITD was on midline, a jnd could be obtained by looking for firing rates either greater or smaller than the firing rate at midline. The lower jnd was usually obtained by looking for a decrease in firing rate. As duration increased, jnds either decreased or increased, depending on unit type, whereas when level increased, jnds generally increased.