Mean Sensation Research Articles

The effect of superior pedicle breast reductions on breast sensation

The aim of this study was to assess nipple, areola and breast skin sensation after breast reductions with two different superior pedicle techniques: a short, vertical scar technique compared to a long, inverted-T scar technique. Thirty-six women with a vertical technique (group I) and ten women with an inverted-T technique (group II) with a resection weight of ≤500 g per breast completed their 1-year follow-up. The four modalities used to evaluate sensation were pressure with Semmes–Weinstein filaments, vibration with a vibrometer, and temperature and pain perception on a qualitative basis. The evaluation revealed that 1-year after breast reduction, the sensation was either reduced, unaltered, or improved in both groups. In the nipple, the mean sensation was markedly reduced throughout all qualities in both groups with the exception of pain, which was enhanced. In the areola, the mean sensation was also reduced in all qualities in both groups. In the quadrants of the skin, mean sensation was improved in terms of pressure and vibration in group I (8.3% normal pressure values preoperatively vs. 70% normal pressure values postoperatively) but reduced in the lower quadrant of the skin in group II with the inverted-T scar. This reduction of pressure was also significant (p = 0.04) in comparison with group I. Apart from this difference between the two groups, this study showed that in breast reductions with a superior pedicle technique, the long-scar technique did not lead to a greater reduction of sensation in the nipple and areola than the short-scar technique.

Validation of a real-time urodynamic measure of urinary sensation

The purpose of this study was to test the feasibility and validity of a continuous measurement of urinary sensation during cystometry. Subjects continuously recorded their level of urinary sensation during cystometry with the use of urodynamic diagnoses and responses to the Medical Epidemiologic and Social Aspects of Aging (MESA) and Urinary Distress Inventory (UDI) scales. Trends in urinary sensation recordings by increasing percentage of maximum cystometric capacity (MCC) were captured and compared with the use of growth curves. Fifty-one women participated: 18 patients had detrusor overactivity incontinence (DOI); 15 patients had urodynamic stress incontinence; 9 patients had mixed incontinence, and 9 patients did not demonstrate incontinence. In the volume range between 35% and 75% of MCC, the mean sensation level was higher in the DOI group than the other groups (P < .04). Urge sensation at 50% of MCC correlated with UDI and MESA urge subscales (rho = 0.34, p < .03 and rho = 0.39, p < .02). This study demonstrates that the Urgeometer measurement is feasible and correlates with urodynamic diagnosis and the severity and bother from urge incontinence.

How reliable and valid is the Brief Sensation Seeking Scale (BSSS‐4) for youth of various racial/ethnic groups?

To assess the reliability and validity of the Brief Sensation Seeking Scale BSSS-4 by race/ethnicity. Six waves of nationally representative, cross-sectional, Legacy Media Tracking Survey (LMTS) data. Analyses are based on a sample size of 24 328 individuals. Response rates for the individual survey administrations range from 60% to 30%. Data were collected by telephone, from April 2001 to January 2004. Youth, aged 12-17 years, who completed the LMTS. Sensation seeking was measured using the four-item scale, BSSS-4, published by Stephenson et al. in 2003. A series of items from the LMTS was used to measure youth intention to smoke and smoking behavior. Mean sensation seeking scores increased as the risk for established smoking increased. African American youth who are open to smoking or have experimented with cigarettes had lower mean sensation seeking scores than their white and Hispanic counterparts. Coefficient alpha and average corrected item-total correlations suggest that the BSSS-4 is a less reliable measure of sensation seeking for African American youth compared to white and Hispanic youth. The BSSS-4 is a useful tool for identifying youth at risk for smoking; however, it is less reliable and valid for African American youth compared with other youth. Future research should investigate whether other existing sensation seeking scales are equally reliable and valid across race/ethnicity, and whether an alternative scale could or should be developed that would measure sensation seeking more effectively among African American youth.

Double-masked study of the effects of nepafenac 0.1% and ketorolac 0.4% on corneal epithelial wound healing and pain after photorefractive keratectomy

Two NSAIDs--nepafenac 0.1% and ketorolac tromethamine 0.4%-were compared in terms of their effects on corneal reepithelialization and pain after photorefractive keratectomy (PRK) in a randomized, double-masked, contralateral eye, multicenter study. A total of 40 healthy adult patients who were undergoing sequential bilateral PRK received nepafenac 0.1% and ketorolac 0.4% in contralateral eyes, 1 drop 3 times daily for 3 d after bandage contact lens insertion. Patients were assessed on postoperative days 1, 3, 4, 5, and 7. At each visit, patients provided a general rating of pain. Each patient also assessed the sensation of each eyedrop following instillation (after-drop pain, irritation, burning/stinging, and overall comfort). Starting on day 3, epithelial defect size was assessed. Mean epithelial defect size was similar between treatments at each postoperative visit (P>.05). The average time-to-healing was 4.18 d for nepafenac 0.1% and 4.00 d for ketorolac 0.4% (P=.3134). No statistical difference was observed between nepafenac 0.1% and ketorolac 0.4% in mean postoperative pain scores (P>.05). On day 3, the nepafenac 0.1% group had significantly lower mean sensation scores than did the ketorolac 0.4% group for after-drop pain (P=.0090), irritation (P=.0007), and burning/ stinging (P=.0003). Mean overall comfort score was also significantly better for nepafenac 0.1% on day 3 (7.43 vs 6.41; P<.0001). Nepafenac 0.1% and ketorolac 0.4% provide postoperative pain relief after PRK surgery without associated adverse effects on corneal epithelial healing. Nepafenac 0.1% treatment may offer greater comfort upon instillation in patients who have undergone PRK.

Tear‐film lipid layer morphology and corneal sensation in the development of blinking in neonates and infants

The aim of the study was to evaluate the role of lipid layer thickness and corneal sensation in the development of blinking in neonates. The study group comprised sixty-four neonates and infants (mean age 27.5 +/- 15 (sd) weeks, range 3.4-52) whose mothers were attending a general practice healthy baby clinic. Spontaneous eye-blink activity was determined from digital videographic recordings; tear film lipid layer morphology wasexamined using interference patterns produced by the Keeler Tearscopetrade mark Plus over a five-point grading scale (higher grades are associated with thick and stable lipid films); corneal sensation threshold was assessed with the Non-Contact Corneal Aesthesiometer (NCCA), using the eye-blink response as an objective indication that the cooling stimulus had been felt; palpebral aperture dimensions were measured using calibrated digital still images of the eye in the primary position. The overall mean spontaneous blink-rate was found to be 3.6 (+/- 0.3) blinks min(-1), and the mean interblink time was 21.6 (+/- 2.8) s. The lowest blink-rates were observed in the 0-17-week age group (average 2 blinks min(-1)). The blink-rate showed a highly significant correlation with age (r = 0.46, P < 0.01). The overall mean lipid layer grading was 3.6 (+/- 0.2 SE) arbitrary units. Higher grades were found in the newborn and the mean grading score reduced with age (P < 0.01). The mean sensation threshold to blink (TTB) was 0.69 (0.04 SE) mbar, which did not differ from a control group of older subjects (P > 0.05). There was a rapid increase in palpebral aperture length and width from birth to 1 year old, with surface area increasing by 50% over the same period. We concluded that the low rate of spontaneous eye blink activity in neonates is associated with a thick stable lipid layer that may be a function of a small palpebral aperture. Furthermore, neonates appear to have the capacity to detect ocular surface cooling, which is a major trigger for spontaneous blinking.

P0988 RECTAL FUNCTION IN FUNCTIONAL NON-RETENTIVE FECAL SOILING (FNRFS)

Introduction: To date children with FNRFS are believed to suffer from a mental disturbance. To what extent abnormalities in rectal function may be involved, has not been evaluated. We evaluated rectal sensation and compliance in these patients using the barostat. Methods: Rectal sensation (first sensation, urge to defecate and pain), and compliance were determined using a barostat (pressure controlled, intermittent distension procedure). Results: Rectal function was evaluated in 19 children with FNRFS (15 M, mean age 10.0 ± 1.9 yrs) and compared with 22 healthy volunteers (11 M, mean age 12.7 ± 2.6 yrs) (HV). Mean sensation thresholds (first sensation, urge to defecate and pain) were not significantly different from HV. Moreover, mean rectal compliance in FNRFS (14 ± 4.0 ml/mmHg) was not significantly different from HV (16 ± 2 ml/mmHg). A subgroup (4/19) of FNRFS patients showed an abnormal rectal function: 2 patients (11%) showed disturbed rectal sensation for urge (cutoff: mean of HV + 2SD). Additionally, another 2 patients (11%) had an abnormal rectal compliance (cutoff: mean of HV + 2SD). Conclusion: Rectal function is normal in the majority of patients with FNRFS underscoring that fecal retention does not play a role in the symptomatology in this patient group. However, in a subgroup, increased compliance (11%) or decreased sensation (11%) can be demonstrated suggesting impaired rectal function as possible underlying pathophysiological mechanism.

Reliability of the Non-Contact Corneal Aesthesiometer and its comparison with the Cochet–Bonnet aesthesiometer

Aims-: To determine the repeatability of measurement of the corneal sensation threshold using the Non-Contact Corneal Aesthesiometer (NCCA); to evaluate the effect of the air-jet diameter and stimulus duration on the threshold; and to compare the sensation thresholds found with the NCCA and with the Cochet–Bonnet Aesthesiometer (C–BA), on the same group of normal, human subjects.Methods-: For all experiments, only the central corneal sensation thresholds were measured. (1) NCCA Repeatability; 17 subjects tested at the same time on five separate days. (2) NCCA Air-Jet Diameter; 15 subjects tested using four different air-jets: 0.35, 0.5, 1 and 2mm. (3) NCCA Stimulus Duration; 15 subjects tested using three stimulus durations: 0.5, 0.9 and 1.5 sec. (4) NCCA and C–BA; 43 subjects tested using each instrument in turn.Results-: (1) No significant differences in mean sensation threshold were detected across the five days of testing, or between individual days. (2) 0.5 and 1mm air-jets produce least variability in mean sensation threshold. (3) No significant difference in mean sensation thresholds was found between the three test durations. (4) For each subject, there was no correlation between each instrument’s mean sensation threshold.Conclusions-: (1) The NCCA was able to assess the corneal sensation threshold in an accurate and repeatable manner. (2) The optimum test parameters were found using the 0.5mm air-jet, over a stimulus duration of 0.9 sec. (3) The C–BA has serious deficiencies in its design which limit its ability to accurately measure corneal sensitivity at low stimulus thresholds.

Reliability of the Non‐Contact Corneal Aesthesiometer and its comparison with the Cochet–Bonnet aesthesiometer

To determine the repeatability of measurement of the corneal sensation threshold using the Non-Contact Corneal Aesthesiometer (NCCA); to evaluate the effect of the air-jet diameter and stimulus duration on the threshold; and to compare the sensation thresholds found with the NCCA and with the Cochet-Bonnet Aesthesiometer (C-BA), on the same group of normal, human subjects. For all experiments, only the central corneal sensation thresholds were measured. (1) NCCA Repeatability; 17 subjects tested at the same time on five separate days. (2) NCCA Air-Jet Diameter; 15 subjects tested using four different air-jets: 0.35, 0.5, 1 and 2 mm. (3) NCCA Stimulus Duration; 15 subjects tested using three stimulus durations: 0.5, 0.9 and 1.5 sec. (4) NCCA and C-BA; 43 subjects tested using each instrument in turn. (1) No significant differences in mean sensation threshold were detected across the five days of testing, or between individual days. (2) 0.5 and 1 mm air-jets produce least variability in mean sensation threshold. (3) No significant difference in mean sensation thresholds was found between the three test durations. (4) For each subject, there was no correlation between each instrument's mean sensation threshold. (1) The NCCA was able to assess the corneal sensation threshold in an accurate and repeatable manner. (2) The optimum test parameters were found using the 0.5 mm air-jet, over a stimulus duration of 0.9 sec. (3) The C-BA has serious deficiencies in its design which limit its ability to accurately measure corneal sensitivity at low stimulus thresholds.

Patient Tolerance and Ocular Surface Staining Characteristics of Lissamine Green versus Rose Bengal

Purpose: To determine patient tolerance and ocular surface staining characteristics of 1% lissamine green versus 1% rose bengal solutions in patients with dry eye and in those with normal ocular surfaces by comparison of subjective sensation and objective staining scores.Methods: Twelve patients with keratoconjunctivitis sicca and eight subjects with no ocular surface disease recorded their symptoms on a graded scale (0-5) and the duration of symptoms after instillation of one drop of 1% lissamine green and 1% rose bengal on two different occasions in different order. Lissamine green and rose bengal staining patterns were recorded on a graded scale (0-4) by one of the authors.Results: For patients with keratoconjunctivitis sicca mean sensation score with lissamine green (2.42) was significantly lower (P= 0.00006) than with rose bengal (4.58). The duration of symptoms was significantly longer (P= 0.0007) after rose bengal instillation as well. For subjects with no ocular surface disease, mean sensation score with Lissamine green (1.375) was significantly lower (P= 0.01) than with rose bengal (2.5). In this group, duration of symptoms also was significantly longer (P= 0.001) after rose bengal instillation. In both groups, there was no difference in objective staining scores.Conclusion: Lissamine green is better tolerated than rose bengal by patients and is equally as effective as rose bengal in evaluating the ocular surface in keratoconjunctivitis sicca.

Threshold and magnitude exponent function correlations for the human tongue

This study was designed to investigate possible relationships between threshold and suprathreshold lingual tactile processes, and to determine how accurately mean suprathreshold scaling values represent the behavior of individual subjects. Lingual vibrotactile threshold and suprathreshold values were obtained from 26 normal young adults. Results indicated that there was no statistically significant correlation between the threshold and suprathreshold data. It was also determined that mean sensation magnitude values may not accurately represent the behavior of individual subjects.

Clinical Application of Auditory Evoked Brain Stem Responses elicited by Bone-Conducted Stimuli

Auditory evoked brain stem responses elicited by air and bone-conducted sinusoidal one wave stimuli (0.5, 1, 2 and 4kHz) were studied in patients affecteed by conductive, neurosensory or mixed type hearing disorders. We set 0dBNSL as the mean sensation level of six normal hearing adults. As the maximum bone-conducted stimuli producible be our equipment is 45dBNSL, no responses may by elicited by bone-conducted stimuli when the patient's sensation level is more than 35dBNSL.The A-B gaps obtained by ABR were compared with the ones by pure-tone audiometry.The A-B gaps obtained by these two methods were approximately equal, but in some cases showed some differences varying from-20dB to+20dB.The bone-conducted ABR thresholds were compared with the puretone auditory thresholds for bone conduction. The ABR thresholds elicitied by low frequency stimuli were influenced by hearing level in high frequencies. But the thresholds by both methods were similar in all frequencies (0.5, 1, 2 and 4kHz). As regards frequency specificity, we also found the usefulness of the bone-conducted ABR thresholds in clinical cases.

Binaural Interactions of Impulsive Stimuli and Pure Tones

The time-vs-intensity trade (ΔT/ΔI) in binaural lateralization was measured for pure tones and impulsive stimuli by the null method for high-pass and low-pass clicks at a repetition rate of 20 pps and pure tones of 200, 500, and 700 cps. Mean sensation levels (SL) of 20, 30, and 40 db and interaural intensity differences of 0, 4, and 6 db were used. The data on four subjects indicate a difference between high-pass and low-pass clicks: for instance, ΔT/ΔI≈0.025 msec/db for low-pass clicks below 1000 cps and I = 30 db SL, whereas at the same intensity ΔT/ΔI≈0.060 msec/db for high-pass clicks above 4000 cps. It is concluded that the time vs-intensity trade is important for the localization of high-frequency impulsive stimuli. The interaural intensity difference also affects the ability to liberalize since the error of lateralization is least when both the interaural intensity difference and interaural time difference are zero. From the foregoing and from experiments with two liberalized images, it is concluded that the timing information used in binaural lateralization travels along frequency-dependent neural pathways. Any physiological timing signal must be able to explain this phenomenon.