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PubMed2006

Ecstasy use and self-reported depression, impulsivity, and sensation seeking: a prospective cohort study.

Although there are indications that ecstasy users have higher levels of depression, impulsivity, and sensation seeking, it is unknown whether these are consequences of ecstasy use or predisposing factors for starting ecstasy use. We prospectively assessed the predictive value of depression, impulsivity, and sensation seeking on future first time ecstasy use. We also assessed whether depression, impulsivity, and sensation seeking had changed after first ecstasy use. Depression, impulsivity, and sensation seeking were assessed using self-report questionnaires in 188 ecstasy-naive volunteers with high probability for future ecstasy use. After a mean follow-up of 17 months, measurements were repeated in 59 incident ecstasy users (mean 6.0 tablets) and 61 matched persistent ecstasy-naive volunteers. Only experience seeking (subscale of the sensation seeking scale) predicted future ecstasy use (OR -- 1.05, 95% CI 1.00 to 1.10), but after adjustment for potential confounders this was not significant anymore. At follow-up, significant effects of ecstasy use on the general and the disinhibition subscale of the sensation seeking scale were observed (after adjustment for potential confounders: regression coefficient B 0.51, 95% CI 0.20 to 0.83 and B -- 3.25, 95% CI 1.74 to 4.76, respectively). These data indicate that depression, impulsivity, and sensation seeking do not predict first time ecstasy use in a population of young adults with the intention to start using ecstasy and that low level ecstasy use does not seem to cause depression or impulsivity. However, low level ecstasy use may increase (certain aspects of) sensation seeking.

Adolescent↗
PubMed1999

Sensation seeking and drug use by adolescents and their friends: models for marijuana and alcohol.

OBJECTIVE: To investigate the prospective influence of individual adolescents' sensation seeking tendency and the sensation seeking tendency of named peers on the use of alcohol and marijuana, controlling for a variety of interpersonal and attitudinal risk and protective factors. METHOD: Data were collected from a cohort of adolescents (N = 428; 60% female) at three points in time, starting in the eighth grade. Respondents provided information about sensation seeking, the positivity of family relations, attitudes toward alcohol and drug use, perceptions of their friends' use of alcohol and marijuana, perceptions of influence by their friends to use alcohol and marijuana, and their own use of alcohol and marijuana. In addition, they named up to three peers, whose sensation seeking and use data were integrated with respondents' data to allow for tests of hypotheses about peer clustering and substance use. RESULTS: Structural equation modeling analyses revealed direct effects of peers' sensation seeking on adolescents' own use of both marijuana and alcohol 2 years later. An unexpected finding was that the individual's own sensation seeking had indirect (not direct) effects on drug use 2 years later. CONCLUSIONS: These findings indicate the potential importance of sensation seeking as a characteristic on which adolescent peers cluster. Furthermore, the findings indicate that, beyond the influence of a variety of other risk factors, peer sensation seeking contributes to adolescents' substance use.

Adolescent↗
PubMed2003

Cryotherapy, Sensation, and Isometric-Force Variability.

OBJECTIVE: To determine the changes in sensation of pressure, 2-point discrimination, and submaximal isometric-force production variability due to cryotherapy. DESIGN AND SETTING: Sensation was assessed using a 2 x 2 x 2 x 3 repeated-measures factorial design, with treatment (ice immersion or control), limb (right or left), digit (finger or thumb), and sensation test time (baseline, posttreatment, or postisometric-force trials) as independent variables. Dependent variables were changes in sensation of pressure and 2-point discrimination. Isometric-force variability was tested with a 2 x 2 x 3 repeated-measures factorial design. Treatment condition (ice immersion or control), limb (right or left), and percentage (10, 25, or 40) of maximal voluntary isometric contraction (MVIC) were the independent variables. The dependent variables were the precision or variability (the standard deviation of mean isometric force) and the accuracy or targeting error (the root mean square error) of the isometric force for each percentage of MVIC. SUBJECTS: Fifteen volunteer college students (8 men, 7 women; age = 22 +/- 3 years; mass = 72 +/- 21.9 kg; height = 183.4 +/- 11.6 cm). MEASUREMENTS: We measured sensation in the distal palmar aspect of the index finger and thumb. Sensation of pressure and 2-point discrimination were measured before treatment (baseline), after treatment (15 minutes of ice immersion or control), and at the completion of isometric testing (final). Variability (standard deviation of mean isometric force) of the submaximal isometric finger forces was measured by having the subjects exert a pinching force with the thumb and index finger for 30 seconds. Subjects performed the pinching task at the 3 submaximal levels of MVIC (10%, 25%, and 40%), with the order of trials assigned randomly. The subjects were given a target representing the submaximal percentage of MVIC and visual feedback of the force produced as they pinched the testing device. The force exerted was measured using strain gauges mounted on an apparatus built to measure finger forces. RESULTS: Sensation of pressure was less (ie, it took greater pressure to elicit a response) after ice immersion, thumbs were more affected than index fingers, and the decrease was greater in the right limb than the left. Two-point discrimination was not affected by cryotherapy but was higher in the finger than in the thumb under all conditions. Isometric-force variability (standard deviation of mean isometric force) was greater as percentage of force increased from 10% to 40% of MVIC. Targeting accuracy (root mean square error) was decreased at 40% of MVIC. Accuracy and force variability were not affected by cryotherapy. CONCLUSIONS: The application of cryotherapy and reduced sensation of pressure appear to have little effect on motor control of the digits. These results support the hypothesis that the use of cold is not contraindicated for use as an analgesic before submaximal rehabilitative exercise focusing on restoring neuromuscular control to injured tissues.

Journal Article↗
PubMed1997

Intraoperative mapping of sensate flaps. Electrophysiologic techniques and neurosomal boundaries.

BACKGROUND: The desirability of restoring sensation to the upper aerodigestive tract has led to an expanded use of sensate flaps for reconstruction of mucosal defects. Sensation can be restored via preformed neural pathways through the anastomosis of recipient and donor nerves, provided that the sensate flap falls within the boundaries of the neurosome for the identified sensory nerve. OBJECTIVES: To perform detailed electrophysiologic mappings of neurosomes of potential sensate flap donor sites, to describe their variability, and to investigate the usefulness of intraoperative mapping in terms of flap design and harvesting. DESIGN: A case series of 27 patients who were undergoing free flap reconstruction of various postablative head and neck defects were examined. Two silver-silver chloride recording electrodes were placed in direct contact with the dissected sensory nerve, and the overlying skin was either mechanically or electrically stimulated. Auditory feedback, as well as visualization of the responses on an oscilloscope, determined whether the stimulated area fell within the neurosome. This technique was applied to the lateral antebrachial cutaneous nerve of the radial forearm flap (n = 15), the lateral sural cutaneous nerve of the fibula flap (n = 5), the subcostal nerve of the iliac crest flap (n = 6), and the dorsal cutaneous rami of spinal nerve T-1 or T-2 of the scapula flap (n = 1). RESULTS: The neurosome of the lateral antebrachial cutaneous nerve was relatively consistent with the variability only at the distal boundary (ie, the dorsum of the hand). The neurosome of the lateral sural cutaneous nerve was more variable, falling into 2 distinct innervation patterns: one showing innervation that was limited to the upper lateral and posterior portions of the calf and the other demonstrating significant extension into the lower half of the calf. The neurosome of the subcostal nerve showed little variability and consistently overlapped the proposed skin paddle. The neurosome of the T-1 or T-2 spinal nerve was mapped in 1 patient and is described. CONCLUSIONS: The consistency of neurosomal boundaries is dependent on the donor site. Intraoperative mapping of flap donor sites may not only assure the harvesting of a true sensate flap, but may also allow for intraoperative decision making with regard to possible modifications of flap design and harvesting techniques. Two new sensate flaps from the iliac crest and scapula are accurately described.

Adult↗
PubMed2006

Measuring sensation in the feet of patients with rheumatoid arthritis.

OBJECTIVES: (1) To determine the test-retest reliability of monofilaments pressed against the skin as a method of assessing sensation in the feet of patients with rheumatoid arthritis (RA) and in controls using two grades of monofilaments; (2) to determine the stability of findings over 6 weeks; and (3) to calculate initial estimates of frequency of loss of sensation and to investigate its association with disease status. METHOD: Clinical examination of the feet was undertaken in 51 patients with RA and 20 normal controls. Six sites on each foot were tested twice with both 10 g and 3 g research grade monofilaments and this was repeated after 6 weeks. Disease status was measured using the Disease Activity Score, the Health Assessment Questionnaire, visual analogue scales of pain, and the acute phase response using erythrocyte sedimentation rate and plasma viscosity. RESULTS: Reproducibility was high for 3 g (kappa=0.73) and 10 g (kappa=0.75) monofilaments. The best balance between sensitivity (58.8%) and specificity (87.5%) for distinguishing the feet of patients from the feet of controls was using the 3 g filament and defining reduced protective sensation as being sensitive to less than 11 of 12 applications. Using this definition, the prevalence of reduced protective sensation is 59% in the patient group and 12.5% in the feet of controls. There was some variation in sensation over 6 weeks in the patient group, but this was not related to measures of clinical status. CONCLUSION: The use of monofilaments in assessing sensation levels in the RA foot is repeatable and reproducible over a six-week period and requires only a short time to perform. The frequency of reduced sensation in the feet of patients with RA was greater than previously reported. Future studies should assess relationships with disease duration and inflammatory status.

Adult↗
PubMed2003

Measuring the sensations of urge and bladder filling during cystometry in urge incontinence and the effects of neuromodulation.

AIMS: As urge and urgency contribute greatly to a patient's symptoms, it follows that sensory evaluation combined with noninvasive neuromodulation during urodynamics may provide new criteria for improving patient selection for an implantable stimulator. The purpose of this research was to develop and validate an objective measure of bladder sensations during filling cystometry and then to apply this technique to evaluate the effects of neuromodulation on the sensations of urge measured in this way. METHODS: In study 1 a new patient-activated keypad device was tested during urodynamics to measure bladder sensations according to a 0-4 scale and validated by using a technique adapted from a standard psychophysical sensory threshold testing method. In study 2 the effects of pudendal afferent nerve stimulation on measured sensations of urge were assessed during cystometry with patients as their own controls. Forty-three patients diagnosed with idiopathic detrusor instability were studied; 10 participated in study 1 and 35 in study 2. RESULTS: The new device gave reliable and repeatable measures of sensations with statistically significant differences in bladder volume at each of the urge levels tested (Wilcoxon matched pairs test). Neuromodulation suppressed urinary urge in 89% of the 35 patients. This effect was associated with a statistically significant increase in bladder volume at all urge levels. CONCLUSIONS: A new patient operated key-pad device provided a reliably objective measure of sensations of urge during urodynamics without the need for prompting. Neuromodulation using noninvasive pudendal afferent stimulation suppressed these sensations whilst increasing bladder volume.

Electric Stimulation Therapy↗
PubMed1977

Sensation evoked by bipolar intrapulpal stimulation in man.

Bipolar intrapulpal stimulation was applied to human teeth using the same procedure as in animal experiments. The effects of variation of stimulus parameters on the quality of sensation were studied. A prepain sensation exists which cannot be explained by diffusion of the stimulus to periodontal tissues. When the intensity of stimulation is increased, the prepain sensation is gradually replaced by a pinprick sensation. With long, high intensity stimulation, an acute long lasting very painful sensation appears. To evoke a pinprick sensation the best stimulation seems to be a 50 msec train (0.5 msec, 300 Hz, 0.5 mA). Longer train duration and a higher intensity of current are necessary to evoke a long lasting, acute very painful sensation. Since the exclusively Adelta and C nerve fiber content of the dental pulp is well documented and since it is possible to avoid current diffusion outside the dental pulp cavity, the tooth pulp implantation seems to be a good technic for studying pain, as long as the investigator uses adequate stimulation.

Dental Pulp↗
PubMed1987

Referred sensations in chronic pain patients.

This clinical note describes an unusual phenomenon of referred sensation reported in a sample of 98 chronic pain patients during electrical stimulation. Thirty-nine percent reported a variety of sensations referred to different parts of the body. Of these, 74% reported the sensations referred to the painful region. Among the sensations were paresthesias, pain, temperature changes, and pressure or constriction. The patients who had referred sensations had lower ratings of depression and had undergone more surgical operations than those who did not report referred sensations. Three case reports of patients with phantom limb pain are presented to illustrate the vividness with which these sensations are experienced. These data suggest that deafferentation due to disease, injury or other lesions of the CNS lead to a hypersensitivity and an increased likelihood of referred pain of long duration.

Amputation Stumps↗
PubMed2003

Electrophysiological assessment of sensations arising from the bladder: are there objective criteria for subjective perceptions?

PURPOSE: Initial bladder filling sensation, first and strong desire to void are subjective perceptions that occur periodically during the urine storage mode of bladder function, representing sensory input from the lower urinary tract. To our knowledge methods for evaluating sensory bladder function are not available. We studied a simple electrophysiological procedure for the objective assessment of bladder sensations using sympathetic skin responses and surface pelvic floor electromyography. MATERIALS AND METHODS: Informed consent was provided by 8 healthy male subjects, who were administered 20 mg. furosemide and 1 l. fluid to drink. Palmar and plantar sympathetic skin responses, and surface pelvic floor electromyogram were continuously recorded during bladder filling, voluntary pelvic floor contraction and voiding. RESULTS: First desire to void evoked simultaneous sympathetic skin responses and pelvic floor contractions. This pattern appeared periodically with the desire to void sensation as well as with strong desire to void at maximum bladder capacity and it correlated well with the subjective sensation of the subjects. Voluntary pelvic floor contraction decreased the subjective intensity of the desire to void sensation as well as sympathetic skin response activity for the same short period. During voiding sympathetic skin responses almost complete absence of sympathetic skin responses was observed. CONCLUSIONS: Sensations arising from the bladder induce combined activation of sympathetic skin responses and pelvic floor activity. This coherence indicates synchronized activation and inactivation of the autonomic and somatic pathways necessary for appropriate urine storage and coordinated voiding. Our observations may introduce a new approach for objectively assessing subjective sensations arising from the urinary tract.

Adult↗
PubMed2002

Globus sensation caused by gastroesophageal reflux disease.

OBJECTIVES: This study was designed to examine whether or not gastro esophageal reflux disease (GERD) is implicated in globus sensation. METHODS: The subjects were 25 patients (16 men/9 women; mean age: 51, range 25-69 years) complaining of globus sensation with one or more of four laryngeal findings suspected of having GERD, such as pooling of saliva, erythema of posterior one-third of larynx, inter-arytenoids edema, and granuloma. All 25 patients were administrated a proton pump inhibitor (PPI) for a period of 8 weeks. All were given esophageal endoscopies, laryngoscopes, and questionnaire before and after PPI dosing. The questionnaire survey was conducted to investigate changes in globus sensation and three symptoms specific to GERD including heartburn, regurgitation, and belching. Subjective symptoms were totalled by the over all scores of the three subjective symptoms which served as an index of severity of GERD. RESULTS: Fifty-two percent (13/25) of patients had reflux esophagitis. The esophagitis were improved after PPI administration except one case. The incidences of GERD symptoms were high (heart burn 68% (17/25), belching 49% (10/25) and regurgitation 76% (19/25)), and most of these symptoms ameliorated by PPI administration. The laryngeal findings were improved in all patients. Subjective symptoms were improved in 68% (17/25) of globus patients. The improvement rate of total score (before PPI dosing/after PPI dosing) was compared between the two groups: one with improved globus sensation (17 patients) and the other without (8 patients). The improvement rate was significantly higher in the group with improved globus sensation (P<0.05). This means that globus sensation improved because of the improvement in GERD. CONCLUSION: GERD is therefore concluded to be an inducing factor of globus sensation.

Adult↗
PubMed2006

Sensation seeking, alcohol use, and sexual behaviors among sexually transmitted infection clinic patients in Cape Town, South Africa.

Alcohol use is associated with risks for HIV/AIDS. The association between alcohol and sexual risk may be accounted for by sensation seeking personality. However, sensation seeking in relation to substance use and HIV risk has not been examined in Africa. In this study, 292 men and 219 women receiving sexually transmitted infection (STI) diagnostic and treatment services in Cape Town, South Africa, completed anonymous behavioral surveys. Structural modeling was used to test a model of alcohol use and sensation seeking in relation to sexual risk behaviors. Results showed that sensation seeking and alcohol use in sexual contexts were related to HIV risks, controlling for gender and marital status. The association between sensation seeking and HIV risk was partly accounted for by alcohol use in proximity to sex. In contrast to studies conducted in the United States, sensation seeking was not related to alcohol-sex outcome expectancies. These findings suggest that alcohol use is an important HIV transmission risk factor for many STI clinic patients and that interventions for individuals who are characterized as sensation seekers are urgently needed in South Africa.

Adolescent↗
PubMed1999

Sensory nerve repair in perforator flaps for autologous breast reconstruction: sensational or senseless?

The spontaneous return of sensation in autologously reconstructed breasts, especially in the Transverse Rectus Abdominis Myocutaneous (TRAM) flap, generated the belief that sensory reinnervation by nerve repair of the flap would be superfluous. This study compares the sensation of the following non-reconstructed and reconstructed breasts: (1) non-operated breasts; (2) flaps of patients reconstructed with the Deep Inferior Epigastric Perforator (DIEP) flap with sensory nerve repair; (3) flaps of patients reconstructed with the Deep Inferior Epigastric Perforator (DIEP) flap without nerve repair; and (4) flaps of patients reconstructed with the free TRAM flap without nerve repair. Statistically significant lower pressure thresholds were found for DIEP flaps with nerve repair through Semmes-Weinstein testing. More segments of the DIEP flaps with nerve repair reacted to cold, warm and vibratory stimuli compared to flaps without nerve repair. Delayed but satisfactory sensory evoked potential responses were obtained for all reconstructed breasts, but in 46% of TRAM flaps no response could be registered compared with 23% and 0% for DIEP flaps without and with nerve repair, respectively. Questionnaires confirmed the objective data and showed return of erogenous sensation in 30% of the patients with DIEP flaps with nerve repair. Our data reconfirm the possibility of spontaneous return of sensation in pedicled and/or free lower abdominal flaps without nerve repair. Nerve repair in free DIEP flaps nevertheless does restore sensation earlier postoperatively, increases the quality and quantity of sensation in the flap and has a higher chance of providing erogenous sensation. The benefits obtained outweigh the disadvantages of the increased operating time.

Adult↗
PubMed1996

Sensation-seeking, criminality, and spinal cord injury: a case-control study.

A retrospective case-control study was performed in New Orleans, Louisiana, in 1985-1986 to test the hypotheses that 1) criminality is a risk factor for severe injury, and 2) the association between criminality and injury can be explained in terms of a common underlying factor--increased sensation-seeking tendencies. A total of 140 males with spinal cord injury were individually matched with 140 driver's license holders on age, race, sex, educational attainment, and zip code of residence and were interviewed by telephone. Criminality prior to spinal cord injury was measured by self-report and police records, and sensation seeking was measured by the Disinhibition and Boredom Susceptibility subscales of Zuckerman's Sensation-Seeking Scale (Form V). Those with spinal cord injuries were significantly more likely than controls to report a history of juvenile delinquency, adult criminality, and incarceration prior to the time of spinal cord injury. Statistically significant but modest difference were also found between cases and controls with respect to Disinhibition, Boredom Susceptibility, and the combined Sensation-Seeking Scale score. Matched-pairs logistic regression analysis indicated that the association between sensation seeking and spinal cord injury remained significant after controlling for criminality, with an estimated relative risk of 2.05 (95% confidence interval 1.67-2.53). However, the association between criminality and spinal cord injury also remained significant after controlling for sensation seeking (estimated relative risk = 2.04, 95% confidence interval 1.09-3.82). On the basis of these results, criminality and sensation seeking may be statistically significant but independent predictors of spinal cord injury.

Adult↗
PubMed2002

Eyelid sensation after supratarsal lid crease incision.

PURPOSE: To determine the severity and duration of the loss of eyelid sensation after upper eyelid crease incision. METHODS: This clinic-based case study was performed by analyzing observational measurements of patients undergoing upper blepharoplasty or ptosis surgery. Eighty-three eyelids of 50 patients were studied. A Cochet-Bonnet filament-type aesthesiometer was used to obtain all measurements. Preoperative and postoperative measurements were recorded at 1 week, 1 month, and final (2-6 months) time periods. Statistical analysis evaluated the degree and duration of the sensory loss and the extent of recovery during the evaluation period. Recovery of sensation was defined as a numerical reading within one point of baseline. RESULTS: The mean aesthesiometry reading was calculated at the preoperative (3.45), 1-week (1.20), 1-month (1.56), and final postoperative (2.56) periods. Paired t testing showed a decreased but significant difference in sensation measurement at each comparison. Recovery of sensation to within one point occurs at the preoperative to late time period comparison. All but 4 of the 68 eyelids tested at the 1-week postoperative time period had a measured loss of sensation. Of the 44 eyelids tested at the final time period, all but 1 had regained some or all of this sensory loss. CONCLUSIONS: Loss of skin sensation in the eyelid after upper eyelid crease incision blepharoplasty or blepharoptosis repair occurs in most patients and should be considered an expected outcome of the procedure. Partial to complete recovery of eyelid sensation over 2 to 6 months should also be expected, though in rare instances this does not occur.

Adolescent↗
PubMed1999

Role of sensation in swallowing function.

OBJECTIVES: Sensation in the oral cavity and laryngopharynx has long been believed to be crucial for normal swallowing. One illustration of this belief has been intense interest in reconstruction after cancer resection using sensate tissue transfer as a means of improving swallowing function. A contrarian view is that mucosal sensation, by itself, is, in fact, relatively unimportant to swallowing function. STUDY DESIGN: A prospective study was designed to test the hypothesis that normal swallow function can occur with anesthesia of the upper aerodigestive tract mucosa. METHODS: Baseline (sensate) swallowing function of 13 healthy adults was assessed via video endoscopic swallow studies (VESS). Each subject was then topically anesthetized with lidocaine applied to the oral cavity, oropharynx, hypopharynx, and larynx. Swallowing was then reassessed via VESS and compared to the baseline examination to look for differences in function. RESULTS: There was little difference in swallowing ability between sensate and anesthetized states, even though all the subjects felt that their swallowing had been profoundly disrupted after lidocaine was applied. The main difference was a small increase in the time from food administration to swallowing. A few experienced trace aspiration, which was instantly eliminated on subsequent swallows with simple coaching. CONCLUSION: Normal swallowing can occur spontaneously or with simple coaching even with complete anesthesia of the upper aerodigestive tract mucosa. Current beliefs about the value of sensate free flaps and the importance of sensation in swallowing in general may need refinement.

Adult↗
PubMed2006

Pain drawing scoring is not improved by inclusion of patient-reported pain sensation.

STUDY DESIGN: This is a retrospective study of 250 patients who describe low back pain with pain drawings. A computer application using artificial neural networks was designed to analyze pain drawings and evaluate the contribution of pain sensation to drawing classification. OBJECTIVE: The primary goal of this study was to assess the contribution of patient recorded pain sensation marks in classifying pain drawings into one of five broadly defined categories. The hypothesis was that including pain sensation would improve classification. SUMMARY OF BACKGROUND DATA: With no perfect diagnostic test for patients with low back pain, many approaches have been proposed and are used. One common diagnostic tool is the pain drawing. Several quantitative methods have been proposed to score the drawings. Some methods use pain sensation in the scoring; however, the contribution of pain sensation has not been defined. METHODS: A custom computer application classified the pain drawing. Data consisted of 250 pain drawings from patients with low back pain. RESULTS: Patient recorded pain sensation is not necessary in computer-based scoring of pain drawings. CONCLUSION: Patient-reported pain sensation does not improve classification when quantitatively scoring pain drawings.

Diagnosis, Computer-Assisted↗
PubMed2003

Rectal sensation test helps avoid pain of apical prostate biopsy.

PURPOSE: Apical cores obtained during transrectal prostate biopsy are associated with greater pain than cores obtained from the remainder of the gland. We present a method to minimize this pain. MATERIALS AND METHODS: During 30 consecutive apical biopsies the needle was purposefully placed above all rectal pain fibers, which are anatomically present only below the dentate line. All patients received a periprostatic nerve block prior to biopsy. The patient was asked if he felt the sharp sensation of the needle as it was placed lightly against the rectal mucosa when the needle was aimed at apex (the rectal sensation test). If so, the needle was advanced cranially 2 to 3 mm or until he could no longer detect its light touch. The probe handle was then rotated dorsally, pulling the rectal mucosa downward until the needle was again aimed at the apex. Patients were asked to report a visual analog pain score for each biopsy. These results were compared to those obtained when doing 30 consecutive apical biopsies without the rectal sensation test. RESULTS: The average visual analog pain score for apical biopsy was 1.25 (range 0 to 2.2) for patients in whom the rectal sensation test was used to bypass rectal pain sensory fibers. The average score in control patients in whom the rectal sensation test was not used was higher at 2.28 (range 0.3-6.2). These results were statistically significant (p > 0.0005). CONCLUSIONS: Increased sensitivity to apical prostate biopsy is due to rectal pain fibers located below the dentate line. These fibers and the associated pain may be safely avoided by passing through the rectal wall above the dentate line. The rectal sensation test easily identifies the sensate area below the dentate line. Painless apical biopsy can then be achieved by rotating the ultrasound probe to aim the biopsy needle in the desired path.

Biopsy, Needle↗
PubMed1989

Sensations evoked by intraneural microstimulation of C nociceptor fibres in human skin nerves.

1. Seventy-one C polymodal nociceptors supplying glabrous and hairy skin in limbs of awake human volunteers were identified on the basis of cutaneous stimulus-response characteristics recorded intraneurally by microneurography (MNG). The large majority of such units were primarily detected during intraneural microstimulation (INMS) on the basis of subjective quality and cutaneous localization of evoked painful sensation. Electrophysiological studies were supplemented with rigorous psychophysical testing during microstimulation delivered at intraneural C recording sites. 2. The conduction velocity of single C nociceptor units could be shown to become transiently slowed following repetitive INMS at threshold intensity for conscious sensation. Such 'marking' witnessed that particular C units, identified by recording, had been effectively activated during INMS and psychophysical testing. 3. Cognitive attributes of sensations evoked from C recording sites by INMS at threshold intensity for perception were estimated psychophysically for subjective quality, temporal attributes and localized projection. There was remarkable matching of physiological unit type (C polymodal nociceptor) with subjective quality of evoked sensation (dull or burning pain). Further, there was remarkable spatial matching of receptive field of given C nociceptors with projected field of the pain sensation evoked from the C recording site by INMS delivered at threshold intensity for conscious sensation. 4. Dissociated A nerve fibre blocks caused by compression-ischaemia did not abolish the sensation of burning pain projected to hairy skin, evoked by INMS delivered at C recording sites. 5. While the double matching of (a) subjective quality and spatial localization with (b) objective physiological unitary type and receptor location, coupled with the results of A blocks, provide evidence that C nociceptor fibres can be fairly selectively activated during INMS, the results also attest that C polymodal nociceptors from human skin evoke delayed dull or burning pain, accurately projected to a defined locus in skin, even after spatial summation is reduced to a minimum.

Adult↗