SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Trapezoidal indentations of the skin by a 0.5-mm-diameter probe were presented at different rates and loads (forces) to the human fingertip, in order to compare estimates of population responses of cutaneous mechanoreceptors with the quality and magnitude of tactile sensations. The subjects were first trained to attend to and evaluate variations in the magnitude of touch sensations associated with the onset ramp, the plateau period, and the offset ramp. They examined a series of line drawings that illustrated a variety of temporal profiles for sensation magnitude. The line drawings provided a straight-forward means of describing temporal fluctuations of sensation intensity, which corresponded well to psychophysical ratios that were determined subsequently with a matching procedure. Influences of ramp rate on qualities of touch sensations were evaluated by tabulating verbal descriptions of sensory experiences. Each of three rate conditions generated a different quality of sensation during the dynamic portions of stimulation. Onsets and offsets at 100 g/s were described as "taps". During ramps at 10 g/s the quality was described as "rolling" or "moving". At 1 g/s no sense of motion was detected; instead, a "pressure" sensation was identified. Touch sensations during the plateau were always described as a pressure. The subjective magnitudes of touch sensations associated with the onset, plateau, and offset were equated by comparing different components of paired stimuli. At 100 g/s, when subjects matched the offset sensation from the first of a pair of stimuli with the onset sensation from the second, the force of the stimulus producing the offset sensation was 1.3 times greater than the intensity of the stimulus that produced the onset sensation. Matching of the plateau sensation (evaluated during the last 1.5 s of the 2.5-s plateau period) with the onset sensation required a plateau stimulus that was 1.7 times greater in force than the stimulus which produced the onset. Comparison of stimulus intensities producing a match of plateau and offset sensations with stimulus intensities predicted from the previous matches (onset versus offset and onset versus plateau) demonstrated a mean within-subject error of 4%. The mean ratio of plateau to offset forces that produced a match was 1.8:1.3. In a matching procedure in which subjects compared the subjective magnitudes of plateau sensations following onset ramps of different rates, onset ramp rate significantly influenced the magnitude of pressure sensations. The ratios of plateau forces which produced equal magnitudes of sensation following 1, 10, and 100 g/s ramps were 1.6:1.3:1.0.(ABSTRACT TRUNCATED AT 400 WORDS)
1. We have studied the sensations evoked by threshold microstimulation (TMS) in the area of the human principal sensory nucleus of the thalamus [ventralis caudalis (Vc)] in patients (n = 11) undergoing stereotactic surgery for the treatment of movement disorders and pain. Preoperatively, patients were trained to describe somatic sensory stimuli using a standard list of descriptors. This same list was used to describe sensations evoked intraoperatively by thalamic microstimulation. Stimulation sites (n = 216) were defined by location within the area where the majority of cells had a reproducible response to innocuous cutaneous stimulation (core region) or in the cellular area posterior and inferior to the core region (posteroinferior region). 2. TMS-evoked sensations were categorized as paresthetic if the descriptors "tingle," "vibration," or "electric current" were chosen by the patient to describe the sensation and as thermal/pain if the descriptors "cool," "warm," "warm and cool," or "pain" were chosen. Thermal/pain sensations were evoked by stimulation in 82% (9/11) of patients and at 19% of sites studied. These results suggest that thalamic microstimulation can evoke thermal/pain sensations reproducibly across patients. 3. Thermal/pain sensations were evoked more frequently by stimulation at sites in the posteroinferior region (30%) than by stimulation at sites in the core region (5%). Nonpainful thermal sensations composed the majority of thermal/pain sensations evoked by stimulation in both the core (80%) and posteroinferior regions (86%). Sites where stimulation evoked pain and nonpainful cool sensations were found anterior to the area where nonpainful warm sensations were evoked. Thermal/pain sensations were evoked at sites located medially near the border between the core and posteroinferior regions. 4. Radiologic techniques were used to determine the presumed nuclear location of stimulation sites. Thermal/pain sensations were evoked less frequently by stimulation in the part of Vc included in the core region than by stimulation in any of the following: the part of Vc included in the posteroinferior region, ventralis caudalis portae nucleus, ventralis caudalis parvocellularis nucleus, or the white matter underlying the ventral nuclear group. 5. The location of the sensation evoked by stimulation [projected field (PF)] varied widely in size. PFs were categorized as large if they involved more than one part of the body (e.g., face and arm) or if they crossed at least one joint proximal to the metacarpophalangeal joint or to the metatarsophalangeal joint. PFs were more frequently large at sites where thermal/pain sensations were evoked by TMS (33%) than at those where paresthesia were evoked (6%).(ABSTRACT TRUNCATED AT 400 WORDS)
In patients who undergo oral cavity reconstruction, loss of sensation plays a vital role in producing disturbances in postoperative oral function. Microsurgical techniques have provided a method of addressing this deficit through the use of sensate cutaneous free flaps in which microneural anastomoses are performed between a sensory nerve supplying the flap, and a recipient nerve in the head and neck. The purpose of this study was to compare the cutaneous sensation of the radial forearm flap and lateral arm flap donor sites, the two most commonly used intraoral sensate flaps. For comparison, sensation was also determined in five intraoral sites: the tip of tongue, lateral tongue, cheek, gingiva, and hard palate. Sensation was evaluated at the two potential donor sites in 66 random subjects using static and moving two-point discrimination, thermal sensation differences, and Semmes-Weinstein monofilament pressures. In the same subjects Semmes-Weinstein monofilament pressures were used to evaluate intraoral sensation. Information was recorded on age, sex, smoking and denture status. All four sensory evaluations demonstrated that the lateral arm flap donor site was more sensitive than the radial forearm donor site. Thermal sensitivity differentials (0.52 vs. 0.40 degrees C, p < 0.001), static two-point discrimination (15.4 vs. 15.0 mm, p < 0.2), moving two-point discrimination (5.8 vs. 4.8 mm, p < 0.03), and Semmes-Weinstein monofilament pressures (5.10 vs. 4.08 g per square millimeter, p < 0.001) all indicated a more sensitive lateral arm flap donor site. Older subjects had significantly decreased sensation at both donor sites based on static two-point discrimination and Semmes-Weinstein monofilament testing. No sex differences were noted. Based on Semmes-Weinstein monofilament testing in the mouth, the tip of the tongue is the most sensitive area (2.26 g per square millimeter), followed by the hard palate (3.60 g per square millimeter), the lateral tongue (4.08 g per square millimeter), the cheek (4.77 g per square millimeter), and the gingiva (8.06 g per square millimeter). Smokers had significantly decreased sensation at the tip of tongue and hard palate. Denture wearers had significantly diminished sensation in all intraoral locations except the lateral tongue. Older patients had significantly diminished sensation at all intraoral sites. No sex differences were noted. The lateral arm flap donor site is a more sensitive region than the radial forearm flap donor site. However, the lateral arm flap donor site is less sensitive than the tip of tongue and hard palate, while the radial forearm flap donor site is less sensitive than the tip of tongue, hard palate, lateral tongue, and cheek. This suggests that for certain locations, intraoral sensate flaps may require measures such as sensory reeducation protocols to approach normal recipient site sensation.
The rectum is insensitive to stimuli capable of causing pain and other sensations when applied to a somatic cutaneous surface. It is, however, sensitive to distension by an experimental balloon introduced through the anus, though it is not known whether it is the stretching or reflex contraction of the gut wall, or the distortion of the mesentery and adjacent structures which induces the sensation. No specific sensory receptors are seen on careful histological examination of the rectum in humans. However, myelinated and non-myelinated nerve fibres are seen adjacent to the rectal mucosa, but no intraepithelial fibres arise from these. The sensation of rectal distension travels with the parasympathetic system to S2, S3 and S4. The two main methods for quantifying rectal sensation are rectal balloon distension and mucosal electrosensitivity. The balloon is progressively distended until particular sensations are perceived by the patient. The volumes at which these sensations are perceived are recorded. Three sensory thresholds are usually defined: constant sensation of fullness, urge to defecate, and maximum tolerated volume. The modalities of anal sensation can be precisely defined. Touch, pain and temperature sensation exist in normal subjects. There is profuse innervation of the anal canal with a variety of specialized sensory nerve endings: Meissner's corpuscles which record touch sensation, Krause end-bulbs which respond to thermal stimuli, Golgi-Mazzoni bodies and pacinian corpuscles which respond to changes in tension and pressure, and genital corpuscles which respond to friction. In addition, there are large diameter free nerve endings within the epithelium. The nerve pathway for anal canal sensation is via the inferior haemorrhoidal branches of the pudendal nerve to the sacral roots of S2, S3 and S4. Anal sensation may be quantitatively measured in response to electrical stimulation. The technique involves the use of a specialized constant current generator and bipolar electrode probe inserted in the anal canal. The equipment is generally available and the technique has been shown to be an accurate and repeatable quantitative test of anal sensation.
This study investigated the quality and magnitude of sensations evoked by electrical tooth pulp stimulation. Detection threshold (the minimum current intensity that evoked a sensation) and pain threshold were determined for tooth pulp stimuli varying in frequency from 5 to 500 Hz. The effect of frequency and intensity of tooth pulp stimulation on the magnitude of sensations was assessed using visual analog scales and verbal descriptor scales. Detection thresholds were stable over experimental sessions and independent of the frequency of the stimulating current. Pain threshold varied as a function of frequency with a minimum value at 100 Hz. Stimuli that evoked non-pain sensations at low frequencies evoked pain sensations when frequency was increased from 5 to 100 Hz. Subjects were able to scale non-pain sensations over a range of stimulus intensities and frequencies. The lowest currents evoked sensations that were non-painful and were of constant magnitude despite changes in the frequency of stimulation. Higher stimulus currents evoked sensations that were non-painful at low stimulus frequencies and painful at high stimulus frequencies. Sensation magnitude at each stimulus intensity increased as a function of frequency. Temporal summation occurred in proportion to stimulus intensity. These findings suggest that the non-pain sensations evoked in tooth pulp are mediated by a distinct population of afferents that are not involved in the coding of pain. High frequency stimulation that increased the discharge rate of the lowest threshold pulpal afferents resulted in no summation of non-pain sensation and never produced pain. However, high frequency stimulation evoked greater magnitude sensations at higher stimulus currents, indicating that central summation mechanisms were critical for higher threshold afferents signaling more intense non-pain and pain sensations.
OBJECTIVE: To investigate the features of selective attention in patients with irritable bowel syndrome (IBS) and the effect of psychological hint on visceral sensation in IBS patients. METHODS: A set of 36 modified investigation cards originally developed for depression patients and including 12 cards describing gastrointestinal (GI) symptoms, 12 cards describing respiratory symptoms, and 12 cards with neutral terms, was used to investigate selective attention. 36 patients with diagnosis of IBS based on Rome II criteria, 23 patients with asthma, and 26 healthy volunteers, all without hemorrhoid, were asked to select one card from the set and put it in an envelop. A rectal balloon was inserted into the rectum of the examinees, then the balloon was inflated by pumping air so as to distend the rectum and the thresholds of initial filling sensation, evacuation sensation, urgent evacuation sensation, and utmost tolerance sensation were recorded. The examinees were asked to talk about something so as to divert their attention, and then examination of thresholds of rectal sensation and the time needed for diverting attention were recorded. After a rest for 5 approximately 10 minutes, the examinees were asked to fill the contents of selective attention they still remembered in a recording card. Then pictures of anatomy and pathology of colon were shown and conversation about gastrointestinal diseases was made to the examinees (as malignant stimuli) the changes of thresholds were recorded again. RESULTS: More terms about GI diseases were selectively recalled by the IBS patients than by asthma patients and healthy controls (all P < 0.001). During rectal distention, IBS patients had lower thresholds of initial sensation (21 +/- 5 mm Hg), evacuation sensation (36 +/- 9 mm Hg), urgent evacuation sensation (51.3 +/- 14.2 mm Hg), and utmost tolerance sensation (67 +/- 17 mm Hg) in comparison with the other two groups (both P < 0.001). After diverting the examinees' attention by talking and reading, the thresholds of the above mentioned different kinds of sensation in different groups increased significantly as compared with the basic values (all P < 0.05), in particular, the threshold of initial sensation in IBS patients increased markedly (P < 0.01). Focusing the examinees' attention on GI stimuli by reading pictures of malignant gastrointestinal diseases significantly decreased the sensation thresholds in IBS patients (P < 0.05). However, no remarkable change in the thresholds was recorded in the nonpatients. CONCLUSION: Selective attention of GI symptoms is the cognitive-behavioral characteristic of patients with IBS. Diverting the examinees' attention may decrease their response to stimuli. Psychological hint exerts significant influence on the rectal pain sensitivity of IBS patients. Psychotherapy may be helpful in treatment of IBS.
OBJECTIVE: In order to improve insights in rectal filling sensation, we studied pouch filling sensations after ileal J pouch-anal anastomosis (IPAA) before and after re-establishment of bowel continuity. METHODS: Anal manometry and a pouch filling sensation test were performed before as well as 1 and 6 weeks after closure of the loop ileostomy in 17 patients who had undergone restorative proctocolectomy with stapled (8 patients) or manual pouch-anal anastomosis (9 patients). The results were compared with those of 12 control subjects. RESULTS: Before ileostomy closure, pouch pressure necessary for inducing the respective sensation thresholds was higher than in controls; the difference was significant for constant and urge sensation. The volumes for urge and maximum tolerable sensation level were significantly lower, with reduced pouch compliance. After stoma closure, pressure and volume thresholds at all sensation levels became completely comparable with control data. No relevant differences were observed between stapled and manual ileal pouch-anal anastomoses. CONCLUSIONS: All levels of filling sensation levels are preserved after restorative proctocolectomy and their parameters are comparable with those of normal rectal filling sensation. Diversion of an ileal J pouch results in resetting of filling sensation thresholds towards lower volume and higher pressure values, but all sensation thresholds normalize within 6 weeks after stoma closure. These data document that neither the rectum, nor the mucosa of the anorectal junction and upper part of the anal canal are involved in filling and urge sensation.
The use of functional brain imaging techniques has led to considerable advances in our understanding of brain processing of human visceral sensation. The use of complementary techniques such as functional MRI, positron emission tomography, magnetoencephalography, and EEG has led to the identification of a network of brain areas that process visceral sensation. These studies suggest that unlike somatic sensation, which has an intense homuncular representation in the primary somatosensory cortex (SI), visceral sensation is primarily represented in the secondary somatosensory cortex, whereas representation in SI is vague. This difference could account for the poor localization of visceral sensation in comparison with somatic sensation. However, in a manner similar to that of somatic sensation, visceral sensation is represented in the paralimbic and limbic structures such as the insular, anterior cingulate, and prefrontal cortices. These areas are likely to mediate the affective and cognitive components of visceral sensation. Recent studies suggest that negative emotional factors such as fear, and cognitive factors such as attention can modulate the brain processing of visceral sensation in the insular and anterior cingulate cortices. In addition, alterations in the pattern of cortical processing of visceral sensation have been described in patients with functional gastrointestinal pain. It is likely that future research into the factors that modulate the brain processing of visceral sensation in health and disease are likely to improve further our understanding of the pathophysiology of functional visceral pain disorders.
Painful and non-painful pressure sensations from muscle are generally accepted to exist but the peripheral neural correlate has not been clarified. The aim of the present human study was to assess the non-painful and painful pressure sensitivity with (1) anaesthetised skin, and (2) anaesthetised skin combined with a block of large diameter muscle afferents. The skin was anaesthetised by a topically applied anaesthetic cream and later lidocaine was administrated subcutaneously. The pressure sensitivity was assessed quantitatively by computer-controlled pressure stimulation on the anterior tibial muscle. Thresholds to detection, pain and pain tolerance were assessed. In the first experiment, computer-controlled needle insertion depths evoking touch and pain sensations were used to assess the efficacy of cutaneous anaesthesia. Touch and pain sensations evoked during needle insertions were found to be superficial in intact skin but when anaesthetised, touch sensation was occasionally evoked at depths related to penetration of the fascia. With the skin completely anaesthetised to brush and von Frey hair pinprick stimulation, skin indentation with the strongest von Frey hair caused a sensation described as a deep touch sensation. Simultaneously, pressure detection and pain thresholds increased but it was still possible to elicit non-painful and painful pressure sensation in all subjects. In a second experiment, a differential nerve block of group I and II afferent fibres was obtained by full-leg ischaemia simultaneously with cutaneous anaesthesia. The efficacy of the tourniquet block was continuously assessed by a battery of somatosensory tests (heat, brush, vibration, electrical and movement detection) applied at the foot simultaneously with pressure stimulation on the anterior tibial muscle. After 20 min of ischaemia, group II afferent fibres mediating the sensations of movement detection, vibration and brush on the foot was blocked but the heat pain threshold was not affected. In this condition (anaesthetised skin and block of group I and II fibres from deep tissue) a pressure sensation was evoked in 70% of subjects although the pressure detection threshold was increased. The pressure pain sensitivity was decreased, which, however, might indicate a partial block of group III and IV muscle afferents. In a third experiment, the tactile sensations elicited by electrical stimulation of the tibialis anterior muscle and skin at the lower leg were significantly decreased after 20 min of ischaemia, validating the blocking effects of group I and II nerve fibres. The present data show a marginal contribution of cutaneous afferents to the pressure pain sensation that, however, is relatively more dependent on contributions from deep tissue group III and IV afferents. Moreover, a pressure sensation can be elicited from deep tissue probably mediated by group III and IV afferents involving low-threshold mechanoreceptors.
Despite evidence that systemic morphine preferentially attenuates second pain sensations that are presumed to result from activation of unmyelinated (C) nociceptors, most animal models of nociception elicit sensations that result from or are dominated by activation of myelinated (A-delta) nociceptors. Therefore, methods were developed to directly compare the effects of morphine on late (second) pain sensations and early onset (first) pain sensations in an animal model. In order to establish appropriate stimulus parameters, human psychophysical experiments compared characteristics of sensations evoked by brief (pulsed) thermal stimulation and ramp-and-hold thermal stimulation. Brief (500 msec) contact of a pre-heated thermode with the skin produced late pain sensations with peripheral conduction velocities in the range of C afferents, as estimated by latencies from stimulation of proximal and distal sites on the leg. The sensations evoked by brief contact increased with successive contacts (pulses) at 0.4 Hz, demonstrating temporal summation of sensation intensity. Pretreatment of the skin with capsaicin enhanced the late pain sensations from pulsed stimulation. In contrast, peak sensations evoked by ramp-and-hold thermal stimulation were evoked at similar latencies from disparate sites on the leg, and capsaicin pretreatment of the skin did not increase the magnitude of these sensations. The pulsed and ramp-and-hold forms of stimulation were used in a paradigm designed to test for differential effects of systemic morphine on operant responses of non-human primates. Low doses of morphine reduced operant responding to pulsed thermal contact, while higher doses were required to affect responses to ramp-and-hold thermal stimulation. The low doses of morphine did not suppress non-nociceptive (intertrial) motor responses, indicating that motor inhibition was not responsible for the effects on escape responses to pulsed stimulation. Measurements of skin temperature 10 cm from the site of stimulation showed that morphine had no effect on baseline temperature but attenuated changes in skin temperature that were elicited by pulsed and by ramp-and-hold stimulation. This effect of morphine on skin temperature responses could not account for the reduction of operant responsivity to thermal stimulation. These results support previous findings that systemic morphine preferentially attenuates second pain sensations, and a new animal model of morphine-sensitive thermal nociception is established. These findings demonstrate the importance of defining the sources of afferent input and the response measures in experiments which attempt to measure antinociceptive effects of pharmacological agents.
The first aim of this study was to assess prospectively the incidence of phantom breast sensations (PB sensations) and phantom breast pain (PB pain) in a sample of patients treated for breast cancer (n=204) by means of a modified radical mastectomy (n=82). Patients were assessed 6 weeks, 6, 12 and 24 months after mastectomy, by means of a questionnaire. After 24 months, assessments of 74 (90%) patients were available. Two years after mastectomy, PB sensations were present in 19% (n=14) of the patients and PB pain was present in 1% (n=1) of the patients. Over time the percentage of patients with PB sensations remained relatively stable (around 20%) but for PB pain the percentage reduced from 7% to 1%. The amount of suffering as a result of PB sensations or PB pain was very limited. PB sensations and PB pain are of little clinical relevance in the 24 months following mastectomy. The second aim of this paper was to analyse the influence of research methodology on the prevalences of PB sensations and PB pain previously reported. Research design, assessment method and publication date were recorded. Data were weighted according to the number of women investigated. Linear regression analysis was performed to analyse the influences of methodology on the prevalences of PB sensations and PB pain. Of the 29 studies identified, 23 were cross-sectional and 6 were prospective. In 17 studies patients were interviewed and in 12 studies a questionnaire was used. A prospective design resulted in prevalences of PB sensations and PB pain averagely 8% lower respectively 9% higher than in cross-sectional studies. The use of an interview resulted in prevalences of PB sensations and PB pain averagely 13% lower respectively 5% lower than questionnaire use. Prevalences of PB sensations and PB pain reduce averagely with 0.08% respectively 0.13% per year since 1950. It is concluded that research design and assessment method have a significant influence on reported prevalence of PB sensations and PB pain.
PURPOSE: Following orthognathic surgery, patients use qualitatively different words to describe the altered sensation on their face that results from tissue inflammation and nerve injury. These words indicate normal, hypoesthetic, paresthetic, and dysesthetic sensations, and reflect the intrusiveness of the alteration. Our intent was to study the words chosen by patients from a standardized list to characterize sensory recovery during the first 6 months after surgery and to examine whether patients who underwent different surgical procedures tended to choose different sets of words. PATIENTS AND METHODS: Patients' selections from a list of 27 words that described their assessment of spontaneous and evoked facial sensations were obtained before surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. Data were obtained from 146 patients enrolled in a randomized controlled clinical trial designed to evaluate the potential of sensory retraining in the rehabilitation of patients who experience impairment in sensory function after nerve injury. Mantel Haenszel general correlation and row mean score statistics were used to assess the association between time and word choice and to compare the word choice categories of 4 surgical groups: bilateral sagittal split osteotomy (BSSO) only, with or without genioplasty; BSSO + Le Fort I, with or without genioplasty. RESULTS: In general, the number of words selected to describe the alteration in sensation decreased over time, as did the intrusiveness of the category of words chosen. However, the intrusiveness remained the same or worsened from 1 week to 6 months for 32% of patients. With increased time after surgery, the percentage of patients who reported altered evoked sensations exceeded the percentage who reported spontaneous sensations. For example, at 6 months the altered sensation of 66% of the patients was classified in the paresthesia and dysesthesia categories by the evoked assessment of sensation; whereas, that of only 47% of the patients were classified as such by the spontaneous assessment. The addition of Le Fort I to BSSO did not affect the way patients reported altered sensation on their lower face. Hypoesthesia and paresthesia, but not dysesthesia, were less of a problem on the midface than on the lower face after BSSO + Le Fort I. Patients who had genioplasty more frequently chose descriptors for the lower face that reflected soft tissue trauma and inflammation ("swollen," "tender," and "burning") than patients without genioplasty; however, this difference decreased with time after surgery. CONCLUSION: The current findings indicate that patients' selection of words differentiates individuals who experienced only a simple loss in sensation (ie, present negative symptoms), those who experienced active sensations that are not normally present (ie, present positive symptoms), and those whose active sensations are additionally uncomfortable or painful. It is possible that continued study of the latter group of patients will reveal patterns of word usage that predict poor long-term recovery and disabling sensory disorders.
STATEMENT OF PROBLEM: Reported incidences of altered sensation after placement of mandibular implants range from a low of 0% to almost 44%, making it difficult to advise subjects regarding risk. PURPOSE: This study involved presurgical and postsurgical assessment of sensation in the lips and chins of 75 subjects, all of whom objectively demonstrated normal sensation before surgery. MATERIAL AND METHODS: Objective and subjective tests were administered before, and at planned intervals for 12 months after, the placement of 2 implants in the anterior mandible. RESULTS: Objective changes were observed in only 1 subject and then only at the 2-week postsurgery interval. There were significant differences for all subjects in subjective sensation changes from baseline to 2 weeks after surgery (P =.007) and from 2 weeks to 6 months (P =.003) or 12 months (P =. 003). There was a higher percentage of subjects with normal sensation before surgery who reported sensory changes 2 weeks after implant placement (34% vs 24% for all subjects), but only 1% of subjects still reported altered sensation 1 year later. Although there were no significant differences between men and women in reports of altered sensation, more women than men noted sensation changes 2 weeks after implants were placed (25% vs 13%). There appeared to be no relationships among gender, the degree of ridge resorption, and reports of altered sensation. CONCLUSION: Thus, although approximately 24% of subjects may report altered sensation in the short-term after implant surgery in the anterior mandible, the problem appears to be a transient one, with only about 1% experiencing sensation changes 1 year after implant surgery.
1. Immediately after breath-holding at end-expiratory level, there is a certain period of no particular respiratory sensation which is terminated by the onset of an unpleasant sensation and followed by progressive discomfort during breath-holding. This period, defined as the time from the start of voluntary breath-holding to the point where the onset of an unpleasant sensation occurs, is designated "the period of no respiratory sensation'. Although it has been shown that the maximum breath-holding performance is improved with successive trials, it is not clear whether this training effect exerts a similar influence on the period of no respiratory sensation during breath-holding. 2. Since the training effect seems to be associated with the stresses of breath-holding, we hypothesized that the initial period of no respiratory sensation during breath-holding might be less influenced by the training effect. 3. We studied 13 normal subjects who performed repeated breath holds while continuously rating their respiratory discomfort using a visual analogue scale. In addition, we measured the hypercapnic ventilatory response of each individual and obtained the relationship between the slope of the hypercapnic response curve and breath-holding periods. 4. Our results showed that there was little training effect on the period of no respiratory sensation and that the period of no sensation during breath-holding is inversely related to the slope of the hypercapnic ventilatory response curve. 5. The period of no respiratory sensation was also measured in eight patients with chronic obstructive pulmonary disease. The values of the period of no respiratory sensation in patients with chronic obstructive pulmonary disease were apparently lower than those obtained in normal subjects. 6. These findings suggest that measurement of the period of no respiratory sensation can be a useful clinical test for the study of genesis of dyspnoea.
Nurses prepare patients for chest tube removal, yet little has been written to indicate the sensations to be expected during this routine procedure. The sensations reported by patients and factors that could influence those sensations were examined in this study. The sample consisted of 36 patients after thoracic surgery (24 men and 12 women), all of whom were scheduled to have either a mediastinal or a pleural tube removed. They reported their sensations and the intensity of those sensations (using a 100 mm visual analog scale) within 15 minutes after tube removal. The most frequently reported sensation during chest tube removal was burning, followed by pain and pulling with mean intensities of 64, 62, and 45, respectively. Subjects reported having few sensations after the tube was removed with only five reporting soreness in the chest. The sensations and intensities did not differ for those who did and did not receive analgesia or for those having a pleural tube versus a mediastinal tube removed. The sensations were similar for the old and young subjects with younger subjects reporting higher intensities. Women reported pain more frequently than men, but the intensities of the sensations reported by men and women were not significantly different. The sensations reported during chest tube removal differ from those described in the literature and can be used to prepare patients more appropriately for chest tube removal.