Spectral frequency and the modulation of the acoustic startle reflex by background noise.

The rat's (Long-Evans) acoustic startle reflex to a high-frequency tone burst (10.5 kHz) was depressed by intense high-frequency band-pass noise (8–26 kHz) but enhanced by low frequency noise (1–2 kHz). However, contrary to the hypothesis that the depression of startle in intense background noise is produced by sensory masking, the reflex to a low-freqency tone burst (at 1 kHz) was depressed by both high- and low-frequency band-pass noise. Two additional hypotheses are offered to supplement sensory masking in order to explain the asymmetry in these data. The first is that the intratympanic reflex, which acts as a high pass filter on acoustic input, is elicited in intense backgrounds. The second is that acoustic startle reflexes elicited by intense low-frequency tones are in part elicited by their high-frequency distortion products and that these distortion products are then masked by high-frequency background noise. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biphasic modulation of spinal nociceptive transmission from the medullary raphe nuclei in the rat

The modulatory effects of electrical and chemical (glutamate) stimulation in the rostral ventromedial medulla (RVM) on spinal nociceptive transmission and a spinal nociceptive reflex were studied in rats. Electrical stimulation at a total 86 sites in the RVM in the medial raphe nuclei (n = 54) and adjacent gigantocellular areas (n = 32) produced biphasic (facilitatory and inhibitory, n = 43) or only inhibitory (n = 43) modulation of the tail-flick (TF) reflex. At these 43 biphasic sites in the RVM, facilitation of the TF reflex was produced at low intensities of stimulation (5-25 microA) and inhibition was produced at greater intensities of stimulation (50-200 microA). At 43 sites in the RVM, electrical stimulation only produced intensity-dependent inhibition of the TF reflex. Activation of cell bodies in the RVM by glutamate microinjection reproduced the biphasic modulatory effects of electrical stimulation. At biphasic sites previously characterized by electrical stimulation, glutamate at a low concentration (5 nmol) produced facilitation of the TF reflex; a greater concentration (50 nmol) only inhibited the TF reflex. In electrophysiological experiments, electrical stimulation at 62 sites in the RVM produced biphasic (n = 26), only inhibitory (n = 26), or only facilitatory (n = 10) modulation of responses of lumbar spinal dorsal horn neurons to noxious cutaneous thermal (50 degrees C) or mechanical (75.9 g) stimulation. Facilitatory effects were produced at lesser intensities of stimulation and inhibitory effects were produced at greater intensities of stimulation. The apparent latencies to stimulation-produced facilitation and inhibition, determined with the use of a cumulative sum method and bin-by-bin analysis of spinal neuron responses to noxious thermal stimulation of the skin, were 231 and 90 ms, respectively. The spinal pathways conveying descending facilitatory and inhibitory influences were found to be different. Descending facilitatory influences on the TF reflex were conveyed in ventral/ventrolateral funiculi, whereas inhibitory influences were conveyed in dorsolateral funiculi. The results indicate that descending inhibitory and facilitatory influences can be simultaneously engaged throughout the RVM, including nucleus raphe magnus, and that such influences are conveyed in different spinal funiculi.     

Phantom auditory sensation in rats: An animal model for tinnitus.

To measure tinnitus induced by sodium salicylate injections, 84 rats were used in a conditioned suppression paradigm. In Exp 1, Ss were trained with a conditioned stimulus/stimuli (CS) consisting of the offset of a continuous background noise. One group began salicylate injections before Pavlovian training, a 2nd group started injections after training, and a control group received daily saline injections. Resistance to extinction was profound when injections started before training but minimal when initiated after training, suggesting that salicylate-induced effects acquired differential conditioned value. In Exp 2, salicylate treatments were mimicked by substituting a 7 kHz tone in place of respective injections, resulting in effects equivalent to salicylate-induced behavior. A 3rd experiment included a 3 kHz CS, and again replicated the salicylate findings. In Exp 4, we decreased the motivational level, and the sequential relation between salicylate-induced effects and suppression training was retained. Findings support the demonstration of phantom auditory sensations in animals. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Circadian modulation of the rat acoustic startle response.

The acoustic startle response (ASR) of male rats was measured during several sessions over a 24-hr period in both a light–dark cycle and a constant-dark condition. Each session consisted of 10 trials each at 80, 90, 100, 110, and 120 dB white noise. The results indicate robust daily and circadian modulation of ASR amplitude that consist of an approximately 2-fold nocturnal increase at eliciting-stimuli intensities above 80 dB. Similar results were observed in female rats in constant-dark conditions. To determine whether daily changes in auditory thresholds were responsible for the observed modulation, ASR reflex modification procedures were used. These procedures were designed to measure auditory thresholds at frequencies of 10 and 40 kHz at several times of day. The results suggest a lack of significant circadian differences in auditory thresholds at these frequencies. This study demonstrates a novel role of the rat circadian system in the modulation of ASR amplitude. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Colour cues for leaf food selection by long-tailed macaques (Macaca fascicularis) with a new suggestion for the evolution of trichromatic colour vision

Fast-rate otoacoustic emissions (OAEs) were used to determine the inward and outward transmission change produced by the stapedial muscle reflex. The subjects were otologically normal adult volunteers. Satisfactory recordings were obtained from a total of 16 ears. Runs of 16 click-evoked OAEs were recorded at a rate of 4282 clicks/s using the maximum length sequence (MLS) technique, with a contralateral tone presented at 10 dB above the contralateral acoustic reflex threshold during the recording of OAEs 5-12 in each run. The OAEs recorded with the contralateral tone were compared with those recorded without the tone to determine the effect of the acoustic reflex. An analysis of the OAEs in 0.5 kHz frequency bands suggested that the reflex produced significant attenuation of low frequency sound with smaller effects at high frequencies, which included amplification for some subjects. For eight of the 16 ears there was an increase in OAE amplitude with the acoustic reflex for at least one frequency band. At low frequencies (1, 1.5 kHz) the inward transmission change produced by the acoustic reflex appeared to be similar in magnitude to the outward transmission change.     

Detection of ultrasonic tones and simulated dolphin echolocation clicks by a teleost fish, the American shad (Alosa sapidissima)

The authors previously reported that American shad (Alosa sapidissima) can detect sounds from 100 Hz to 180 kHz, with two regions of best sensitivity, one from 200 to 800 Hz and the other from 25 to 150 kHz [Mann et al., Nature 389, 341 (1997)]. These results demonstrated ultrasonic hearing by shad, but thresholds at lower frequencies were potentially masked by background noise in the experimental room. In this study, the thresholds of the American shad in a quieter and smaller tank, as well as thresholds for detecting stimulated echolocation sounds of bottlenosed dolphins was determined. Shad had lower thresholds for detection (from 0.2 to 0.8 kHz) in the quieter and smaller tank compared with the previous experiment, with low-frequency background noise but similar thresholds at ultrasonic frequencies. Shad were also able to detect echolocation clicks with a threshold of 171 dB re: 1 microPa peak to peak. If spherical spreading and an absorption coefficient of 0.02 dB/m of dolphin echolocation clicks are assumed, shad should be able to detect echolocating Tursiops truncatus at ranges up to 187 m. The authors propose that ultrasonic hearing evolved in shad in response to selection pressures from echolocating odontocete cetaceans.     

Role of vagal afferents in the acute ventilatory responses to inhaled wood smoke in rats

Spontaneous inhalation of wood smoke (approximately 6 ml) via tracheostomy immediately evoked either a slowing of respiration (SR) or an augmented inspiration (AI) in each of the 76 anesthetized Sprague-Dawley rats studied. The SR was abolished after perineural capsaicin treatment of both cervical vagi (PCT; n = 20) but persisted during cooling of both vagi to 6.7 degrees C (VGC, n = 12); PCT selectively blocked the conduction of unmyelinated C fibers, whereas VGC differentially blocked the conduction of myelinated fibers. In contrast, the AI was eliminated during VGC (n = 10) but was unaffected by PCT (n = 5). Furthermore, after the SR was abolished in rats with PCT, an AI became the dominant immediate response to inhaled wood smoke. Conversely, after the AI was eliminated in rats receiving VGC, a SR was instantly evoked by inhaled wood smoke. Removal of smoke particulates did not affect the SR (n = 17) but did prevent the AI in 5 of the 12 rats studied. These results suggest the following: 1) the SR is a reflex resulting from stimulation of bronchopulmonary C-fiber nerve endings by the gas-phase smoke; 2) the AI results from excitation of lung irritant receptors by the gas-phase and/or smoke particulates; and 3) in intact animals, both types of vagal bronchopulmonary afferents are probably activated by inhaled wood smoke.     

Characteristics of tinnitus induced by head injury

OBJECTIVE: To determine if the characteristics of tinnitus produced by head trauma are specific and exclusive when compared with other origins of tinnitus. DESIGN: Retrospective study using clinic test results and data from the Tinnitus Data Registry compiled from questionnaires, interviews, and testing. Tinnitus produced by head injury was compared with tinnitus of mixed origins, including no known origin. SETTING: A tinnitus referral clinic where all patients must see an otologist or an ear, nose, and throat physician prior to attending the clinic. PATIENTS: All patients had severe to moderately severe constant tinnitus and presented with tinnitus as the primary symptom. RESULTS: No exclusive characteristics were found to describe head injury-induced tinnitus. The tinnitus for the group with head injury was statistically significantly (P = .004) louder and occurred with greater incidence of continuing pain in the ears. The group with head injury also had more episodes of dizziness and a more severe form of tinnitus. However, no marked difference was noted in pitch of tinnitus, complexity (number of sounds) of tinnitus, or the minimum masking level. CONCLUSIONS: This retrospective study found that tinnitus induced by head injury was significantly (P = .004) louder than tinnitus induced from other causes but, interestingly, did not require higher levels of masking. The patients with head injury-induced tinnitus more frequently (P = .0003) displayed residual inhibition although the duration of residual inhibition was not different from that of the comparison group. Other symptoms associated with the tinnitus onset were more frequently mentioned by the group with head trauma-induced tinnitus, except for the condition of pressure sensation in the ears. Using a severity questionnaire, the group with head trauma-induced tinnitus rated their tinnitus as being more severe than did the comparison group. However, such things as pitch of the tinnitus, masking level, acceptance of wearable maskers, general hearing level, and complexity of the tinnitus did not distinguish the two groups.     

Enhanced involvement of endothelin in the haemodynamic sequelae of endotoxaemia in conscious, hypertensive, transgenic ((mRen-2)27) rats

1. Age-matched (3-4 months old) male, heterozygous, hypertensive, transgenic ((mRen-2)27) rats (abbreviated to TG rats) and the normotensive control animals (homozygous, Hannover Sprague-Dawley rats (abbreviated to SD rats), were chronically instrumented for the assessment of regional haemodynamic responses to continuous lipopolysaccharide (LPS) infusion (150 microg kg(-1) h(-1), i.v.) 2. The early (1-2 h) hypotension in SD rats (-11+/-3 mmHg; n=7) was significantly less than that in TG rats (-35+/-3 mmHg; n=8), but by 24 h mean arterial blood pressure (MAP) in both strains of rat was not different from the pre-LPS value (SD rats: baseline, 108+/-3 mmHg; 24 h LPS, 112+/-4 mmHg; TG rats: baseline, 171+/-2 mmHg; 24 h LPS, 169+/-3 mmHg). At this stage in the SD rats there was a renal vasodilatation (delta vascular conductance, 29+/-10 [kHz mmHg(-1)]10(3)) but not in TG rats (delta vascular conductance 2+/-3[kHz mmHg(-1)]10(3)). 3. Co-infusion of LPS and the non-selective endothelin receptor antagonist, SB 209670 (600 microg kg(-1) bolus, 600 microg kg(-1) h(-1)) between 24 and 31 h in SD rats caused a fall in MAP of 16+/-2 mmHg accompanied by hindquarters vasodilatation (delta vascular conductance 11+/-3 (kHz mmHg(-1))10(3)). In TG rats, under the same conditions, the fall in MAP was -60+/-6 mmHg, and there were renal, mesenteric and hindquarters vasodilatations (delta vascular conductance, 23+/-5, 32+/-7, and 14+/-4 (kHz mmHg(-1))10(3), respectively). All effects, except the hindquarters vasodilatation, were greater in TG than in SD rats. 4. In TG rats infused with LPS alone for 31 h, between 24 and 31 h the fall in MAP was -17+/-4 mmHg, and the changes in renal, mesenteric and hindquarters vascular conductances were 5+/-3, -4+/-5, and 12+/-4 (kHz mmHg(-1)10(3), respectively. 5. Administration of the angiotensin (AT1)-receptor antagonist, losartan (10 mg kg(-1), i.v.) following co-infusion of LPS and SB 209670 between 24 and 31 h caused similar falls in MAP in SD and TG rats (-12+/-3 and -14+/-4 mmHg, respectively). 6. These results, together with previous findings, are consistent with a relative enhancement of the contribution of endothelin to the maintenance of cardiovascular status in endotoxaemic TG rats, particularly through a mesenteric vasoconstrictor action.     

Increased sensitivity of the cough reflex in progressive systemic sclerosis patients with interstitial lung disease

Cough is a common presenting symptom of interstitial lung disease (ILD). The aim of this study was to examine the cough reflex in patients with progressive systemic sclerosis (PSS), with and without associated ILD. The cough reflex to inhalation of chloride deficient solutions and capsaicin was determined in patients with PSS with associated ILD (n=12), compared to patients with PSS without ILD (n=12). In addition, patients with a chronic dry cough (n=12) and healthy subjects (n=10) without cough were studied. Cough responses to inhalation of isotonic solutions containing 150, 75, 37.5 and 0 mM Cl- ions and of capsaicin (0.9-500 mM) were measured. PSS patients with ILD reported a significantly higher cough score than PSS patients without ILD (p<0.03). ILD patients coughed more than those without ILD to Cl- of 37.5 and 0 mM (19.1+/-5.0 vs 6.2+/-1.9 coughs x min(-1) (p<0.03), and 29.2+/-5.0 vs 14.1/-4.1 coughs x min(-1) (p<0.04), respectively). The log concentration of capsaicin causing two or five coughs was lower in PSS with ILD compared to PSS without ILD (0.74+/-0.15 mM vs 2.12+/-0.26 mM; p<0.002). Patients with chronic dry cough had a similar degree of response to low-chloride and capsaicin solutions as patients with PSS and ILD, whilst healthy controls had a similar degrees of response to PSS patients. There is an increased cough reflex in patients with interstitial lung disease, which may represent sensitization of airway sensory nerves. This may be the basis for the chronic dry cough in patients with interstitial lung disease.     

Early postoperative nutrition after laparoscopic and open colorectal resection

OBJECTIVE: In the United Kingdom in 1994-95 about 16,500 women aged 50 to 64 were asked to come back earlier than the usual three yearly screening interval for further mammography (early rescreen (ES)) or for a range of further investigations at an assessment centre (early recall (ER)). This study aimed at providing epidemiological data on ES/ER, in particular, how often and why it is used, and what the outcome is of using it. SETTING: National Health Service breast screening programme in the United Kingdom. METHODS: All breast screening units were invited to complete a postal questionnaire. Two reminders were sent. The units were asked retrospectively to provide breast screening data about women aged 50 to 64 from their local computer systems. Women placed on ES/ER were followed up for at least one year. RESULTS: The response rate was 71% (69/97), of which 14% (10/69) were unable to provide the required data, leaving 59 completed questionnaires (61%). The rate of placing women on ES/ER was above 1.0% for 26/54 (48%) responding breast screening units and above 2.0% for 13/54 (24%) units. Women were placed on ES/ER because of (a) previous breast cancer (21% of cases; cancer detection rate 2.4%), (b) diagnostic uncertainty (51%; cancer detection rate 3.0%), or (c) family history (27%; cancer detection rate 0.6%). Breast screening units with a high rate of placing women on ER were significantly more likely to have a high recall rate (rs = 0.63; n = 53; p < 0.0005) or a high benign surgical biopsy rate (rs = 0.33; n = 49; p < 0.05), or both. The cancer detection rate of ES/ER tended to decrease with increasing ES/ER rates (rs = -0.37; n = 51; p < 0.01). CONCLUSIONS: A relatively large number of women were placed on ES or ER for a range of reasons. If the recommendations given are followed, the number of women placed on ER may be reduced while maintaining the cancer detection rate at the required level. The option of ES should not be used.     

Attenuation of salicylate-induced tinnitus by Ginkgo biloba extract in rats

The effects of an extract from Ginkgo biloba, EGb 761, on tinnitus were tested using an animal model of tinnitus. Daily oral administration of EGb 761 in doses from 10 to 100 mg/ kg/day began 2 weeks before behavioral procedures and continued until the end of the experiment. Tinnitus was induced by daily administration of 321 mg/kg sodium salicylate s.c. (corresponding to 275 mg/kg/day of salicylate acid) in fourteen groups of pigmented rats, 6 animals/group. The results from salicylate- and EGb-761-treated animals were compared to control groups receiving either salicylate, saline, or EGb 761 only in doses of 100 mg/kg. Administration of EGb 761 resulted in a statistically significant decrease of the behavioral manifestation of tinnitus for doses of 25, 50 and 100 mg/kg/ day.     

Diagnostic testing following screening mammography in the elderly

BACKGROUND: To provide some sense of the general frequency and timing of diagnostic testing following screening mammography in the United States, we investigated the experience of women screened in the Medicare population. METHODS: By use of Medicare's National Claims History System, we identified a cohort (n=23172) of women 65 years old or older screened during the period from January 1, 1995, through April 30, 1995, and tracked each woman over the subsequent 8 months for the performance of additional breast imaging and biopsy procedures. Using two claims-based definitions for newly detected breast cancer, we also estimated the positive predictive value of screening mammography. RESULTS: For every 1000 women aged 65-69 years who underwent screening, 85 (95% confidence interval [CI]=79-91) had follow-up testing in the subsequent 8 months; 76 (95% CI=71-82) had additional breast imaging, and 23 (95% CI=20-26) had biopsy procedures. Corresponding numbers for women aged 70 years or more were similar. Some women underwent repeated examinations; 13% of those receiving diagnostic mammograms had more than one; 11% of those undergoing biopsy procedures had more than one. About half of the women who underwent a biopsy had the procedure more than 3 weeks after the imaging test upon which the decision to perform a biopsy was presumably made. The estimated positive predictive value of an abnormal screening mammogram (defined as a mammogram that engendered additional testing) was 0.08 (95% CI=0.06-0.10) for women aged 65-69 years and 0.14 (95% CI=0.12-0.16) for women aged 70 years or more. CONCLUSION: Additional testing is a frequent consequence of screening mammography and may require a considerable period of time to come to closure. The need for additional testing, however, is weakly predictive of cancer.     

Detection of silent intervals between noises activating different perceptual channels: some properties of "central" auditory gap detection

This article describes four experiments on gap detection by normal listeners, with the general goal being to examine the consequences of using noises in different perceptual channels to delimit a silent temporal gap to be detected. In experiment 1, subjects were presented with pairs of narrow-band noise sequences. The leading element in each pair had a center frequency of 2 kHz and the trailing element's center frequency was parametrically varied. Gap detection thresholds became increasingly poor, sometimes by up to an order of magnitude, as the spectral disparity was increased between the noise bursts that marked the gap. These data suggested that gap-detection performance is impoverished when the underlying perceptual timing operation requires a comparison of activity in different perceptual channels rather than a discontinuity detection within a given channel. In experiment 2, we assessed the effect of leading-element duration in within-channel and between-channel gap detection tasks. Gap detection thresholds rose when the duration of the leading element was less than about 30 ms, but only in the between-channel case. In experiment 3, the gap-detection stimulus was redesigned so that we could probe the perceptual mechanisms that might be involved in stop consonant discrimination. The leading element was a wideband noise burst, and the trailing element was a 300-ms bandpassed noise centered on 1.0 kHz. The independent variable was the duration of the leading element, and the dependent variable was the smallest detectable gap between the elements. When the leading element was short in duration (5-10 ms), gap thresholds were close to 30 ms, which is close to the voice onset time that parses some voiced from unvoiced stop consonants. In experiment 4, the generality of the leading-element duration effect in between-channel gap detection was examined. Spectrally identical noises defining the leading and trailing edges of the gap were presented to the same or to different ears. There was a leading-element duration effect only for the between channel case. The mean gap threshold was again close to 30 ms for short leading-element durations. Taken together, the data suggest that gap detection requiring a temporal correlation of activity in different perceptual channels is a fundamentally different task to the discontinuity detection used to execute gap detection performance in the traditional, within-channel paradigm.     

Plasticity of the acoustic startle response in the acutely decerebrate rat.

In 4 experiments, plasticity of the acoustic startle reflex was measured in male albino Sprague-Dawley rats in which a complete transection between the forebrain and midbrain was made. During a period from 60 to 100 min after surgery, startle amplitude in the transected Ss was relatively stable and comparable with that of controls (anesthetized with halothane and placed in a stereotaxic instrument). During this period the transection did not alter the temporal recovery process (with intervals of 2, 4, 8, or 16 sec) or auditory prepulse inhibition (with intervals of 25, 50, 100, 500, or 1,000 msec) or the normal reduction in startle caused by high levels of background noise. The transection did prevent the normal increase in startle caused by moderate levels of background noise and eliminated within-session habituation. The effect on habituation was particularly noticeable since the curves of the transected and nontransected Ss actually crossed. Results are dicussed in terms of how the transection procedure can be used to evaluate various hypotheses about underlying mechanisms of startle plasticity. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus-produced reflex inhibition in the rat during induction of and recovery from barbiturate anesthesia.

Reported 3 experiments which show that the inhibitory effect of a preliminary stimulus on the acoustic startle reflex was disrupted during the induction of sodium pentobarbital (40 mg/kg) in a total of 50 male Holtzman rats. In Exp I (n = 35) and II (n = 8), Ss were injected with the barbiturate, and a startle stimulus was presented either alone or preceded by a white noise burst. Results show that (a) stimulus inhibition was present immediately after injection, (b) was lost during a phase of hyperreactivity which accompanied induction of the anesthesia, and (c) recovered as reactivity diminished in the anesthetic state. Exp III showed that inhibition recovered during an intervening stage prior to complete areflexia and that this recovery revealed that the earlier and later inhibitory failure cannot be ascribed to a drug-dependent degradation in a hypothetical inhibitory system. It was suggested that the expression of reflex inhibition depends on the balanced interplay of excitatory and inhibitory processes which are differentially sensitive to drug intake. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of vision and task complexity on Hoffmann reflex gain

Previous research demonstrates modulation of the Hoffmann reflex amplitude and gain during changes in environmental conditions. H-reflex gain (defined in this study as the ratio of H-reflex amplitude to average soleus background EMG) is considered a functional measure of reflex modulation. In this study the effects of manipulating visual input and surface stability were to investigated in 17 subjects under four experimental conditions: (1) vision-stable surface, (2) no vision-stable surface, (3) vision-unstable surface, and (4) no vision-unstable surface. In each condition, subjects performed fifteen trials of a single leg stance for 7 s. The H-reflex was electrically elicited at the end of each trial by delivering a 1 ms square wave stimulation to the tibial nerve in the popliteal online for each trial (sampling rate = 2 kHz). An analysis of variance revealed significant decreases in H-reflex gain for the visual (F1.16 = 4.71, P < 0.05) and, surface conditions (F1.16 = 7.67, P < 0.05), however there was no interaction (F1.16 = 0.48, P < 0.05), between these variables. These results suggest that supraspinal mechanisms, possibly presynaptic inhibition, modulate H-reflex gain across environmental conditions. We conclude that visual and possibly cutaneous inputs were responsible for driving presynaptic inhibition and thus decreasing H-reflex gain.     

Detecting intimate partner violence in family and divorce mediation: A randomized trial of intimate partner violence screening.

Handling mediation cases with a history of intimate partner violence (IPV) is one of the most controversial issues in the field of divorce mediation. Before deciding whether and how to mediate cases with IPV, mediators must first detect violence. Using random assignment of cases to an enhanced screening condition (n = 30) and to a standard screening control condition (n = 31), we compared information gathered from a brief, behaviorally specific IPV screening questionnaire to mediators' independent determination of the presence or absence of violence using standard mediation clinic screening procedures. Mediators did not label as violent about half of the cases reporting IPV on the screening questionnaire. Mediators were more likely to report IPV when fathers were reported (by mothers) to have engaged in a greater number of differing violent behaviors, but a score reflecting severity and frequency of party reported violence did not predict mediator detection of violence. In cases with two mediators, mediators did not always agree on whether or not the case involved IPV. Possible reasons for the differences in mediator and party reports of IPV are considered, and we emphasize the potential importance of using systematic methods to screen for violence in divorce mediation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A gap detection tactility test for sensory deficits associated with carpal tunnel syndrome

An automated gap detection tactility test was investigated for quantifying sensory deficits associated with carpal tunnel syndrome (CTS). The test, which involved sensing a tiny gap in an otherwise smooth surface by probing with the finger, had functional resemblance to many work-related tactile activities such as detecting scratches or surface defects. Gap detection thresholds were measured using the converging staircase method of limits paradigm. Sixteen normal subjects between 21 and 66 years of age were tested for studying important factors affecting gap detection thresholds. Actively probing with the index finger had a threshold almost an order of magnitude more sensitive (mean = 0.19 mm, SD = 0.11 mm) than passive touch (mean = 1.63 mm, SD = 0.62 mm), which was similar to two-point discrimination. Average thresholds decreased by 24% as contact force increased from 25 to 75 g. Performance in this tactility test quickly stabilized and showed little learning effects over the period of the test, as evidenced by the lack of significant differences between six replicates. The results were highly repeatable. No significant threshold differences were observed between test and retest trials on different days, or between dominant and non-dominant hands. A contact force of 50 g was recommended as optimal for this test since it required moderate force but resulted in a smaller threshold compared with 25 or 75 g. A companion study was conducted using eight normal subjects and ten subjects diagnosed as having CTS. Average gap detection threshold, when finger probing was allowed, was 0.20 mm (SD = 0.11 min) for the normal subjects and increased two-fold to 0.40 mm (SD = 0.19 mm) for the CTS subjects. Average gap detection threshold, when the finger probing was not allowed, was 1.71 mm (SD = 0.53 mm) for the normal subjects and increased by 48% to 2.53 mm (SD = 0.87 mm) for the CTS subjects. The results suggest that people suffering from CTS may experience similar functional deficits in daily living and work activities. The small inter-subject variability makes this test a candidate for having utility as a monitoring test for loss of cutaneous tactile sensitivity.     

Consequences of controlling background sounds: The effect of experiential avoidance on tinnitus interference.

Objective: Masking by the use of sounds has been one of the most commonly applied means of coping with tinnitus. The ability to control auditory stimulation represents a potentially important process involved in tinnitus masking strategies. Little is, however, known about the consequences of control on tinnitus experience. The present study investigated the effects of control of background sounds (type and loudness) on perceived intrusiveness of tinnitus and cognitive performance. Design: Using an experimental design with a series of trials, participants with clinically significant tinnitus (N = 35) were randomly assigned to 1 of 2 experimental manipulation conditions (control of sounds vs. no control of sounds). Measures: Self-reported tinnitus interference and the Digit-Symbol subtest served as dependent measures. Results: Latent growth curve modeling showed that individuals assigned to the condition with control exhibited faster growth rates on tinnitus interference (increased interference) and demonstrated slower rates of improvement on cognitive performance measures over trials compared to individuals assigned to the condition with no control. Conclusion: These results suggest that efforts to control tinnitus through sounds can be associated with increased disability in individuals with tinnitus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)