Consecutive Testing Sessions Research Articles

Absolute reliability of isokinetic knee flexion and extension measurements adopting a prone position

The main purpose of this study was to determine the absolute and relative reliability of isokinetic peak torque (PT), angle of peak torque (APT), average power (PW) and total work (TW) for knee flexion and extension during concentric and eccentric actions measured in a prone position at 60, 180 and 240° s(-1). A total of 50 recreational athletes completed the study. PT, APT, PW and TW for concentric and eccentric knee extension and flexion were recorded at three different angular velocities (60, 180 and 240° s(-1)) on three different occasions with a 72- to 96-h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CV(TE)), percentage change in the mean (ChM) and relative reliability with intraclass correlations (ICC(3,1)). For both the knee extensor and flexor muscle groups, all strength data (except APT during knee flexion movements) demonstrated moderate absolute reliability (ChM < 3%; ICCs > 0·70; and CV(TE) < 20%) independent of the knee movement (flexion and extension), type of muscle action (concentric and eccentric) and angular velocity (60, 180 and 240° s(-1)). Therefore, the current study suggests that the CV(TE) values reported for PT (8-20%), APT (8-18%) (only during knee extension movements), PW (14-20%) and TW (12-28%) may be acceptable to detect the large changes usually observed after rehabilitation programmes, but not acceptable to examine the effect of preventative training programmes in healthy individuals.

Absolute Reliability of Hamstring to Quadriceps Strength Imbalance Ratios Calculated Using Peak Torque, Joint Angle-Specific Torque and Joint ROM-Specific Torque Values

The main purpose of this study was to determine the absolute reliability of conventional (H/Q(CONV)) and functional (H/Q(FUNC)) hamstring to quadriceps strength imbalance ratios calculated using peak torque values, 3 different joint angle-specific torque values (10°, 20° and 30° of knee flexion) and 4 different joint ROM-specific average torque values (0-10°, 11-20°, 21-30° and 0-30° of knee flexion) adopting a prone position in recreational athletes. A total of 50 recreational athletes completed the study. H/Q(CONV) and H/Q(FUNC) ratios were recorded at 3 different angular velocities (60, 180 and 240°/s) on 3 different occasions with a 72-96 h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CVTE), percentage change in the mean (CM) and intraclass correlations (ICC) as well as their respective confidence limits. H/Q(CONV) and H/Q(FUNC) ratios calculated using peak torque values showed moderate reliability values, with CM scores lower than 2.5%, CV(TE) values ranging from 16 to 20% and ICC values ranging from 0.3 to 0.7. However, poor absolute reliability scores were shown for H/Q(CONV) and H/Q(FUNC) ratios calculated using joint angle-specific torque values and joint ROM-specific average torque values, especially for H/Q(FUNC) ratios (CM: 1-23%; CV(TE): 22-94%; ICC: 0.1-0.7). Therefore, the present study suggests that the CV(TE) values reported for H/Q(CONV) and H/Q(FUNC) (≈18%) calculated using peak torque values may be sensitive enough to detect large changes usually observed after rehabilitation programmes but not acceptable to examine the effect of preventitive training programmes in healthy individuals. The clinical reliability of hamstring to quadriceps strength ratios calculated using joint angle-specific torque values and joint ROM-specific average torque values are questioned and should be re-evaluated in future research studies.

Enhanced attenuation of nicotine discrimination in rats by combining nicotine-specific antibodies with a nicotinic receptor antagonist

Tobacco addiction requires activation by nicotine of a variety of central nicotinic acetylcholine receptors (nAChRs). In animals, both nAChR antagonists and immunization against nicotine can reduce nAChR activation by nicotine and block a variety of addiction-relevant behaviors. However, clinical use of nAChR antagonists for smoking cessation is limited by dose-related side effects, and immunization does not reliably produce sufficient antibody levels in smokers to enhance smoking cessation rates. Combining these approaches may be one way of addressing the limitations of each while enhancing overall efficacy. This study examined the individual and combined effects of passive immunization with the monoclonal nicotine-specific antibody Nic311 and the nicotinic receptor antagonist mecamylamine (MEC) on nicotine's discriminative stimulus effects. Rats were trained to discriminate 0.4mg/kg of nicotine from saline using a two-lever operant discrimination procedure. Antagonism of nicotine discrimination by Nic311 (160mg/kg i.v.) and ascending doses of MEC (0.03, 0.1, 0.3, and 1.0mg/kg s.c.) was assessed across four consecutive daily 2-min extinction test sessions using a 2×2 design. Nic311 alone produced a 24–48% reduction in % nicotine-lever responding (%NLR) across all four test sessions. MEC produced a dose-dependent decrease in %NLR, with no effect at the two lowest doses and 80–93% attenuation at the two highest doses. Nic311 combined with MEC significantly suppressed %NLR at every MEC dose (85–92% reduction across all four test sessions). Very low doses of MEC that were ineffective alone completely blocked nicotine discrimination when combined with Nic311. These data demonstrate that nicotine-specific antibodies and MEC can work synergistically to suppress the subjective effects of nicotine and suggest that low doses of MEC may significantly enhance the efficacy of immunotherapy.

Between-Seasons Test-Retest Reliability of Clinically Measured Reaction Time in National Collegiate Athletic Association Division I Athletes

Reaction time is typically impaired after concussion. A clinical test of reaction time (RT(clin)) that does not require a computer to administer may be a valuable tool to assist in concussion diagnosis and management. To determine the test-retest reliability of RTclinmeasured over successive seasons in competitive collegiate athletes and to compare these results with a computerized measure of reaction time (RT(comp)). Case series with repeated measures. Preparticipation physical examinations for the football, women's soccer, and wrestling teams at a single university. 102 National Collegiate Athletic Association Division I athletes. The RT(clin) was measured using a measuring stick embedded in a weighted rubber disk that was released and caught as quickly as possible. The RT(comp) was measured using the simple reaction time component of CogState Sport. Data were collected at 2 time points, 1 season apart, during preparticipation physical examinations. Outcomes were mean simple RT(clin) and RT(comp). The intraclass correlation coefficient estimates from season 1 to season 2 were 0.645 for RT(clin) (n = 102, entire sample) and 0.512 for RT(comp) (n = 62 athletes who had 2 consecutive valid baseline CogState Sport test sessions). The test-retest reliability of RT(clin) over consecutive seasons compared favorably with that of a concurrently tested computerized measure of reaction time and with literature-based estimates of computerized reaction time measures. This finding supports the potential use of RT(clin) as part of a multifaceted concussion assessment battery. Further prospective study is warranted.

Monitoring changes in physical performance with heart rate measures in young soccer players

The aim of the present study was to verify the validity of using exercise heart rate (HRex), HR recovery (HRR) and post-exercise HR variability (HRV) during and after a submaximal running test to predict changes in physical performance over an entire competitive season in highly trained young soccer players. Sixty-five complete data sets were analyzed comparing two consecutive testing sessions (3-4 months apart) collected on 46 players (age 15.1 ± 1.5 years). Physical performance tests included a 5-min run at 9 km h(-1) followed by a seated 5-min recovery period to measure HRex, HRR and HRV, a counter movement jump, acceleration and maximal sprinting speed obtained during a 40-m sprint with 10-m splits, repeated-sprint performance and an incremental running test to estimate maximal cardiorespiratory function (end test velocity V (Vam-Eval)). Possible changes in physical performance were examined for the players presenting a substantial change in HR measures over two consecutive testing sessions (greater than 3, 13 and 10% for HRex, HRR and HRV, respectively). A decrease in HRex or increase in HRV was associated with likely improvements in V (Vam-Eval); opposite changes led to unclear changes in V (Vam-Eval). Moderate relationships were also found between individual changes in HRR and sprint [r = 0.39, 90% CL (0.07;0.64)] and repeated-sprint performance [r = -0.38 (-0.05;-0.64)]. To conclude, while monitoring HRex and HRV was effective in tracking improvements in V (Vam-Eval), changes in HRR were moderately associated with changes in (repeated-)sprint performance. The present data also question the use of HRex and HRV as systematic markers of physical performance decrements in youth soccer players.

Single and repeated baclofen treatment attenuates the discriminative stimulus effects of morphine in rats

The GABA B agonists block the rewarding properties of opiates. However, the role of GABA B receptors in the discriminative properties of these drugs has received little attention. In this line, the present study was performed to investigate the effects of acute (Experiment 1) and chronic (Experiment 2) pretreatment with baclofen on the discriminative stimulus effects of morphine. Rats were trained to discriminate morphine (5 mg/kg i.p.) from saline under a two-lever fixed-ratio schedule of food reinforcement. Experiment 1: a morphine generalization curve was obtained under standard conditions in control and baclofen (1 and 2 mg/kg i.p.) pretreated animals. Acute baclofen pretreatment attenuated morphine-lever responding and response rate at both doses. Experiment 2: the animals were randomly divided in two groups and a morphine generalization curve was obtained in daily consecutive test sessions before (TEST1) and after (TEST2) chronic saline (Group I) or chronic baclofen (2 mg/kg) (Group II) administration. As expected, chronic saline pretreatment was ineffective, while chronic baclofen pretreatment attenuated the stimulus properties of morphine, without modifying the rate-decreasing effect of the drug.The data support a role for GABAergic neurotransmission in the discriminative effects of opiates and demonstrate that a short-term treatment with baclofen is useful for decreasing the sensitivity to narcotic cue.

Sleep latency and efficiency are associated with increases in temporal summation across consecutive pain testing sessions in disorder

Sleep latency and efficiency are associated with increases in temporal summation across consecutive pain testing sessions in disorder

Intersession Reliability of Kinematic and Kinetic Variables During Vertical Jumps in Men and Women

To investigate the intersession reliability of selected kinematic and kinetic variables during countermovement vertical jumps (CMJs). Thirty-five men and 35 women performed CMJs on a force platform during four testing sessions each separated by 1 wk. Kinematic variables included time in the air (TIA), take-off velocity (TOV), total vertical displacement of the center of mass (TJH), and countermovement depth, whereas kinetic variables included positive impulse, negative impulse, vertical stiffness, and rates of force development. Systematic bias was assessed by calculating the 90% confidence interval of the change in the mean between consecutive testing sessions and between the first and final testing session for each variable. Coefficients of variation (CV) and intraclass correlation coefficients (ICC) were also calculated. Systematic bias was observed only for peak rate of force development during the concentric phase of the movement. For TIA, TOV, and TJH, CV values ranged from 1.7% to 6.6%, with ICC values ranging from 0.82 to 0.97. The other variables showed greater variation (CV range: 1.7% to 39.9%; ICC range: 0.04 to 0.99). Only slight gender differences were found in the reliability statistics, and the reliability of most of the variables was diminished as the time between the testing sessions was increased. Even though practitioners can expect good reliability for jump height measured from a force platform in men and women, other kinematic and kinetic variables often assessed during vertical jumps may not be reliable.

Practicality of a computerized system for cognitive assessment in the elderly

Background Early detection and diagnosis are critical to dementia care. However, many early cases remain undiagnosed as a result of the impracticality of neuropsychological testing, particularly in primary care. Mindstreams is an office-based computerized system for measuring cognitive function in multiple domains, with demonstrated validity, test-retest reliability, and sensitivity to treatment effects. This study evaluated its feasibility for assessment of the elderly. Methods Usability data were collected after each of 2,888 consecutive initial-visit testing sessions at the first 11 clinical centers to use Mindstreams. The χ 2 goodness-of-fit test was employed to determine whether patients and supervisors more often rated tests easy versus hard to use. Separate analyses were run for non–computer users, patients older than 75 years, and poor performers (≤1 standard deviation on overall battery performance). Results For all patients (n = 2,888; age, 64.7 ± 18.2 years), 83% rated the tests easy to use ( P < .001). Seventy-three percent of non–computer users, 70% of patients older than 75, and 69% of poor performers rated them easy to use ( Ps < .001). Supervisor ratings and ease of understandability ratings were similar. For all patients, 76% of supervisor ratings indicated no patient frustration ( P < .001). Seventy-eight percent of ratings for non–computer users, 76% for patients older than 75, and 74% for poor performers indicated no frustration ( Ps < .001). Conclusions Mindstreams was easily employed, including in patients with considerable cognitive impairment, supporting its practicality for in-office cognitive assessment of the elderly. The availability of such valid and practical assessment suggests the feasibility of integrating the technology within a clinical algorithm for improved detection of cognitive decline.

9. Innovation in research instruction: Pilot testing of team learning to promote peer reviewed grantwriting by clinician trainees

We piloted the combination of Team-Based Learning (TBL) with interactive in-class instruction in grantsmanship to test its effectiveness in preparing clinician trainees to produce a national (CIHR) peer reviewed operating grant in a small class setting. The approach was integrated into a university graduate quantitative method and design course delivered to five trainees in 12 weekly 4hr sessions. Outcomes to assess knowledge acquisition, retention and application included percentage scores in seven TBL individual and student team tests (each containing 15-20 multiple-choice items), student participation in a mock peer review and student own submission of an operating grant (using CIHR peer review evaluation criteria to assess methodological coherency and soundness of the research design and plan, feasibility, relevancy and innovativeness). Also assessed were student perception of the approach on their learning (7 item questionnaire) and two peer teaching evaluations.&#x0D; In seven consecutive testing sessions, percentage scores for the individual tests were 80, 72, 76, 71, 83, 75 and 80 and corresponding team scores were 96, 96, 83, 100, 95, 97, and 97 suggesting an 18% increase in individual knowledge with team testing. Overall, student achievements were 93% for mock peer review and 78% for grant production. Trainees rated TBL and the interactive in-class activities as effective in consolidating knowledge and promoting complex research design decision making. Evaluations of the teaching were 4.7 and 4.8 out of 5. Findings suggest students mastered course content, that team learning increased individual knowledge and that trainees linked theory to successfully produce a CIHR operating grant. These pilot findings call for larger prospective studies to test the combined approach in larger classes and with other populations of clinician trainees. &#x0D; The clinician scientist: yesterday, today and tomorrow. Canadian Institutes of Health Research. http://www.cihr-irsc.gc.ca/e/pdf_22084.htm. Accessed February 25, 2007.&#x0D; Ringel SP. Steiner JF, Vickrey BG, Spencer SS. Training clinical researchers in neurology: We must do better. Neurology 2001; 57:388-392.&#x0D; Haidet P, O’Malley KJ, Boyd R. An initial experience with “Team Learning’ in medical education. Academic Medicine 2002; 77: 40-41.

The reliability of the Movement Assessment Battery for Children for preschool children with mild to moderate motor impairment

Objectives : To provide further evidence of the test—retest reliability and agreement of the Movement Assessment Battery for Children (M-ABC), a standardized motor test used for identification and evaluation of children with mild to moderate motor impairment. Both the stability of total test scores and classification according to specified cut-off points were examined. Design and setting : Children were tested on the M-ABC, three times with an interval of three weeks between each assessment. Participants : Thirty-three 4- and 5-year-old children with poor motor performance, 24 boys and 9 girls. Results : A systematic practice effect between three consecutive testing sessions was shown. This was significant for the total score and two of the three subscores. Test—retest reliability of the total test score yielded an intraclass correlation coefficient (ICC) of 0.88. The total impairment score ranged between 0 and 40. The standard error of measurement (SEM) of this score was 2.4, resulting in a least detectable difference of 6.6 (with alpha set at 5%). The agreement over three testing sessions (κ) was 0.72. Conclusions : The total impairment score of the M-ABC is a reliable measure for identification of mild to moderate motor impairment in young children. Repeated testing on the M-ABC at intervals of three weeks results in a systematic measurement error and is not recommended. The SEM is substantial. Follow-up of preschool children with the M-ABC as a single outcome measure is not appropriate.

The differential relationship between cocaine use and marijuana use on decision-making performance over repeat testing with the Iowa Gambling Task

Decision-making deficits are a robust cognitive correlate of substance abuse, but few studies have addressed the long-term differential associations of cocaine use and marijuana (MJ) use on decision-making. This study utilized the Iowa Gambling Task (IGT), a widely used measure of decision-making, to investigate the relationship between cocaine and MJ use and IGT learning. We analyzed between and within group differences across two consecutive testing sessions in abstinent users of either MJ or cocaine. We assessed long-term correlates of the use of these drugs by evaluating users after 25 days of enforced abstinence. Results showed that both cocaine users and MJ users performed worse than controls on the total IGT net score. All groups showed learning between Session 1 and Session 2, but the cocaine users showed the smallest increase in performance. The pattern of learning from the beginning to the end (block × block) of the IGT (Session 2) was different for the drug groups, with the cocaine group showing more learning than the MJ group. Dose-related measures of cocaine use (g/week) and MJ use (joints/week) predicted IGT performance (the heavier the drug use the lower the performance). Differential correlates of cocaine use and MJ use on decision-making learning may have important implications for the development of novel treatment interventions.

A note on social dominance and learning ability in the domestic chicken ( Gallus gallus)

Relatively little is known about the relationship between social behavior and specific cognitive abilities of the chicken. It is uncertain whether dominant birds have a cognitive advantage over subordinate birds that might facilitate their superior position in the social hierarchy. Likewise, it is unknown whether subordinate birds compete successfully with higher ranking birds because their cognitive capacities compensate for physical deficits. In this study, the relationship between the chicken's position in the dominance hierarchy and its performance on a cognitive task was explored. Ten pairs of New Hampshire domestic roosters ( Gallus gallus) were observed to determine dominance or subordinance within dyads. All birds were then trained and tested on a visual discrimination learning task. Discriminative stimuli were orange and green plastic discs. Correct stimuli (orange or green) were randomly assigned to birds. Placement of the discs (left or right of center) was also randomly assigned and counterbalanced to avoid a side bias. Birds were rewarded with food for pecking at the correct disc. Criterion for task completion was 80% correct responses on three consecutive test sessions or 86% correct on two consecutive sessions. All subjects met the test criterion. The number of trials to criterion was compared between dominant and subordinate birds using a paired t-test. No difference was found in performance between dominant and subordinate birds ( p > 0.05) suggesting that in chickens, ability to learn a novel visual discrimination task is not well correlated with rank. Additional studies, particularly using different learning paradigms, are needed to confirm these results.

The entorhinal cortex plays a role in extinction

In this study, we analyzed the participation of the entorhinal cortex in extinction of a learned aversive response. Rats with infusion cannulae aimed to the entorhinal cortex were trained in a one-trial step-down inhibitory avoidance task (IA) and submitted to four consecutive daily test sessions without the footshock, a procedure that induced extinction of the conditioned response in control animals. When infused into the entorhinal cortex immediately after the first extinction session at doses able to block consolidation of IA memory, the NMDA receptor antagonist, AP5 (25 nmol/side), the inhibitor of protein synthesis anisomycin (300 nmol/side) and the inhibitor of CaMKII, KN-93 (10 nmol/side), but not the MEK1/2 inhibitor PD-98059 (5 nmol/side) hindered extinction of the IA response. The same results were obtained when the interval between the first and second test session was 48 instead of 24 h. The data indicate that normal functionality of the NMDA receptors, together with CaMKII activity and protein synthesis are necessary in the entorhinal cortex at the time of the first test session to generate extinction. Our results also suggest that the ERK1/2 pathway does not play a role in this process.

Oculomotor behaviour in simultanagnosia: A longitudinal case study

The aim of the present single case study was to investigate oculomotor recovery in a patient with simultanagnosia due to biparietal hypoxic lesions. Applying visual exploration as well as basic oculomotor tasks in three consecutive test sessions – i.e. 8 weeks, 14 weeks, and 37 weeks after brain damage had occurred – differential recovery was observed. While visual exploration remarkably improved, an impaired disengagement of attention persisted. The improvement of exploration behaviour is interpreted within an oculomotor network theory and implications for a deficit-specific recovery from simultanagnosia are discussed.

Memory extinction requires gene expression in rat hippocampus

Rats with cannulae in the dorsal CA1 region of the hippocampus were trained in one-trial step-down inhibitory avoidance, and submitted to four consecutive daily test sessions without the footshock. This produced extinction of the conditioned response in control animals. The bilateral infusion into the CA1 region of the dorsal hippocampus of two different inhibitors of gene transcription, DRB (80 μg/side) or α-amanitin (25 pg/side), or of the protein synthesis inhibitor, anisomycin (80 μg/side) blocked extinction of the CR. The treatments were effective when given 15 min before, but not 1 or 3 h after the first test session. Retrieval itself was not affected by the drugs. The treatments did not affect general activity in an open field or anxiety levels measured in an elevated plus maze. The data indicate that gene transcription and protein synthesis are necessary at the time of the first test session in order to generate extinction. These requirements are to be expected from learning that involves new synaptic associations.

Effect of stress on feeding behavior in rats: individual differences

Abstract The experiment was conducted to study individual differences in stress-induced changes of food intake in rats and to examine concomitant changes of non-eating behaviors. Eating and non-eating behaviors were measured during five consecutive test sessions under stressful noise (95 dB white noise, n =18) and control conditions (60 dB white noise, n =18). Two thirds of the stressed rats were classified as normophagic, one third showed hypophagic responses. Hypophagic rats spent less time eating and more time grooming and resting than normophagic and control rats. Hypophagic rats also showed an increased tendency of scanning movements during eating and an increased tendency to leave the food area. Their eating speed was significantly lower than that of the normophagic rats. Hypophagic rats were characterized by a heightened reactivity to stressors which may have counteracted the adaptation to the stressful feeding situation. Results point to a role of biological factors for individual differences in stress-induced changes of eating.

Altered adaptive behaviour expressed in an open-field paradigm in experimental hepatic encephalopathy

Chronic hepatic encephalopathy (HE) encounters a neuropsychiatric syndrome arising as a complication to liver dysfunction. Patients with chronic HE display a great variety of neuropsychiatric symptoms including such mental derangements as adaptational difficulty, and deteriorated learning and memory capacity. The portacaval shunt (PCS) in the rat is a widely used model for experimental chronic HE. In the present study, the adaptive capacity of unhabituated PCS rats and sham-operated control rats were studied by measuring two exploratory behaviours (locomotion and rearing) during 5 or 60 min, at four consecutive days or nights with 24 h between sessions. The results revealed that PCS and sham-operated control rats showed parallel behavioural outcome over the four sessions in the 5-min trial. However, at the four consecutive test sessions in the 60-min trials, the sham-controls displayed a continuing decrease in overall activity between sessions whereas the PCS rats evidenced a repeated and stable activity level. These results indicate a presence of a long-term habituation deficiency as exhibited by the PCS rats. Additionally, the results indicate that differences in normal open-field motor behaviour between PCS rats and controls may not be found if such tests are conducted repeatedly during night-time but may emerge when tested repeatedly during daytime. The results may also be interpreted as a possible impaired learning/memory capacity in PCS rats. However, further investigations of how the PCS procedure affects entities of adaptation and learning ability are needed before any conclusions may be drawn since this is the first report of such an impairment in experimental chronic HE when represented by the PCS rat.

Odorant Threshold Following Methyl Bromide-Induced Lesions of the Olfactory Epithelium

YOUNGENTOB, S. L., J. E. SCHWOB, P. R. SHEEHE AND L. M. Youngentob. Odorant threshold following methyl bromide-induced lesions of the olfactory epithelium. PHYSIOL BEHAV 62(6) 1241–1252, 1997.—The present study assessed the functional consequences of peripheral olfactory destruction on the minimum detectable levels of stimulation for the odorants 2-propanol, d-limonene, and ethyl acetoacetate. Using standard operant techniques, eight Long–Evans rats were trained to criterion on an air versus odor differential response task. Odorant threshold was then determined on 10 consecutive testing sessions, using a computer-automated olfactometer and psychophysical tracking procedure. Following the last testing session, the rats were lesioned by exposing them to 330 ppm methyl bromide gas for 6 h. For each lesioned animal the anatomical state of the olfactory epithelium was evaluated relative to behavioral performance on the odorant threshold task at 3 days postlesion. For the group of rats, a comparison of pre- and postlesion performance demonstrated that, on the average, odor sensitivity was not altered by lesions that destroy roughly 95–98% of the epithelium. However, analysis of individual cases illustrated that two of the eight rats showed an elevation in odor sensitivity, albeit minimally, that was considered different from the prelesion performance. For those animals affected, we could extract no apparent relationship between the behavioral findings and the extent of anatomical damage. The results of this study demonstrate the remarkable capacity of the olfactory system to maintain normal or near-normal detection sensitivity in the face of massive damage. This capacity presumably reflects both the normal exposure of the epithelium to continual injury and the importance of maintained olfactory function for the survival of the animal.

Scanning Behavior of Rats During Eating Under Stressful Noise

Krebs, H., P. Weyers, M. Macht, H.-G. Weijers and W. Janke. Scanning behavior of rats during eating under stressful noise. Physiol Behav 62(1) 151–154, 1997.—Behavioral ecological theories postulate that threatening environments should increase eating speed and vigilance during feeding. In the present experiment, eating speed and scanning behavior during eating were measured in 36 rats in 5 consecutive test sessions under stressful noise (95 dB white noise, n = 18) and control conditions (60 dB, n = 18) after the animals had been habituated to the test environment. Intense noise induced an increase of scanning rate and eating speed. These effects are similar to those reported for novel and light environments.