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PubMed2002

Effects of acute and repeated systemic administration of ketamine on prefrontal acetylcholine release and sustained attention performance in rats.

RATIONALE: The effects of non-competitive N-methyl- D-aspartate (NMDA) receptor antagonists model aspects of schizophrenic symptomatology. Because effects on both cortical cholinergic transmission and attentional processes have been hypothesized to represent components of the properties of psychotogenic drugs, the present study investigated the effects of ketamine on the activity of cortical cholinergic inputs and attentional performance. OBJECTIVE: To determine the effects of acute and repeated ketamine administration on cortical acetylcholine release and performance of rats in an operant task designed to assess sustained attention performance. METHODS: Experiment 1 assessed the effects of ketamine (2.0-20.0 mg/kg, i.p.) on medial prefrontal acetylcholine release using in vivo microdialysis. In experiment 2, animals were pretreated with 2.0 mg/kg or 25.0 mg/kg ketamine for 7 days. Cortical acetylcholine release was assessed in these rats following the subsequent administration of a 'challenge' dose of 2.0 mg/kg on days 1, 8, and 15 following completion of the pretreatment regimen. Experiment 3 assessed the effects of acute ketamine administration (2.0, 4.0, and 8.0 mg/kg, i.p.) on sustained attention performance. In experiment 4, animals trained in the sustained attention task were pretreated with 25.0 mg/kg ketamine or vehicle for 7 days. In these animals, the performance effects of 2.0 mg/kg ketamine administered 1, 8, or 15 days after completion of the pretreatment regimen were assessed. RESULTS: The acute administration of ketamine dose dependently increased cortical acetylcholine release by up to 250% above baseline and for over 40 min following the highest dose of ketamine. Pretreatment with 2.0 mg or 25.0 mg/kg did not robustly alter the effects of subsequent ketamine administration on cortical acetylcholine release. In animals performing the sustained attention task, administration of the highest dose of ketamine resulted in high levels of errors of omission, while the administration of the two smaller doses did not affect performance. Pretreatment with 25.0 mg/kg disrupted the attentional performance during the pretreatment period, but it did not affect the baseline performance thereafter. Furthermore, ketamine pretreatment did not systematically alter the performance effects of subsequent ketamine administration. CONCLUSIONS: The robust stimulation of cortical acetylcholine release represents a potent component of the pharmacological effects of ketamine. The effects of acute ketamine on attentional performance were limited to high rates of omissions. Repeated ketamine administration 'sensitized' neither cortical acetylcholine release nor attentional performance. These effects of repeated ketamine differ substantially from those of another major psychotogenic drug, amphetamine, and thus support the view that ketamine and amphetamine model fundamentally different aspects of schizophrenia.

Acetylcholine↗

PubMed1994

The reluctance of house staff to perform mouth-to-mouth resuscitation in the inpatient setting: what are the considerations?

OBJECTIVE: Medical house staff are required to perform cardiopulmonary resuscitation (CPR) as part of their job responsibilities. Previously it has been shown that house staff are reluctant to perform mouth-to-mouth resuscitation (MMR) in an out of hospital setting. Therefore, whether reluctance to perform MMR extends to the inpatient setting, and, if so, the reasons for this reluctance were investigated. DESIGN: All 74 internal medicine house officers of a large metropolitan hospital responded to presentations of hypothetical inpatient cardiac arrest scenarios to assess their willingness to perform MMR. SETTING: A 1200 bed university-affiliated teaching hospital in Los Angeles, California. SUBJECTS: All categorical internal medicine house officers at this hospital. INTERVENTIONS: This study is a survey which concerns whether the house officer would perform mouth-to-mouth resuscitation in different hypothetical cardiac arrest scenarios. RESULTS: Forty-five percent would perform MMR on an unknown patient and 39% would perform MMR in the elderly patient scenario. Only 16% would do MMR on a patient with a small amount of blood on his lips and only 7% would perform MMR on a patient with presumed acquired immunodeficiency syndrome. Medical housestaff were much more reluctant to perform MMR on elderly, trauma, or presumed immunodeficient patients in an inpatient setting than in an outpatient setting. All house staff that indicated their unwillingness to perform MMR cited fear of human immunodeficiency virus infection as their reason. CONCLUSION: Medical housestaff are quite reluctant to perform MMR in an inpatient setting. Thus, educating the medical house staff about the percent of patients that survive inpatient cardiac arrest and the actual risks of contracting infectious diseases, especially HIV infections, from MMR and preventative measures, such as effective barrier masks, should result in an increased willingness of physicians to perform MMR or mouth-to-mask ventilation on inpatients.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Psychobiology of stage fright: the effect of public performance on neuroendocrine, cardiovascular and subjective reactions.

Subjective, neuroendocrine and cardiovascular functions were studied in high- and low-anxious musicians performing privately and publicly. Musicians were designated as "high-anxious" if they reported at least one episode of performance-related tremor and as "low-anxious" if they never had experienced tremor while performing in public. All musicians performed privately and publicly while measurements of subjective, neuroendocrine and cardiovascular functions were made. Ratings of effort and distress were made prior to performance. Heart rate was monitored telemetrically before, during and after performance. Urinary epinephrine, norepinephrine and cortisol were sampled after public and private performance, respectively. Situational factors influenced most measures. Epinephrine, norepinephrine, cortisol, heart rate and ratings of distress but not effort increased from private to public performance. Heart rate was higher in high- than in low-anxious musicians during public performance but similar during private performance. The increase in neuroendocrine activation from private to public performance was similar in the high- and low-anxious groups. It is concluded that heart rate is a sensitive measure of both situational and individual determinants of performance-related distress.

Achievement↗

PubMed2006

Educational performance of pediatric cochlear implant recipients in mainstream classes.

OBJECTIVES: The present study documents the school performance of 20 pediatric cochlear implant recipients who attended mainstream classes and compares their educational performance with their normally hearing peers. METHODOLOGY: All 20 school-aged children who underwent cochlear implantation at the Universiti Kebangsaan Malaysia cochlear implant programme participated in this study. Three measures were employed to assess the school performance. First, using the SIFTER teacher-rating scale, the second measure was the child's examination results, and the third was the child's standing compared to his/her peers in language subject, mathematics, and the overall academic performance during the end of semester examinations. RESULTS: The SIFTER rating scale indicated that only 11.8% of the children were identified as not educationally at risk, 17.6% passed four of the SIFTER subtests, whereas the other 71.6% failed in at least two of the subtests on SIFTER. The highest pass rate was obtained in behavior subtest (76.5%), followed by classroom participation (70.6%), attention (58.8%), academic (47.1%), and communication (11.8%). On the educational performance, the cochlear implant recipients performed significantly better in mathematics (mean scores 62.67%; S.D. 22.24) than in language (mean scores 49.96%, S.D. 25.88) (p<0.01). In the overall examination performance, 25.00% had above average performance (>75th percentile), 18.75% had average performance (25-75th percentile), and another 56.25% performed at below average (<25th percentile). CONCLUSION: Children with cochlear implant were rated poorly in the SIFTER communication subtest. It is possible that language deficit presents an educational challenge in these children. The educational performance of children with cochlear implants in mainstream classes varies. Although 43.75% of them thrive well in a full-time mainstream setting, a significant percentage of them (56.25%) performed at below the average level. These findings reemphasize that although a cochlear implant has successfully provided deaf children with a good hearing potential, the majority of its recipients still require additional educational supports in order to function well in the mainstream educational setting.

Child↗

PubMed1999

Associations of performance-based and self-reported measures of visual function. The Beaver Dam Eye Study.

OBJECTIVE: To describe and compare performance-based and self-reported measures of visual function and to evaluate how each varied with age and how the performance-based measures were associated with the responses to self-reported questions about visual function. DESIGN: Population-based epidemiologic study. PARTICIPANTS: Adults participating in the first follow-up of the Beaver Dam Eye Study (n = 3,722). MAIN OUTCOME MEASURES: Performance-based measures of vision including current binocular, best-corrected and near visual acuities, sensitivity to light as measured by an automated perimeter, contrast sensitivity, and self-reported measures from a standardized interview. RESULTS: All performance-based and self-reported visual functions decreased with increasing age (p < 0.0001 for each). On average, women did more poorly than men on all the performance-based measures (p < 0.0001 for each), and on some of the self-reported measures. For both genders, correlations among the performance-based measures ranged from 0.38 to 0.67. In general, individuals reporting good visual function or little difficulty with visual tasks scored better on performance-based measures compared to individuals whose questionnaire responses reflected limited visual function. Overall, about 39% of drivers reported that their vision caused them to limit their night driving. Correlations of performance-based with self-reported measures of visual function were greater for best-corrected, binocular and near visual acuity compared to correlations of visual sensitivity to light and contrast sensitivity. There were 1,285 persons whose best-corrected acuity was better than their current binocular acuity and there were 97 people with visual impairment considering only current binocular acuity whose vision improved to better than 20/40 after refraction. CONCLUSIONS: Performance-based and self-reported measures of visual function were consistently and inversely related to age. Performance-based measures were, in general, more highly correlated between themselves than were self-reported measures. Self-reported visual functions were significantly positively correlated with all performance-based measures, but correlations were moderate. While high contrast measures are usually used in clinical settings and in many studies, the data suggest that in assessing function it is appropriate to measure several different aspects of vision, both performance-based and self-assessed. Our data give some indication of the impact these visual functions have on daily life as reflected by night driving and on near and distant visual acuity. New refractive corrections would likely improve the visual acuity in many older adults.

Adult↗

PubMed1991

Does self-efficacy predict performance in experienced weightlifters?

Previous studies that have examined self-efficacy-performance relationships have used novice performers. It is unclear if these findings would generalize to "experienced" performers. Based on Bandura's self-efficacy theory, this study was designed to investigate (a) the effects of false information feedback on self-efficacy beliefs and subsequent weightlifting performance, and (b) whether self-efficacy or past performance is most related to subsequent weightlifting performance. Experienced weightlifters engaged in six performance sessions, each consisting of a one-repetition-maximum bench press. Male subjects (N = 36) were randomly assigned to one of three treatment groups: accurate performance information, false information that they lifted more than their actual lift, or false information that they lifted less than their actual lift. Before each session, subjects indicated the amount of weight they were 100%, 75%, and 50% confident they could lift. Results replicated existing research findings regarding deception and performance; false positive feedback increased future bench press performance. In addition, results indicated that past weightlifting performance accounted for nearly all of the variance in subsequent performance. This finding is discussed in light of the difficulty in extending the predictions of self-efficacy theory to sport settings where athletes have gained experience by undergoing repeated training trials.

Adult↗

PubMedDate not supplied

Effect of sentence length and complexity on working memory performance in Hungarian children with specific language impairment (SLI): A cross-linguistic comparison.

BACKGROUND: English-speaking children with specific language impairment (SLI) perform more poorly than their typically developing peers in verbal working memory tasks where processing and storage are simultaneously required. Hungarian is a language with a relatively free word order and a rich agglutinative morphology. AIMS: To examine the effect of linguistic structure on working memory performance. It was examined whether syntactic complexity has a larger impact on working memory performance than sentence length in Hungarian-speaking children, similar to the findings in English speaking children. METHODS & PROCEDURES: In Experiment 1, performance accuracy was measured with two linguistic span tasks that included stimuli with varying sentence length and syntactic complexity. Experiment 2 examined the impact of sentence length and morphological complexity on working memory performance. OUTCOMES & RESULTS: Children with SLI performed more poorly than their age-matched peers in all working memory tasks. Their error patterns differed from those of children with typical language development. Children with SLI produced a high number of interference errors that indicate poor executive functions. The findings were compared with previous results of English-speaking children. Complexity affected working memory performance accuracy differently across languages. In English, it was the increase of syntactic complexity that resulted in a decrease in performance accuracy, whereas in Hungarian, it was the morphological complexity that had a large impact on working memory performance. CONCLUSIONS: Working memory performance depends on the linguistic characteristics of the language tested. In both English- and Hungarian-speaking children, complexity has a larger effect on verbal working memory performance than the length of the stimuli. However, complexity affects working memory performance accuracy differently across languages.

Analysis of Variance↗

PubMed1995

Relationship between quantity of undergraduate science preparation and preclinical performance in medical school.

PURPOSE: The primary purpose of this study was to determine whether a relationship existed between the quantities of undergraduate science education completed by medical students and their subsequent preclinical performances in medical school. The secondary purpose of the study was to determine the nature of any relationship present and to re-verify standard predictors of preclinical performance in medical school. METHOD: This study was undertaken at Albany Medical College in conjunction with Sage Graduate School, Albany, New York. The analysis encompassed 120 systematically and 80 randomly selected medical student academic records (200 total cases) from the entering classes of 1977 through 1992. Twelve distinct variables were collected. Data transformations were completed as required, and the data subsequently standardized. Standard descriptive statistics, correlation between variables, t-tests between systematically and randomly selected groups, and factor analysis were performed on the data collected. RESULTS: It was determined that there was no significant relationship between total hours of undergraduate science completed and average preclinical performance in medical school. In addition, correlation between subdivisions of total hours of undergraduate science (total hours of chemistry, total hours of biology, total hours of math, and total hours of physics) and subdivisions of average preclinical performance (year-one preclinical performance and year-two preclinical performance) also proved to be nonsignificant. However, significant relationships between average preclinical performance and its subdivisions and other standard predictors of preclinical performance (Medical College Admission Test score and science grade-point average) were found to be in line with values in recent literature. In addition, significant relationships were found with the National Board of Medical Examiners Part I examination. Factor analysis of all variables yielded three underlying factors: medical school preclinical performance factor, undergraduate performance factor, and quantity of non-life-sciences factor. CONCLUSION: Quantity of science-based undergraduate premedical education, either in its entirety or in subdivisions, did not materially affect the performances of the selected medical school students in their preclinical years of medical school.

Achievement↗

PubMed1997

Evaluating GPAs and MCAT scores as predictors of NBME I and clerkship performances based on students' data from one undergraduate institution.

PURPOSE: To examine the relationships among undergraduate student characteristics, standardized indicators of medical school academic performance, and clinical performances in an institution where the undergraduate grading system was not a confounding factor. METHOD: In 1993 data were collected retrospectively for the classes of 1990-1993 in the University of California, Riverside (UCR)/University of California, Los Angeles, Biomedical Sciences Program, in which all the students completed their undergraduate studies at UCR. Data were collected on the students' demographic characteristics, undergraduate grade-point averages (UGPAs), Medical College Admission Test (MCAT) scores, National Board of Medical Examiners Part I (NBME I) scores, and clinical performances as measured by core clerkship grades. Regression analyses were used to evaluate (1) the relationship between clinical performances and data available at admission and (2) the relationship between NBME I scores and the same variables. The top and bottom 25% of each class were identified by UGPAs and compared by their NBME I scores and clinical performances to determine whether differences noted at admission continued to separate the students. Differences were tested using independent two-tailed t-tests. RESULTS: Of the 92 students, data were available for 88 (96%); 39% were female and 38% were foreign-born. The sample was fairly heterogeneous in terms of UGPAs, MCAT scores, clinical performance grades, and NBME I scores. Results of the first regression analysis indicated that mean clinical performance was not related to any of the undergraduate predictors of performance or to the students' demographics. The second regression analysis indicated that MCAT scores and cumulative science UGPAs were related to performance on the NBME I, as were country of origin and sex. The students in the top and bottom 25% differed significantly in their scores on the NBME I, but not in their clinical performances. CONCLUSION: Although UGPAs and MCAT scores are good indicators of NBME I performance, they are still not useful in predicting clinical performance, even when the students' data are taken from the same undergraduate institution.

California↗

PubMed2002

Speech recognition performance of patients with sensorineural hearing loss under unaided and aided conditions using linear and compression hearing AIDS.

OBJECTIVES: This study compared speech recognition performance on the Northwestern University Auditory Test No. 6 (NU-6) and the Connected Speech Test (CST) for three hearing aid circuits (peak clipping [PC], compression limiting [CL], and wide dynamic range compression [WDRC]) in adults with symmetrical sensorineural hearing loss. The study also questioned whether or not hearing aid benefit for the three circuits was dependent upon the speech level and the signal-to-babble ratio (S/B) and upon the degree and slope of hearing loss. DESIGN: Unaided speech recognition performance for NU-6 and CST materials presented from a loudspeaker at 0 degrees was measured during Visit 1, and both unaided and aided performance was measured at 3-mo intervals during Visits 2 to 4. The NU-6 was presented in quiet at a conversational speech level of 62 dB SPL. The CST was presented in 10 listening conditions-three S/B (-3, 0, and 3 dB) at each of three speech levels (soft speech at 52 dB SPL, conversational speech at 62 dB SPL, and loud speech at 74 dB SPL) and in quiet at 74 dB SPL. Uncorrelated multi-talker babble was presented from two loudspeakers at 45 degrees on each side of the main speaker. Hearing aid benefit was examined for 360 subjects divided into four groups of hearing loss, pure tone average <40 dB HL and slope <10 dB/octave or >10 dB/octave and hearing loss >40 dB HL for the two slope categories. RESULTS: Hearing aid benefit (aided minus unaided performance) measured on the NU-6 in quiet exceeded 31 rau for all three circuits. Although small statistical advantages were found for the WDRC, the differences were approximately 2% and are not considered clinically relevant. Unaided CST performance showed a complex relationship between presentation level and signal-to-babble ratio that was further confounded by the degree of hearing loss. For the two mild hearing loss groups and for each of the three nominal signal-to-babble ratios, CST performance decreased by 20 rau for the -3 dB S/B to 6 rau for the 3 dB S/B as speech level increased from 52 to 74 dB SPL. In contrast, unaided performance increased by 32 to 13 rau with signal level for all signal-to-babble ratios for the two >40 dB hearing loss groups. Overall, aided CST performance exceeded unaided performance for all 10 conditions. As expected, hearing aid benefit was greatest (27 rau) for soft speech and smallest for loud speech (6 rau). Differences among the hearing aid circuits were small with only one significant difference; the WDRC at 62/0 was poorer by 3 rau than the other two circuits. When the CST data were analyzed as a function of hearing loss, five pair-wise comparisons were significant. In contrast to the unaided performance, aided performance for all hearing loss groups decreased as presentation level increased, even though the signal-to-babble ratio was constant. CONCLUSIONS: All three hearing aids circuits provided benefit over the unaided condition in both quiet and noise. The greatest benefit was measured for soft speech in the more severe hearing loss groups. Although only small differences were measured among the three hearing aid circuits, significant differences favored the PC and CL circuits over the WDRC in the mild hearing loss groups and favored the WDRC over the PC in the more severe, sloping hearing loss group. An interesting interaction between speech level, signal-to-babble ratio, degree of hearing loss, and amplification was found. For a constant signal-to-babble ratio, recognition performance decreased as speech level increased from 52 to 74 dB SPL. The effect was most marked in the milder hearing loss groups and in the aided conditions, and occurred at even the lowest speech levels.

Adult↗

PubMed1999

Distribution of psychological aspects in subgroups of chronic low back pain patients divided on the score of physical performance.

This study investigates whether different subgroups of chronic low back pain patients (CLBPs) differ in psychological aspects assessed with the Symptom Checklist (SCL-90) and the Multidimensional Pain Questionnaire (MPI-DLV). Four subgroups of CLBPs are discerned using the results of lumbar dynamometry: 1. Patients with performances lower than healthy subjects (expected performance; n = 45). 2. Patients with performances comparable to healthy subjects (normal performance; n = 18). 3. Patients with inconsistent test behaviour (submaximal performance; n = 6). 4. Patients with performances that could be either maximal or submaximal (gray-zone performance; n = 10). Significant differences in psychological aspects were found between patients with submaximal and patients with expected performances but not between patients with normal and patients with expected performances. All patients with submaximal performance report a high degree of psychological distress, in contrast to 30% of those with normal performance and 20% of those with expected performance. Because of the differences found in psychological aspects between the CLBP subgroups, it is thought that a physical screening together with a psychological screening provides better insight in the two aspects of the deconditioning syndrome and thus can give better treatment indications than a physical screening alone.

Adult↗

PubMed2006

Effect of training on word-recognition performance in noise for young normal-hearing and older hearing-impaired listeners.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of a training program for hearing-impaired listeners to improve their speech-recognition performance within a background noise when listening to amplified speech. Both noise-masked young normal-hearing listeners, used to model the performance of elderly hearing-impaired listeners, and a group of elderly hearing-impaired listeners participated in the study. Of particular interest was whether training on an isolated word list presented by a standardized talker can generalize to everyday speech communication across novel talkers. DESIGN: Word-recognition performance was measured for both young normal-hearing (n = 16) and older hearing-impaired (n = 7) adults. Listeners were trained on a set of 75 monosyllabic words spoken by a single female talker over a 9- to 14-day period. Performance for the familiar (trained) talker was measured before and after training in both open-set and closed-set response conditions. Performance on the trained words of the familiar talker were then compared with those same words spoken by three novel talkers and to performance on a second set of untrained words presented by both the familiar and unfamiliar talkers. The hearing-impaired listeners returned 6 mo after their initial training to examine retention of the trained words as well as their ability to transfer any knowledge gained from word training to sentences containing both trained and untrained words. RESULTS: Both young normal-hearing and older hearing-impaired listeners performed significantly better on the word list in which they were trained versus a second untrained list presented by the same talker. Improvements on the untrained words were small but significant, indicating some generalization to novel words. The large increase in performance on the trained words, however, was maintained across novel talkers, pointing to the listener's greater focus on lexical memorization of the words rather than a focus on talker-specific acoustic characteristics. On return in 6 mo, listeners performed significantly better on the trained words relative to their initial baseline performance. Although the listeners performed significantly better on trained versus untrained words in isolation, once the trained words were embedded in sentences, no improvement in recognition over untrained words within the same sentences was shown. CONCLUSIONS: Older hearing-impaired listeners were able to significantly improve their word-recognition abilities through training with one talker and to the same degree as young normal-hearing listeners. The improved performance was maintained across talkers and across time. This might imply that training a listener using a standardized list and talker may still provide benefit when these same words are presented by novel talkers outside the clinic. However, training on isolated words was not sufficient to transfer to fluent speech for the specific sentence materials used within this study. Further investigation is needed regarding approaches to improve a hearing aid user's speech understanding in everyday communication situations.

Adult↗

PubMed1990

Academic, social and cultural factors influencing medical school grade performance.

Studies of medical student performance have focused on various factors, including premedical academics, maturity, familial background and support, and personal experiences with illness. Most studies have been conducted in countries with highly developed educational systems and similar cultural and social systems. It is not clear that these findings can be applied to developing countries, where the educational and cultural experiences may be very different, and where medical instruction is carried out in a non-native language. Information was obtained from a survey of 153 fifth- and sixth-year medical students at King Abdulaziz University in Saudi Arabia. The survey measured premedical educational, social and cultural experiences that might affect medical school performance. Men performed as well as women in the medical school despite heavy familial and social commitments. Women's performance seems to be more influenced by changes in living environment. Achievement in premedical years was correlated positively with grade performance in medical school. Competence in the high-school English courses was related to medical school performance. Interest in the study of medicine prior to medical school was not related to performance. Other motivations, such as social gains, financial benefits or family wish, were related to lower performance. Current interest in clinical medicine correlated negatively with performance. Students motivated by the presence of chronic ill health in their families performed significantly lower. Factors influencing medical school performance in developed countries had similar impact on medical students in a developing country. Social factors, unique to the country, also play a role in medical student performance.

Achievement↗

PubMed1998

Survey of injuries among West End performers.

OBJECTIVES: To obtain more information about injuries of West End performers. METHODS: A retrospective survey of 269 performers appearing in 20 West End productions (12 dramas and eight musicals). RESULTS: In current productions, 46% of all performers sustained at least one injury for an average of 0.87 injuries per performer. Lower extremity injuries were the most common for dancers (52.2% of injuries) and actors (43.2%) with neck and back injuries the second most common. Sprains and strains were the most common diagnoses. 61% of performers thought that their injuries were preventable. Most performers consulted nonphysician healthcare providers. Factors significantly influencing the risk of injuries for performers include female sex, a history of previous injuries, missed performances due to previous injuries, more physically demanding roles, and performing on raked (angled) stages. CONCLUSION: West End performers commonly sustain injuries. Although primary prevention of most theatrical injuries is not possible, modification of raked stages may reduce the incidence. This study may be helpful to the growing number of healthcare providers who practice performing arts medicine and may stimulate additional concern and research in the medical and theatrical communities about the performance injuries of professionals, amateurs, and theatrical students worldwide.

Accidents, Occupational↗

PubMed1990

Spontaneous running increases VO2max and running performance in rats.

The effect of spontaneous running activity on maximal O2 consumption (VO2max), running performance, and submaximal O2 consumption (VO2submax, running economy) was studied in rats to determine whether this exercise mode can produce significant training adaptations. Twenty male Long-Evans rats (300 +/- 20 g) were housed in spontaneous activity running wheels, and after 8 wk they were divided into high-, average-, and low-performing groups according to the average spontaneous running distance and tested for maximal running performance, VO2max, and VO2submax. The average-performing rats ran 52% longer than the control rats (P less than 0.01) and 19% longer than the low-performing rats (P less than 0.05). There was no difference in maximum running time to exhaustion between the average- and high-performing rats. The low-performing rats ran 28% longer than the control rats (P less than 0.05). The VO2max of the average-performing rats was 12% greater than in the control rats (P less than 0.01). There were no differences in VO2max between either low-performing and control rats or between average- and high-performing rats. Although the VO2submax was not different between low-, average-, and high-performing rats, in all three groups it was lower than in the control rats (P less than 0.01). Accordingly, we recommend that only those Long-Evans rats that, on average, spontaneously run greater than 11.6 km/wk for a minimum of 8 wk be considered to have undergone a training effect. Rats that perform poorly can be identified as early as 2 wk after the start of training.

Animals↗

PubMed1998

Spectrum of aerobic endurance running performance in eleven inbred strains of rats.

The goal of this study was to identify inbred rat strains that could serve as useful models for exploration of the genetic basis of aerobic endurance performance. Six rats of each gender from 11 different inbred strains were tested for 1) maximal running capacity on a treadmill and 2) isolated cardiac performance. Running performance was estimated from 1) duration of the run, 2) distance run, and 3) vertical work performed. Cardiac output, during constant preload and afterload, was taken as a measure of cardiac performance from an isolated working heart preparation. The COP rats were the lowest performers and the DA rats were the best performers by all estimates of running performance. Across the 11 strains, the distance run correlated positively with isolated cardiac performance (r = 0.87). Estimates of performance were as follows (COP vs. DA strain, respectively): duration of run, 19.9 +/- 1.8 vs. 41.5 +/- 2. 2 min; distance run, 298 +/- 30 vs. 840 +/- 64 m; vertical work, 15 +/- 1.7 vs. 40 +/- 4.4 kg/m. These approximately 2.5-fold differences in running performance between the COP and DA suggest that these strains could serve as models for evaluation of the genetic basis of variance in aerobic performance.

Aerobiosis↗

PubMed1998

Changes in brain activity during motor learning measured with PET: effects of hand of performance and practice.

The aim of this study is to assess brain activity measured during continuous performance of design tracing tasks. Three issues were addressed: identification of brain areas involved in performing maze and square tracing tasks, investigation of differences and similarities in these areas related to dominant and nondominant hand performance, and most importantly, examination of the effects of practice in these areas. A total of 32 normal, right-handed subjects were instructed to move a pen with the dominant right hand (16 subjects) or nondominant left hand (16 subjects) continuously through cut-out maze and square patterns with their eyes closed during a 40-s positron emission tomography (PET) scan to measure regional blood flow. There were six conditions: 1) holding the pen on a writing tablet without moving it (rest condition); 2) tracing a maze without practice; 3) tracing the same maze after 10 min of practice; 4) tracing a novel maze; and tracing an easily learned square design at 5) high or 6) low speed. To identify brain areas generally related to continuous tracing, data analyses were performed on the combined data acquired during the five tracing scans minus rest conditions. Areas activated included: primary and secondary motor areas, somatosensory, parietal, and inferior frontal cortex, thalamus, and several cerebellar regions. Then comparisons were made between right- and left-hand performance. There were no significant differences in performance. As for brain activations, only primary motor cortex and anterior cerebellum showed activations that switched with hand of performance. All other areas, with the exception of the midbrain, showed activations that were common for both right- and left-hand performance. These areas were further analyzed for significant conditional effects. We found patterns of activation related to velocity in the contralateral primary motor cortex, related to unskilled performance in right premotor and parietal areas and left cerebellum, related to skilled performance in supplementary motor area (SMA), and related to the level of capacity at which subjects were performing in left premotor cortex, ipsilateral anterior cerebellum, right posterior cerebellum and right dentate nucleus. These findings demonstrate two important principles: 1) practice produces a shift in activity from one set of areas to a different area and 2) practice-related activations appeared in the same hemisphere regardless of the hand used, suggesting that some of the areas related to maze learning must code information at an abstract level that is distinct from the motor performance of the task itself.

Adult↗

PubMed1991

The assessment and treatment of performance anxiety in musicians.

OBJECTIVE: Performance anxiety in musicians may be severe enough to require intervention but has been the subject of relatively little clinical research. The authors' objectives were to describe the results of a comprehensive clinical and laboratory assessment and to perform a double-blind, placebo-controlled study comparing buspirone, cognitive-behavior therapy, and the combination of these treatments for performance anxiety. METHOD: Ninety-four subjects were recruited by mass media announcements and were seen in a university-based outpatient psychiatric clinic. Assessments were 1) questionnaires for all 94 subjects, 2) diagnostic interview of 50 subjects, and 3) laboratory performance of 34 subjects. Treatment conditions were 1) 6 weeks of buspirone, 2) 6 weeks of placebo, 3) a five-session, group cognitive-behavior therapy program with buspirone, or 4) the cognitive-behavior therapy program with placebo. Treatment outcome measures included subjective anxiety ratings and heart rate measures during a laboratory performance, a questionnaire measure of performance confidence, and a blind rating of musical performance quality. RESULTS: All subjects fulfilled criteria for DSM-III-R social phobia. Of the 15 full-time professional musicians, ten had tried propranolol and three had stopped performing. Most of the subjects had substantial anxiety and heart rate increases during laboratory speech and musical performances. Cognitive-behavior therapy resulted in statistically significant reductions in subjective anxiety, improved quality of musical performance, and improved performance confidence. Buspirone was not an effective treatment. CONCLUSIONS: Cognitive-behavior therapy is a viable treatment approach for performance anxiety in musicians.

Adult↗