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Biomedical subjects

B Bonke

Publications and source records attributed to B Bonke.

At least 19 recordsLinked to original sources
PubMed1997

The influence of psychological variables on postoperative anxiety and physical complaints in patients undergoing lumbar surgery.

Previous research has indicated that postoperative distress is influenced by diverse biographic, medical and psychological variables, such as personality, coping behaviours and anxiety. The influence of state variables, apart from anxiety and coping behaviour, has received scant attention. Furthermore, the influence of coping behaviour has remained unclear. The present study investigated coping behaviour and indications of physical distress, i.e., preoperative fatigue, leg pain and back pain, besides preoperative anxiety, as predictors of postoperative anxiety and physical complaints in 126 patients undergoing lumbar surgery. Preoperative anxiety and leg pain independently predicted more postoperative anxiety beyond the influence of age, sex and medical variables. Preoperative anxiety and fatigue independently predicted more postoperative physical complaints. No associations were found between the coping behaviours and the postoperative variables. The implications of these results are discussed in relation to intervention strategies aimed at diminishing the stress of surgery.

Adaptation, Psychological↗
PubMed1996

Memory during general anesthesia: practical and methodological aspects.

Evidence coming from several studies into memory and awareness during general anesthesia suggests that in surgical patients who seem to be adequately anesthetized (i.e., unaware of what happens in the operating theater), some form of cognitive functioning is preserved. This finding has important implications both for clinical practice and for memory research. In order to give the methodological background of the present situation in this field of research, this article deals, on the basis of recent experiments, with important methodological aspects of studies into perception and memory during general anesthesia.

Anesthesia, General↗
PubMed1996

Therapeutic suggestion has not effect on postoperative morphine requirements.

This study was designed to confirm the effect of therapeutic intraoperative auditory suggestion on recovery from anesthesia, to establish the effect of preoperative suggestion, and to assess implicit memory for intraoperative information using an indirect memory task. Sixty consenting unpremedicated patients scheduled for elective gynecologic surgery were randomly divided into three equal groups: Group 1 received a tape of therapeutic suggestions preoperatively, and the story of Robinson Crusoe intraoperatively; Group 2 heard the story of Peter Pan preoperatively and therapeutic suggestions intraoperatively; Group 3 heard the Crusoe story preoperatively and the Peter Pan story intraoperatively. A standardized anesthetic technique was used with fentanyl, propofol, isoflurane, and nitrous oxide. After surgery, all patients received patient-controlled analgesia (PCA) with a standardized regimen. In the 24 h postsurgery, morphine use was recorded every 6 h and at 24 h an indirect memory test (free association) was used to test for memory of the stories. Anxiety scores were measured before surgery and at 6 and 24 h postsurgery. There were no significant differences between groups for postoperative morphine use, pain or nausea scores, anxiety scores, or days spent in hospital after surgery. Seven of 20 patients who heard the Pan story intraoperative gave a positive association with the word "Hook," whereas 2 of 20 who did not hear the story gave such an association. Indirect memory for the Pan story was established using confidence interval (CI) analysis. (The 95% CI for difference in proportion did not include zero). No indirect memory for the Crusoe story could be demonstrated. This study did not confirm previous work which suggested that positive therapeutic auditory suggestions, played intraoperatively, reduced PCA morphine requirements. In contrast, a positive implicit memory effect was found for a story presented intraoperatively.

Adult↗
PubMed1996

Processing familiar and unfamiliar auditory stimuli during general anesthesia.

We tested memory priming for auditory stimuli presented during general propofol-sufentanil anesthesia in 58 patients undergoing day-case arthroscopic surgery. Stimuli were presented via headphones and consisted of common facts (Group A, 29 patients), or familiar or unfamiliar full names of fictitious people (GRoup B, 29 patients). Group A was expected to give more correct answers to questions about the common facts than Group B, when tested postoperatively, and Group B to attribute more fame to presented names than Group A (famous names test). Because the process for learning new or unfamiliar stimuli (elaboration) in particular may be impaired under general anesthesia, more memory priming was expected for familiar than for unfamiliar material. No significant differences were demonstrated between the two groups in performance on common facts or in fame attributed to the names. The amount of memory priming, however, was positively related to one of two measures of preoperative anxiety.

Acoustic Stimulation↗
PubMed1996

Information processing during general anesthesia: evidence for unconscious memory.

Memory for words presented during general anesthesia was studied in two experiments. In Experiment 1, surgical patients (n = 80) undergoing elective procedures under general anesthesia were presented shortly before and during surgery with words via headphones. At the earliest convenient time after surgery (within 5 h) and 24 h later, memory was tested by asking patients to complete auditorily presented word stems with the first word that came to mind and to leave out words they remembered having heard earlier (exclusion task). Moreover, patients were requested to perform a "yes/no" forced-choice recognition task to assess recognition memory for both the pre- and intraoperative words. Memory for the material presented during anesthesia was demonstrated immediately after surgery and 24 h later by means of both tasks. In a second similar experiment (n = 80), the results were replicated. These findings show that anesthetized patients can process information that was presented intraoperatively.

Adolescent↗
PubMed1995

The Multidimensional Fatigue Inventory (MFI) psychometric qualities of an instrument to assess fatigue.

The Multidimensional Fatigue Inventory (MFI) is a 20-item self-report instrument designed to measure fatigue. It covers the following dimensions: General Fatigue, Physical Fatigue, Mental Fatigue, Reduced Motivation and Reduced Activity. This new instrument was tested for its psychometric properties in cancer patients receiving radiotherapy, patients with the chronic fatigue syndrome, psychology students, medical students, army recruits and junior physicians. We determined the dimensional structure using confirmatory factor analyses (LISREL's unweighted least squares method). The hypothesized five-factor model appeared to fit the data in all samples tested (AGFIs > 0.93). The instrument was found to have good internal consistency, with an average Cronbach's alpha coefficient of 0.84. Construct validity was established after comparisons between and within groups, assuming differences in fatigue based on differences in circumstances and/or activity level. Convergent validity was investigated by correlating the MFI-scales with a Visual Analogue Scale measuring fatigue (0.22 < r < 0.78). Results, by and large, support the validity of the MFI.

Adult↗
PubMed1995

Implicit memory performance of patients with Alzheimer's disease: a brief review.

Memory can be assessed with either explicit or implicit tasks. Implicit memory tasks, in contrast with explicit tasks, do not refer to conscious recollection of a previous learning experience. Implicit memory is revealed by a change in task performance that can be attributed to previous learning. Amnesic patients perform poorly on explicit memory tasks, but exhibit normal performance on implicit tasks. Recently, researchers have studied the implicit memory performance of patients with Alzheimer's disease. This article aims to give an overview of the performance of Alzheimer patients on four tasks of implicit memory. Compared with normal elderly controls, patients with Alzheimer's disease seem to demonstrate impaired performance on conceptual, but not on perceptual, implicit memory tasks. This dissociation could yield important information about the neurologic systems subserving implicit memory processes. Some suggestions for future research into the implicit memory of Alzheimer patients are given.

Aged↗
PubMed1995

Assessment of preoperative anxiety: comparison of measures in patients awaiting surgery for breast cancer.

We have compared three measurements of anxiety to determine their equivalence in assessing anxiety before surgery. Forty-four patients awaiting breast cancer surgery completed the state scale of the state-trait anxiety inventory (STAI), the hospital anxiety and depression scale (HAD) and a 100-mm visual analogue scale (VAS). Analysis restricted to correlations between the scales gave the misleading impression that VAS scores were inconsistent with those of the HAD and STAI. However, when scores were considered in relation to normative cut-off values to categorize anxiety levels, the three scales showed good agreement. We conclude that the scales were equivalent in their assessment of anxiety before surgery, but that reference to normative data was important in establishing such equivalence and in determining the patient's state.

Adult↗
PubMed1995

The effect of midazolam premedication on implicit memory activation during alfentanil-nitrous oxide anaesthesia.

Eighty-three patients were given midazolam 0.1 mg.kg-1 by intramuscular injection as premedication before general anaesthesia with alfentanil-nitrous oxide. During anaesthesia patients were presented (through headphones) with either statements about common facts of some years ago (group A) (n = 43) or new verbal associations, e.g. names of fictitious, nonfamous people (group B) (n = 40). In a previous study with the same anaesthetic technique, but without premedication there was significant activation of implicit memory (p < 0.001). In this study we found no explicit or implicit memory for the auditory information presented during anaesthesia. Midazolam premedication can prevent implicit memory activation during alfentanil-nitrous oxide anaesthesia.

Adult↗
PubMed1995

Implicit memory for stimuli presented during inhalation anesthesia in children.

During general inhalation anesthesia, neutral phrases including either the color blue or yellow combined with one of two objects, ball or kite, were repeatedly presented to 36 children undergoing eye surgery. Postoperative testing with a coloring and two-choice task was performed to detect preferences for the colors and objects presented under anesthesia. No preference attributable to implicit memory could be demonstrated, and there was no explicit recollection of intraoperative events. Memory of intraoperative events occurring during inhalation anesthesia was not demonstrated with the present methodology in young children.

Anesthesia, Inhalation↗
PubMed1994

[Implicit memory in patients with Alzheimer disease: a concise review].

Experimental psychologists have made a distinction between explicit and implicit memory tasks. In contrast to explicit tasks implicit ones do not refer to conscious recollection of a previous learning episode. Implicit memory is revealed by a change in task performance which can be attributed to previous learning. Amnesic patients, by definition, perform poorly on explicit memory tasks, but exhibit normal performance on certain implicit tasks. In recent years, investigators have studied the implicit memory capabilities of patients with Alzheimer's disease. The present article aims to give an overview of the performance of Alzheimer patients on four tasks of implicit memory. Compared with normal elderly persons, patients with Alzheimer's disease seem to demonstrate impaired performance on conceptual, but not on perceptual implicit memory tasks. This dissociation could yield important information about the neurological systems subserving implicit memory processes. Some suggestions for future research into implicit memory in Alzheimer patients are given.

Aged↗
PubMed1993

Implicit memory for stimuli presented during anaesthesia: role of anaesthetic cocktail and memory test.

Recently, investigators have used so-called implicit memory tests to investigate 'hearing' during general anaesthesia. Some of them were able to demonstrate auditory perception in anaesthetized patients, but others have failed to find any evidence for intraoperative stimulus registration. We argue that differences in anaesthetic cocktails and memory tests can explain why some researchers have produced positive results, supportive of information-processing under anaesthesia, and others have not. It appears that stimulus registration can occur during surgery, regardless of anaesthetic technique. However, processing of complex information may only be possible during nitrous oxide anaesthesia.

Acoustic Stimulation↗
PubMed1993

Awareness and recall during general anesthesia. Facts and feelings.

BACKGROUND: Experiences of awareness and recall during general anesthesia can be most distressing for patients. To obtain relevant information, the authors systematically interviewed patients in whom awareness during surgery had occurred, and questioned them about their experiences. METHODS: Twenty-six patients, referred by colleagues, described the facts and feelings they had experienced during the period of awareness, and whether these had had any consequences. Available anesthetic records were independently judged by three experienced anesthesiologists for relevant parameters. RESULTS: Auditory perception and the sensation of paralysis were most frequently mentioned, followed by the sensation of pain. Patients' feelings were mostly related to anxiety, panic, powerlessness, and helplessness. Eighteen patients (70%) experienced unpleasant aftereffects, including sleep disturbances, dreams and nightmares, and flashbacks and anxiety during the day. Only nine patients (35%) had informed their anesthesiologists about what had taken place. Twelve anesthetic records were assessed. In three, the occurrence of awareness had been indicated, while, in a fourth, it was noted that an amnesic drug had been given at a moment of increased blood pressure. Experienced anesthesiologists were unable to reliably distinguish awareness cases from matched controls when judging the records. CONCLUSIONS: Details recalled from the period of awareness correspond with data from the literature. The anesthesiologist's role in discussing, and dealing with, traumatic experiences related to anesthesia may be of great importance. The hand-written anesthetic record is of limited value in retrospectively explaining why awareness and recall have occurred.

Adult↗
PubMed1993

Implicit memory during balanced anaesthesia. Lack of evidence.

The effect of the number of presentations on implicit memory for words was studied in anaesthetised patients. During standardised, balanced anaesthesia, 81 surgical patients were presented with less common specimens of familiar word categories. For each of three word categories the number of word presentations varied between the patients (0 (control), 5, or 30 presentations). Postoperatively, repetition priming was tested by asking patients to generate exemplars for each of the word categories. No implicit memory for the words presented during anaesthesia was found and consequently no effect of number of word presentations could be demonstrated. It is suggested that this finding, which contradicts previous results, may be caused by the relatively low familiarity of the words used.

Adult↗
PubMed1993

Implicit learning during enflurane anaesthesia in spontaneously breathing patients?

Forty-one patients breathing spontaneously during enflurane anesthesia were presented (via headphones) either with statements about common facts of some years ago, or new verbal associations, i.e. names of fictitious people. Postoperatively, there were no differences between the two groups in the responses to questions about the common facts or attribution of fame to the fictitious people. This finding suggests that unconscious learning and activation may not occur during enflurane anaesthesia without neuromuscular block.

Adult↗
PubMed1993

Patient-controlled analgesia (PCA) leads to more postoperative pain relief, but also to more fatigue and less vigour.

This investigation evaluated patient-controlled analgesia (PCA) for subjective well-being and mood in the postoperative period in comparison with the intramuscular (im) administration of morphine given on demand. Patients scheduled for elective upper abdominal surgery were assigned at random to either PCA (n = 17) or im morphine (n = 14). The PCA group experienced significantly more pain relief and consumed more morphine than those who received im morphine. The PCA patients suffered from more fatigue and showed less vigour than the im group. Neither preoperative trait anxiety nor locus of control was associated with postoperative pain in either of the groups.

Adult↗