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Biomedical subjects

T Sand

Publications and source records attributed to T Sand.

At least 55 records · Page 3Linked to original sources
PubMed1997

The reproducibility of cephalic pain pressure thresholds in control subjects and headache patients.

Pain pressure thresholds (PPT) were measured at 13 cephalic points bilaterally in 30 headache patients (10 with tension-type headache, 10 with migraine and 10 with cervicogenic headache) and 10 control subjects on three different days. During the sessions, the subjects reported their pain intensity on the right and left sides of the head on a visual analogue scale (VAS). The variability between days was estimated as a coefficient of repeatability (CR = 2 standard deviations of intraindividual differences). The mean CR across all 13 locations was larger in headache patients (2.0 kg/cm2) than in controls (1.68 kg/cm2). Variability (CR) was larger in headache patients as compared to control subjects for 11 of the 13 points (p = 0.02). Reliability was better in controls (intraclass correlation coefficients (ICC) ranging from 0.55 to 0.85) than in headache patients (ICC ranging from 0.43 to 0.78). A moderate negative association between PPT and pain intensity was demonstrated. The intraindividual PPT difference (PPT on the most painful occasions-PPT on the least painful occasions) was negative at 12 of 13 cephalic points (p = 0.003, across-location mean difference: -0.20 kg/cm2). The PPT differed significantly from one day to the next. A part of this variation was presumably related to the circumstances around the procedure; thresholds were lower when the subjects came directly to algometry without any preceding medical examination at all 13 points (p = 0.0002). These results have implications for the planning of future algometer studies. The sample size that is required in studies of headache patients is greater than that in studies of healthy subjects, especially when patients suffer from pain during the PPT session. Particular attention should be paid to circumstances (e.g. preceding medical investigations) around the algometry procedure in order to reduce variability.

Adult↗
PubMed1997

Cognitive function in type 1 diabetic children with and without episodes of severe hypoglycaemia.

We assessed the effect of diabetes and of episodes of severe hypoglycaemia on cognitive function in 28 diabetic children. Fifteen diabetic children (age 12.9 (SD 2.0) years) had experienced 1-4 episodes of severe hypoglycaemia. Five of these children diseased before the age of 5 years (SH-eod subgroup), and ten diseased after this age (SH-lod subgroup). Thirteen diabetic children (age 13.1 (SD 2.0) years) had not experienced episodes of severe hypoglycaemia (non-SH group). Each diabetic child was compared with a healthy control child of the same age and gender and with a similar social background. Neuropsychological assessment was blinded. The neuropsychological tests were grouped into one of seven cognitive domains. We found no effect on cognitive performance from diabetes per se or from severe hypoglycaemia in children with late-onset diabetes. However, early-onset diabetes was associated with low scores in two cognitive domains: psychomotor efficiency and attention. The SH-eod subgroup had lower scores than the SH-lod subgroup in psychomotor efficiency (p < 0.05) and also had lower scores than the SH-lod subgroup and the non-SH group in measures of attention (p < 0.05). Our results may indicate a slight cognitive dysfunction in children with early-onset diabetes who have experienced episodes of severe hypoglycaemia early in childhood.

Adolescent↗
PubMed1996

Natural evolution of late whiplash syndrome outside the medicolegal context.

BACKGROUND: In Lithuania, few car drivers and passengers are covered by insurance and there is little awareness among the general public about the potentially disabling consequences of a whiplash injury. We took this opportunity to study the natural course of head and neck symptoms after rear-end car collisions. METHODS: In a retrospective questionnaire-based cohort study, 202 individuals (157 men; 45 women) were identified from the records of the traffic police department in Kaunas, Lithuania. These individuals were interviewed 1-3 years after experiencing a rear-end car collision. Neck pain, headache, subjective cognitive dysfunction, psychological disorders, and low back pain in this group were compared with the same complaints in a sex-matched and age-matched control group of uninjured individuals selected randomly from the population register of the same geographic area. FINDINGS: Neck pain was reported by 71 (35% [95% CI 29-42]) accident victims and 67 (33% [27-40]) controls. Headache was reported by 107 (53% [46-60]) accident victims and 100 (50% [42-57]) controls. Chronic neck pain and chronic headache (more than 7 days per month) were also reported in similar proportions (17 [8.4%; 5-13] vs 14 [6.9%; 4-12] and 19 [9.4%; 6-15] vs 12 [5.9%; 3-10]) by the two groups. Of those who reported chronic neck pain or daily headache after the accident, substantial proportions had had similar symptoms before the accident (7/17 for chronic neck pain; 10/12 for daily headache). There was no significant difference found. No one in the study group had disabling or persistent symptoms as a result of the car accident. There was no relation between the impact severity and degree of pain. A family history of neck pain was the most important risk factor for current neck symptoms in logistic regression analyses. INTERPRETATION: Our results suggest that chronic symptoms were not usually caused by the car accident. Expectation of disability, a family history, and attribution of pre-existing symptoms to the trauma may be more important determinants for the evolution of the late whiplash syndrome.

Accidents, Traffic↗
PubMed1996

Reproducibility of the cold pressor test: studies in normal subjects.

The reproducibility of the cold pressor test was studied in healthy subjects. A non-invasive method was utilized for estimating beat-to-beat arterial blood pressure (BP) and heart rate (HR). The study population of 17 healthy volunteers consisted of two groups. In the first group (Group 1, n = 11), a 1-min test was performed three times during the same day. In the second group (Group 2, n = 6), a 2-min test was repeated at the same time of the day on three consecutive days. In both groups, the test response was defined as the 46- to 60-s mean, minus the prestimulus 15 s baseline mean. In Group 1, a fair test-retest reliability was observed for the systolic BP response (intraclass correlation coefficient R = 0.57). Large intraindividual HR and diastolic BP variabilities were found. The intraindividual testretest difference in Group 1 ranged from -8 to 11 beats/min (SD = 4.3, R = 0.49) for the HR, from -16 to 13 mmHg (SD = 6.3) for systolic BP, and form -21 to 20 mmHg (SD = 9.7, R = 0.23) for diastolic BP. Even larger variability was observed when the test was repeated on different days (Group 2). Thus, the maxim that the response pattern to the cold pressor test is fairly constant for each individual may not be true. It does not seem to be advisable to use the results from one solitary cold pressor test. The use of replicated measurements and large sample sizes in comparative studies to compensate for the low to moderate reliability of the cold pressor test is recommended.

Adolescent↗
PubMed1996

Quantitative EEG in type 1 diabetic children with and without episodes of severe hypoglycemia: a controlled, blind study.

We investigated the EEG frequency distribution by quantitative EEG (QEEG) in 28 children with type 1 diabetes and 28 age- and sex-matched control children. Among the diabetic children, 15 had experienced episodes of severe hypoglycemia (SH group) and 13 had not experienced such episodes (non-SH group). The EEG analysis was blind. Frequency analysis of 15 EEG epochs, each of 4 s duration, was performed. QEEG showed increased theta activity in the SH group bilaterally in the frontocentral region and a slight trend toward more delta activity in diabetic children than control children bilaterally in the occipital electrodes. The relative alpha amplitude was decreased in the SH group at several locations. Abnormal standard EEG (diffuse theta activity) was observed in two SH patients and one non-SH patient. All control children had normal standard EEG. We conclude that episodes of severe hypoglycemia may affect frontocentral function slightly in some diabetic children.

Adolescent↗
PubMed1995

Caffeine influence on the motor steadiness battery in neuropsychological tests.

Caffeine is a widely used drug with various biological effects. The present investigation focuses on a possible influence of caffeine upon motor steadiness performance in tests routinely used in neuropsychological testing. Twenty-four healthy females between 23 and 38 years were investigated in a randomised double-blind crossover study. A significantly poorer motor steadiness performance was found after ingestion of 300 mg of caffeine as compared to a placebo (decaffeinated coffee). Both error time and error count were increased after caffeine consumption. Caffeine also tended to reduce maze coordination test performance. We conclude that caffeine intake preferably should be avoided before neuropsychological testing of motor steadiness.

Adult↗
PubMed1995

Exteroceptive suppression of temporalis muscle activity: a blind study of tension-type headache, migraine, and cervicogenic headache.

Exteroceptive suppression of temporalis muscle activity (ES2 duration) has been reported to be reduced in chronic tension-type headache in previous open studies (with varying stimulus and analysis methods). We studied ES2 duration and latency in 11 patients with chronic tension-type headache, 10 patients with cervicogenic headache, 11 migraine patients, and 9 headache-free control subjects. The investigator was blinded as to the diagnostic category. Electrical stimuli of 0.5 ms duration and at least three times sensory threshold (median 9.6 mA) were used. ES2 was obtained in all but one (control) subject and the control ES2 duration mean was 33.5 (SD 8.5) ms (80% EMG amplitude reduction criterion). Mean ES2 duration differences were not found between the four groups. None of the headache patients had ES2 durations below the control group range. ES2 duration tended to decrease with increasing duration of headache history. Consistent asymmetries of ES2 latency and duration were not found among patients with (unilateral) cervicogenic headache. Thus, the role of ES2 in headache diagnosis still seems to be unsettled.

Adult↗
PubMed1995

Frequency of hyperprolactinaemia due to large molecular weight prolactin (150-170 kD PRL).

Of 605 hyperprolactinaemic sera (prolactin > 1000 mU l-1 determined with PRL DELFIA, Wallac) in the routine diagnostic (PRL was measured in 10,737 sera) 26% had an increased amount of PRL with molecular weight (MW) = 150-170 kD (150-170 kD PRL or bigbig PRL). In a series of serum samples from 660 healthy subjects, only one female with hyperprolactinaemia due to increased 150-170 kD PRL was found. The 150-170 kD PRL constituted less than 1% of the total PRL found in 11 patients with prolactinoma (macroprolactinoma, PRL 8800-500,000 mU l-1). When determined with five different commercially available immunometric assays, the PRL values in the sera with large amounts of 150-170 kD were increased in all sera in four of five assays, although they varied widely. The clinical implications of hyperprolactinaemia due to increased 150-170 kD PRL are still uncertain.

Adult↗
PubMed1994

Inhibition of cholesteryl ester transfer protein activity in hamsters alters HDL lipid composition.

We investigated the role of cholesteryl ester transfer protein (CETP) in hamsters by using a monoclonal antibody (MAb) that inhibited hamster CETP activity. MAbs were prepared against partially purified human CETP and screened for inhibiton of 3H-cholesteryl oleate (CE) transfer from LDL to HDL in the presence of human plasma bottom fraction (d > 1.21 g/ml). Antibody 1C4 inhibited CE transfer activity in both human plasma bottom fraction (IC50 = approximately 4 micrograms/ml) and in whole plasma from male Golden Syrian hamsters (IC50 = approximately 30 micrograms/ml). Purified MAb 1C4 was injected into chow- and cholesterol-fed hamsters, and blood was collected for analysis of plasma CETP activity and HDL lipid composition. Plasma CETP activity was inhibited by 70%-80% at all and HDL lipid composition. Plasma CETP activity was inhibited by 70%-80% at all times up to 24 h following injection of 500 micrograms MAb 1C4 (approximately 3.7 mg/kg). The amount of antibody required for 50% inhibition at 24 h post-injection was 200 micrograms (approximately 1.5 mg/kg). Inhibition of hamster CETP activity in vivo increased hamster HDL cholesterol by 33% (P < 0.0001), increased HDL-CE by 31% (P < 0.0001) and decreased HDL-triglyceride by 42% (P < 0.0001) (n = 36) as determined following isolation of HDL by ultracentrifugation. An increase in HDL cholesterol and a redistribution of cholesterol to a larger HDL particle were also observed following fast protein liquid chromatography (FPLC) gel filtration of plasma lipoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Neck pain in the general population.

STUDY DESIGN: A randomized cross-sectional questionnaire was used to determine the prevalence of neck pain in Norwegian adults. OBJECTIVES: The frequency and duration of neck pain were assessed. SUMMARY OF BACKGROUND DATA: Reliable epidemiologic studies on the prevalence of neck pain in the general population have been sparse. METHODS: A questionnaire that inquired about neck pain within the last year was sent to a random sample of 10,000 adult Norwegians. RESULTS: Overall, 34.4% of the responders had experienced neck pain within the last year. A total of 13.8% reported neck pain that lasted for more than 6 months. CONCLUSIONS: Chronic neck pain is a frequent symptom in the general population, particularly in women. Although reservations have to be taken as to the interpretation, the reported prevalence of persisting pain after whiplash injuries is of the same magnitude as the prevalence of chronic neck pain in the general population.

Adolescent↗
PubMed1994

The blink reflex in chronic tension-type headache, migraine, and cervicogenic headache.

R1 and R2 blink reflex latencies were investigated blind in 10 patients with cervicogenic headache, 11 patients with chronic tension-type headache, 11 patients with migraine, and 9 headache-free controls. There were no R1 or R2 latency differences between the four groups. The latency of R1 increased significantly with headache duration in tension-type headache patients. Shorter R1 latencies were found on the symptomatic side than on the non-symptomatic side in cervicogenic headache patients. The results suggest that a state of hyperactivity may be present in the ipsilateral trigeminal nucleus in cervicogenic headache. Hypoactivity, however, may develop over time in tension-type headache.

Adult↗
PubMed1994

Tension headache: botulinum toxin paralysis of temporal muscles.

The pathogenetic mechanism of tension headache (TH) is still unknown. The role of pericranial muscle tension in TH is also enigmatic. To evaluate this factor in chronic TH, pericranial muscles were paralysed in 6 chronic TH patients, using botulinum toxin. All patients fulfilled the IHS criteria of chronic TH associated with involvement of the pericranial muscles, but not the current criteria for cervicogenic headache. The patients were followed-up regularly with evaluation of the paralysis, changes in pain intensity, and pressure pain threshold measurements. We primarily only injected the temporal muscle on the one side, using the other side as a control. Contralateral muscles were in some cases injected at a later stage. In our study, we did not find any significant reduction in pain intensity, as measured by the visual analogue scale, nor any changes in pressure pain threshold, as measured by an algometer. On the basis of our observations, we conclude that muscle tension in these muscles possibly plays a minor role in the genesis of chronic TH. In our study, however, we have only treated a limited number of patients, and only one pericranial muscle has been injected systematically. Further studies of various neck/posterior head muscles ought to be performed in order to further evaluate a possible effect of tension in the pericranial musculature in producing this type of pain.

Adult↗
PubMed1994

Neurophysiological studies in chronic paroxysmal hemicrania and hemicrania continua.

To explore the possible involvement of the pain control system, pain pressure threshold (PPT), nociceptive flexion reflex (RIII), blink and corneal reflexes have been studied for pain perception assessment in 12 patients with chronic paroxysmal hemicrania (CPH) and 12 patients with hemicrania continua (HC). PPT was found to be reduced in HC and CPH when separately compared to controls. In addition, a significant reduction of subjective pain perception (Tp) which was most marked on the symptomatic side, has been demonstrated after sural nerve stimulation in CPH. The RIII reflex threshold on the symptomatic side was significantly reduced when patients were compared to controls. No major differences between CPH and HC as regards blink reflex latencies were found; nor was any such difference observed when comparing the two headache groups to controls. The corneal reflex thresholds were found significantly reduced bilaterally in CPH, irrespective of whether the treatment was given or not.

Adult↗
PubMed1994

Idiopathic normal pressure hydrocephalus: the CSF tap-test may predict the clinical response to shunting.

A follow-up study was performed in nine patients with idiopathic normal pressure hydrocephalus (NPH) 37 months (mean) after shunting and 10 non-operated controls with comparable degrees of ventricular enlargement, gait disorder, and dementia. Five operated patients vs. no controls reported sustained general improvement (p < 0.02). Objectively improved gait at follow-up (compared with preoperative status) was found in five of the six tested NPH-patients vs. none of the controls (p < 0.005). Improved gait and/or psychometric function was found in four of six NPH vs. none of eight control patients (p < 0.02) after drainage of 40 ml cerebrospinal fluid (CSF tap-test). Improved gait during the CSF tap-test predicted continued improvement at follow-up. Temporal horn size was the only radiological variable which showed a (moderate) positive correlation with resistance to CSF absorption and rate of pressure increase. The size of the third ventricle diminished in parallel with clinical improvement.

Adult↗
PubMed1994

Quantitative electroencephalography in idiopathic normal pressure hydrocephalus: relationship to CSF outflow resistance and the CSF tap-test.

Quantitative electroencephalography from the occipito-parietal region, gait, and psychometric tests were performed in patients with idiopathic normal pressure hydrocephalus (NPH) before and after drainage of 40 ml CSF. The results were compared to those in demented controls. The EEG results were also analyzed with respect to possible correlations with clinical, CSF dynamics, and psychometric variables. Significant differences between NPH patients and demented controls were not found neither in baseline EEG variables nor regarding the CSF tap-test-related change in EEG. The EEG-response to the CSF tap-test did not often exceed the day-to-day test-retest variability. In NPH patients, EEG slowing (relative delta and theta power) correlated significantly with CSF outflow-resistance (p < 0.002). Relative theta power correlated with the Thurstone's Identical Forms test (p < 0.05). Significant correlations between EEG and Bingley's Memory Test were found for the control group but not among NPH patients (p < 0.05). Thus, EEG band-power variables seem to reflect some of the pathophysiology involved in idiopathic normal pressure hydrocephalus, particularly increased resistance to CSF outflow. The practical value of the presently applied EEG method in NPH-diagnosis and prognostic evaluation seems to be limited, however.

Adult↗
PubMed1994

ABR amplitude and dispersion variables. Relation to audiogram shape and click polarity.

ABR amplitude behaviour to condensation (C) and rarefaction (R) clicks was investigated in normal ears, ears affected by Ménière's disease and ears with high-frequency hearing loss (HF ears). The wave IV-V amplitude-intensity function was steeper in ABRs evoked by R than by C clicks. This may suggest that two different cochlear generator components, one intensity-dependent as well as one polarity-dependent, contribute to click-evoked ABRs. Wave IV-V amplitude was significantly higher in Ménière ears compared to HF ears in spite of comparable 2-4 kHz hearing loss in the two groups. Hence, audiometric steepness (which is lower in Ménière ears than in HF ears) seems to predict the wave IV-V amplitude decline more precisely than the 2-4 kHz perception threshold. The wave IV-V dispersion variable (SR IV-V) was close to normal in Ménière ears, while wave IV-V was more dispersed in HF ears. In general, C click ABRs were less affected than R click ABRs by 'peripheral' factors (i.e. intensity and audiometric steepness).

Acoustic Stimulation↗
PubMed1993

Non-convulsive status epilepticus in the adult mentally retarded. Classification and role of benzodiazepines.

Non-convulsive status epilepticus (NCS) is rarely encountered and may appear with a psychiatric mask. As clouding of consciousness is the major ictal manifestation, the condition may easily be overlooked in the mentally retarded. We have studied 11 mentally retarded patients with NCS. Since NCS with a focal onset may have a generalized ictal EEG pattern, a classification of NCS solely based on the seizure classification may be misleading. In some patients, it is impossible, both clinically and on the basis of EEG recordings, to distinguish between continuous complex partial seizures and atypical absences. We therefore propose a revised classification of NCS based on the ictal EEG pattern and the epilepsy syndrome diagnosis (I) NCS in generalized epilepsy syndromes, (II) NCS in localization-related epilepsy, (a) with localized EEG features, (b) with generalized EEG features, and (c) with transitional EEG features, and (III) undetermined NCS. Four of our patients were classified as Group I, two as Group IIa, one as Group IIb, one as Group IIc, and three as Group III. Benzodiazepines at small or standard doses may be ineffective in terminating NCS, particularly in the Lennox-Gastaut Syndrome. The identification of trigger factors is essential. Drugs seemed to be the most important precipitants in our patients; in three, NCS was induced by recurrent rectal diazepam over-administration. This complication of rectal diazepam treatment in epilepsy has not been addressed previously.

Adult↗