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Biomedical subjects

A K Karlsson

Publications and source records attributed to A K Karlsson.

13 recordsLinked to original sources
PubMed2001

Early interdisciplinary rehabilitation programme for whiplash associated disorders.

PURPOSE: To assess the clinical outcomes of a multidisciplinary rehabilitation programme for early intervention of chronic whiplash associated disorders (WAD). The primary aim of the programme was to increase levels of activity and independence in patients suffering WAD. METHODS: Ninety subjects with purported chronic symptoms associated with whiplash associated disorder (WAD) were referred to a multi-centre multi-modal 5- and 8-week rehabilitation programme in 1997-1998, during which prospective and retrospective functional and psychological evaluations were conducted, the follow-up was to 6 months. RESULTS: Subjects indicated they were satisfied with the programme. Retrospective evaluation indicated increased ability to cope with and control pain and, to some extent, psychological aspects. The pain intensity in the neck and upper back were significantly decreased at 6 months follow-up. However, for most of the functional and psychological markers, no significant changes were found. CONCLUSIONS: A multi-modal rehabilitation programme for the chronic suffering attributed to WAD had positive effects according to several aspects of the retrospective evaluations, but according to most of the aspects evaluated prospectively the programme does not appear to have significant benefits.

Adult↗
PubMed1999

Insulin resistance and sympathetic function in high spinal cord injury.

OBJECTIVE: Cardiovascular disease (CVD) is today one of the main causes of death and affects spinal cord injured (SCI) earlier than able-bodied. Risk factors for CVD, such as decreased glucose tolerance, insulin resistance and increased fat mass, are all reported among SCI subjects and may be related to changes in sympathetic nervous system (SNS) function. METHODS: In order to test our hypothesis of a relationship between metabolic disturbances and alterations in SNS function, glucose and adipose tissue metabolism was investigated by the hyperinsulinaemic normoglycaemic clamp and microdialysis. Body composition was determined by DEXA-scanning. The SNS function was evaluated in total body as well as above and below lesion level by radiolabelled noradrenaline (NA) isotope dilution technique. A 24 h continuous plasma-NA monitoring was performed in seven SCI subjects. RESULTS: Following an oral glucose load the SCI group demonstrated normal glucose tolerance but impaired insulin sensitivity with a maximum insulin value of 83 mU x l(-1) in SCI compared to 50 in siblings, while adipose tissue metabolism was normal compared to siblings. Fat tissue mass constituted 34% of body mass in SCI group compared to 21% in weight-matched controls. Peripheral afferent activation resulted in increased blood pressure, decreased heart rate and reduction in muscle and skin blood flow. Furthermore, lipolysis below lesion level was activated by peripheral stimulation (89-135 micromol x l(-1)). The 24 h continuous monitoring revealed p-NA levels > 1.40 nmol x l(-1) sufficient to induce lipolysis in 20% of the registrations. NA spillover below lesion level increased substantially following peripheral afferent stimulation (0.06-0.90 pmol x min x (-1) x 100 g(-1)), whereas spillover above lesion level increased during central activation. CONCLUSIONS: We found signs of decreased insulin sensitivity and increased fat tissue mass. Peripheral activation of SNS was visualised in the SCI group by increased transmitter spillover as well as increased lipolysis and vasoconstriction. The diurnal registration of NA levels indicated frequent episodes of peripheral sympathetic activation in the group. This may compensate for the inability of central activation of SNS and may contribute to maintain lipolysis activity as well as to generate insulin resistance in the group.

Absorptiometry, Photon↗
PubMed1999

Autonomic dysreflexia.

Autonomic dysreflexia (AD) may complicate spinal cord injured (SCI) subjects with a lesion level above the sixth thoracic level. There are several ways to remove triggering factors and, furthermore, new trigger mechanisms may be added by the introduction of new treatments. New data about the pathogenic mechanisms have been suggested in recent years as well as signs of metabolic effects associated with the reaction. This review of the syndrome includes clinical aspects of the AD reaction; the known pathogenic mechanisms, the incidence and prevalence and triggering factors. AD is associated with some cases of severe morbidity, including cerebral haemorrhage, seizures and pulmonary oedema. Symptomatic as well as specific treatments are discussed. Finally, some further questions are raised by the necessity of a proper definition of the syndrome, the revealing of the underlying pathophysiology, and new investigations concerning incidence and prevalence.

Autonomic Nervous System Diseases↗
PubMed1998

Aural rehabilitation in the elderly: supply of hearing aids related to measured need and self-assessed hearing problems.

Three age cohorts of elderly persons in Göteborg (70, 75 and 88 years of age) were studied regarding hearing aid (HA) rehabilitation, on the one hand, and measured and self-assessed hearing, on the other. The participants, 615 in number, were representative of their ages and were selected from a geriatric population study. At age 70, 12% of the participants had been equipped with HAs. At age 75, the corresponding figure was 14% and at age 88, 32%. The correlations between self-assessed and audiometrically measured hearing were reasonably high (r = 0.5-0.7). According to the result for the self-assessed measure, we estimate that elderly persons with pure-tone averages (PTAs) at 30 dB HL (0.5-4 kHz, better ear) are in need of aural rehabilitation. Nevertheless, few subjects with PTAs between 30 and 49 dB HL have been equipped with HAs. At age 88, almost 20% of those with pronounced problems had no HA. Very few participants with no documented hearing problems for aural rehabilitation had been equipped with HAs.

Aged↗
PubMed1998

Regional sympathetic function in high spinal cord injury during mental stress and autonomic dysreflexia.

Centrally mediated sympathetic stimulation of subjects who have suffered a spinal cord injury (SCI) does not activate the decentralized part of the body below the level of the lesion, whereas experimental data indicate an exaggerated response above the level of the lesion. SCI subjects may exhibit an autonomic dysreflexia reaction following afferent stimulation below the level of the lesion. In order to investigate the function of the sympathetic nervous system above and below the level of the lesion, regional noradrenaline spillover was measured by means of steady-state isotope dilution technique above (forearm) and below (leg) the level of the lesion at baseline, during mental stress and following bladder stimulation in nine SCI subjects (mean age 41 years; level of injury C7-T4; mean duration of injury 13.8 years). The results from the SCI subjects were also compared with those from 10 weight- and age-matched control subjects, both at rest and during mental stress. Body composition was determined by dual energy X-ray absorptiometry scanning and arm/leg blood flow by occlusion plethysmography. At baseline, total and regional noradrenaline spillover did not differ between the groups. Mental stress increased mean arterial pressure in both groups. Heart rate (76 versus 64 beats/min; P < 0.05) and arm noradrenaline spillover (2.73 versus 1.71 pmol/min/100 g; P < 0.05) increased more in spinal cord injury subjects than in control subjects, whereas total body (2826 versus 3783 pmol/min; P < 0.01) and leg noradrenaline spillover (0.23 versus 0.41 pmol/min/100 g; P < 0.05) increased only in the control group. During bladder stimulation, SCI subjects reacted with a marked increase in mean arterial pressure and leg noradrenaline spillover (from 0.06 to 0.91 pmol/min/100 g; P < 0.05) and their leg blood flow decreased. Regional and total noradrenaline clearance were similar in the two groups. In conclusion, peripheral afferent stimulation below the level of the lesion in spinal cord injury subjects gives rise to a marked noradrenaline spillover from the decentralized part of the sympathetic nervous system suggesting a remaining, but qualitatively altered, neuronal function. Centrally mediated stimulation induced an exaggerated response above the level of the lesion.

Absorptiometry, Photon↗
PubMed1997

Regulation of lipolysis by the sympathetic nervous system: a microdialysis study in normal and spinal cord-injured subjects.

To evaluate the regulation of lipolysis by the sympathetic nervous system, eight spinal cord-injured (SCI) subjects with a lesion above T5 resulting in a decentralization of the lower-body sympathetic nervous system and adrenal medulla (age, 36 +/- 2 years; weight, 82 +/- 5 kg; body fat mass, 26.8 +/- 3.0 kg; all mean +/- SE) and nine control subjects (age, 33 +/- 2; weight, 80 +/- 3; NS; body fat mass, 16.1 +/- 1.5 kg; P < .01) were investigated after fasting overnight. Each subject was studied with subcutaneous microdialysis and 133Xe-clearance adipose tissue blood flow (ATBF) in the umbilical and clavicular regions during postabsorptive rest and after sympathoexcitatory stimulation by means of mental stress and isometric handgrip exercise. SCI subjects had an increased body fat mass, hyperinsulinemia, and an elevated lipolytic rate at rest compared with control subjects. ATBF and lipolysis were activated to a normal extent following mental stress and isometric handgrip exercise in the umbilical region in control subjects. ATBF was increased in tissue above but not below the lesion level in SCI subjects following mental stress. Glycerol release was not different between groups in either tissue region despite significantly lower noradrenaline and adrenaline levels in SCI subjects. This finding argues against a significant adrenergic control of the lipolytic rate at rest. Furthermore, the small differences in stimulated glycerol release between groups, as well as the increased plasma glycerol levels in SCI subjects, cast doubt on the view that interruption of adrenergic activity below the lesion is the sole mechanism underlying the increased body fat mass in SCI subjects.

Adult↗
PubMed1997

Peripheral afferent stimulation of decentralized sympathetic neurons activates lipolysis in spinal cord-injured subjects.

Spinal cord-injured (SCI) subjects exhibit a normal lipolytic rate despite the failure of centrally mediated sympathoexcitatory stimuli to activate lipolysis. Peripheral afferent stimulation below the lesion level induces an exaggerated autonomic reaction in SCI with lesion levels above T5, ie, so-called autonomic dysreflexia. The metabolic effects of induced dysreflexia were investigated in five SCI subjects (age, 35 +/- 8 years; duration of paresis, 15 +/- 7.5 years [mean +/- SD]; lesion level, T3 to T4, n = 2, C7, n = 3) following bladder stimulation. Subcutaneous glycerol concentrations were measured by microdialysis above and below the lesion level. Diurnal plasma noradrenaline (NA) and adrenaline levels were continuously monitored in seven SCI subjects (lesion level T3 to T4, n = 2; C4 to C7, n = 5). Bladder stimulation resulted in an increased mean arterial pressure ([MAP] 81 +/- 8 to 114 +/- 11 mm Hg, P < .05), a decreased heart rate (70 +/- 3 to 54 +/- 4 beats/min, P < .05), and an increased plasma NA (0.70 +/- 0.49 v 3.27 +/- 1.56 nmol/L, P < .05). Interstitial glycerol was increased in the decentralized region (89 +/- 12 to 135 +/- 21 mumol/L, P < .05), whereas no reaction was found in the centrally innervated region. Plasma concentrations of glycerol and insulin increased. Diurnal monitoring showed periods of increased plasma NA sufficient to induce lipolysis (> 1.4 nmol/L) during 20% of the registration period. The data suggest that peripheral afferent stimulation below the lesion level increases NA release and activates lipolysis and that frequent episodes of activation are found in SCI subjects with tetraplegia or high paraplegia.

Adult↗
PubMed1997

Differentiated norepinephrine spillover in human skeletal muscle.

Most neurophysiological studies have shown similar sympathetic outflow to arm and leg. However, some direct microneurographic recordings indicate differentiated sympathetic outflow to limbs both at rest and during mental stress. Hence, differentiated levels of norepinephrine (NE) spillover could prevail. By steady-state infusion of [3H]NE and body composition determination by dual-energy X-ray absorptiometry-scan, we simultaneously assessed arm and leg NE spillover related to 100 g tissue and total limb weight. NE spillover was lower in leg than arm (0.26 vs. 1.51 pmol.min-1.100 g-1, P < 0.05), and the difference remained when expressed as a function of total limb weight (66 vs. 137 pmol/min, P < 0.05). Fractional extraction of [3H]NE was similar in arm and leg. Neuronal uptake blockade by desipramine was more effective in leg than arm; fractional extraction in leg decreased by 32% (P < 0.05) but was unaltered in arm. Thus a lower NE spillover was observed from leg than arm, possibly reflecting a lower sympathetic outflow and a more neuronally dependent reuptake.

Absorptiometry, Photon↗
PubMed1995

Influence of the sympathetic nervous system on insulin sensitivity and adipose tissue metabolism: a study in spinal cord-injured subjects.

To evaluate insulin sensitivity and adipose tissue metabolism, seven spinal cord-injured (SCI) subjects (age, 43 +/- 6 years; body mass index, 22.8 +/- 1.4; mean +/- SE) and their seven siblings (age, 45 +/- 6 years; body mass index, 24.8 +/- 0.8) were studied using oral glucose (100-g) tolerance tests (OGTTs), euglycemic insulin clamps (insulin infusion, 1 mU/kg.min), and microdialysis of the subcutaneous tissue. Blood glucose and insulin after oral glucose were significantly increased in SCI subjects as compared with their siblings. During insulin clamping, plasma adrenaline increased significantly in controls, but not in SCI subjects. However, the rates of glucose production (2.02 +/- 0.36 v 1.59 +/- 0.09 mg/kg.min) and utilization (5.13 +/- 0.71 v 5.78 +/- 0.34) were similar in the two groups. Furthermore, interstitial subcutaneous glycerol and lactate concentrations before and after oral glucose were similar in the two groups, even in neurally decentralized tissue with broken connection between the central nervous system and peripheral sympathetic nerves. The data suggest that (1) well-mobilized SCI subjects show minor insulin resistance, and (2) sympathetic nervous activity has a minor influence on adipose tissue metabolism in the postabsorptive state, but may affect insulin sensitivity during euglycemic clamping.

Adipose Tissue↗
PubMed1995

Clinical application of distorted speech audiometry.

The clinical validity of four different low-redundant speech tests was calculated using four groups of 83 patients with retrocochlear or central auditory lesions. The speech tests used were: interrupted speech (7 or 10 interruptions/s) time-compressed speech and filtered speech. A comparison between patients and age-matched normal-hearing controls showed that the patients had significantly lower speech recognition score. The best sensitivity ratings of the tests were between 47% and 80%, the highest in patients with cerebellopontine angle tumours and temporal lobe lesions, and the lowest in vascular brainstem lesions. The speech tests with the highest sensitivity were 7 interruptions/s and time-compressed speech.

Adult↗
PubMed1991

Tinnitus in old age.

From the gerontological and geriatric study of 70-year-olds in Göteborg, Sweden, 674 persons were selected to participate in an investigation of tinnitus in old age. The subjects belonged to two cohorts, one of which was followed longitudinally at ages 75 and 79. Some 8-15% of the participants had continuous tinnitus and 20-42% occasional tinnitus. The prevalence of tinnitus was about the same for men as for women. There were significant correlations between tinnitus and exposure to occupational noise. Men with continuous tinnitus had, on average, been exposed to noise for 20-30 years, in contrast to men without tinnitus who had noise exposure of 11-15 years, on average. Those with continuous tinnitus had poorer pure-tone thresholds than those without tinnitus or with occasional tinnitus. Noise-induced hearing loss is an important etiological factor, especially for old men, but other types of hearing losses such as presbyacusis, Ménière's disease, otosclerosis and chronic otitis media also contribute to tinnitus.

Aged↗