Biomedical subjects

K Suominen

Publications and source records attributed to K Suominen.

At least 19 recordsLinked to original sources

PubMed2005

Similarities in the phenotype of the auditory neural substrate in children with Asperger syndrome and their parents.

Asperger syndrome (AS) is a developmental disorder of brain function characterized by deficits in social interaction including difficulties in understanding emotional expressions. Children with AS share some of the behavioural characteristics with their parents and AS seems to run particularly in the male members of the same families. The aim of the present study was to determine whether similarities could be found between children with AS and their parents at central auditory processing. It was found that in children with AS the sound encoding, as reflected by the exogenous components of event-related potentials, was similarly abnormal as in both their mothers and fathers. However, their abnormal cortical auditory discrimination, as indexed by the prolonged latency of the mismatch negativity, resembled that of their fathers but not that of their mothers. The present results suggest that complex genetic mechanisms may contribute to auditory abnormalities encountered in children with AS.

Acoustic Stimulation↗

PubMed2004

Cardiovascular autonomic dysfunction correlates with brain MRI lesion load in MS.

OBJECTIVE: The aim of the present study was to investigate the cardiovascular autonomic control in clinically definite multiple sclerosis (MS) patients with a standardised battery of cardiovascular tests and to correlate these findings with the brain magnetic resonance imaging (MRI) lesion load. METHODS: Fifty-one patients with MS and 50 healthy controls were studied. Brain MRI was performed in all patients showing typical MS lesions. The cardiovascular tests were carried out using a standardised battery. RESULTS: Heart rate (HR) responses to deep breathing (P < 0.05) and tilt table testing (P < 0.001) were significantly decreased in MS patients when compared to those of the controls. Blood pressure (BP) responses in the tilt table test were also impaired in MS patients (diastolic P < 0.001, systolic P < 0.05). Of the different brain areas investigated the total volume of the midbrain MRI lesions (P < 0.05) was the one most clearly associated with the impaired BP responses. CONCLUSIONS: MS results in both reduced HR variation and decreased BP reactions indicating disturbed cardiovascular regulation. In particular, the midbrain lesions found in MS are associated with cardiovascular dysfunction.

Adult↗

PubMed2004

Health care contacts before and after attempted suicide among adolescent and young adult versus older suicide attempters.

BACKGROUND: The pattern of all health care contacts among young people before and after attempted suicide is not well documented. Neither is it known if the health care contacts of young suicide attempters differ from those of older suicide attempters. This study investigated the age-related clinical characteristics of suicide attempters and the pattern of their contacts with health care before and after attempted suicide in different age groups, particularly adolescence and young adulthood. METHOD: All consecutive 1198 suicide attempters treated in hospital emergency rooms in Helsinki between January 1997 and January 1998 were identified and divided into three age groups (15-24 years, 25-39 years, 40 years and over). Data were gathered on all health care contacts 1 year before and after the index attempt. RESULTS: Although adolescent and young adult suicide attempters suffered from severe mental disorders, a remarkable proportion of them were left without psychiatric consultation and aftercare recommendation following the attempt. Two-thirds of 15-19-year-old male suicide attempters had no treatment contact during the month before the attempt, while a quarter of them were referred to psychiatric consultation and a half had no healthcare contact in the month following the attempt. CONCLUSIONS: These findings indicate considerable scope for improvement in the assessment of young suicide attempters and their referral to aftercare.

Adolescent↗

PubMed2004

Evoked EEG patterns during burst suppression with propofol.

BACKGROUND: During EEG suppression with isoflurane or sevoflurane anaesthesia, median nerve stimulation causes cortical responses of two kinds: an N20 wave with a latency of 20 ms and an EEG burst with a latency of 200 ms. We tested the possibility that median nerve stimulation during EEG suppression with propofol would cause an EEG response that was consistent enough to be of use for neuromonitoring. METHODS: Eight patients were anaesthetized with propofol to allow burst suppression. Electrical stimulation of the median nerve was applied during general anaesthesia and the EEG was measured. RESULTS: The EEG response to a painful stimulus had four successive components: (i) N20 and P22 potentials, reflecting activation of fast somatosensory pathways; (ii) a high-amplitude negative wave, possibly reflecting activation of the somatosensory cortex SII bilaterally; (iii) a burst (i.e. a negative slow wave with superimposed 10 Hz activity, probably reflecting an arousal mechanism); and (iv) a 13-15 Hz spindle, probably originating from the thalamus, similar to sleep spindles. These could be seen separately and in different combinations. Bursts and spindles during burst suppression were also seen without stimulation. In deepening propofol anaesthesia, spindles were seen in the continuous EEG before burst suppression was achieved. In deep anaesthesia, spindles were seen when bursts had ceased, and painful stimuli evoked sharp waves without subsequent bursts. CONCLUSION: In addition to SSEP (somatosensory evoked potentials), three different evoked responses are noted that could be useful for clinical monitoring.

Adult↗

PubMed2002

Comparison of heart rate variability analysis methods in patients with Parkinson's disease.

The aim of the present study was to evaluate different analysis methods for revealing heart rate variability (HRV) differences between untreated patients with Parkinson's disease and healthy controls. HRV in standard cardiovascular reflex tests and during a 10 min rest period were measured by time- and frequency-domain and geometrical and non-linear analysis methods. Both frequency- and time-domain measures revealed abnormal HRV in the patients, whereas non-linear and geometrical measures did not. The absolute high-frequency spectral power of HRV was the strongest independent predictor to separate the patients from the controls (p = 0.001), when the main time-domain and absolute frequency-domain measures were compared with each other. When the corresponding normalised spectral units, instead of the absolute units, were used in the comparison, the two best single measures for separating the groups were the 30/15 ratio of the tilting test (p = 0.003) and the max/min ratio during deep breathing (p = 0.024). When the correlations between the different measures were estimated, the time-domain measures, fractal dimension and absolute spectral powers correlated with each other. The frequency- and time-domain analysis techniques of stationary short-term HRV recordings revealed significant differences in cardiovascular regulation between untreated patients with Parkinson's disease and the controls. This confirms cardiovascular regulation failure before treatment in the early stages of Parkinson's disease. The HRV spectral powers, in absolute units, were the most effective single parameters in segregating the two groups, emphasising the role of spectral analysis in the evaluation of HRV in Parkinson's disease.

Adult↗

PubMed2002

Cardiovascular autonomic reactivity is decreased in adolescents with Type 1 diabetes.

AIMS: To characterize autonomic nervous system function by means of the heart rate and blood pressure responses to various stimuli in relation to pubertal maturation in patients with Type 1 diabetes mellitus (DM). METHODS: One hundred out of 138 eligible patients at the Out-patient Diabetes Clinic and 100 healthy control subjects were examined in terms of cardiovascular parameters at rest, during deep breathing and when standing. Heart rate variability was analysed with time domain,frequency domain and fractal dimension parameters. Tanner pubertal staging was performed before the examinations. RESULTS: The time domain parameters of heart rate variability at rest or during standing did not significantly differ between the patients and controls in total or at pubertal stages. In the spectral analysis of heart rate variability the very low frequency band was decreased in the patients during standing (P = 0.023).The increase in the very low frequency (P = 0.013)and low frequency (P = 0.031) spectral powers upon changing from a supine position to standing was attenuated in the patients in total, while no significant differences were observed within the Tanner pubertal stages between patients and controls. Heart rate variability during deep breathing was decreased in the patients with distal polyneuropathy (P = 0.006). CONCLUSIONS: Although cardiovascular integrity is in the main well preserved in adolescent patients with Type 1 DM, these patients are prone to attenuated autonomic nervous system reactivity.

Adolescent↗

PubMed2001

Long-term risk factors for suicide mortality after attempted suicide--findings of a 14-year follow-up study.

OBJECTIVE: To determine the risk of suicide over a 14-year follow-up period, and to investigate the long-term risk factors for suicide using survival analysis. METHOD: Data were collected on all unselected deliberate self-poisoning patients (n=1018) treated during 1983 in the emergency unit of Helsinki University Central Hospital. RESULTS: By the end of the 14 -year follow-up period 222 (21.7%) of these patients had died. Sixty-eight (6.7%) had committed suicide; 44 (9.2%) men and 24 (4.5%) women. The long-term risk factors for suicide were male sex, previous psychiatric treatment, previous suicide attempts, somatic disease and a self-reported 'wish to die' motive for the index suicide attempt. CONCLUSION: The essential risk factors for suicide were being male and having previous suicide attempts. In addition, history of earlier psychiatric treatment, presence of somatic disease and genuine intent to die in the index suicide attempt suggest that the long-term risk has remained high for over a decade. The findings emphasize the need for long-term planning and treatment of suicide attempters met in the emergency room of general hospitals.

Adult↗

PubMed2001

Peripheral nerve function is increasingly impaired during puberty in adolescents with type 1 diabetes.

OBJECTIVE: To evaluate the impact of puberty on peripheral nerve function in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: Of 138 eligible patients with type 1 diabetes, 100 patients (age >9 years and diabetes duration >2 years) attending an outpatient diabetes clinic and 100 age- and sex-matched healthy control subjects took part in this cross-sectional study. Peripheral motor and sensory nerve conduction tests, cardiovascular reflex tests on the autonomic nervous system, and measurements of vibration-perception threshold (VPT) were performed. RESULTS: Nerve conduction velocity (NCV) in the distal motor and sensory nerves, the motor nerve distal latency, and the sensory nerve action potential (SNAP) amplitude were impaired in the adolescent patients with type 1 diabetes. The deterioration in motor NCV, H-reflex latency, and SNAP amplitude became more conspicuous in late puberty and postpuberty and was related to poor metabolic control. A total of 10 patients had distal diabetic polyneuropathy (DP) neurophysiologically, and these patients had significantly lower heart-rate variation in the deep breathing test than the other patients. Three of the patients with DP had peripheral neurological signs or symptoms. A slight difference in the VPT between the patients and control subjects was observed after puberty. CONCLUSIONS: Increasing subclinical motor nerve impairment can be detected during late puberty and after puberty, and sensory NCV and SNAP amplitude are reduced in adolescents with type 1 diabetes. Poor metabolic control during puberty appears to induce deteriorating peripheral neural function in young patients with type 1 diabetes.

Action Potentials↗

PubMed2000

Suppressed sympathetic skin response in Parkinson disease.

The sympathetic skin response (SSR) was used to evaluate sympathetic sudomotor activity in Parkinson disease (PD) and the effects of antiparkinsonian medication on the disease. We recorded SSRs to electric and auditory stimulation in 58 untreated patients with PD and in 20 healthy controls. In addition to amplitude and latency measurements, we examined the number of SSRs evoked by a single stimulus and the response adaptation after repetitive stimuli. The patients with PD subsequently were randomized for administration of levodopa/ carbidopa (n = 19), bromocriptine (n = 20), or selegiline (n = 19) as their initial treatment. The measurements were repeated after 6 months of medication and after a washout period. SSR amplitudes were significantly lower in patients with PD than in the control subjects at baseline. The amplitude reduction was more pronounced in patients with high Unified Parkinson's Disease Rating Scale scores, in those with high tremor scores, and in those with PD symptoms that had lasted more than 1 year. The levodopa/carbidopa and bromocriptine treatments did not influence SSRs, although selegiline slightly decreased the amplitude. The synchronous responses after a single stimulus were more often repetitive in the patients with PD than in the controls, although the response adaptation tendencies were similar. In conclusion, the degenerative process in PD involves the sudomotor system as reflected by the progressive suppression of SSR amplitudes with a correlation to PD symptom duration and clinical disability, whereas PD medications seems to have only minor effects. The changes in amplitude and the repetitiveness of SSRs with normal adaptation may be caused by deficits at several levels of the SSR reflex arch.

Acoustic Stimulation↗

PubMed2000

Levodopa, bromocriptine and selegiline modify cardiovascular responses in Parkinson's disease.

Autonomic nervous system (ANS) involvement is frequently found in Parkinson's disease (PD), but its causal relationship to the disease itself and its medication is unclear. We evaluated the effects of PD medications on cardiovascular ANS functions. Heart rate (HR) responses to normal and deep breathing, the Valsalva manoeuvre and tilting, and blood pressure (BP) responses to tilting and isometric work were measured prospectively in 60 untreated PD patients randomised to receive either levodopa (n = 20), bromocriptine (n = 20) or selegiline (n = 20) as their initial treatment. The results were compared with those of 28 healthy controls. The responses were recorded at baseline, after 6 months on medication and following a 6-week washout period. At baseline HR responses to normal breathing, deep breathing and tilting were already lower and the fall in the systolic BP immediately and at 5 min after tilting was more pronounced in the PD patients than in the controls. Six months' levodopa treatment diminished the systolic BP fall after tilting when compared to baseline, whereas bromocriptine and selegiline increased the fall in systolic BP after tilting and selegiline diminished the BP responses to isometric work. The BP responses returned to the baseline values during the washout period. The drugs induced no change in the HR responses. Thus PD itself causes autonomic dysfunction leading to abnormalities in HR and BP regulation and the PD medications seem to modify ANS responses further. Bromocriptine and selegiline, in contrast to levodopa, increase the orthostatic BP fall and suppress the BP response to isometric exercise reflecting mainly impairment of the sympathetic regulation.

Aged↗

PubMed2000

Auditory P300 event related potential in minor ischemic stroke.

OBJECTIVE: Various degenerative cerebral diseases and even depression may cause abnormalities of the cognitive event related potentials (ERPs). We conducted the present study to elucidate the effects of ischemic stroke on the P300 ERP component. MATERIAL AND METHODS: We recorded the P300 wave using an auditory oddball paradigm in 38 consecutive brain infarct patients with mild neurological deficits at 3 and 12 months post-stroke, and in 29 healthy control subjects. RESULTS: Brain infarction slightly prolonged the P300 latency, and the observed delay was related to the presence and degree of post-stroke depression evaluated with the Zung Depression Scale and the DSM-III criteria. Infarction did not affect the P300 amplitude or its distribution on the scalp. The results of the patients with hemispheric brain infarction and those of the patients with brainstem infarction were similar, and also the values of the patients with the left- and right-sided lesions. The normal physiological correlation between subject age and the P300 latency was absent at 3 months post-stroke, but was present at 12 months post-stroke. CONCLUSION: Brain infarction delays the P300 ERP and temporarily distorts its age-related physiology. The increase of the P300 latency seems to be associated with the post-stroke depression.

Acute Disease↗

PubMed2000

Heart rate variability in patients with untreated Parkinson's disease.

The aim of this study was to evaluate cardiovascular responses as a marker of autonomic nervous system (ANS) disturbances in patients with untreated Parkinson's disease (PD) and to assess the relationship between them and the clinical characteristics of PD. The ANS functions were investigated in 50 patients with PD and 55 healthy subjects by measuring standard cardiovascular autonomic reflexes and heart rate variability (HRV) at rest using spectral analysis (the autoregressive model and the fast Fourier transformation), the percentage of the counts of beat-to-beat variation greater than 50 ms and the fractal dimension. Significantly attenuated HRV and deficient blood pressure reaction to tilting were found in the PD patient group. The patients with hypokinesia/rigidity as the initial symptom of PD had a more pronounced HRV deficit than those with tremor onset. Untreated PD patients suffer significant failure in cardiovascular nervous system regulation, and in patients with hypokinesia/rigidity as their initial disease manifestation the risk of this ANS dysfunction is high. However, in the early stages of PD these changes did not reach significance at individual level.

Adult↗

PubMed2000

Interictal cardiovascular autonomic responses in patients with temporal lobe epilepsy.

PURPOSE: To measure interictal cardiovascular autonomic functions in patients with either refractory or well-controlled temporal lobe epilepsy (TLE). METHODS: For autonomic assessment, heart rate variation during normal and deep breathing, Valsalva maneuver, and tilting were measured in 19 patients with chronic refractory TLE, 19 patients with well-controlled TLE, and 38 age- and sex-matched healthy control subjects. Blood pressure responses to tilting and isometric work also were evaluated. RESULTS: Heart-rate (HR) variation during normal breathing (p = 0.006) and tilting (p = 0.043) was lower in patients with refractory TLE than in control subjects. Heart-rate response to tilting (p = 0.036) was also lower in patients with well-controlled TLE than in control subjects. Blood-pressure responses showed no differences between the patients and the control subjects. Patients taking carbamazepine (CBZ) medication had decreased HR responses to deep breathing (p = 0.046) and to tilting (p = 0.014) compared with the control subjects. CONCLUSIONS: Refractory TLE seems to be associated with dysfunction of the cardiovascular autonomic regulation, manifesting as impaired HR responses to certain stimuli. Interictal autonomic dysfunction is seen in patients with well-controlled TLE as well, but it may be more evident in patients with refractory epilepsy. CBZ medication may also be associated with altered autonomic cardiac control.

Adult↗

PubMed1999

Tibial nerve somatosensory evoked potentials during EEG suppression in sevoflurane anaesthesia.

OBJECTIVES AND METHODS: Cortical tibial nerve somatosensory evoked potentials (TSEPs) were recorded from 10 subjects in sevoflurane anaesthesia in order to study TSEP during EEG suppression. RESULTS: With a stimulation frequency less than one per second the major component was a positive wave which had maximal amplitude parietally ipsilaterally to stimulus and mean latency of 46.1 ms. It probably corresponds to the P40 wave. It was preceded by a widespread smaller positive wave, which corresponds to the subcortical P30 wave. In two patients a high amplitude negative wave, a couple of milliseconds before the positive wave, and maximal parietally contralateral to stimulus, was seen. All later waves were absent. CONCLUSION: The results are in agreement with our previous results from median nerve SEPs showing that the first cortical response from primary somatosensory cortex is enhanced, and later waves are suppressed. Hence, recording TSEPs during EEG suppression provides a way to record the activity of the primary somatosensory cortex accurately and rapidly due to the very good signal to noise ratio, so that even single responses to stimuli can be seen without averaging. Our results suggest that new cortical generators, which are not recordable awake, may be discovered in some patients.

Adult↗

PubMed1998

Single-sweep cortical somatosensory evoked potentials: N20 and evoked bursts in sevoflurane anaesthesia.

Cortical evoked responses to median nerve stimulation were recorded from 21 subjects during sevoflurane anaesthesia at the level of burst suppression in EEG. The N20/P22 wave had the typical form of a negative wave postcentrally, and positive precentrally. The amplitude exceeded 4 microV in all patients, making it easily visible without averaging on the low-amplitude suppression. These results show that two kinds of somatosensory evoked potential can be studied without averaging during EEG suppression in deep anaesthesia. One is the localised N20/P22 wave, which is seen regularly during suppression after stimuli with intervals exceeding 1 s. The other is the burst, involving the whole cortex, which is not evoked by every stimulus. We suggest that somatosensory evoked potentials can be monitored during sevoflurane-induced EEG suppression, and often can be evaluated reliably from a couple of single sweeps with stimulation interval exceeding 1 s. The enhancement of early cortical components of SEP, their adaptation to repeated stimuli, and the disappearance of later polysynaptic components during EEG suppression, give new possibilities to study the generators of SEP and the different effects of anaesthetics.

Adult↗

PubMed1998

Interictal cardiovascular autonomic responses in patients with epilepsy.

PURPOSE: To evaluate the interictal autonomic nervous system function in 84 patients with epilepsy: 37 with newly diagnosed, previously untreated epilepsy, and 47 patients receiving long-term carbamazepine (CBZ), phenytoin (PHT), or valproate (VPA) monotherapy, or CBZ plus PHT, or CBZ plus VPA for their seizure disorder. METHODS: We assessed autonomic control of the cardiovascular regulatory system by standardized cardiovascular reflex tests measuring changes in heart rate (HR) and blood pressure (BP) at rest and after certain stimuli. RESULTS: The HR and BP responses were similar to those of control subjects in patients with newly diagnosed epilepsy. However, HR variation during normal breathing and maximum systolic BP increase in isometric work were diminished in patients, who had been treated with antiepileptic drugs (AEDs) for epilepsy for a long time. Diminished HR responses to the Valsalva maneuver were noted in patients receiving CBZ as monotherapy and during deep breathing in patients receiving CBZ combined with PHT or VPA. Furthermore, patients receiving CBZ had diminished BP responses in isometric work. When analyzed in relation to epilepsy type, suppressed HR responses in normal breathing were associated with primary generalized epilepsy (PGE), whereas diminished BP responses in isometric work were associated with partial epilepsy. Two patients with recently diagnosed partial epilepsy and 1 patient receiving long-term CBZ monotherapy for partial epilepsy had two abnormal cardiovascular response test results. CONCLUSIONS: Our results show that cardiovascular responses mediated by both the parasympathetic and sympathetic nervous system are diminished in patients with epilepsy. However, the changes appear to be clinically significant in only a few of them and appear to be associated with CBZ medication. Further studies are needed to detect the underlying complex interactions and clinical significance of autonomic nervous system dysfunction in patients with epilepsy.

Adolescent↗

PubMed1997

Design and implementation of a PC-based data acquisition system for measuring ECG and respiratory signals.

A PC-based system capable of measuring R-R intervals in the electrocardiogram and detecting respiration phases is presented. It consists of standard amplifiers for ECG and respiration signals and a personal computer that detects QRS complexes, inspiration and expiration using low-pass, high-pass and differentiation processes. The performance of the method is evaluated using an application for real ECG and respiratory data.

Electrocardiography↗

PubMed1997

Hopelessness, impulsiveness and intent among suicide attempters with major depression, alcohol dependence, or both.

The present study examined differences in hopelessness, impulsiveness and suicide intent between suicide attempters with either major depression or alcohol dependence, comorbid major depression and alcohol dependence, and those without these disorders. A sample of 114 patients from consecutive cases of attempted suicide referred to a general hospital in Helsinki was interviewed and diagnosed according to DSM-III-R. Suicide intent was measured by the Beck Suicide Intent Scale (SIS) and hopelessness was assessed by the Beck Hopelessness Scale (HS). Impulsiveness of the suicide attempt was measured by two items of the SIS. Suicide attempters with major depression without comorbid alcohol dependence had higher suicide intent and lower impulsiveness than attempters with non-depressive alcohol dependence. Suicide attempts may differ between subjects with major depression, alcoholism or both disorders in terms of impulsiveness and suicide intent.

Adolescent↗