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Biomedical subjects

T Rinne

Publications and source records attributed to T Rinne.

18 recordsLinked to original sources
PubMed1999

Analysis of speech sounds is left-hemisphere predominant at 100-150ms after sound onset.

Hemispheric specialization of human speech processing has been found in brain imaging studies using fMRI and PET. Due to the restricted time resolution, these methods cannot, however, determine the stage of auditory processing at which this specialization first emerges. We used a dense electrode array covering the whole scalp to record the mismatch negativity (MMN), an event-related brain potential (ERP) automatically elicited by occasional changes in sounds, which ranged from non-phonetic (tones) to phonetic (vowels). MMN can be used to probe auditory central processing on a millisecond scale with no attention-dependent task requirements. Our results indicate that speech processing occurs predominantly in the left hemisphere at the early, pre-attentive level of auditory analysis.

Acoustic Stimulation↗
PubMed1999

Effect of internal thoracic artery preparation on blood loss, lung function, and pain.

BACKGROUND: Postoperative blood loss, respiratory distress, and pain after coronary artery operation were assessed in a prospective, randomized, clinical study comparing two techniques of internal thoracic artery preparation. METHODS: In group A (n = 57) the internal thoracic artery was dissected with the entire surrounding connective tissue after opening the pleura, using routine lateral pleural drainage. In group B (n = 55) a venoarterial pedicle was prepared without surrounding muscle leaving the pleura intact. We assessed blood loss, clinical outcome, lung function, location, intensity, and quality of pain 6 days and 3 months after the operation. RESULTS: Significantly higher blood loss was observed in group A (A, 608+/-58 mL; B, 470+/-48 mL; p = 0.027). Forced expiratory volume in 1 second was significantly decreased in group A 6 days after surgery (A, 76.0%+/-1.6%; B, 83.2%+/-1.6%; p = 0.020). The forced expiratory volume in 1 second correlated to inspiratory vital capacity, which confirmed the advantage of the venoarterial technique (A, 0.771+/-0.021; B, 0.832+/-0.020; p = 0.003). Vital capacity was significantly higher in the venoarterial group at 3 months (A, 85.2%+/-2.1%; B, 98.5%+/-1.2%; p = 0.009), but not on postoperative day 6. The incidence of pleural effusion and atelectasis was significantly higher in group A (effusion: A, 52.6%; B, 23.6%; p = 0.002; atelectasis: A, 42.1%; B, 20.0%, p = 0.015). Sternal pain (A, 36.8%; B, 9.1%; p = 0.001) and suspenders pain (A, 33.3%; B, 7.3%; p = 0.001) occurred more often in group A. When using a multidimensional pain score, patients in group A experienced significantly sharper (6 days: A, 6.7+/-0.3; B, 3.3+/-0.2; p = 0.018; 3 months: A, 3.5+/-0.3; B, 1.4+/-0.3; p = 0.046) and more annoying pain (6 days: A, 7.6+/-0.2; B, 2.7+/-0.1; p = 0.036; 3 months: A, 6.6+/-0.3; B, 2.3+/-0.2; p = 0.040). CONCLUSIONS: These results demonstrate that the venoarterial preparation technique is superior to conventional internal thoracic artery preparation regarding postoperative blood loss, lung function, and pain.

Female↗
PubMed1999

Tracheostomy in cardiosurgical patients: surgical tracheostomy versus ciaglia and fantoni methods.

BACKGROUND: Patients requiring prolonged mechanical ventilation are not uncommon in a cardiosurgical intensive care unit. Elective tracheostomy is considered the airway treatment of choice in these patients. METHODS: To evaluate different techniques for tracheostomy, we prospectively investigated 120 patients who had conventional open (n = 40), minimally invasive percutaneous dilatational (n = 40), or translaryngeal (n = 40) tracheostomy techniques. The main areas of investigation included oxygenation index (partial pressure of arterial oxygen divided by fraction of inspired oxygen), complications, infection, and cost. RESULTS: The oxygenation index decreased in almost every patient, regardless of the technique used, but the extent of decrease was significantly lower in both minimally invasive techniques compared with the conventional method. Overall complication rate was 12.5% both in open tracheostomy and in percutaneous dilatational tracheostomy, whereas no complications occurred in translaryngeal tracheostomy procedures. Bacterial contamination of the tracheostomy site was found in 35% of the open tracheostomies, whereas no infection was seen in percutaneous dilatational or translaryngeal tracheostomies. In terms of costs, PDT ($506) and TLT ($362) were both much cheaper than open tracheostomy ($699). CONCLUSIONS: Percutaneous dilatational and translaryngeal tracheostomies are safe and cost-effective procedures that can be done easily at the patient's bedside and thus are attractive alternatives to conventional surgical tracheostomy in long-term airway access in a cardiosurgical intensive care unit.

Adult↗
PubMed1998

The mismatch negativity for duration decrement of auditory stimuli in healthy subjects.

The amplitude and latency of the mismatch negativity (MMN) elicited by occasional shorter-duration tones (25 and 50 ms) in a sequence of 75 ms standard tones were studied in 40 healthy subjects (9-84 years). The replicability and age dependence of the MMN-responses were determined. The 25 ms deviant tone evoked a clear response in 39 of the subjects, while the 50 ms deviant tone evoked an observable MMN only in 32 of the subjects. The MMN peak amplitude for the 25 ms deviants was significantly larger than for the 50 ms deviants. There was no significant difference in the peak latencies (measured from stimulus offset). For the 25 ms deviant, the amplitude diminished with increasing age. The MMN curves for the 25 ms deviant, measured on separate days in 14 subjects, looked very replicable. As a result of noise and filtering effect, the product-moment correlations were poor. The results indicate that the signal-to-noise ratio for the MMN to 25 ms deviants, obtained even in a 25 min recording session, is large enough for clinical use and individual diagnostics when undetectable (or very low amplitude) MMN is used as a sign of pathology. However, judged from the low correlation coefficients, despite the good replicability in visual evaluation, better methods for MMN quantification have to be used for clinical follow-up.

Acoustic Stimulation↗
PubMed1998

Does lidocaine protect the heart during coronary revascularisation?

BACKGROUND: Lidocaine has been used as the primary antiarrhythmic agent for ventricular arrhythmias during acute myocardial infarction (MI) and open heart surgery. Its cardioprotective effects have been studied in experimental settings and also during angioplastic reperfusion and coronary revascularisation. The basic mechanism of action, probably also involved with cardioprotection, has been demonstrated to be blockade of cardiac sodium channels. In this open study we investigated the contribution of continuous lidocaine infusion to cardioprotection during coronary revascularisation with blood cardioplegia. METHODS: During coronary revascularisation with cold blood cardioplegia, a study group of 50 patients received a prophylactic lidocaine infusion for 20 h started with a bolus dose before aortic clamping; another group of 50 patients without the infusion served as a control group. Serum troponin T concentration, serum creatine kinase MB activity and electrocardiography were the main parameters recorded. RESULTS: Serial measurement of Troponin T (P = 0.06) and CK-MB values: (P = 0.09) were slightly lower in the lidocaine group, but the differences were not statistically significant. CONCLUSION: Lacking statistically significant evidence of improved cardioprotection, lidocaine infusion cannot be recommended as a routine treatment during coronary revascularisation.

Anti-Arrhythmia Agents↗
PubMed1997

Electrophysiological evidence for cross-modal plasticity in humans with early- and late-onset blindness.

It is commonly believed that sensory deprivation can lead to cross-modal reorganization in an immature but not in a mature brain. The results of the present study suggest, however, that plasticity between sensory modalities is possible even in adults: activity indicating involvement of parietal or occipital brain areas in pitch-change discrimination was found in individuals blinded after childhood. Event-related brain potentials of early blinded (before the age of 2 years), late-blinded (12-28 years of age), and sighted adults were recorded to stimulus sequences consisting of standard tones occasionally replaced by deviant tones. Even when participants were not attending to auditory stimuli, the deviant tones elicited the mismatch negativity (MMN) in each group. There were no significant MMN front-back scalp distribution differences among the groups. However, when participants were detecting deviant stimuli, these stimuli elicited N2 and P3 waves that were posterior in distribution in both groups of blind participants relative to those of the sighted participants. These results suggest that cross-modal reorganization may occur even in the mature human brain.

Adult↗
PubMed1996

MEG-compatible multichannel EEG electrode array.

We describe an EEG electrode array, which is designed to facilitate simultaneous multichannel EEG and MEG recordings. The special electrode design allows shorter preparation times and more reliable contacts than commercially available solutions. The electrode array is magnetically compatible with MEG and the low-profile electrodes consume minimal space inside the magnetometer.

Electrodes↗
PubMed1996

The ontogenetically earliest discriminative response of the human brain.

Speech sounds elicited electric brain responses in healthy premature infants born 30-35 weeks after conception, demonstrating that the human brain is able to discriminate speech sounds even at this early age, well before term, and supporting previous results suggesting that the human fetus may learn to discriminate sounds while still in the womb. We presented preterm infants with stimulus sequences consisting of a repetitive vowel that was occasionally replaced by a different vowel. This infrequent vowel elicited a response resembling the adult mismatch negativity, which is known to reflect the brain's automatic detection of stimulus change. The present results constitute the ontogenetically earliest discriminative response of the human brain ever recorded.

Brain↗
PubMed1996

Protective action of hydroxyethyl rutosides on singlet oxygen challenged cardiomyocytes.

1. The effect of a standardized mixture of beta-hydroxyethyl rutosides against oxidative damage in singlet oxygen-challenged isolated cardiac myocytes from adult rats was investigated. The morphology of the myocytes was evaluated as an indicator for cell viability (elongated, rod shaped cells vs. hypercontracted, rounded cells). The determination of the production of thiobarbituric acid reactive substances served as an indicator for lipid peroxidation. 2. Exposure to singlet oxygen which was generated by photo-excitation of rose bengal (10(-7) M) reduced the number of rod shaped (vital) cardiomyocytes by 78.5 +/- 2.5% and increased the production of thiobarbituric acid reactive substances by 1180 +/- 150% in comparison to incubation with control buffer. 3. Coincubation of the cells with beta-hydroxyethyl rutosides (concentration range: 6.7 pg ml-1 to 670 micrograms ml-1) increased the number of rod shape cardiomyocytes after exposure to singlet oxygen in a dose-dependent bell-shaped manner. A significant protective effect was observed at beta-hydroxyethyl rutosides concentrations ranging from 0.67 ng ml-1 to 67 ng ml-1. 4. In spite of their protective action, beta-hydroxyethyl rutosides did not reduce the accumulation of thiobarbituric acid reactive substances, used as an indicator for lipid peroxidation. 5. The data suggest that beta-hydroxyethyl rutosides exert a protective action against oxygen radical-induced damage of cardiac myocytes at very low concentrations without interfering with lipid peroxidation.

Animals↗
PubMed1995

Age-related functional differences between auditory cortices: a whole-head MEG study.

Auditory evoked magnetic fields (AEFs) were recorded from 10 healthy younger and 10 older subjects using a whole-head magnetometer. Two blocks of tone pips were presented to the left ear with constant inter-stimulus intervals (ISIs) of 0.5 and 2.5 s. The amplitude of P50m, unlike that of N100m, was larger in the older subjects. In both groups, the peak latencies of P50m and N100m responses were significantly shorter over the contralateral than ipsilateral cortex. The interhemispheric latency difference of N100m was significantly increased with age. These findings suggest that ageing delays signal processing in the ipsilateral auditory cortex and that ageing affects consecutive AEFs in a different manner.

Acoustic Stimulation↗
PubMed1995

Variability and replicability of the mismatch negativity.

The interindividual variation and test-retest stability of the mismatch negativity (MMN) and N1 components of the event-related potential (ERP) were investigated by presenting standard (85%) and deviant tones (15%) to 10 young subjects in 2 sessions separated by 1 month. Deviant tones in different blocks were either frequency or duration changes with interstimulus intervals (ISIs) of 0.5 and 1.5 sec. The results showed a fairly good test-retest stability of the MMN amplitude for both types of changes with each ISI at the group level. The amplitude of the duration MMN showed significant individual test-retest stability. The N1 amplitude showed high stability at both the group and individual levels. Both the MMN and N1 showed considerable interindividual variation. The results suggest that MMN and N1 can be used in follow-up studies not only at the group level but possibly at the individual level also.

Adolescent↗
PubMed1995

Bilateral loss of vestibular function.

The clinical findings in 53 patients with bilateral vestibular failure (BVF) seen in a neurological hospital are reported. Bilateral acoustic neuromas were excluded. Seven patients (13%) had progressive cerebellar degeneration; these patients had no hearing complaints but showed gait ataxia, abnormal eye movements and cerebellar atrophy on neuro-imaging. Referral in these patients was primarily for eye movement assessment, and BVF was usually unsuspected. Neuropathies were present in 5 patients (9%), usually with normal central (brainstem-cerebellar) ocular motor function and variable patterns of hearing loss. The single largest group was idiopathic BVF (11 patients, 21%), patients presenting with vertiginous episodes, progressive unsteadiness or brief paroxysms of oscillopsia; auditory function, eye movements, neurological examination and imaging were usually normal. Nine patients (17%) suffered ototoxicity, mostly due to gentamicin; hearing was normal or mildly impaired. In 6 patients (11%) BVF was post-meningitic, with concomitant auditory loss. Autoimmune disease was found in 5 patients (9%); other organs were involved by the disease, and hearing was impaired but eye movements were spared. Miscellaneous neurological, otological or neoplastic diseases accounted for the remaining 10 patients. This study suggests that i) in patients with cerebellar degenerations, BVF may be underdiagnosed as the unsteadiness may be attributed only to the cerebellar disorder, ii) some patients with idiopathic BVF present with only minor visual or vestibular symptoms, and iii) detailed immunological screenings should be undertaken more often, in view of the significant proportion of patients with autoimmune and idiopathic BVF.

Caloric Tests↗
PubMed1993

Comparison of cardioprotection with crystalloid and blood cardioplegia in CABG patients.

One hundred patients scheduled for elective coronary artery bypass grafting (CABG) were randomly allocated to two groups for myocardial preservation:blood cardioplegia (BCP) or crystalloid cardioplegia (CCP). The study protocol comprised recording of the following parameters: mode of resumption of cardiac rhythm, CK-MB analysis, ECG recording, cardiac output measurement, cross-clamping and perfusion times, and clinical outcome. The study period covered the time from commencement of anesthesia to the first postoperative morning. Spontaneous resumption of sinus rhythm was recorded only in the BCP group (22/51 v 0/49, P < 0.001). CK-MB values were similar in both groups, but 1 hour postoperatively the BCP group had lower values (58.8 +/- 26.7 v 74.5 +/- 31.5 U/L, P = 0.0098 by t test). Fifteen patients in the BCP group did not receive any electric countershock; this subgroup had very low CK-MB values. There were four intraoperative myocardial infarctions in the BCP group and two in the CCP group (BCP: 3/51 v CCP: 3/49, P = 0.68). The results suggest better cardioprotection with blood cardioplegia in this subgroup of patients. Spontaneous resumption of normal cardiac rhythm seems to indicate good myocardial preservation, as reflected in markedly lower CK-MB values in this subgroup.

Blood↗
PubMedDate not supplied

Bilateral loss of vestibular function: clinical findings in 53 patients.

The clinical presentations and aetiologies of a series of 53 cases of bilateral vestibular failure (BVF) seen by the authors over a decade were evaluated by retrospective review of the medical records. Thirty-nine per cent of patients had associated neurological disease; 13% had a progressive cerebellar syndrome with disabling gait ataxia, abnormal eye movements and cerebellar atrophy on neuro-imaging. BVF was usually unsuspected. Nine per cent had cranial or peripheral neuropathies and in this group there was no abnormality of brain stem/cerebellar oculomotor function, but hearing loss was common. Eleven per cent revealed BVF and hearing loss secondary to meningitis, and 6% had other neurological disorders. Idiopathic BVF was found in 21% of cases, characterised by paroxysmal vertigo and/or oscillopsia, but no abnormal clinical signs. Gentamicin ototoxicity accounted for a further 17%, while autoimmune disease was present in 9% of patients. Otological or neoplastic disease was diagnosed in the remaining 13% of patients. It was concluded that neurological, audiological and ocular motor assessments allow the probable cause of BVF to be defined in approximately 80% of cases. A group of BVF related to autoimmune pathologies is reported for the first time, indicating the need for immunological screening. Idiopathic BVF may present with only minor visual or vestibular symptoms, while in patients with cerebellar degeneration, BVF may be unsuspected and, thus, underdiagnosed.

Adult↗
PubMedDate not supplied

Aging effects on auditory processing: an event-related potential study.

Deviant tones randomly embedded in a sequence of standard tones elicit an event-related potential (ERP) called the mismatch negativity (MMN), which reflects automatic stimulus-change detection in the human auditory system. When the tones are attended, deviant tones elicit also an N2b component that partly overlaps the MMN. Sequences of standard and deviant (probability 0.15) tones were presented to 13 healthy younger and 13 older subjects. Deviant stimuli were, in separate blocks, either occasional shorter duration or higher frequency tones. The interstimulus interval (ISI) was, in separate blocks, either 0.5 s or 1.5 s, and in the frequency-change condition also 4.5 s. Aging affected neither frequency nor duration of MMN with the 0.5 s ISI. This finding indicates that automatic stimulus discrimination per se is not impaired with normal aging. However, with a 4.5-s ISI the MMN/N2b-complex attenuated significantly more in the older than younger subjects. This suggests that the stimulus trace decays faster or that involuntary attention switching is less sensitive with aging.

Acoustic Stimulation↗