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Plamen Tzvetanov

Publications and source records attributed to Plamen Tzvetanov.

10 recordsLinked to original sources
PubMed2007

Stimulated jitter in the masseter muscle: normative values.

Nineteen healthy volunteers (median age, 25; range, 18-51 years) were enrolled in a study to obtain normative values for stimulated jitter in the masseter muscle. Axonal microstimulation was performed via a monopolar needle electrode introduced in the masseter 2-2.5 cm above the mandibular angle on the line connecting it with the lateral canthus. The recording single-fiber electromyography (SFEMG) electrode was inserted anteriorly in the twitching area of the muscle. The mean consecutive difference (MCD) values for the 426 endplates studied followed a distribution skewed to the left, with a minimum value of 4.3 micros, maximal 44.7 micros, and a maximum of distribution at 11 micros. Mean pooled MCD measured 16.0 micros, and the mean of mean MCD per study was 13.6 micros. The value of the 95th upper percentile for an individual fiber was 29.3 micros. We suggest an upper normal limit for mean MCD per study of 21 micros and upper normal limit of MCD for individual fibers of 30 micros. The stimulated jitter study of masseter muscle is easy and reliable.

Adolescent↗
PubMed2006

Abnormal levels of serum antielastin antibodies in children with diabetes mellitus type 1.

Antibodies to alpha-elastin (elastin breakdown product) and elastin sequences devoid of cross-linked regions (linear elastin) are found in the serum of all human subjects and correlate with their respective serum peptide levels. The aim of this study was to determine if the serum level of antielastin antibodies (AEAbs) differs between type 1 diabetic children and nondiabetic children. Enzyme-linked immunosorbent assay was used to measure the levels of immunoglobulin (Ig)G and IgM AEAbs in the sera of 45 diabetic children (mean age 12.8 +/- 3.2 years, diabetes duration 5.3 +/- 3.6 years). Twenty-two children presented with vascular complications (group 1), whereas 23 displayed no vascular complications (group 2). The controls were 18 healthy children (mean age 11.9 +/- 2.3 years). Diabetic patients showed statistically significant higher levels of IgM alpha-AEAbs (0.82 +/- 0.26 vs 0.61 +/- 0.14, p = .0013) than the control group. In group 1, alpha-AEAbs showed statistically significant higher level than controls: IgG (0.86 +/- 0.42 vs 0.59 +/- 0.12; p = .0109) and IgM (0.88 +/- 0.24 vs 0.61 +/- 0.14; p = .0001). IgM antilinear elastin antibodies (ALEAbs) in group 1 were significantly lower than in controls (0.462 +/- 0.191 vs 0.652 +/- 0.127; p = .0009). IgG alpha-AEAbs showed correlation with microalbuminuria (r = -.26; p = .05) and IgM ALEAbs correlated with microalbuminuria (r = -.32; p = .035). IgG alpha-AEAbs correlated with neuropathy (r = -.32; p = .035). Group 1 patients displayed a correlation between IgG ALEAbs and retinopathy (r = -.48; p = .023) and IgM ALEAbs and microalbuminuria (r = .52; p = .014). Levels of AEAbs and ALEAbs can serve as immunologic markers of the extent of elastin degradation. These markers may provide a tool to study elastin metabolism and a potential clinical role for AEAbs in the pathogenesis and development of vascular complications in diabetic children.

Adolescent↗
PubMed2006

False localising levels in spinal cord compression.

OBJECTIVE: To describe three cases with false localising levels illustrating the difficulty in clinical diagnosis of spinal cord compression. PATIENTS AND METHODS: Three patients (aged 53, 55 and 57 years) developed acute (in one) and subacute (in two) spinal cord syndrome with paraparesis, bladder symptoms and sensory levels suggesting lower thoracic or higher lumbar involvement. Imaging at suspected levels was normal. Follow-up investigations after a significant delay showed compression at higher levels (up to 11 segments). Diagnoses were surgically verified. In one patient who died, post mortem investigation discloseed a caudally situated artery of Adamkiewicz and absent vicarious vessels at T7-T8 that are usually present in such cases. CONCLUSIONS: The well known but rare phenomenon of false localizing sensory levels in spinal cord syndromes should be kept in mind. Its causes can lie in remote higher levels of compressive lesion or in vascular compromise due to variants of the blood supply.

Diagnostic Errors↗
PubMed2005

Prognostic value of median and tibial somatosensory evoked potentials in acute stroke.

The predictive values of early somatosensory evoked potentials (SSEPs) for the functional outcome after stroke are investigated. Ninety-four stroke patients (mean age: 61.2, S.D.: 11.8) with CT confirmed diagnoses of middle cerebral artery (MCA) infarction in 71 and supratentorial intracerebral hemorrhage in 23. Median and tibial SSEPs were recorded within 3 days of onset. SSEP parameters were compared to motor (MRC) and functional ability (Barthel index) followed up at 1, 3, 6 and 12 months. Upper limb MRC remains the strongest single predictor of functional outcome, determining 54.3% of Barthel index value at 12 months. The highest predictive value among SSEP parameters has N20-P25 amplitude ratio-34.5%. Combined application of upper limb MRC and N20-P25 amplitude ratio provided significantly stronger prognostic information-66%. Combined assessment of SSEP parameters and muscle power in acute stroke considerably improves prediction of functional outcome.

Activities of Daily Living↗
PubMed2005

The bifid visual evoked potential-normal variant or a sign of demyelination?

OBJECTIVE: To prospectively evaluate the diagnostic significance of bifid VEP at initial presentation. MATERIALS AND METHODS: A hundred and sixteen patients (46 males and 70 females, age 15-54, mean 28.8), with a clinical suspicion of multiple sclerosis (MS), underwent pattern-shift VEP investigation between 1992 and 1998. They were further followed by clinical, CSF, MRI means for at least 5 years (mean 7.2). Twenty-six patients remained healthy, while 90 developed demyelinating disease (in 71 MS and in 19 optic neuritis was the final diagnosis). Fifty healthy persons (20 males aged 18-51, mean 28.8 and 30 females aged 18-48, mean 26.2) represented the control group. The number of persons with bifid VEP in each group are analyzed. RESULTS: In the controls one out of 50 exhibited bifid VEP configuration. Of 26 patients with unconfirmed suspicion for MS again one had such responses. Bifid VEP were significantly more frequent in patients with demyelinative pathology (nine out of 90, 10.0%, P (chi-squared) < 0.01). CONCLUSIONS: Bifid VEP is rarely observed in healthy persons. Its presence should suggest the possibility of demyelinating disease and prompt further investigation and follow-up.

Adolescent↗
PubMed2005

Muscle hypertrophy with complex repetitive discharges in C-6 radiculopathy.

OBJECTIVE: To report on a case of post-denervation muscle hypertrophy in an unusual distribution. CASE REPORT: A 52-year-old patient with severe flaccid paraparesis after polio developed unilateral C-6 radiculopathy that resolved with conservative treatment. Within 2 years marked hypertrophy, stiffness and pain in the muscles in the affected myotome developed. EMG discovered abundant complex repetitive discharges (CRD) within hypertrophic muscles. On biopsy, true hypertrophy of muscle fibers and some group atrophy was found. Steroid treatment relieved the symptoms and significantly suppressed the CRD. The possible causative role of CRD for hypertrophy in partially denervated muscle is discussed.

Humans↗
PubMed2005

Predictive value of median-SSEP in early phase of stroke: a comparison in supratentorial infarction and hemorrhage.

OBJECTIVE: To compare the prognostic value of median somatosensory evoked potentials (M-SSEP) changes in the early phase of supratentorial infarction and hemorrhage. MATERIAL AND METHODS: This study includes 130 patients (mean age 62+/-11.4 years, 43 women, large middle cerebral artery territory infarction in 36 patients, restricted/lacunar in 55, massive supratentorial hemorrhage in 10, small/medium size hemorrhage in 31). M-SSEP were recorded early (0-7 days in ischemia, 0-21 days in hemorrhage) and patients stratified into groups with absent, abnormal, normal response. Clinical state was determined by the Medical Research Council (MRC) scale, Barthel Index and Rankin score and followed for at least 6 months. RESULTS: Moderate prognostic correlation was established between N20-P25 amplitudes (r=0.34, p<0.05) and N20-P25 amplitude ratio (r=0.45, p<0.01) and Barthel Index at 6 months in patients with ischemic stroke. Moderate relationship (r=-0.34, p<0.05) exists also between N20-P25 ratio and Rankin score at 6 months in patients with small/medium size hemorrhage. In large infarctions and small/medium size cerebral hemorrhages correlations with all clinical indices of outcome are weak. In massive hemorrhage, only a weak correlation (r=-0.19, p<0.05) between amplitude ratio and Rankin score was found. The combination of initial MRC and N20-P25 amplitude ratio has 10% (in hemorrhage) to 15% (in infarction) greater prognostic value (p<0.05) than initial alone. CONCLUSIONS: M-SSEP have independent predictive value regarding functional recovery in ischemic stroke and small/medium size cerebral hemorrhage. Combined assessment of initial MRC and M-SSEP substantially improves prognosis in acute stroke.

Activities of Daily Living↗
PubMed2003

Median SSEP changes in hemiplegic stroke: long-term predictive values regarding ADL recovery.

OBJECTIVE: To assess the predictive value of median somatosensory evoked potentials (SSEP) in the acute phase of brain infarction or hemorrhage regarding long-term prognosis. MATERIALS AND METHODS: Ninety-four stroke patients mean age 61.2, SD 11.8) were included. CT confirmed diagnoses were: cortical middle cerebral artery (MCA) infarction in 35; subcortical MCA 11; mixed 25. By size, infarctions were: massive, 29; restricted, 33; and lacunar, 9. The number of patients with thalamic hemorrhage was 8; putamenal hemorrhage, 7; other, 8. All patients presented with severe hemiparesis (54) or hemiplegia (40) with hemihipoesthesia in 89 patients. Median SSEP were recorded early (up to 7th day, mean 5.2 days, SD 0.72). SSEP parameters (presence/absence of SSEP, absolute and relative latency, amplitude of early waveforms) were compared to motor (Medical Research Council scale) and functional ability (Barthel index) at 3 and 12 months after stroke. RESULTS: Absolute N20 amplitudes and amplitude ratio evidenced almost similar predictive values that reached 66.4% at 12 months. Combined application of N20 and MRC gains provided significantly stronger prognostic information which reached 72%. CONCLUSIONS: Median SSEP parameters may serve as independent predictors of outcome. Most informative in prognosis in the early stage of stroke was the combined assessment of MRC and N20-P25 amplitude ratio.

Activities of Daily Living↗
PubMedDate not supplied

Can SSEP results predict functional recovery of stroke patients within the "therapeutic window"?

OBJECTIVES: To investigate the prognostic value of median somatosensory evoked potentials (mSSEP) within the "therapeutic window" of ischemic stroke. MATERIALS AND METHODS: Twenty-two patients (mean age 60.8 +/- 14.8 years) with first ischemic stroke in middle cerebral artery territory without contraindications for thrombolysis underwent mSSEP investigation within 3 hours of onset. Stroke topography was verified within 48 hours by computed tomography. M-SSEP results (presence, amplitude and amplitude ratio, latency and central conduction time) were compared to severity of motor deficit at onset and to recovery at 6 months. RESULTS: M-SSEP were present in 17 patients, 7 of whom had partial and 10--complete motor recovery. Absence of mSSEP was found in 5 persons. None recovered function of the arm and only 2 were ambulatory at 6 months. CONCLUSIONS: In the earliest phase of ischemic stroke absence of mSSEP response is reliable predictor of poor functional outcome.

Adult↗