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| 2. |
- Kouyoumdjian, Joao Aris, et al.
(author)
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Concentric needle single fiber electromyography : Comparative jitter on voluntary-activated and stimulated Extensor Digitorum Communis
- 2008
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In: Clinical Neurophysiology. - : Elsevier BV. - 1388-2457 .- 1872-8952. ; 119:7, s. 1614-1618
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Journal article (peer-reviewed)abstract
- Objective: To compare the jitter values in voluntarily activated (v-CNE) and stimulated (s-CNE) techniques for Extensor Digitorum Communis muscle using a disposable concentric needle electrode (CNE). Quantifying jitter using a CNE in conjunction with a stimulated technique has not been reported previously. Methods: Forty-one normal subjects were studied, 15 male and 26 female with a mean age of 34.1 +/- 10.7 years (19-55). The jitter values were expressed as the mean consecutive difference (MCD) of 20 analyzed potential pairs using v-CNE and 30 isolated potentials using s-CNE. Results: The mean MCD (n = 41) was 23.0 +/- 2.8 mu s for v-CNE and 18.2 +/- 2.2 mu s for s-CNE. The mean jitter of all recorded potentials was 22.9 +/- 6.7 mu s for v-CNE (n = 820) and 18.3 +/- 5.2 mu s for s-CNE (n = 1230). Upper limits for the 18th (v-CNE) and 27th highest (s-CNE) MCD were 38.9 and 30 mu s, respectively (95% confidence limit). The jitter decrease in s-CNE compared to v-CNE was 1:0.79. Conclusions: Our findings of the jitter values using CNE were similar to other published reports using the voluntarily activated technique; however, these are the first described for the stimulated technique using CNE. Significance: The present study confirms that CNE can be used for the stimulated jitter acquisition and measurement, although certain precautions must be taken regarding signal quality, e.g., observing minimal summation.
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| 3. |
- Kouyoumdjian, João Aris, et al.
(author)
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Reference jitter values for concentric needle electrodes in voluntarily activated extensor digitorum communis and orbicularis oculi muscles.
- 2008
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In: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 37:6, s. 694-699
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Journal article (peer-reviewed)abstract
- The aim of this study was to estimate normal jitter in voluntarily activated extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles using a disposable concentric needle electrode (CNE). The EDC of 67 normal subjects (22 males and 45 females, mean age 35.5 ± 10.2 years) and the OOc of 50 normal subjects (13 males and 37 females, mean age 37.9 ± 9.6 years) were studied. Jitter values were expressed as the mean consecutive difference (MCD) of 20 potential pairs. The mean MCD for EDC was 23.6 ± 3.1 µs (upper 95% confidence limit [CL]: 29.7 µs). The mean MCD of all potential pairs (n = 1340) was 23.5 ± 7.3 µs (95% CL: 38.2 µs). The mean MCD for the 18th highest value was 31.4 ± 4.9 µs (95% CL: 41.2 µs). The mean MCD for OOc was 24.7 ± 3.1 µs (95% CL: 31.0 µs). The mean MCD of all potential pairs (n = 1000) was 24.7 ± 7.1 µs (95% CL: 39.0 µs). The mean MCD for the 18th highest value was 32.7 ± 4.1 µs (95% CL: 40.9 µs). Our reported CNE jitter values obtained during voluntary activation represent the largest series currently available. The suggested practical limit in the EDC for mean MCD was 30 µs and for outliers was 42 µs, and in the OOc for mean MCD was 31 µs and 41 µs for outliers. The present study confirms that CNE can be used to assess jitter values, although certain precautions must be taken.
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- Løseth, Sissel, et al.
(author)
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Early diabetic neuropathy : thermal thresholds and intraepidermal nerve fibre density in patients with normal nerve conduction studies.
- 2008
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In: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 255:8, s. 1197-1202
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Journal article (peer-reviewed)abstract
- OBJECTIVES To determine whether neuropathy in diabetic patients with normal nerve conduction studies could be detected by measurements of thermal thresholds and quantification of intraepidermal nerve fibre (IENF) density, and to evaluate differences in parameters between patients with and without neuropathic symptoms. METHODS A total of 22 patients with and 37 patients without sensory symptoms suggesting distal neuropathy were included. Measurements of warm and cold perception thresholds and skin biopsy for quantification of IENFs were performed distally on the leg. Reference data were used to normalize test results for age and height or gender of individual patients by calculating the Z-scores. RESULTS IENF density was significantly reduced in both symptomatic and asymptomatic patients compared to controls (p < 0.001), and in patients with symptoms compared to those without (p = 0.01). Thermal thresholds were significantly elevated (more abnormal) in patients with symptoms compared to controls (p < 0.01), but only for cold perception threshold (CPT) (p < 0.001) in the asymptomatic group. When comparing symptomatic and asymptomatic patients, there was no statistically significant difference in thermal thresholds. Depletion of IENFs in skin biopsy was the most frequent abnormal finding in the subgroup of patients with neuropathic symptoms (36 %) followed by abnormal CPT (27 %). CONCLUSION Patients with diabetes and normal nerve conduction studies had significantly lower IENF density and higher CPT than controls, whether they had symptoms of polyneuropathy or not. In patients with neuropathic symptoms, abnormal IENF density predominated and seemed thus to be the most sensitive tool of detecting small diameter nerve fibre involvement.
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| 5. |
- Nandedkar, Sanjeev D., et al.
(author)
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Quantitative measurements and analysis in electrodiagnostic studies : present and future
- 2008
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In: Future neurology. - : Future Medicine Ltd. - 1748-6971 .- 1479-6708. ; 3:6, s. 745-764
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Journal article (peer-reviewed)abstract
- Electrodiagnostic studies (nerve conduction and needle electromyography) are powerful methods to study diseases of nerves and muscles. Conduction studies are performed to assess the continuity, anatomic course, excitability, number of axons and their synaptic connections, while needle electromyography examination is performed to assess the ‘electrical stability’ of the muscle fiber membrane, and the study of motor units (architecture, activation and number). We have reviewed the relationship between the quantitative measurements and the generators of the recorded potentials. Based on these relationships, the expected patterns of abnormalities for different pathologies are tabulated. This gives us a better appreciation of the sensitivity, specificity and usefulness of different tests when planning and conducting an electrodiagnostic examination. The limitations of current methods are indicated to suggest the need for future development.
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| 6. |
- Nebuchennykh, M., et al.
(author)
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Quantitative sensory testing in patients with polyneuropathy and healthy individuals
- 2008
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In: Acta Neurologica Scandinavica, Supplementum. - : Hindawi Limited. - 0065-1427 .- 1600-5449 .- 0001-6314 .- 1600-0404. ; 117:188, s. 56-61
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Journal article (peer-reviewed)abstract
- AIMS Elderly individuals and patients with polyneuropathy often feel heat pain or burning sensation on quantitative sensory testing (QST) of warm perception distally in the lower limbs. We therefore studied heat pain threshold (HPT), warm perception threshold (WPT) and the difference between heat pain and warm perception thresholds in 48 patients with symptoms and signs of polyneuropathy matched according to age and gender with 48 healthy persons. METHODS QST (using method of limits) was performed on the distal calf and the dorsal foot. RESULTS Particularly in the neuropathy group several individuals (58%) had an unpleasant feeling, often burning, when the thresholds according to the WPT algorithm were recorded. Difference between heat pain and warm perception thresholds in the lower calf of the patients was 3.9 +/- 3.5 and 5.8 +/- 3.4 degrees C in the controls (P = 0.012), and on the foot 3.8 +/- 2.8 vs 5.3 +/- 3.6 degrees C (P = 0.02). CONCLUSIONS When performing QST it is important to assess also quality features of warm perception, such as burning and heat pain sensation.
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| 7. |
- Rostedt Punga, Anna, et al.
(author)
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Electrophysiological signs and the prevalence of adverse effects of acetylcholinesterase inhibitors in patients with myasthenia gravis
- 2007
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In: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 37:3, s. 300-307
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Journal article (peer-reviewed)abstract
- The aim of this prospective study was to assess whether extra discharges (EDs), sometimes following the compound muscle action potential, could be used as a neurophysiological indicator of overdose of acetylcholinesterase inhibitors (AChEIs) in patients with myasthenia gravis (MG). The characteristics and frequency of EDs were explored and the correlation of EDs with cholinergic side effects was also determined. Twenty-two MG patients (14 women, 8 men; 61 ± 16 years of age) with daily AChEI treatment were examined. The mean disease duration was 10 years (range 2-62 years) and all patients had been treated with AChEI since MG onset. Both single and repetitive stimulation of the ulnar and accessory nerves were performed before and 60 min after oral pyridostigmine bromide (PB) administration and after additional edrophonium injection. Fatigue, side effects, and AChE activity in blood were assessed before and 60 min after PB intake. The daily dose of PB ranged from 150 to 900 mg/day. Fourteen patients (64%) experienced daily cholinergic adverse effects, and muscarinic side effects correlated with AChE activity. Eleven patients (50%) developed EDs after oral PB. Among the eight patients with daily nicotinic side effects, EDs were significantly (P < 0.05) more common. Additionally, older patients were more prone to develop cholinergic side effects and EDs. Thus, when EDs are found, patients should be asked about daily muscular symptoms, which may be related to AChEI treatment and not solely to MG. Muscle Nerve, 2007
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| 8. |
- Rostedt Punga, Anna, et al.
(author)
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Monozygous twins with neuromuscular transmission defects at opposite sides of the motor endplate
- 2009
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In: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 119:3, s. 207-211
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Journal article (peer-reviewed)abstract
- Disorders affecting the postsynaptic side of the neuromuscular junction include autoimmune myasthenia gravis (MG) as well as some of the congenital myasthenic syndromes (CMS). Lambert-Eaton myasthenic syndrome (LEMS) is an acquired autoimmune neuromuscular disorder in which autoantibodies are directed against the presynaptic calcium channels. Here we describe two monozygous twin brothers: case 1 was diagnosed with an indeterminate form of acquired postsynaptic neuromuscular junction defect at age 32 and case 2 with LEMS at age 47. Case 1 presented clinically with mild generalized myasthenic weakness, neurophysiological examination revealed disturbed neuromuscular transmission along with probable myositis and serum analysis regarding antibodies against the acetylcholine receptor and muscle-specific tyrosine kinase was negative. Case 2 presented with proximal muscle fatigue accompanied by areflexia at rest and antibodies against the P/Q-type voltage-gated calcium channels were present. Neurophysiologically, case 2 had reduced baseline compound motor action potential amplitudes on neurography, decrement on low-frequency repetitive nerve stimulation (RNS) and pathological increment on high frequency RNS. To our knowledge this is the first case report of its kind and adds an intriguing contrast to the more common diagnosis of CMS in monozygous twins.
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| 9. |
- Schreurs, Annabel, et al.
(author)
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Indication of peripheral nerve hyperexcitability in adult-onset subacute sclerosing panencephalitis (SSPE)
- 2008
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In: Neurological Sciences. - : Springer Science and Business Media LLC. - 1590-1874 .- 1590-3478. ; 29:2, s. 121-124
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Journal article (peer-reviewed)abstract
- Subacute sclerosing panencephalitis (SSPE) is a rare chronic, progressive encephalitis that affects primarily children and young adults, caused by a persistent infection of immune-resistant measles virus. Diagnostic hallmarks include widespread cortical dysfunction on EEG, myoclonus, white matter abnormalities on neuroradiological examination and the presence of IgG antimeasles antibodies in the cerebrospinal fluid. We present the first case of SSPE with signs of peripheral nerve hyperexcitability, observed as extra discharges following the compound motor action potential at motor nerve stimulation. In addition we demonstrate the importance of SSPE in the differential diagnosis of adult patients with psychiatric and neurological symptoms.
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