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P51-T A new approach to the radial nerve conduction block determination in the upper arm
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Abstracts / Clinical Neurophysiology 130 (2019) e21–e116
P51-T A new approach to the radial nerve conduction block determination in the upper arm—Vasily Khodulev a,*, Sviatlana Vlasava b (a Republican Research and Clinical Center of Neurology and Neurosurgery, Minsk, Belarus , b Polessky State University, Pinsk, Belarus) ⇑
Corresponding author.
Background: There are technical limitations in the radial nerve studies in the upper arm using surface electrodes. One of the limitations is that stimulation at the axilla and Erb‘s point stimulates the entire brachial plexus along with the radial nerve. Material and methods: Twenty-one healthy volunteers, 55 patients with compressive neuropathies of the radial nerve in the spiral groove and 22 patients with complete radial nerve injuries were studied. Control group (65 radial nerves) consisted of healthy subjects and patients with the undamaged side. Stimulation was carried out at: (1) the distal part of lateral brachium (distal point); (2) Erb’s point (proximal point); (3) the middle part of medial brachium – median and ulnar nerves (additional point). CMAP area recorded from the extensor digitorum was analyzed. Conduction block (CB) in percentage was calculated using the formula: ((distal CMAP + additional CMAP) (proximal CMAP)) 100/(distal CMAP + additional CMAP). Results: In control group and patients with complete nerve injury CB was not registered (4.2 ± 9.8% and 1.7 ± 11.7% respectively), whereas in patients with compressive radial nerve neuropathy CB was 61.2 ± 11.2% (P < 0.001). In patients with the radial nerve complete injury, the proximal CMAP did not differ from the additional CMAP. Conduction velocity in the control group did not differ from that found in neuropathies. Conclusion: Median and ulnar nerves stimulation in the middle part of medial brachium is recommended as an additional brachium diagnostic point for radial nerve CB determination. doi:10.1016/j.clinph.2019.04.414
P52-T Comparison of two variants of the ring-finger test for diagnosing very mild carpal tunnel syndrome—Daniel Gregor Schulze a,b,c,*, Karl Christian Nordby f, Milada Cvancarova Smastuen d,e, Thomas Clemm f, Margreth Grotle c,e, John Anker Zwart a,b,c, Kristian Bernhard Nilsen a,c,g (a Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway , b Department of Neurology, Oslo University Hospital, Oslo, Norway, c Research and Communication Unit for Musculoskeletal Health, Oslo University Hospital, Oslo, Norway, d Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway , e Oslo and Akershus University college, Oslo, Norway, f National Institute of g Occupational Health, Oslo, Norway, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway) ⇑
Corresponding author.
Background: To diagnose carpal tunnel syndrome at a very mild stage is prognostically important and only possible by the use of comparison tests, such as the ring-finger test. The Ring-finger test compares the median and ulnar nerve sensory latency. Patients with typical clinical findings and a median- ulnar latency difference P0.5 ms are classified as having very mild carpal tunnel syndrome (CTS). The test can be performed by recording both nerves at the same time
(simultaneous) or one-at-a-time (consecutive). We aimed to assess if measuring the median and ulnar nerves simultaneously is equivalent to measuring the two nerves consecutively in the orthodromic ring finger test or if it will lead to a different clinical classification of patients. Methods: We calculated the limits of agreement between the simultaneous and the consecutive method based on the medianulnar sensory latency difference derived by both methods in 80 subjects and compared the number of very mild CTS cases (defined as present clinical symptoms and nerve conduction findings) identified by the two methods. Results: Limits of agreement had a range of 0.5 A significantly higher proportion of subjects with very mild CTS was found using the simultaneous method (n = 8 and 2, respectively; p = 0.03). Conclusion: The two methods are not equivalent, as indicated by the poor to moderate agreement between them. The simultaneous method is more sensitive for very mild CTS. When comparing and interpreting results from the ring finger test, neurophysiologists and clinicians should be aware which method was used. doi:10.1016/j.clinph.2019.04.415
P53-T Evaluation of atypical chronic autoimmune inflammatory polyneuropathies - clinical and neurophysiological comparison— Marija Mihailova *, Janis Mednieks (Pauls Stradins CUH, Riga, Latvia) ⇑
Corresponding author.
Background: Chronic autoimmune inflammatory polyneuropathies (CAIP) is a group of rare and potentially treatable conditions that are often underdiagnosed due to non-compatibility with recognized diagnostic criteria that might be partially related to incomplete neurophysiological investigation or lack of follow-up. Methods: Case series study of 4 CAIP patients with atypical clinical and/or neurophysiological features. Results: Case 1. 10 year history of distal weakness in upper extremities (UE), NCS – diffuse conduction slowing with conduction block (CB) and marked sensory involvement. Improvement with IVIG. Case 2. Slow progression of asymmetrical weakness in distal UE and right lower extremity (LE), NCS – axonal loss with CB in all extremities. No response to glucocorticoids, improvement on IVIG. Case 3. Progressive weakness in distal UE with marked sensory involvement and diffuse severe fasciculations, 1st ENMG – no CB, slight axonal loss with demyelination not below 75% of lower normal, slight sensory impairment, with diffuse fasciculations. Follow up ENMG – 1 definitive CB, 2 probable CB (1 in Erb point), with significant demyelination and sensory impairment in UE. Slight improvement with glucocorticoids. Case 4. Progressive asymmetrical tetraparesis LE > UE, with sensory signs proximally in LE and distally in UE and LE. NCS – axonal loss with conduction slowing not below 75% normal range, no CB, no increase in distal latencies, significant sensory nerve involvement. No improvement on IVIG, marked response to glucocorticoids. Conclusions: NCS should be comprehensive, including proximal stimulations. Follow-up ENMG studies and immunomodulatory treatment should be considered in all patients with suspected CAIP. doi:10.1016/j.clinph.2019.04.416
Abstracts / Clinical Neurophysiology 130 (2019) e21–e116
P51-T A new approach to the radial nerve conduction block determination in the upper arm—Vasily Khodulev a,*, Sviatlana Vlasava b (a Republican Research and Clinical Center of Neurology and Neurosurgery, Minsk, Belarus , b Polessky State University, Pinsk, Belarus) ⇑
Corresponding author.
Background: There are technical limitations in the radial nerve studies in the upper arm using surface electrodes. One of the limitations is that stimulation at the axilla and Erb‘s point stimulates the entire brachial plexus along with the radial nerve. Material and methods: Twenty-one healthy volunteers, 55 patients with compressive neuropathies of the radial nerve in the spiral groove and 22 patients with complete radial nerve injuries were studied. Control group (65 radial nerves) consisted of healthy subjects and patients with the undamaged side. Stimulation was carried out at: (1) the distal part of lateral brachium (distal point); (2) Erb’s point (proximal point); (3) the middle part of medial brachium – median and ulnar nerves (additional point). CMAP area recorded from the extensor digitorum was analyzed. Conduction block (CB) in percentage was calculated using the formula: ((distal CMAP + additional CMAP) (proximal CMAP)) 100/(distal CMAP + additional CMAP). Results: In control group and patients with complete nerve injury CB was not registered (4.2 ± 9.8% and 1.7 ± 11.7% respectively), whereas in patients with compressive radial nerve neuropathy CB was 61.2 ± 11.2% (P < 0.001). In patients with the radial nerve complete injury, the proximal CMAP did not differ from the additional CMAP. Conduction velocity in the control group did not differ from that found in neuropathies. Conclusion: Median and ulnar nerves stimulation in the middle part of medial brachium is recommended as an additional brachium diagnostic point for radial nerve CB determination. doi:10.1016/j.clinph.2019.04.414
P52-T Comparison of two variants of the ring-finger test for diagnosing very mild carpal tunnel syndrome—Daniel Gregor Schulze a,b,c,*, Karl Christian Nordby f, Milada Cvancarova Smastuen d,e, Thomas Clemm f, Margreth Grotle c,e, John Anker Zwart a,b,c, Kristian Bernhard Nilsen a,c,g (a Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway , b Department of Neurology, Oslo University Hospital, Oslo, Norway, c Research and Communication Unit for Musculoskeletal Health, Oslo University Hospital, Oslo, Norway, d Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway , e Oslo and Akershus University college, Oslo, Norway, f National Institute of g Occupational Health, Oslo, Norway, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway) ⇑
Corresponding author.
Background: To diagnose carpal tunnel syndrome at a very mild stage is prognostically important and only possible by the use of comparison tests, such as the ring-finger test. The Ring-finger test compares the median and ulnar nerve sensory latency. Patients with typical clinical findings and a median- ulnar latency difference P0.5 ms are classified as having very mild carpal tunnel syndrome (CTS). The test can be performed by recording both nerves at the same time
(simultaneous) or one-at-a-time (consecutive). We aimed to assess if measuring the median and ulnar nerves simultaneously is equivalent to measuring the two nerves consecutively in the orthodromic ring finger test or if it will lead to a different clinical classification of patients. Methods: We calculated the limits of agreement between the simultaneous and the consecutive method based on the medianulnar sensory latency difference derived by both methods in 80 subjects and compared the number of very mild CTS cases (defined as present clinical symptoms and nerve conduction findings) identified by the two methods. Results: Limits of agreement had a range of 0.5 A significantly higher proportion of subjects with very mild CTS was found using the simultaneous method (n = 8 and 2, respectively; p = 0.03). Conclusion: The two methods are not equivalent, as indicated by the poor to moderate agreement between them. The simultaneous method is more sensitive for very mild CTS. When comparing and interpreting results from the ring finger test, neurophysiologists and clinicians should be aware which method was used. doi:10.1016/j.clinph.2019.04.415
P53-T Evaluation of atypical chronic autoimmune inflammatory polyneuropathies - clinical and neurophysiological comparison— Marija Mihailova *, Janis Mednieks (Pauls Stradins CUH, Riga, Latvia) ⇑
Corresponding author.
Background: Chronic autoimmune inflammatory polyneuropathies (CAIP) is a group of rare and potentially treatable conditions that are often underdiagnosed due to non-compatibility with recognized diagnostic criteria that might be partially related to incomplete neurophysiological investigation or lack of follow-up. Methods: Case series study of 4 CAIP patients with atypical clinical and/or neurophysiological features. Results: Case 1. 10 year history of distal weakness in upper extremities (UE), NCS – diffuse conduction slowing with conduction block (CB) and marked sensory involvement. Improvement with IVIG. Case 2. Slow progression of asymmetrical weakness in distal UE and right lower extremity (LE), NCS – axonal loss with CB in all extremities. No response to glucocorticoids, improvement on IVIG. Case 3. Progressive weakness in distal UE with marked sensory involvement and diffuse severe fasciculations, 1st ENMG – no CB, slight axonal loss with demyelination not below 75% of lower normal, slight sensory impairment, with diffuse fasciculations. Follow up ENMG – 1 definitive CB, 2 probable CB (1 in Erb point), with significant demyelination and sensory impairment in UE. Slight improvement with glucocorticoids. Case 4. Progressive asymmetrical tetraparesis LE > UE, with sensory signs proximally in LE and distally in UE and LE. NCS – axonal loss with conduction slowing not below 75% normal range, no CB, no increase in distal latencies, significant sensory nerve involvement. No improvement on IVIG, marked response to glucocorticoids. Conclusions: NCS should be comprehensive, including proximal stimulations. Follow-up ENMG studies and immunomodulatory treatment should be considered in all patients with suspected CAIP. doi:10.1016/j.clinph.2019.04.416