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22. Clinical utility of electrodiagnostic studies in the inpatient setting
Society Proceedings / Clinical Neurophysiology 120 (2009) e89–e126
III-V/MLAEP: P0-Pa in each group were 2.32 ± 0.11/12.68 ± 1.78 ms, 2.41 ± 0.2/14.84 ± 1.48 ms, 2.13 ± 0.19/15.32 ± 2.89 ms, 2.1± 0.12/ 17.22 ± 5.01 ms, 2.01 ± 0.12/16.15 ± 3.23 ms, 1.93 ± 0.11/12.88 ± 1.09 ms, 1.97 ± 0.19/13.25 ± 0.21 ms, 2.07 ± 0.14/12.34 ± 4.52 ms, 2.11 ± 0.4/13.62 ± 4.78 ms, 1.91 ± 0.11/13.16 ± 6.65 ms, respectively. Conclusions: The data collected in this study may serve as a reference for using BAEP and MLAEP in the evaluations of young children with disorders involving the auditory pathway in the brainstem and/or subcortical and cortical areas. doi:10.1016/j.clinph.2008.10.039
22. Clinical utility of electrodiagnostic studies in the inpatient setting—D. Perry, A. Tarulli, R. Nardin, R. Seward, S. Gautam, P. Narayanaswami (Boston, MA, USA) Introduction: Electromyographies (EMGs) performed on patients admitted to the hospital (inpatient EMGs, [IP-EMG]) may be challenging because patients are too ill to cooperate, or because of technical considerations. This study will assess the utility of IP-EMG in the management of patients with suspected neuromuscular disorders. Objectives: To correlate the results of IP-EMG with pre-EMG clinical diagnoses, then to evaluate how results of IP-EMG change the clinical diagnoses and influence diagnostic evaluation and treatment. Methods: A retrospective cohort study of IP-EMGs performed from January 2005 to December 2007 was conducted. Studies were classified into five groups: those (1) confirming the referring diagnosis, (2) differing from the referring diagnosis and explaining the clinical picture, (3) demonstrating incidental findings which did not explain the clinical picture, (4) nondiagnostic, or (5) normal. The authors assessed how frequently the results of IP-EMGs led to additional diagnostic testing and to the introduction of new treatments. Descriptive statistics were used. Results: One hundred and five IP-EMGs that had been performed in 99 patients were analyzed. IP-EMG results confirmed the clinical diagnosis in 55 patients (52%), identified a new relevant diagnosis in 16 patients (15%), and demonstrated only an incidental finding which was not clinically relevant in 16 patients (15%). In 15 patients (14%), IP-EMG was nondiagnostic and was normal in three patients (3%). Additional diagnostic testing was deemed necessary in 13 patients (12%), while additional treatment was needed in 18 patients (17%). Conclusions: IP-EMGs were found to be useful in the management of inpatients with suspected neuromuscular disorders by either confirming the clinical diagnosis or by providing a clinically relevant diagnosis (two-thirds of patients). In approximately onethird of the patients studied, IP-EMGs assisted in planning further testing or seeking additional treatment. doi:10.1016/j.clinph.2008.10.040
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Objective: To evaluate the results of PET responses in TPP. Method: The medical records of a patient sample group that had performed PETs since 2003 were reviewed. The increment and decrement of compound muscle action potentials (CMAPs) were calculated as follows: Increment = [(greatest amplitude after exercise– basal amplitude before exercise)/amplitude before exercise] 100. Decrement = [(greatest amplitude after exercise - smallest amplitude after exercise)/greatest amplitude during or after exercise] 100. Results: PETs were performed by nine patients with TPP. The greatest CMAP amplitudes were primarily observed immediately after exercise. In most cases, the smallest amplitudes were obtained at the end of the test. CMAP increment and decrement were 25.9 ± 15.8 (range 2.5–46.7), and 53.4 ± 9.5% (range 33.1–61.0). Reversed test results were found in one patient, who performed a follow-up PET 5 months after treating thyrotoxicosis. The PET results of another patient who presented with symptoms of thyrotoxicosis (without PP) revealed almost the same abnormal result as in thyrotoxic PP. Conclusions: PET can be used to provide the confirmation of PP presence in thyrotoxic PP as well as to monitor it longitudinally. The study provided an interesting observation that PET could yield abnormal results in thyrotoxicosis without PP, comparable to thyrotoxic PP which suggests a subclinical level of abnormal muscle membrane excitability in this condition. doi:10.1016/j.clinph.2008.10.041
24. Event-related P300 in post-stroke patients—M.H. Baglavajyan, G.S. Grigoryan (Yerevan, Armenia) Introduction: Although cognitive decline in post-stroke patients is very frequent, there are only a few neurophysiologic studies in this field. Objectives: To determine if event-related P300 latency is prolonged in patients with post-stroke cognitive impairment and to evaluate its diagnostic importance. Methods: A total number of 86 patients were assessed comprehensively for 3 months and 1 year after ischemic stroke, then compared with non-stroke control subjects. Medical history, neurological examination, blood tests, and computed tomography were performed. Cognitive functions were assessed by using the Clinical Dementia Rating Scale and the Mini Mental State Exam. Stroke was defined according to World Health Organization criteria. P300 was elicited on the standard electromyography equipment. Results: Following the third month of observation, the P300 latency was significantly higher (p < 0.02) in post-stroke patients as compared to the control subjects. It linearly correlated with the memory and attention impairment and increased by 0.87 ms after a 1 year follow-up. Conclusions: P300 latency is prolonged in patients with cognitive impairment after ischemic stroke. It can be used as a sensitive indicator in identifying early stages of vascular dementia. doi:10.1016/j.clinph.2008.10.042
23. Exercise test in patients with thyrotoxic periodic paralysis—S. Kim 1, H. Kim 2, S. Oh 1, J. Sung 2, Y. Hong 2, S. Kim 3, S. Park 1, K. Lee 1 (1 Sung-Nam, South Korea, 2 Seoul, South Korea, 3 Il-San, South Korea) Introduction: Thyrotoxic periodic paralysis (TPP) is one of the most common secondary hypokalemic periodic paralyses (PPs). A prolonged exercise test (PET) is considered to be useful in confirming the presence of PP, but its diagnostic value in TPP has not fully elucidated.
25. Baroreflex sensitivity differences in orthostatic hypotension at supine position—K.J. Park, S.U. Jung, S.N. Son, H.Y. Kang, N.C. Choi, O.Y. Kwon, B.H. Lim (Jinju, South Korea) Introduction: A tilt table test serves as a useful parameter for diagnosis of orthostatic dizziness and syncope but may prove to be dangerous, as it may induce or provoke the symptoms. The arterial baroreflex is a primary mechanism for the control of blood pressure
III-V/MLAEP: P0-Pa in each group were 2.32 ± 0.11/12.68 ± 1.78 ms, 2.41 ± 0.2/14.84 ± 1.48 ms, 2.13 ± 0.19/15.32 ± 2.89 ms, 2.1± 0.12/ 17.22 ± 5.01 ms, 2.01 ± 0.12/16.15 ± 3.23 ms, 1.93 ± 0.11/12.88 ± 1.09 ms, 1.97 ± 0.19/13.25 ± 0.21 ms, 2.07 ± 0.14/12.34 ± 4.52 ms, 2.11 ± 0.4/13.62 ± 4.78 ms, 1.91 ± 0.11/13.16 ± 6.65 ms, respectively. Conclusions: The data collected in this study may serve as a reference for using BAEP and MLAEP in the evaluations of young children with disorders involving the auditory pathway in the brainstem and/or subcortical and cortical areas. doi:10.1016/j.clinph.2008.10.039
22. Clinical utility of electrodiagnostic studies in the inpatient setting—D. Perry, A. Tarulli, R. Nardin, R. Seward, S. Gautam, P. Narayanaswami (Boston, MA, USA) Introduction: Electromyographies (EMGs) performed on patients admitted to the hospital (inpatient EMGs, [IP-EMG]) may be challenging because patients are too ill to cooperate, or because of technical considerations. This study will assess the utility of IP-EMG in the management of patients with suspected neuromuscular disorders. Objectives: To correlate the results of IP-EMG with pre-EMG clinical diagnoses, then to evaluate how results of IP-EMG change the clinical diagnoses and influence diagnostic evaluation and treatment. Methods: A retrospective cohort study of IP-EMGs performed from January 2005 to December 2007 was conducted. Studies were classified into five groups: those (1) confirming the referring diagnosis, (2) differing from the referring diagnosis and explaining the clinical picture, (3) demonstrating incidental findings which did not explain the clinical picture, (4) nondiagnostic, or (5) normal. The authors assessed how frequently the results of IP-EMGs led to additional diagnostic testing and to the introduction of new treatments. Descriptive statistics were used. Results: One hundred and five IP-EMGs that had been performed in 99 patients were analyzed. IP-EMG results confirmed the clinical diagnosis in 55 patients (52%), identified a new relevant diagnosis in 16 patients (15%), and demonstrated only an incidental finding which was not clinically relevant in 16 patients (15%). In 15 patients (14%), IP-EMG was nondiagnostic and was normal in three patients (3%). Additional diagnostic testing was deemed necessary in 13 patients (12%), while additional treatment was needed in 18 patients (17%). Conclusions: IP-EMGs were found to be useful in the management of inpatients with suspected neuromuscular disorders by either confirming the clinical diagnosis or by providing a clinically relevant diagnosis (two-thirds of patients). In approximately onethird of the patients studied, IP-EMGs assisted in planning further testing or seeking additional treatment. doi:10.1016/j.clinph.2008.10.040
e95
Objective: To evaluate the results of PET responses in TPP. Method: The medical records of a patient sample group that had performed PETs since 2003 were reviewed. The increment and decrement of compound muscle action potentials (CMAPs) were calculated as follows: Increment = [(greatest amplitude after exercise– basal amplitude before exercise)/amplitude before exercise] 100. Decrement = [(greatest amplitude after exercise - smallest amplitude after exercise)/greatest amplitude during or after exercise] 100. Results: PETs were performed by nine patients with TPP. The greatest CMAP amplitudes were primarily observed immediately after exercise. In most cases, the smallest amplitudes were obtained at the end of the test. CMAP increment and decrement were 25.9 ± 15.8 (range 2.5–46.7), and 53.4 ± 9.5% (range 33.1–61.0). Reversed test results were found in one patient, who performed a follow-up PET 5 months after treating thyrotoxicosis. The PET results of another patient who presented with symptoms of thyrotoxicosis (without PP) revealed almost the same abnormal result as in thyrotoxic PP. Conclusions: PET can be used to provide the confirmation of PP presence in thyrotoxic PP as well as to monitor it longitudinally. The study provided an interesting observation that PET could yield abnormal results in thyrotoxicosis without PP, comparable to thyrotoxic PP which suggests a subclinical level of abnormal muscle membrane excitability in this condition. doi:10.1016/j.clinph.2008.10.041
24. Event-related P300 in post-stroke patients—M.H. Baglavajyan, G.S. Grigoryan (Yerevan, Armenia) Introduction: Although cognitive decline in post-stroke patients is very frequent, there are only a few neurophysiologic studies in this field. Objectives: To determine if event-related P300 latency is prolonged in patients with post-stroke cognitive impairment and to evaluate its diagnostic importance. Methods: A total number of 86 patients were assessed comprehensively for 3 months and 1 year after ischemic stroke, then compared with non-stroke control subjects. Medical history, neurological examination, blood tests, and computed tomography were performed. Cognitive functions were assessed by using the Clinical Dementia Rating Scale and the Mini Mental State Exam. Stroke was defined according to World Health Organization criteria. P300 was elicited on the standard electromyography equipment. Results: Following the third month of observation, the P300 latency was significantly higher (p < 0.02) in post-stroke patients as compared to the control subjects. It linearly correlated with the memory and attention impairment and increased by 0.87 ms after a 1 year follow-up. Conclusions: P300 latency is prolonged in patients with cognitive impairment after ischemic stroke. It can be used as a sensitive indicator in identifying early stages of vascular dementia. doi:10.1016/j.clinph.2008.10.042
23. Exercise test in patients with thyrotoxic periodic paralysis—S. Kim 1, H. Kim 2, S. Oh 1, J. Sung 2, Y. Hong 2, S. Kim 3, S. Park 1, K. Lee 1 (1 Sung-Nam, South Korea, 2 Seoul, South Korea, 3 Il-San, South Korea) Introduction: Thyrotoxic periodic paralysis (TPP) is one of the most common secondary hypokalemic periodic paralyses (PPs). A prolonged exercise test (PET) is considered to be useful in confirming the presence of PP, but its diagnostic value in TPP has not fully elucidated.
25. Baroreflex sensitivity differences in orthostatic hypotension at supine position—K.J. Park, S.U. Jung, S.N. Son, H.Y. Kang, N.C. Choi, O.Y. Kwon, B.H. Lim (Jinju, South Korea) Introduction: A tilt table test serves as a useful parameter for diagnosis of orthostatic dizziness and syncope but may prove to be dangerous, as it may induce or provoke the symptoms. The arterial baroreflex is a primary mechanism for the control of blood pressure