- Email: [email protected]
57. A prospective study of autonomic dysfunction among stroke patients
Society Proceedings / Clinical Neurophysiology 120 (2009) e89–e126
Conclusion: Cases of acute focal neuropathy had previously been reported in male weight lifters and are typically characterized by acute onset of weakness with minimal pain. In this case, however, the patient experienced significant pain and only subtle weakness. More importantly, the evidence of denervation in this case does not follow the distribution of a peripheral nerve or nerve root; rather, it is confined only to the two muscles specifically targeted by the performance of a novel exercise. This pattern of abnormality is indicative of significant local tissue damage, and illustrates the dangers of aggressive weight training in early adolescence. doi:10.1016/j.clinph.2008.10.074
57. A prospective study of autonomic dysfunction among stroke patients—P.N. Souayah 1, N. Krivitskaya 1, A. Nasar 2, A. Qureshi 3 (1 Newark, NJ, USA, 2 NewYork, NY, USA, 3 Minneapolis, MN, USA) Introduction: Autonomic tone influences the variation of heart rate to respiration (RR). Interval variation and quantitative measures of this variation are used to characterize sympathovagal control. Objectives: To determine the frequency and to identify the associated characteristics of autonomic dysfunction among patients who have had a stroke. Methods: RR interval variation was prospectively assessed in patients with left-hemisphere strokes (n = 21), right-hemisphere strokes (n = 14), and brainstem/cerebellar or bilateral stroke (n = 5). Results: A total of 40 patients were studied for 14 ± 21 days after symptom onset. The median National Institutes of Health Stroke Scale (NIHSS) score was 13. The average RR interval variation was 12.5 ± 10% among the studied patients. Autonomic dysfunction defined by RR interval variation of less than 10% was detected in 21 of 40 patients (moderate 5–10% in 12 and severe <5% in eight patients). Eight of the 20 patients who were studied after the first week of symptom onset demonstrated autonomic dysfunction. A clear relationship with the site of lesion or NIHSS score 10 or greater and presence of autonomic dysfunction was not observed. Patients with hemorrhagic stroke demonstrated a trend toward higher frequency of autonomic dysfunction (p = 0.1). The RR interval variation became normal in two patients who underwent repeated assessments after 45 and 23 days, respectively, after the first assessment in parallel to prominent resolution of neurological deficits. Concomitant peripheral nerve conduction studies performed in 20 patients did not reveal any evidence of large fiber neuropathy in 12 patients. Conclusions: Even after the first week following the symptom onset, autonomic dysfunction is relatively common after stroke and is presumably centrally mediated. doi:10.1016/j.clinph.2008.10.075
58. Asymmetric phenotype associated with rare Myelin protein zero mutation—N. Souayah 1, P. Siao Tick Chong 2 (1 Newark, NJ, USA, 2 Boston, MA, USA) Introduction: Myelin protein zero (MPZ) mutations cause demyelinating sensorimotor polyneuropathy. The phenotypes vary from severe neonatal forms to milder adult forms. Objectives: To report a family with an asymmetric phenotype associated with MPZ mutation.
e105
Results: A 36-year-old man developed weakness of left little finger adduction 3 years earlier. Weakness progressed to his other limbs. An examination revealed mildly high-arched feet with asymmetric weakness of ulnar-innervated muscles (left > right) and asymmetric weakness of peroneal-innervated muscles (right > left). The patient has stocking glove sensory deficits. Motor nerve conduction velocities ranged from 18.4 to 24.4 m/s in the upper extremities and from 14.8 to 22.7 in the lower extremities. Left median partial motor conduction block was noted at the forearm segment. Distal motor latencies and F-wave latencies were markedly prolonged. Left ulnar motor conduction studies (abductor digiti minimi, first dorsal interosseous) did not show focal slowing across the elbow. Sensory potentials were absent. Genetic testing demonstrated MPZ mutation with ARG98HIS amino acid change. The patient’s father is 68-yearold with hearing loss but no other symptoms. An examination revealed high-arched feet, asymmetric leg muscle bulk, and weakness (right > left), peroneal-innervated muscles weaker than tibial-innervated muscles, and weakness of the upper extremities (distal > proximal), ulnar-innervated muscles worse than median-innervated muscles, generalized areflexia, and stocking glove sensory deficits. The patient’s 2-year-old son is ‘‘clumsy (falls frequently), and has a history of neonatal laryngomalacia. He has a flat feet, areflexia, and has experienced difficulty standing on the individual right versus left leg. The patient’s paternal grandfather had high-arched feet and hearing loss. Conclusions: ARG98HIS MPZ mutation causes a relatively mild and asymmetric demyelinating sensorimotor polyneuropathy. doi:10.1016/j.clinph.2008.10.076
59. Nerve conduction studies and intra-epidermal nerve fiber density for the diagnosis of distal symmetric polyneuropathy— M.L. Reyzelman, M. Benatar (Atlanta, GA, USA) Introduction: Nerve conduction studies (NCSs) are routinely used to diagnose distal symmetric polyneuropathy (DSP), but their accuracy is controversial. An important drawback in the previous studies have been the lack of an independent gold standard against which the accuracy of NCSs could be compared. Objectives: To independently establish the accuracy of NCSs for (1) the clinical diagnosis of DSP using symptoms and signs and (2) the pathological diagnosis of DSP, based on reduced intra-epidermal nerve fiber (IENF) density. Methods: This was a retrospective cohort study. A clinical (symptoms and signs of DSP) or a pathological (decreased IENF density) gold standard was used to define the presence or absence of DSP. Sensitivity and specificity of various NCSs using different percentile thresholds for differentiating normal from abnormal were obtained, and receiver-operating curve analysis was used to determine the overall diagnostic accuracy of NCSs. Results: Sensitivity of NCS for DSP was poor, ranging between 30 and 52% for sural amplitude and 33–39% for sural/radial amplitude ratio (SRAR). Sural amplitude correctly distinguished neuropathy from nonneuropathy in 59% of cases based on the clinical gold standard, and in 77% of cases when the pathological gold standard was used. The diagnostic accuracy of SRAR for DSP was 53% based on a clinical gold standard, as compared to 69% with the pathological gold standard. Conclusions: NCSs are highly specific for DSP, however, they are relatively insensitive. A pathological gold standard allows for greater overall diagnostic accuracy of NCSs for DSP. doi:10.1016/j.clinph.2008.10.077
Conclusion: Cases of acute focal neuropathy had previously been reported in male weight lifters and are typically characterized by acute onset of weakness with minimal pain. In this case, however, the patient experienced significant pain and only subtle weakness. More importantly, the evidence of denervation in this case does not follow the distribution of a peripheral nerve or nerve root; rather, it is confined only to the two muscles specifically targeted by the performance of a novel exercise. This pattern of abnormality is indicative of significant local tissue damage, and illustrates the dangers of aggressive weight training in early adolescence. doi:10.1016/j.clinph.2008.10.074
57. A prospective study of autonomic dysfunction among stroke patients—P.N. Souayah 1, N. Krivitskaya 1, A. Nasar 2, A. Qureshi 3 (1 Newark, NJ, USA, 2 NewYork, NY, USA, 3 Minneapolis, MN, USA) Introduction: Autonomic tone influences the variation of heart rate to respiration (RR). Interval variation and quantitative measures of this variation are used to characterize sympathovagal control. Objectives: To determine the frequency and to identify the associated characteristics of autonomic dysfunction among patients who have had a stroke. Methods: RR interval variation was prospectively assessed in patients with left-hemisphere strokes (n = 21), right-hemisphere strokes (n = 14), and brainstem/cerebellar or bilateral stroke (n = 5). Results: A total of 40 patients were studied for 14 ± 21 days after symptom onset. The median National Institutes of Health Stroke Scale (NIHSS) score was 13. The average RR interval variation was 12.5 ± 10% among the studied patients. Autonomic dysfunction defined by RR interval variation of less than 10% was detected in 21 of 40 patients (moderate 5–10% in 12 and severe <5% in eight patients). Eight of the 20 patients who were studied after the first week of symptom onset demonstrated autonomic dysfunction. A clear relationship with the site of lesion or NIHSS score 10 or greater and presence of autonomic dysfunction was not observed. Patients with hemorrhagic stroke demonstrated a trend toward higher frequency of autonomic dysfunction (p = 0.1). The RR interval variation became normal in two patients who underwent repeated assessments after 45 and 23 days, respectively, after the first assessment in parallel to prominent resolution of neurological deficits. Concomitant peripheral nerve conduction studies performed in 20 patients did not reveal any evidence of large fiber neuropathy in 12 patients. Conclusions: Even after the first week following the symptom onset, autonomic dysfunction is relatively common after stroke and is presumably centrally mediated. doi:10.1016/j.clinph.2008.10.075
58. Asymmetric phenotype associated with rare Myelin protein zero mutation—N. Souayah 1, P. Siao Tick Chong 2 (1 Newark, NJ, USA, 2 Boston, MA, USA) Introduction: Myelin protein zero (MPZ) mutations cause demyelinating sensorimotor polyneuropathy. The phenotypes vary from severe neonatal forms to milder adult forms. Objectives: To report a family with an asymmetric phenotype associated with MPZ mutation.
e105
Results: A 36-year-old man developed weakness of left little finger adduction 3 years earlier. Weakness progressed to his other limbs. An examination revealed mildly high-arched feet with asymmetric weakness of ulnar-innervated muscles (left > right) and asymmetric weakness of peroneal-innervated muscles (right > left). The patient has stocking glove sensory deficits. Motor nerve conduction velocities ranged from 18.4 to 24.4 m/s in the upper extremities and from 14.8 to 22.7 in the lower extremities. Left median partial motor conduction block was noted at the forearm segment. Distal motor latencies and F-wave latencies were markedly prolonged. Left ulnar motor conduction studies (abductor digiti minimi, first dorsal interosseous) did not show focal slowing across the elbow. Sensory potentials were absent. Genetic testing demonstrated MPZ mutation with ARG98HIS amino acid change. The patient’s father is 68-yearold with hearing loss but no other symptoms. An examination revealed high-arched feet, asymmetric leg muscle bulk, and weakness (right > left), peroneal-innervated muscles weaker than tibial-innervated muscles, and weakness of the upper extremities (distal > proximal), ulnar-innervated muscles worse than median-innervated muscles, generalized areflexia, and stocking glove sensory deficits. The patient’s 2-year-old son is ‘‘clumsy (falls frequently), and has a history of neonatal laryngomalacia. He has a flat feet, areflexia, and has experienced difficulty standing on the individual right versus left leg. The patient’s paternal grandfather had high-arched feet and hearing loss. Conclusions: ARG98HIS MPZ mutation causes a relatively mild and asymmetric demyelinating sensorimotor polyneuropathy. doi:10.1016/j.clinph.2008.10.076
59. Nerve conduction studies and intra-epidermal nerve fiber density for the diagnosis of distal symmetric polyneuropathy— M.L. Reyzelman, M. Benatar (Atlanta, GA, USA) Introduction: Nerve conduction studies (NCSs) are routinely used to diagnose distal symmetric polyneuropathy (DSP), but their accuracy is controversial. An important drawback in the previous studies have been the lack of an independent gold standard against which the accuracy of NCSs could be compared. Objectives: To independently establish the accuracy of NCSs for (1) the clinical diagnosis of DSP using symptoms and signs and (2) the pathological diagnosis of DSP, based on reduced intra-epidermal nerve fiber (IENF) density. Methods: This was a retrospective cohort study. A clinical (symptoms and signs of DSP) or a pathological (decreased IENF density) gold standard was used to define the presence or absence of DSP. Sensitivity and specificity of various NCSs using different percentile thresholds for differentiating normal from abnormal were obtained, and receiver-operating curve analysis was used to determine the overall diagnostic accuracy of NCSs. Results: Sensitivity of NCS for DSP was poor, ranging between 30 and 52% for sural amplitude and 33–39% for sural/radial amplitude ratio (SRAR). Sural amplitude correctly distinguished neuropathy from nonneuropathy in 59% of cases based on the clinical gold standard, and in 77% of cases when the pathological gold standard was used. The diagnostic accuracy of SRAR for DSP was 53% based on a clinical gold standard, as compared to 69% with the pathological gold standard. Conclusions: NCSs are highly specific for DSP, however, they are relatively insensitive. A pathological gold standard allows for greater overall diagnostic accuracy of NCSs for DSP. doi:10.1016/j.clinph.2008.10.077