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Macromastia and carpal tunnel syndrome – Is there an association?
British Society for Clinical Neurophysiology / Clinical Neurophysiology 118 (2007) e153–e156
e155
activity, decreased activity in inferior parietal and precuneous cortex and also, importantly, by their pontine initiation and a well time-locked amygdalo parahippocampal-pontine sequence.
as well as for changes in membrane potential, and that mathematical modelling can be a useful aid to interpreting excitability abnormalities.
doi:10.1016/j.clinph.2006.07.233
doi:10.1016/j.clinph.2006.07.235
Central motor conduction abnormalities in D90A homozygous familial amyotrophic lateral sclerosis—A. Osei-Lah 1, M. Turner 1, N. Leigh 1, P. Anderson 2, K.R. Mills 1 (1 Academic Neuroscience Centre, King’s College Hospital, London, UK, 2 Department of Neurology, Umea˚ University Hospital, Umea˚, Sweden)
Nerve excitability changes of motor axons in Fabry disease suggest an ischaemic component to nerve dysfunction—S.V. Tan 1, P. Lee 1, R.J.L. Walters 1, A. Mehta 1, H. Bostock 2 (1 National Hospital for Neurology and Neurosurgery, Queen Square, London, UK, 2 Institute of Neurology, University College, London, UK)
In contrast to sporadic ALS, patients with familial ALS homozygous for the D90A-SOD1 mutation have been reported to have markedly prolonged central motor conduction times (CMCTs). With ethics committee approval, we have studied 10 such patients using transcranial magnetic stimulation by recording motor evoked potentials (MEPs) from the resting or voluntarily activated first dorsal interosseous muscle. In two patients, threshold exceeded the maximum output of the stimulator. In the remaining eight patients mean (SD) CMCT was 8.9 (2.5) ms with the muscle at rest. In two patients the MEP consisted of two distinct components, the second at a latency of 41 and 44 ms, respectively. In the active state, four patients showed the normal reduction in MEP latency (0.2–1.8 ms) when compared with the resting state. In the other four, MEP latency with the muscle active was longer than in the relaxed state by 14.0 (4.7) ms. We postulate that in this subgroup of patients, intracortical or intraspinal presynaptic inhibition prevents delivery of the fast component of the corticospinal volley to the spinal mononeurone.
Fabry disease is an X-linked galactosidase A deficiency, which results in a small fibre neuropathy, with episodes of painful acroparaesthesiae. The pathogenesis of the neuropathy is poorly understood, but intracellular glycolipid accumulation is presumed responsible, whether by interfering with membrane proteins, by cytotoxicity, or by causing a microvasculopathy. In this study, we used multiple nerve excitability measurements to investigate the membrane properties of median motor axons in 20 Fabry patients with symptomatic disease but without hyperkalemia. Excitability measures, including threshold electrotonus and recovery cycle (refractory period, superexcitability and late subexcitability) were compared with data from 35 normal controls. In Fabry patients, depolarizing threshold electrotonus was reduced (P < 0.0001), as was superexcitability (P < 0.001), but late subexcitability was normal. These abnormalities resemble those in axons depolarized by ischaemia. The data support an ischaemic origin of nerve dysfunction, probably due to glycolipid deposition in vascular endothelium. Excitability studies provide a non-invasive method for assessing the nerve microenvironment and may be useful for monitoring responses to treatment.
doi:10.1016/j.clinph.2006.07.234
doi:10.1016/j.clinph.2006.07.236
Nerve excitability changes in puffer fish poisoning—H. Bostock 1,2, C.S-Y. Lin 1,2, M.C. Kiernan 1 (1 Prince of Wales Medical Research Institute, University of New South Wales, Australia, 2 Institute of Neurology, University College, London, UK) Many species of the puffer fish family (Tetraodontidae) harbour marine bacteria that synthesize the sodium channel blocker tetrodotoxin (TTX). Four patients hospitalised after consuming puffer fish soup were investigated by nerve excitability testing. Multiple excitability measurements were made on median motor axons at the wrist, using a recently described protocol. The patient axons had abnormally high thresholds and short strength-duration time constants, while all components of the recovery cycle (refractoriness, superexcitability and late subexcitability) were reduced. The greatest abnormalities were in threshold electrotonus: each patient was outside the 99.9% confidence limits for normal controls, with less threshold decrease than normal on depolarization and more threshold increase on hyperpolarization. These distinctive excitability abnormalities were mimicked by a two-compartment (node–internode) electrical model of human motor axons, when transient and persistent sodium permeabilities were reduced by half. We conclude that excitability studies provide a sensitive test for sodium channel block,
Macromastia and carpal tunnel syndrome – Is there an association?—O.C. Iwuagwu 1, A.A. Bajalan 2, A. Reese 1, P.J. Drew 1 (1 University of Hull Academic Surgical Unit, Castle Hill Hospital, Cottingham, UK, 2 Department of Clinical Neurophysiology, Hull Royal Infirmary, Hull, UK) Introduction: Macromastia is a common complaint among women. The prevalence of electrophysiologically confirmed, symptomatic carpal tunnel syndrome (CTS) is about 3% among women. The association of macromastia and CTS has been previously addressed by clinical assessment alone. Methodology: A consecutive list of 31 patients with macromastia, requesting breast reduction, between August 2002 and April 2003 were recruited. Physical characteristics recorded included age, body mass index and breast size. Clinical and electrophysiological assessments of the upper limb were performed. Statistical analysis was done using version 11 SPSS statistical program. Results: The mean age was 40.5years (range of 17–63 years). The mean body mass index (BMI) was 27.5 (range 20–36). Electrophysiological testing revealed 7 out of 31 (22%) to have prolonged median nerve latency conduction time of greater than 0.40 ms. Age, chest circumference and the ratio of measurement
e156
British Society for Clinical Neurophysiology / Clinical Neurophysiology 118 (2007) e153–e156
nipple-to-inframammary line (N–C) to chest circumference were independent predictors of CTS (P = 0.05). Conclusion: The incidence of CTS in patients with macromastia is raised compared to previous epidermiological studies of prevalence. Age, chest circumference and breast size have a positive correlation with the incidence of CTS. doi:10.1016/j.clinph.2006.07.237
Ipsilateral eye blinking during seizures—Y. Langan 1, V. Ramesh 2, A. Jenkins 3, I.S. Schofield 1, M. Lai 1 (1 Department of Clinical Neurophysiology, Royal Victoria Infirmary and General Hospital, Newcastle, UK, 2 Department of Paediatric Neurology, Newcastle General Hospital, UK, 3 Department Of Neurosurgery, Newcastle General Hospital, Newcastle, UK)
JL is a 12-year-old girl who presented with a five-year history of stereotyped events. Each episode would begin with blinking of the right eye followed by dystonic posturing of the left side. Multiple such episodes occurred every day. She experienced generalised tonic clonic seizures rarely. Routine EEG demonstrated seizure activity over the right frontal lobe and MRI scan revealed a dysplastic right frontal lobe. Her seizures remained intractable despite multiple antiepileptic drugs so right frontal lobectomy was performed with corticography. Thus far seizure frequency and severity is improved although the patient still experiences daily events. Histology is awaited. A review of the literature has revealed that while ipsilateral eye blinking is rare it is a good localising sign. doi:10.1016/j.clinph.2006.07.238
e155
activity, decreased activity in inferior parietal and precuneous cortex and also, importantly, by their pontine initiation and a well time-locked amygdalo parahippocampal-pontine sequence.
as well as for changes in membrane potential, and that mathematical modelling can be a useful aid to interpreting excitability abnormalities.
doi:10.1016/j.clinph.2006.07.233
doi:10.1016/j.clinph.2006.07.235
Central motor conduction abnormalities in D90A homozygous familial amyotrophic lateral sclerosis—A. Osei-Lah 1, M. Turner 1, N. Leigh 1, P. Anderson 2, K.R. Mills 1 (1 Academic Neuroscience Centre, King’s College Hospital, London, UK, 2 Department of Neurology, Umea˚ University Hospital, Umea˚, Sweden)
Nerve excitability changes of motor axons in Fabry disease suggest an ischaemic component to nerve dysfunction—S.V. Tan 1, P. Lee 1, R.J.L. Walters 1, A. Mehta 1, H. Bostock 2 (1 National Hospital for Neurology and Neurosurgery, Queen Square, London, UK, 2 Institute of Neurology, University College, London, UK)
In contrast to sporadic ALS, patients with familial ALS homozygous for the D90A-SOD1 mutation have been reported to have markedly prolonged central motor conduction times (CMCTs). With ethics committee approval, we have studied 10 such patients using transcranial magnetic stimulation by recording motor evoked potentials (MEPs) from the resting or voluntarily activated first dorsal interosseous muscle. In two patients, threshold exceeded the maximum output of the stimulator. In the remaining eight patients mean (SD) CMCT was 8.9 (2.5) ms with the muscle at rest. In two patients the MEP consisted of two distinct components, the second at a latency of 41 and 44 ms, respectively. In the active state, four patients showed the normal reduction in MEP latency (0.2–1.8 ms) when compared with the resting state. In the other four, MEP latency with the muscle active was longer than in the relaxed state by 14.0 (4.7) ms. We postulate that in this subgroup of patients, intracortical or intraspinal presynaptic inhibition prevents delivery of the fast component of the corticospinal volley to the spinal mononeurone.
Fabry disease is an X-linked galactosidase A deficiency, which results in a small fibre neuropathy, with episodes of painful acroparaesthesiae. The pathogenesis of the neuropathy is poorly understood, but intracellular glycolipid accumulation is presumed responsible, whether by interfering with membrane proteins, by cytotoxicity, or by causing a microvasculopathy. In this study, we used multiple nerve excitability measurements to investigate the membrane properties of median motor axons in 20 Fabry patients with symptomatic disease but without hyperkalemia. Excitability measures, including threshold electrotonus and recovery cycle (refractory period, superexcitability and late subexcitability) were compared with data from 35 normal controls. In Fabry patients, depolarizing threshold electrotonus was reduced (P < 0.0001), as was superexcitability (P < 0.001), but late subexcitability was normal. These abnormalities resemble those in axons depolarized by ischaemia. The data support an ischaemic origin of nerve dysfunction, probably due to glycolipid deposition in vascular endothelium. Excitability studies provide a non-invasive method for assessing the nerve microenvironment and may be useful for monitoring responses to treatment.
doi:10.1016/j.clinph.2006.07.234
doi:10.1016/j.clinph.2006.07.236
Nerve excitability changes in puffer fish poisoning—H. Bostock 1,2, C.S-Y. Lin 1,2, M.C. Kiernan 1 (1 Prince of Wales Medical Research Institute, University of New South Wales, Australia, 2 Institute of Neurology, University College, London, UK) Many species of the puffer fish family (Tetraodontidae) harbour marine bacteria that synthesize the sodium channel blocker tetrodotoxin (TTX). Four patients hospitalised after consuming puffer fish soup were investigated by nerve excitability testing. Multiple excitability measurements were made on median motor axons at the wrist, using a recently described protocol. The patient axons had abnormally high thresholds and short strength-duration time constants, while all components of the recovery cycle (refractoriness, superexcitability and late subexcitability) were reduced. The greatest abnormalities were in threshold electrotonus: each patient was outside the 99.9% confidence limits for normal controls, with less threshold decrease than normal on depolarization and more threshold increase on hyperpolarization. These distinctive excitability abnormalities were mimicked by a two-compartment (node–internode) electrical model of human motor axons, when transient and persistent sodium permeabilities were reduced by half. We conclude that excitability studies provide a sensitive test for sodium channel block,
Macromastia and carpal tunnel syndrome – Is there an association?—O.C. Iwuagwu 1, A.A. Bajalan 2, A. Reese 1, P.J. Drew 1 (1 University of Hull Academic Surgical Unit, Castle Hill Hospital, Cottingham, UK, 2 Department of Clinical Neurophysiology, Hull Royal Infirmary, Hull, UK) Introduction: Macromastia is a common complaint among women. The prevalence of electrophysiologically confirmed, symptomatic carpal tunnel syndrome (CTS) is about 3% among women. The association of macromastia and CTS has been previously addressed by clinical assessment alone. Methodology: A consecutive list of 31 patients with macromastia, requesting breast reduction, between August 2002 and April 2003 were recruited. Physical characteristics recorded included age, body mass index and breast size. Clinical and electrophysiological assessments of the upper limb were performed. Statistical analysis was done using version 11 SPSS statistical program. Results: The mean age was 40.5years (range of 17–63 years). The mean body mass index (BMI) was 27.5 (range 20–36). Electrophysiological testing revealed 7 out of 31 (22%) to have prolonged median nerve latency conduction time of greater than 0.40 ms. Age, chest circumference and the ratio of measurement
e156
British Society for Clinical Neurophysiology / Clinical Neurophysiology 118 (2007) e153–e156
nipple-to-inframammary line (N–C) to chest circumference were independent predictors of CTS (P = 0.05). Conclusion: The incidence of CTS in patients with macromastia is raised compared to previous epidermiological studies of prevalence. Age, chest circumference and breast size have a positive correlation with the incidence of CTS. doi:10.1016/j.clinph.2006.07.237
Ipsilateral eye blinking during seizures—Y. Langan 1, V. Ramesh 2, A. Jenkins 3, I.S. Schofield 1, M. Lai 1 (1 Department of Clinical Neurophysiology, Royal Victoria Infirmary and General Hospital, Newcastle, UK, 2 Department of Paediatric Neurology, Newcastle General Hospital, UK, 3 Department Of Neurosurgery, Newcastle General Hospital, Newcastle, UK)
JL is a 12-year-old girl who presented with a five-year history of stereotyped events. Each episode would begin with blinking of the right eye followed by dystonic posturing of the left side. Multiple such episodes occurred every day. She experienced generalised tonic clonic seizures rarely. Routine EEG demonstrated seizure activity over the right frontal lobe and MRI scan revealed a dysplastic right frontal lobe. Her seizures remained intractable despite multiple antiepileptic drugs so right frontal lobectomy was performed with corticography. Thus far seizure frequency and severity is improved although the patient still experiences daily events. Histology is awaited. A review of the literature has revealed that while ipsilateral eye blinking is rare it is a good localising sign. doi:10.1016/j.clinph.2006.07.238