Combined testing of autonomic and sensory dysfunction in patients with unilateral facial flushing and sweating during exercise.

AIMS OF THE STUDY: Patients with unilateral facial flushing are occasionally referred to clinical neurophysiological evaluation with the question of the site of lesion. These patients may have a mixture of autonomic and sensory symptoms. We wanted to study to which extent a combined autonomic and sensory clinical neurophysiological testing before and after exercise may help in the diagnostic evaluation of the patients. PATIENTS AND METHODS: Five patients were investigated at rest with quantitative sensory thresholds (QST, measurement of thermal thresholds) and quantitative sudomotor axon reflex test (QSART) in all extremities. Sweet volumes (QSWEAT) and skin temperatures were then measured after 30 to 60 minutes of exercise. RESULTS: Marked side-to-side differences were observed for QST and QSART at rest as well as for QSWEAT and skin temperatures following exercise, in accordance with the patients' symptoms. However, asymptomatic abnormal findings were also demonstrated in the feet of four patients, following both crossed and non-crossed distributions. EMG/neurography and MRI-findings were normal in all patients and no aetiological explanations were found. CONCLUSION: Combined autonomic and sensory testing including the legs provided evidence of unexpectedly more widespread abnormalities, including asymptomatic findings. Although the patients presented with seemingly similar symptoms, there was a striking heterogeneity in their results, suggesting different sites of dysfunction. An extracranial lesion was considered likely in one or maybe two patients, while the possibility of a central lesion had to be considered in the three other patients.

Peripheral neuropathy caused by severe hypothermia.

OBJECTIVE: To report follow-up data in the evaluation of peripheral neuropathy in a 29-year old female after accidental deep hypothermia (13.7°C) in 1999. METHODS: Nerve conduction studies (NCS) and electromyography (EMG) were performed 20 days after the accident and again after 5 months and 1, 3, 5 and 11 years. Macro EMG was performed after 3, 5 and 11 years. To evaluate small fiber function, RR-interval, sympathetic skin response, quantitative sensory testing and skin biopsy for quantification of intra-epidermal nerve fiber density were performed in 2009. RESULTS: In the intensive care unit sensory and motor responses were absent except for the tibial nerves, and EMG showed profuse denervation. Improvement of amplitudes and conduction velocities was seen during the first 5 years. Muscular atrophy of hand muscles persisted. Large fibers were involved more extensively than small fibers. CONCLUSIONS: A severe axonal sensorimotor polyneuropathy developed in the intensive care unit following severe hypothermia. The mechanism was most likely cold injury to peripheral nerves. SIGNIFICANCE: The clinical picture and the laboratory findings indicate that even multi-organ dysfunction and, of specific interest in this study, a severe axonal degeneration may come to a good restitution after long time.

Myotonia congenita and myotonic dystrophy in the same family: coexistence of a CLCN1 mutation and expansion in the CNBP (ZNF9) gene.

Myotonia is characterized by hyperexcitability of the muscle cell membrane. Myotonic disorders are divided into two main categories: non-dystrophic and dystrophic myotonias. The non-dystrophic myotonias involve solely the muscle system, whereas the dystrophic myotonias are characterized by multisystem involvement and additional muscle weakness. Each category is further subdivided into different groups according to additional clinical features or/and underlying genetic defects. However, the phenotypes and the pathological mechanisms of these myotonic disorders are still not entirely understood. Currently, four genes are identified to be involved in myotonia: the muscle voltage-gated sodium and chloride channel genes SCN4A and CLCN1, the myotonic dystrophy protein kinase (DMPK) gene, and the CCHC-type zinc finger, nucleic acid binding protein gene CNBP. Additional gene(s) and/or modifying factor(s) remain to be identified. In this study, we investigated a large Norwegian family with clinically different presentations of myotonic disorders. Molecular analysis revealed CCTG repeat expansions in the CNBP gene in all affected members, confirming that they have myotonic dystrophy type 2. However, a CLCN1 mutation c.1238C>G, causing p.Phe413Cys, was also identified in several affected family members. Heterozygosity for p.Phe413Cys seems to exaggerate the severity of myotonia and thereby, to some degree, contributing to the pronounced variability in the myotonic phenotype in this family.

Is obstructive sleep apnea syndrome associated with headache?

OBJECTIVE: Obstructive sleep apnea syndrome (OSA) is a common disorder in the general population. Although the mechanisms remain obscure, an association with headache has been reported. We aimed to assess the frequency of OSA in a population of headache patients based on a stratified sampling technique using questionnaire and polysomnography (PSG). METHODS: The survey was provided to new outpatients examined by a neurologist for headache over a 2-year period of time. The patients completed a headache diary during 30 days and those at risk of OSA went through a PSG examination. RESULTS: Of 903 headache patients, 75 reported heavy snoring and episodes of interrupted nocturnal breathing (8%). Among 43 patients examined with PSG, 14 (1.5% of the total study population) had an apnea/hypopnea index of 5 or higher. Eleven of the patients reported morning headache. CONCLUSION: The frequency of OSA in a patients referred to specialist for headache problems is not higher than what is reported for the general population. The relatively low rate of OSA in this selected group of patients with headache referred to neurology for second opinion does not support the notion that OSA brings about headache.

A rare form of painful nondystrophic myotonia.

OBJECTIVE: In this paper we report a painful nondystrophic myotonia which has not been previously described. Pain is a rare symptom in myotonia. We report a myotonic disorder in a 34-year-old woman and her 14-year-old daughter. Painful cramps occur during and after exercise in the mother, and both patients can demonstrate unusual contractions in the tongue. In the present study we try to evaluate the mechanisms behind the unique finding of trains of high amplitude of positive waves, not seen in the earlier known myotonic conditions. METHODS: Clinical investigations and electromyography with single and dual channel recordings and muscle morphometry were performed. RESULTS: The electromyographic recordings reveal positive waves, fibrillation potentials and myotonic discharges. In addition, extraordinary findings were made of trains of high frequency positive potentials with very high amplitudes and with conduction block along the muscle fibres. CONCLUSIONS: In this new form of myotonia with likely dominant heredity, the specific finding of trains of high amplitude positive waves indicates ephaptic transmission within bundles of neighbouring muscle fibres.

Increased risk of median nerve dysfunction in floor cleaners: a controlled clinical and neurophysiological study.

We studied median nerve involvement in a group of asymptomatic handworkers at risk for carpal tunnel syndrome, and we evaluated damage to thin and thick nerve fibres in the distribution area of the median nerve. Considering floor cleaners as workers at high risk of developing cumulative traumatic disorders in the wrist, we included 42 cleaners and 41 controls. We assessed nerve conduction studies, vibration threshold, and temperature and pain thresholds of the median nerve. The cleaners had significantly impaired motor nerve conduction velocity (p = 0.006), longer sensory distal latency (p = 0.01), lower sensory amplitude (p = 0.0005), and increased difference in heat and cold threshold of the median nerve (p = 0.0002). Increased temperature threshold was associated with prolonged sensory distal latency of the median nerve in the cleaners. In conclusion, impaired neurophysiological variables in the median nerve in floor cleaners compared with controls confirm the hypothesis that those workers are at risk of developing median nerve dysfunction. Sensory nerves seem to be more susceptible to injury than motor branches.

Mutations in CAV3 cause mechanical hyperirritability of skeletal muscle in rippling muscle disease.

Hereditary rippling muscle disease (RMD) is an autosomal dominant human disorder characterized by mechanically triggered contractions of skeletal muscle. Genome-wide linkage analysis has identified an RMD locus on chromosome 3p25. We found missense mutations in positional candidate CAV3 (encoding caveolin 3; ref. 5) in all five families analyzed. Mutations in CAV3 have also been described in limb-girdle muscular dystrophy type 1C (LGMD1C; refs. 6,7), demonstrating the allelism of dystrophic and non-dystrophic muscle diseases.

Peripheral neuropathy in systemic lupus erythematosus--a longitudinal study.

OBJECTIVE: Peripheral neuropathy (PN) is reported to occur in 5-27% of patients with systemic lupus erythematosus (SLE) mostly as a length-dependent sensorimotor axonopathy. Studies over time have not been performed. Design - Longitudinal study. SUBJECTS AND METHODS: Thirty-three Caucasian SLE patients consented to participate in the study and were subjected to clinical examination, laboratory tests, and nerve conduction velocity (NCV) studies. At the follow-up 7 years later, 7 patients (21%) were dead, 4 refused to participate, and 2 did not want to perform NCV studies. Twenty patients were thus available for longitudinal study. RESULTS: When all SLE patients were considered on a group basis at follow-up, 8 (33%) out of 24 NCV parameters showed significant deterioration despite correction for time, while 16 (67%) were unchanged. Analysis of change from baseline showed that, except for F-responses, several NCV changes were highly dependent (negative regression coefficients) on baseline levels at start of study. No demographic, laboratory, or disease associated quantitative factor was associated with these changes in NCV parameters over time. Nor was a consistent effect on NCV parameters from any qualitative demographic or disease associated factor confirmed by Repeated Measures ANOVA analyses. CONCLUSIONS: A modest progressive neuropathic process exists in patients with SLE. Important is also the finding that, over time, the abnormalities of NCV parameters fluctuate in the individual patients, and the impairments are not necessarily irreversible. This study also shows no association to medication, demographic-, or other disease associated factors.

Impact of occupational variables in carpal tunnel syndrome.

OBJECTIVE: We studied the impact of work-related factors on the outcome in patients operated for carpal tunnel syndrome. METHODS: The population consisted of 106 CTS patients who worked at the time of operation. We registered social and occupational data from the patients. RESULTS: Median time of sick leave was 7 weeks for the total group. Sixty-four percent reported a relationship between their work and the disease. Eighty-nine percent of the operated patients returned to their previous work after operation. CONCLUSIONS: A majority of the patients attributed the CTS-related symptoms to their occupation. Work-related factors may therefore be one possible explanation for the socioeconomical consequences of CTS. A permanent drop-out from work in more than 1 out of 10 patients after CTS treatment indicate that CTS form a substantial socioeconomical burden in the society.

Spectrum of CLCN1 mutations in patients with myotonia congenita in Northern Scandinavia.

Myotonia congenita is a non-dystrophic muscle disorder affecting the excitability of the skeletal muscle membrane. It can be inherited either as an autosomal dominant (Thomsen's myotonia) or an autosomal recessive (Becker's myotonia) trait. Both types are characterised by myotonia (muscle stiffness) and muscular hypertrophy, and are caused by mutations in the muscle chloride channel gene, CLCN1. At least 50 different CLCN1 mutations have been described worldwide, but in many studies only about half of the patients showed mutations in CLCN1. Limitations in the mutation detection methods and genetic heterogeneity might be explanations. In the current study, we sequenced the entire CLCN1 gene in 15 Northern Norwegian and three Northern Swedish MC families. Our data show a high prevalence of myotonia congenita in Northern Norway similar to Northern Finland, but with a much higher degree of mutation heterogeneity. In total, eight different mutations and three polymorphisms (T87T, D718D, and P727L) were detected. Three mutations (F287S, A331T, and 2284+5C>T) were novel while the others (IVS1+3A>T, 979G>A, F413C, A531V, and R894X) have been reported previously. The mutations F413C, A531V, and R894X predominated in our patient material. Compound heterozygosity for A531V/R894X was the predominant genotype. In two probands, three mutations cosegregated with myotonia. No CLCN1 mutations were identified in two families. Our data support the presence of genetic heterogeneity and additional modifying factors in myotonia congenita.

Myopathy and neuropathy in rheumatoid arthritis. A quantitative controlled electromyographic study.

OBJECTIVE: To test the hypothesis that patients with rheumatoid arthritis (RA) have clinical or subclinical evidence of peripheral neuropathy or myopathy. METHODS: We studied 40 seropositive women with RA, mean age 46.6 years (SD 6.4), and 56 healthy controls, mean age 43.0 years (SD 9.1). Patients had a mean disease duration of 13.0 years (SD 7.8). We performed electromyographic examination of 4 muscles [extensor digitorum communis (EDC), biceps brachii (BB), vastus lateralis (VL), and tibialis anterior (TA)] on the right side in both groups. Quantitative data included percentage of polyphasic potentials, motor unit potential amplitude, area, duration, turns, and number of polyphasic potentials. RESULTS: There were statistically significantly higher proportions of polyphasic potentials in 3 muscles in patients compared with controls. Mean number of phases in EDC was 4.6 (SD 0.4) in the patients and 4.1 (0.5) in controls (p = 0.0001). The values for the VL were 4.1 (SD 0.4) in patients compared with 3.6 (0.4) in controls (p = 0.0001), and in the TA 4.5 (SD 0.5) versus 4.0 (0.4) (p = 0.0001). We also found significantly increased duration of motor unit potentials in the VL and TA of patients. The amplitudes of motor unit action potentials were not significantly different in the 2 groups. CONCLUSION: The study reveals an increased prevalence of neurogenic but not myogenic changes in patients with RA compared with controls.

Cerebral computed tomography and electroencephalography compared with neuropsychological findings in systemic lupus erythematosus.

Central nervous system involvement was evaluated in 36 patients with systemic lupus erythematosus (SLE) using cerebral computed tomography (CT), electroencephalography (EEG), and a neuropsychological test battery. The purpose was to investigate whether brain dysfunction as assessed by comprehensive neuropsychological investigation is associated with findings of routine investigation methods such as CT and EEG which are available in most hospitals. Abnormal EEG was found in 19%, and CT revealed cerebral atrophy in 47% of SLE patients. Few neuropsychological functions were affected by the presence of abnormal EEG, cerebral atrophy, or infarcts. Significant associations were found only between cortical atrophy and impairment of tactile spatial problem-solving and motor dexterity, and between cortical infarcts and motor dexterity in the dominant hand. The value of conventional EEG in assessing cerebral SLE is negligible, except for identifying epileptic activity and focal pathology. Cerebral CT has little relevance in predicting brain dysfunction as established by neuropsychological assessment in SLE, except for detecting cortical atrophy and infarcts.

Linkage analysis narrows the critical region for oculodentodigital dysplasia to chromosome 6q22-q23.

Oculodentodigital dysplasia (ODDD) is an autosomal dominant condition with high penetrance and variable expressivity. The anomalies of the craniofacial region, eyes, teeth, and limbs indicate abnormal morphogenesis during early fetal development. Neurologic abnormalities occur later in life and appear to be secondary to white matter degeneration and basal ganglia changes. In familial cases, the dysmorphic and/or neurodegenerative components of the phenotype can be more severe and/or present at a younger age in subsequent generations, suggesting genetic anticipation. These clinical features suggest that the ODDD gene is pleiotropic with important functions throughout pre- and postnatal development. We have performed two-point linkage analysis with seven ODDD families and 19 microsatellite markers on chromosome 6q spanning a genetic distance of approximately 11 cM in males and 20 cM in females. We have refined the location of the ODDD gene between DNA markers D6S266/D6S261 (centromeric) and D6S1639 (telomeric), an interval of 1.01 (male) to 2.87 (female) cM. The strongest linkage was to DNA marker D6S433 (Zmax = 8.96, thetamax = 0.001). Families show significant linkage to chromosome 6q22-q23 and no evidence for genetic heterogeneity.

The rheumatoid wrist: bilateral MR analysis of the distribution of rheumatoid lesions in axial plan in a female population.

In this case-control study, we analyzed 146 wrists: a) to search for the distribution pattern of the rheumatoid lesions and, b) to correlate the distribution pattern of these lesions with the clinical parameters. Thirty-one patients with rheumatoid arthritis (RA) and 42 controls-all women-were examined by means of a bilateral MR fast field echo (FFE) sequence, in axial plan. The wrist was divided into three regions: metacarpal (level I), carpal (level II) and radioulnar (level III). Erosions were present in thirty (97%) patients and in six (14%) controls. They were asymmetrically distributed at all levels, mainly at level II. Marrow infiltration and bone destruction were seen in 35% of the patients in an asymmetrical pattern at level I and II, respectively. These lesions were absent in the control group. Subchondral cysts were asymmetrically present in both groups-in 48% of the patients at levels II and III, and in 11% of the controls at level II. In the patient group, this asymmetrical pattern of the lesions correlated with the disease duration at levels I and II (p = 0.011 and p = 0.013, respectively). Most lesions were found at the radial force-bearing column of the wrist, more in the right side. Synovial hypertrophy and hyperintense median nerve were evident in 96% and 70% of the patients, respectively. We concluded that contrary to common belief rheumatoid damages to the carpal bones become rather asymmetrical as the disease progresses. The line of force along the radial side of the wrist possibly influences the distribution pattern of the rheumatoid lesions.

Mutations in mitochondrial transfer ribonucleic acid genes in preeclampsia.

OBJECTIVE: We investigated whether maternally inherited mitochondrial deoxyribonucleic acid mutations could be associated with preeclampsia because mendelian models fail to explain all the aspects of inheritance in preeclampsia. STUDY DESIGN: In two families with a high occurrence of preeclampsia and eclampsia the 22 mitochondrial transfer ribonucleic acid genes were sequenced in eight and three women, respectively. RESULTS: An A-to-G mutation in transfer ribonucleic acidleu[UUR] at nucleotide 3243 was found in one family, and in the other there was an A-to-G mutation at nucleotide 12308 in transfer ribonucleic acidleu[CUN]. Mutations of mitochondrial transfer ribonucleic acid genes are generally considered to have systemic consequences, which might explain the multiorgan involvement seen in preeclampsia. CONCLUSION: We report for the first time mutations in mitochondrial transfer ribonucleic acid genes in two families with a high occurrence of preeclampsia and eclampsia. Mitochondrial dysfunction caused by point mutations of mitochondrial deoxyribonucleic acid is maternally inherited, but in the case of mutations of nuclear genes mitochondrial dysfunction can be inherited as an autosomal recessive or dominant trait.

Generator sites for spontaneous activity in neuromyotonia. An EMG study.

A 16-year-old female patient with symptoms and signs compatible with neuromyotonia was studied with various neurophysiological tests and with muscle biopsy. Nerve conduction studies revealed signs of axonal motor neuropathy. EMG showed denervation in distal muscles, and moderate neurogenic changes in other muscles. Abundant spontaneous motor unit activity was recorded in all muscles. This activity did not disappear upon proximal nerve blockade with local anaesthetics. Based on the shape of spontaneous discharges and their behaviour on nerve stimulation and during voluntary effort, the site of generation was suggested. This varied for different discharges, from proximally in the nerve, to various sites along the intramuscular nerve tree. In some axons there were signs of conduction block proximal to the generation site for the spontaneous discharges. Different axons showed various degrees of abnormality; local hyperexcitability triggering new impulses only after the passage of a preceding impulse, increased hyperexcitability generating spontaneous activity, total impulse blocking, and finally axonal degeneration. Treatment with dihydantoin reduced the spontaneous activity with concomitant clinical improvement.

Quantitative magnetic resonance imaging and the electrophysiology of the carpal tunnel region in floor cleaners.

OBJECTIVES: The purpose of this study was to evaluate possible structural changes of the wrist and subclinical damage in the median nerves of healthy floor cleaners. METHODS: Twenty-four cleaners and 19 referents (noncleaners), all women, underwent bilateral magnetic resonance (MR) wrist examination and nerve conduction studies. They were all randomly selected from an occupational health service. From MR images the volumes of the wrist, carpal tunnel, and thenar and hypothenar muscles were calculated, as well as the signal intensity of the median nerve, bilaterally. RESULTS: No significant difference in the volume of the carpal tunnel was found in the two groups. The relative signal intensity of the median nerve was 0.55 for the cleaners and 0.48 for the referents (P = 0.05). The mean nerve conduction velocity values were 55.2 m.s-1 for the right median nerve of the cleaners and 57.4 m.s-1 for the right median nerve of the referents (P = 0.03). The median nerve of the cleaners had a mean sensory amplitude of 128.2 microV compared with 162.8 microV for the referents (P = 0.01). There was a tendency towards a longer distal latency of the median nerve in the cleaner group. CONCLUSIONS: This study revealed subclinical intrinsic damage to the median nerve, as demonstrated by MR, and poorer electrophysiological nerve function among workers at high risk (cleaners) compared with workers at lower risk (noncleaners).

Bilateral fast MR imaging of the rheumatoid wrist.

To evaluate the structural changes in the carpal tunnel and possible intrinsic median nerve damages in RA patients, quantitative bilateral magnetic resonance imaging (MRI) of the wrists was performed by means of a fast imaging sequence. Thirty-three women with RA and 42 controls were examined. The length of the carpal tunnel, the carpal tunnel volume/wrist volume (CTV/WV) ratio and the signal intensity of the nerve were calculated in both groups, bilaterally. The CTV/WV ratio was 0.12 in the patients and 0.11 in the control group (p = 0.007). A negative association was found between disease duration and carpal tunnel volume/wrist volume ratio (p = 0.049). Mean distal latency in the right motor median nerve was 3.0 +/- 0.4 msec (patients) and 3.4 +/- 0.6 msec (controls) (p = 0.002). Mean values in the right sensory branch were 1.2 +/- 0.1 msec (patients) and 1.4 +/- 0.3 (controls) (p = 0.01). The lack of association between the size of the carpal canal and neurophysiological parameters found in this study may suggest a possible protection of the median nerve by the increased canal size in patients with RA.

Nerve conduction studies in rheumatoid arthritis.

We performed a controlled study in search of possible differences in nerve conduction parameters in 52 patients with rheumatoid arthritis (RA) and 77 healthy controls. Nerve conduction studies (NCS) including recordings of motor and sensory amplitudes, the nerve conduction velocities and the distal latencies were investigated in both groups. The mean summed amplitude of compound muscle action potentials was 30.3 mV (SD = 7.9) in the patients compared with 35.9 mV (SD = 6.8) in the controls (p = 0.0001). Contrary to this, the mean values for motor distal latency was 14.3 msec (SD = 2.0) in the patients and 15.9 msec (SD = 1.8) in the controls (p = 0.0001). Decreased values for nerve conduction studies found in the patients may indicate impaired nerve functions in RA. However, the summed motor and sensory distal conduction were in fact better in the patient group.

The 3243 MELAS mutation in a pedigree with MERRF.

A mutation at base pair (bp) 3243 in mitochondrial DNA has been associated with mitochondrial myopathy, encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). A mutation at bp 8344 has been described as the cause of myoclonic epilepsy and ragged-red fiber disease (MERRF). Mitochondrial DNA was analyzed in a family with symptoms and signs consistent with MERRF. The DNA regions flanking bp 3243 and bp 8344 were amplified using the polymerase chain reaction, and the products were digested with restriction enzymes. The MELAS mutation at bp 3243 was found, but not the mutation at bp 8344. This illustrates the diverse clinical manifestations of the MELAS mutation.