[Myoclonus]

Myoclonus, an involuntary movement disorder reveals itself with a wide variety of short muscle twitches or jerks, and may cause severe disability. From a clinical perspective, it is sometimes difficult to discriminate myoclonus from other central movement disorders. Moreover, myoclonus has a spectrum of causes including rare neurological syndromes and uncommon manifestations of systemic disease. Its pathogenesis is only partially understood. Neurophysiologic investigations suggest a close relationship between certain types of myoclonic jerking and epilepsy. The use of anticonvulsants for treatment of myoclonus has its basis in such observations and empirical evidence. Often high doses or a combination of drugs, or both are required, with, however, serious side effects.

[Hepatic encephalopathy]

Hepatic encephalopathy (HE) is a neuropsychiatric complication of acute and chronic liver disease. Its etiology and pathogenesis are thought to be a complex, metabolically induced, and therefore potentially reversible disturbance in brain functions. The diagnosis is based on demonstrating both a disorder of the central nervous system and a concomitant liver disease as well as the exclusion of any neurological or psychiatric disorder of other etiology. The diagnosis of HE is clinical and displays a wide spectrum of neuropsychiatric symptoms in different degrees of severity. Ancillary diagnostic workup includes laboratory tests, neuroimaging, and neurophysiological exams such as electroencephalography and evoked potentials. The therapy of HE mainly consists of treatment and avoidance of any precipitating conditions such as high protein intake, infections, and gastrointestinal bleeding. Other therapeutic approaches modulate metabolic processes such as ammonium synthesis and excretion, formation of neurotransmitters, and as a last resort liver transplantation. The prognosis depends ultimately on the course of the liver disease.

Stiff man syndrome

Stiff man syndrome (SMS), an uncommon neurological disease, is characterised by symmetrical muscle stiffness and spasms that often lead to skeletal deformity. Variants of the syndrome may involve one limb only (stiff leg syndrome), a variety of additional neurological symptoms and signs such as eye movement disturbances, ataxia, or Babinski signs (progressive encephalomyelitis with rigidity and myoclonus), or be associated with malignant disease (paraneoplastic SMS). Antineuronal autoimmunity and accompanying autoimmune diseases, most often insulin-dependent diabetes mellitus, are characteristic features of SMS and its variants. The condition is frequently misinterpreted as psychogenic movement disturbance, but electromyographic abnormalities and the presence of autoantibodies against glutamic acid decarboxylase (GAD) in both serum and cerebrospinal fluid help to establish the correct diagnosis. The aetiology of SMS is obscure. However, several features suggest that SMS is an autoimmune-mediated chronic encephalomyelitis. In line with this hypothesis, immunomodulation with a front-loaded methylprednisolone regimen reduces stiffness and spasms and improves other neurological symptoms in the majority of patients. Plasmapheresis or intravenous immunoglobulins are effective less frequently. For symptomatic treatment, the benzodiazepines are drugs of first choice. An alternative of last resort is baclofen administered intrathecally via an implanted pump device.

Hypoxic brain damage after intramuscular self-injection of diclofenac for acute back pain

We present a case of hypoxic brain damage that occurred after intramuscular injection of diclofenac due to a severe anaphylactic reaction. A 38-year-old nurse treated herself for acute lower back pain with 100 mg diclofenac intramuscularly. Five minutes later, she collapsed and developed coma and respiratory arrest. After cardiopulmonary resuscitation she was transferred to hospital. On admission she was comatose and received controlled ventilation of the lungs. Magnetic resonance imaging and computerized tomography showed signs of hypoxic brain injury and the patient died from central cardiopulmonary failure 7 days later. Intramuscular treatment with non-steroidal anti-inflammatory drugs such as diclofenac has rare but potentially severe side-effects. Therefore, intramuscular injections are inappropriate and should be replaced with oral or rectal treatment, which has similar absorption profiles.

Interaction of tactile input in the human primary and secondary somatosensory cortex--a magnetoencephalographic study

Interaction of simultaneous tactile input at two finger sites in primary (SI) and secondary somatosensory cortex (SII) was studied by whole-head magnetoencephalography. Short pressure pulses were delivered to fingers of the right and left hand at an interstimulus interval of 1.6 s. The first phalanx of the left digit 1 and four other sites were stimulated either separately or simultaneously. We compared four sites with increasing distance: the second phalanx of left digit 1, left digit 5, and digits 1 and 5 of the right hand. The temporal evolution of source activity in the contralateral SI and bilateral SII was calculated using spatiotemporal source analysis. Interaction was assessed by comparing the source activity during simultaneous stimulation with the sum of the source activities elicited by separate stimulation. Significant suppressive interaction was observed in contralateral SI only for stimuli at the same hand, decreasing with distance. In SII, all digits of the same and the opposite hand interacted significantly with left digit 1. When stimulating bilaterally, SII source waveforms closely resembled the time course of the response to separate stimulation of the opposite hand. Thus, in bilateral simultaneous stimulation, the contralateral input arriving first in SII appeared to inhibit the later ipsilateral input. Similarly, the separate response to input at two unilateral finger sites which arrived slightly earlier in SII dominated the simultaneous response. Our results confirm previous findings of considerable overlap in the cortical hand representation in SII and illustrate hemispheric specialization to contralateral input when simultaneous stimuli occur bilaterally.

Antibodies against glutamic acid decarboxylase: prevalence in neurological diseases

High prevalence of autoantibodies against glutamic acid decarboxylase (GAD-Ab) in stiff man syndrome (SMS) not only helps diagnosis, but also suggests immune mediated impairment of GABAergic functions. However, the presence of GAD-Ab has also been reported in other neurological syndromes. Therefore the prevalence of GAD-Ab was investigated in SMS, progressive encephalomyelitis with rigidity and myoclonus (PERM), and in other neurological diseases (OND). Serum antibodies against the GAD isoforms, GAD65 and GAD67, were investigated with radioimmunoassays in 13 patients with SMS, nine with PERM, 279 consecutive patients with OND, and in 100 normal controls.

RESULTS

Prevalence of GAD65Ab was around 80% in patients with SMS/PERM compared with 5% in patients with OND and 1% in normal controls. Prevalence of GAD67Ab was 60% in SMS/PERM, 2% in patients with OND, and 1% in normal controls. Raised GAD-Ab clustered in an OND subgroup with sporadic progressive ataxia, but not in OND subgroups with recognised neuroimmunological diseases. In conclusion, increased GAD-Ab is neither a non-specific epiphenomenon of neuronal damage nor a common feature of recognised neuroimmunological disorders. In neurological diseases, GAD-Ab may be a pathogenetic agent or a marker for an ongoing autoimmune process, or both.

[Nocturnal spinal fracture--first manifestation of epilepsy]

A 54-year-old patient suffered overnight a double thoracic burst-fracture. One week later during the investigation for a metabolic or endocrinological cause, a witnessed seizure led to an unstable fracture of the humerus and the scapula. The neurological work-up revealed a cerebral astrocytoma as the epileptogenic focus. Forces generated during a tonic-clonic seizure can result in axial skeletal trauma, including thoracic and lumbar burst fractures. Vertebral fractures unrelated to an exogenous trauma are therefore always suspicious of an underlying epileptic disease.

Masking of vertebral artery dissection by severe trauma to the cervical spine

STUDY DESIGN

A prospective case study was performed.

OBJECTIVES

To illustrate the association of cervical trauma with vertebral artery dissection, and to propose a diagnostic and therapeutic algorithm for suspected traumatic vertebral artery dissection.

SUMMARY OF BACKGROUND DATA

Vertebral artery dissection is a recognized but underdiagnosed complication of trauma to the cervical spine. Symptoms of spinal cord injury, however, may obscure those of vertebral artery dissection, presumably causing gross underdiagnosis of this complication.

METHODS

All patients with vertebral artery dissection admitted to the authors' facility between 1992 and 1997 were screened for cervical trauma.

RESULTS

This article presents four patients with severe trauma to the cervical spine, defined as luxation, subluxation, or fracture, in whom symptoms of vertebral artery dissection developed after a delay ranging from several hours to weeks. The traumatic vertebral artery dissection typically was located at the site of vertebral injury or cranial to it. One patient with fracture of the odontoid process survived symptom free without ischemic brain infarctions. Another patient survived with traumatic quadriplegia in addition to large cerebellar and posterior cerebral artery infarctions. Two patients died as a result of fulminant vertebrobasilar infarctions, both with only moderate impairment from the primary spinal cord injury.

CONCLUSIONS

Early signs of vertebral artery dissection include head and neck pain, often localized to the site of intimal disruption, which may be disguised by the signs of the spinal injury. Early Doppler ultrasound and duplex sonography as a noninvasive screening method should be performed for patients with severe trauma to the cervical spine. In cases of vertebral artery dissection, immediate anticoagulation should be initiated. Traumatologists should be aware of this complication in evaluating patients with severe trauma of the cervical spine, and also for a variety of forensic reasons.

The effect of changing stimulus intensities on median nerve somatosensory-evoked potentials

We investigated median nerve somatosensory-evoked potentials (SEP) in 31 healthy volunteers to test the hypothesis that 1) increasing stimulus intensity influences SEP components in both amplitude and latency 2) SEP components respond differently to changing intensities. Cluster analysis and analysis of variance were used for statistical testing. Three groups of components could be found according to latency changes in response to increasing stimulus intensities: N13, and P15, the primary cortical response (N19, P22) and the components over 30 ms. In general, SEP components below 30 ms significantly shortened in latency and increased in amplitude with subsequent saturation. In contrast, in components over 30 ms latencies decreased linearly and amplitudes changed inhomogeneously. The clear effect of stimulus intensity on most median nerve SEP components makes it necessary to maintain comparable stimulus intensities when comparing intra- and interindividual registrations.

Workshop I: Parkinson's disease and sleep--results of the group discussion

The group agreed on the facts that unwanted sleep onset has been observed after non-ergot as well as ergot dopamine agonists, that patients on these drugs need to be warned, that patients who have experienced sleepiness already must not drive a car unless the dosage is lowered and sleepiness has vanished, that a genetic predisposition for narcoleptic cataplexy has to be ruled out, that predictors of so-called sleep attacks need to be explored individually with the help of sleepiness scales and collectively in a careful study, respectively.

Magnetic source imaging of tactile input shows task-independent attention effects in SII

We investigated whether attention to different stimulus attributes (location, intensity) has different effects on the activity of the secondary (SII) somatosensory cortex. Tactile stimuli were applied to the left index finger and somatosensory evoked fields (SEFs) were recorded using a whole-head magnetoencephalography (MEG) system. Two oddball paradigms with stimuli varying in location or intensity were performed in an ignore and an attend condition. Brain sources were estimated by magnetic source imaging. No attention effect was observed for the primary SI area. However, attention enhanced SII activity bilaterally from 55 to 130 ms by 52% in the spatial and 64% in the intensity discrimination task. SII attentional enhancement was very similar in both paradigms and occurred both for deviants and standards.

Diagnostic accuracy of MRI compared to CCT in patients with brain metastases

OBJECTIVES

In patients with extracranial neoplasms, the occurrence and number of brain metastases (BM) are critical for further diagnostic approaches and therapeutic strategies and the patient's prognosis. Although widely accepted, there is surprisingly little evidence in the literature that MRI is superior to CCT. Therefore, in patients with solitary BM according to diagnostic contrast-enhanced computed tomography (CCT), we investigated, what additional information could be gained by contrast-enhanced magnetic resonance imaging (MRI).

METHODS/RESULTS

Among 55 patients with solitary BM according to CCT, 17 had multiple BM on MRI (31%) and 38 had solitary BM in both. Based on a presumed binomial distribution of our data, we calculated a rate of at least 19% of patients with solitary BM on CCT, in which MRI would show multiple lesions (p = 0.05). The two main characteristics for BM missed by CCT were the smaller diameter, which averages 2 cm less than in BM identified with both modalities, and a preferential frontotemporal location.

CONCLUSION

MRI is indeed superior to CCT in the diagnosis of BM the essential reasons besides detection of smaller lesions being a better soft tissue contrast, significantly stronger enhancement with paramagnetic contrast agents, the lack of bone artifacts, fewer partial volume effects, and direct imaging in three different planes. Therefore, MRI is indispensable in the diagnostic workup of patients with BM for choosing the optimum therapeutic approach, especially with regard to the decision whether to operate or to primarily irradiate the patient's metastases.

[Dystonia following peripheral trauma: clinical findings and diagnostic criteria]

Dystonia is a rare neurological complication after peripheral trauma. Incidence and pathophysiology of post-traumatic dystonia are not known. Predisposing factors are sympathetic reflex dystrophia, pre-existing movement disorders or a family history of movement disorders. The main diagnostic goal is to exclude other causes of secondary dystonia. Objective criteria for posttraumatic dystonia are not established, and therefore differentiation from psychogenic dystonia frequently remains difficult. Careful psychiatric examination is obligatory. Clinical criteria are consistency of the symptoms over time and the presence of symptoms compatible with organic dystonia. Polygraphic EMG examinations provide objective correlates of the movement disorder, but exact EMG criteria for the diagnosis of dystonia have yet to be established.

Gating of segmental and transcortical reflexes to human hand muscles depends on the mode of innervation

We investigated the influence of the innervation pattern on the transmission of reflexes to a hand muscle. Reflexes were elicited by repetitive median nerve stimulation and recorded from the abductor pollicis brevis muscle. Both H and long loop reflexes were exclusively attenuated by irregular isotonic thumb abduction. In 10 of 15 experiments the long loop reflex was blocked completely. Inhibition intercalated between the H and long loop reflexes also decreased considerably. The observed attenuation of both spinal and supraspinal reflexes is suspected to take place mainly at the spinal level. Among the possible mechanisms, reciprocal inhibition is the most likely.

Epitope spreading and a varying but not disease-specific GAD65 antibody response in Type I diabetes. The Childhood Diabetes in Finland Study Group

AIMS/HYPOTHESIS

The aim of this study was to analyse the conformational and linear epitope profiles of glutamic acid decarboxylase antibody (GAD65-ab)-positive sera to find disease-specific epitope profiles and to study, whether GAD65-ab epitope recognition changes or spreads during the prediabetic period and, thus, can provide markers to differentiate early from later stages of progression to diabetes.

METHODS

Sera from subjects before (n = 21), at onset (n = 44), or at increased risk of Type I (insulin-dependent) diabetes mellitus (n = 20) and from patients with stiff-man syndrome (SMS, n = 18) or polyendocrine autoimmune syndrome (PAS, n = 21) were analysed for conformational and linear GAD65 epitope recognition by an immunohistochemical blocking test based on human monoclonal GAD65-ab (MICA 1-10) and western blotting of a GAD65 epitope-cDNA-library.

RESULTS

A redundant reactivity of many GAD65-ab positive sera to three major conformational (EP-1, EP-2, EP-3) and two dominant linear epitope clusters (amino acid 1-124 and 535-585) was observed in diabetes, polyendocrine autoimmune syndrome and stiff-man syndrome and no disease-specific epitopes or epitope-profiles were detected. Epitope recognition broadened with higher titres and with the vulnerability of patients to acquire additional autoimmune diseases apart from diabetes. Low GAD65-ab serum titres (< 1200 arbitrary units) and EP-1 recognition in the absence of EP-2 binding characterised the early immune response. Changing epitope profiles combined stable recognition of EP-1 with gain or loss of reactivity to C-terminal epitopes during follow-up.

CONCLUSION/INTERPRETATION

A maturing autoantibody response, which could spread from EP-1-recognition to other regions of GAD65, resulted in titre-related rather than disease-specific epitope profiles which were not sufficient to predict whether GAD65-ab positive subjects will progress to Type I diabetes, autoimmune polyendocrine syndrome or stiff-man syndrome.

[Late myelopathy after chemonucleolysis. Case report and review of the literature]

Chemonucleolysis is a debated therapeutic method for herniated lumbar disc. We report a patient who suffered a sequence of characteristic sequels cumulating in late-onset myelopathy with persistent spastic paraplegia, sensory loss below T8 and bladder incontinence. Complications of chemonucleolysis are less frequent as compared to herniated disc surgery, but may cause severe impediment. Serious complications are anaphylactic shock, intracranial or spinal hemorrhage and transverse myelitis. This has to be taken into account for indication and patient information.

The "CMT rat": peripheral neuropathy and dysmyelination caused by transgenic overexpression of PMP22

We have generated a transgenic rat model of Charcot-Marie-Tooth disease type 1A (CMT1A) providing formal proof that this neuropathy can be caused by increased expression of peripheral myelin protein-22 (PMP22). Heterozygous PMP22-transgenic rats develop muscle weakness and gait abnormalities as well as reduced nerve conduction velocities and EMG abnormalities, which closely resemble recordings in patients with CMT1A. Dys- and demyelination, Schwann cell hypertrophy, and "onion bulb" formation are also similar to findings in humans. When bred to homozygosity, transgenic rats completely fail to elaborate myelin, but all myelin-forming Schwann cells segregate with axons in the normal one-to-one ratio. Although arrested at this "promyelin" stage, differentiation proceeds in homozygous rats at the molecular level, as demonstrated by high-level expression of myelin structural genes. Intracellular trafficking of the wild-type protein is not visibly impaired, even when strongly overexpressed, suggesting that PMP22 blocks myelin assembly in a late Golgi/cell membrane compartment of the affected Schwann cell.

[Neuralgic neuropathies--complex pathogenesis and therapy. Trigeminal neuralgia--neuralgic shoulder amyotrophy--post-herpetic neuralgia]

A wide spectrum of manifestations and causes makes the diagnosis of neuralgic neuropathies difficult. In most cases, however, clinical and/or electrophysiological signs of a peripheral nerve disorder can be established. The pathomechanisms underlying pain are complex and not fully understood. They are not limited to the site of a lesion, but encompass the entire peripheral neurone, and may even involve the central neurones. Pathobiological correlates of chronic pain have been identified to involve the entire pain-mediating neuronal pathway.

Immune-mediated retinopathy in a patient with stiff-man syndrome

BACKGROUND

Stiff-man syndrome is a rare neurological disorder characterised by rigidity and violent spasms of the body musculature. In the majority of patients, presence of antibodies against glutamic acid decarboxylase (GAD), the enzyme synthesizing gamma-aminobutyric acid (GABA), suggests an autoimmune attack against GABA-ergic inhibitory neurons. We report a 32-year-old patient with stiff-man syndrome and anti-GAD antibodies who developed subacute progressive loss of vision in the right eye, and in the left eye 18 months thereafter.

METHODS

Ophthalmological work-up included electro-retinogram (ERG), visual evoked potentials (VEP) and fluorescein angiography. Antiretinal antibodies were investigated using an indirect immunofluorescence technique on frozen sections of macaque retina with patients serum and FITC-conjugated goat antihuman immunoglobulin. Staining with monoclonal anti-GAD65 antibodies and with serum from three healthy normals served as controls.

RESULTS

Visual acuity of both eyes decreased to 0.16 within a span of 6 weeks. Perimetry revealed a central scotoma in the visual field of both eyes. VEP and flash ERG were progressively disturbed on the right eye. On the left eye, initially only pattern ERG and photopic responses were abnormal. Follow-up recordings revealed widespread pathology of photopic single and flicker responses. Immunofluorescence revealed strong reactivity of the inner plexiform layer and to a lesser extent staining of the outer plexiform layer at dilutions of 1:1000 with patients serum. The same retinal staining pattern was obtained with monoclonal anti-GAD65 antibodies.

CONCLUSIONS

These findings suggest autoimmune retinopathy, mediated by anti-GAD65 autoantibodies as the underlying cause of visual loss.

Novel GLRA1 missense mutation (P250T) in dominant hyperekplexia defines an intracellular determinant of glycine receptor channel gating

Missense mutations as well as a null allele of the human glycine receptor alpha1 subunit gene GLRA1 result in the neurological disorder hyperekplexia [startle disease, stiff baby syndrome, Mendelian Inheritance in Man (MIM) #149400]. In a pedigree showing dominant transmission of hyperekplexia, we identified a novel point mutation C1128A of GLRA1. This mutation encodes an amino acid substitution (P250T) in the cytoplasmic loop linking transmembrane regions M1 and M2 of the mature alpha1 polypeptide. After recombinant expression, homomeric alpha1(P250T) subunit channels showed a strong reduction of maximum whole-cell chloride currents and an altered desensitization, consistent with a prolonged recovery from desensitization. Apparent glycine binding was less affected, yielding an approximately fivefold increase in Ki values. Topological analysis predicts that the substitution of proline 250 leads to the loss of an angular polypeptide structure, thereby destabilizing open channel conformations. Thus, the novel GLRA1 mutant allele P250T defines an intracellular determinant of glycine receptor channel gating.

Lack of effect of oral Mg-supplementation on Mg in serum, blood cells, and calf muscle

Magnesium (Mg) is important for regulating ion transport and cellular metabolism in all body tissues. In skeletal muscle Mg is involved in the neuromuscular activity, excitation, and muscle contraction. Mg deficiency can cause muscle weakness and muscle cramps. Less than 1% of total body Mg is found in serum, yet the serum Mg concentration is used to assess the body's Mg status.

PURPOSE

The purpose of this study was to determine whether an oral Mg supplementation (500 mg Mg-oxide.d-1 for 3 wk) affects exercise performance, clinical symptoms, and the Mg concentration in various body compartments in athletes with low-normal serum Mg levels (N = 10 in each group).

METHODS

In a double-blind, placebo-controlled study, correlation analysis between the Mg concentration in serum, blood cells, and skeletal muscle was performed to establish a measure for muscle cell Mg.

RESULTS

The data indicate that a 3-wk Mg supplementation did not affect exercise performance, neuromuscular activity, or muscle related symptoms. Also, the supplementation did not increase the Mg concentration in serum or any cellular compartment studied. However, in the placebo group the renal Mg clearance decreased, whereas it increased in the subjects receiving Mg supplementation. Correlation analysis revealed that serum Mg only correlated with red cell Mg and that only leukocyte Mg correlated with the nuclear magnetic resonance (NMR)-measured muscle cell Mg concentration.

CONCLUSIONS

These results indicate that Mg supplementation in athletes with low-normal serum Mg did not improve performance and failed to increase the body's Mg stores. Serum Mg appears to be a poor indicator for Mg in skeletal muscle or most other cellular compartments, but the concentration of Mg in mononuclear leukocytes might be used as an indicator of skeletal muscle Mg when NMR is not available.

D2 receptor binding in dopa-responsive dystonia

We have studied dopamine D2 receptor binding by [11C]raclopride positron emission tomography in 14 patients with dopa-responsive dystonia (DRD). Data were compared with 16 levodopa-treated patients with Parkinson's disease (PD) and 26 healthy controls. The results revealed an elevated [11C]raclopride binding index in the putamen and caudate nucleus of DRD patients compared with controls as well as a significant elevation in the caudate nucleus compared with PD patients. The increase of [11C]raclopride binding may be interpreted either as reduced tracer displacement by endogenous dopamine, or as an alteration of the receptor features due to chronic dopamine deficiency. The difference in [11C]raclopride binding in DRD and PD patients in the caudate nucleus suggests that this structure may be of pathophysiological relevance in the presentation of the clinical features of both diseases.

[Polygraphic validation of distraction tasks in clinical differential tremor diagnosis]

In a total of 30 tremor patients (14 with Parkinson's disease, 6 with cerebellar tremor, 4 with essential tremor, 4 with psychogenic tremor, 2 with enhanced physiological tremor), tremor was electromyographically recorded before, during and after contralateral distraction tasks (tapping with the index finger or the tip of the foot, sequential flexion of the 2nd to 5th finger towards the thumb, "keyboarding", and sensory discrimination). 22 of 26 patients with organic tremors spontaneously choose a volitional tapping frequency independent from their tremor frequency. In 4 patients with psychogenic tremor, frequencies of tremor and tapping were locked (n = 3), or tremor disappeared abruptly (n = 1) when contralateral tapping was started. Contralateral "keyboarding" and sensory discrimination revealed no clear differences between organic and psychogenic tremors. Contralateral tapping in further 23 patients (22 with organic tremors and 1 with psychogenic tremor) confirmed these findings. Contralateral tapping appears as the most valid distraction task and may help to differentiate psychogenic from organic tremors.

Neurological outcome in adult patients with early-treated phenylketonuria

Due to the observation of severe neurological symptoms in single patients as well as brain imaging, neuropsychological and neurophysiological abnormalities, the long-term prognosis of treated phenylketonuria is still under discussion. We investigated the neurological outcome of 57 (24 male, 33 female) patients with phenylketonuria (diet onset < 3 months) at a mean age of 23.6 (17-33) years in comparison to control subjects. Methods used were a clinical-neurological examination, tests for fine motor abilities, IQ test (WAIS-R), a neuropsychological attention task and MRI (30 patients only). Tremor was increased in the patients (28%) compared to controls (15%). Fine motor abilities were significantly reduced in three areas: hand-wrist steadiness, finger-hand dexterity and hand-wrist speed. Tremor as well as reduced fine motor skills were not associated with treatment-related variables, e.g. diet onset, strictness of biochemical control or amount of MRI white matter change. IQ was lower in patients (mean 97.6) compared to matched control subjects (mean 105.5). IQ at 12 years was correlated with biochemical control from birth up to the age of 12 and remained stable up to adult age, independent of biochemical control after 12 years of age. In contrast to the other outcome parameters, the performance in a neuropsychological attention task was influenced by the concurrent plasma phenylalanine concentration. Specific late-onset neurological impairment was not identified in this sample of early-treated adults with phenylketonuria.

CONCLUSION

Careful neurological investigation revealed subtle symptoms of brain damage even after early-initiated treatment in adult patients with phenylketonuria. At present it cannot be excluded that further neurological deterioration could emerge later in life. Thus, patients with phenylketonuria - either on or off diet - should be monitored throughout life.

Inhibition of gamma-aminobutyric acid synthesis by glutamic acid decarboxylase autoantibodies in stiff-man syndrome

Stiff-man syndrome (SMS) is a rare disorder of the central nervous system thought to result from an impairment of gamma-aminobutyric acid (GABA)ergic neurotransmission. Autoantibodies to the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD), present in about 60% of SMS patients, have suggested an autoimmune pathogenesis of SMS. By using serum or cerebrospinal fluid from 25 SMS patients, we assessed the effect of GAD autoantibodies (GAD-A) on GAD enzymatic activity in vitro; 83% of GAD-A-positive SMS sera reduced GABA production in crude rat cerebellar extracts, whereas GAD-A- sera from SMS patients or healthy blood donors did not alter the enzyme activity. Inhibition of GABA synthesis by SMS sera was dose dependent and mediated by the purified IgG fraction of the sera. Human monoclonal GAD65-A and IgG purified from serum of GAD-A-positive patients with insulin-dependent diabetes or autoimmune polyendocrine syndrome did not affect GAD activity, suggesting that a specific epitope recognition of GAD-A mediates inhibition of GAD. The disease-specific detection of GAD-inhibitory antibodies is compatible with their functional involvement in the etiopathology of SMS; the relevance of such antibodies in vivo, however, remains to be determined.

Stiff-man syndrome: an overview

Fluctuating stiffness and paroxysmal spasms of the trunk and legs are the primary features of stiff-man syndrome and it's variants, progressive encephalomyelopathy with rigidity and myoclonus (PERM) and stiff-leg syndrome. The spasms characterized by hyperextension of the back and legs are both spontaneous as well as stimulus-sensitive. They can be excruciatingly painful and are frequently accompanied by symptoms of autonomic dysregulation. Hyperreflexia may be the only pathological finding on the neurological examination. Most patients show psychiatric disturbances suggestive of psychogenic movement disorder and this may cause delays in adequate pharmacotherapy. The disease progresses over the span of months to years rendering many patients wheelchair-bound or bedridden. GABA-mimetics are most effective in treating symptoms, but tolerance and life-threatening withdrawal symptoms are common drawbacks. For therapy-refractory patients, intrathecal baclofen represents a good alternative. The diagnosis is based on clinical, biochemical and electrophysiological findings. Spasmodic reflex myoclonus is observed in nearly all SMS patients. It consists of well-reproduced reflex EMG-activity commencing 50-80 ms after medial or tibial nerve stimulation and lasting several seconds thereafter. The activity is first myoclonic then spasmodic in nature, and commonly begins in the muscles most severely affected before spreading bidirectionally along the neuraxis. Spasmodic reflex myoclonus and the high incidence of antibodies against GAD are suggestive of an autoimmune disorder affecting GABAergic neurons in the spinal cord, but the precise locus of dysfunction remains to be elucidated.

Stiff-man syndrome in a woman with breast cancer: an uncommon central nervous system paraneoplastic syndrome

We report a patient who developed stiff-man syndrome, including disabling shoulder subluxation and wrist ankylosis, in association with breast cancer. Immunologic investigations disclosed autoimmunity directed against not only glutamic acid decarboxylase but also amphiphysin, a 128-kd protein located in the presynaptic compartment of neurons. The patient improved after surgery and corticosteroid treatment and has been stable for nearly 4 years on only anti-estrogenics. The triad of stiff-man syndrome, breast cancer, and autoantibodies against amphiphysin identifies a new autoimmune paraneoplastic syndrome of the CNS.

DNA-fragmentation and apoptosis-related proteins of muscle cells in motor neuron disorders

Apoptosis has been described as one of the mechanisms of muscle fiber loss in infantile spinal muscular atrophy. In order to investigate if muscle fiber-apoptosis plays a role in other denervating disorders as well, we studied DNA-fragmentation, a hallmark of apoptosis, by the TUNEL-method and, moreover, the expression patterns of apoptosis-related proteins in 2 patients suffering from ALS and in 6 patients with polyneuropathy. We identified DNA-cleavage in muscle fibers of all these patients. Furthermore, we found strong expression of bax and ICE promoting apoptosis in muscle fibers. However, also strong expression of the anti-apoptotic factor bcl-2 was found. Our findings indicate that defective innervation may prompt muscle fibers to activate an intrinsic "suicide" programme which is promoted by the proapoptotic factors bax and ICE, which seems to induce formation of apoptotic bodies by cleavage of actin. Nevertheless, there are also anti-apoptotic strategies in muscle fibers manifested by expression of the bax-antagonist bcl-2 which is able to neutralize high bax levels.

Muscular involvement in the Holt-Oram syndrome

Holt-Oram syndrome is an autosomal dominant disorder characterised by radial ray and congenital heart defects. Recently, a gene for this disorder has been identified on chromosome 12q24.1, encoding a T box transcription factor. However, the functional role of the gene product is not completely understood. We present results of neurological, radiological, and muscle magnetic resonance imaging (MRI) investigations in 13 patients from eight unrelated families. Besides heart defects, clinical signs ranged from thenar abnormalities to bilateral phocomelia. The former were present in all patients. MRI showed hypoplasia of discrete muscles which clinically showed as non-progressive weakness. The structural pattern of residual muscles was normal on MRI, which together with normal muscular power, electromyography, and muscle enzyme investigations excluded a progressive neuromuscular disorder. The number and location of hypoplastic muscles correlated with the severity of skeletal involvement. Thus, patients with hypoplasia of large and proximal muscles had phocomelia, and those with mere intrinsic hand muscle hypoplasia had only a triphalangeal thumb or no skeletal malformation. On the basis of these observations, we conclude that disturbed fetal limb muscle development is involved in the bony malformations of the upper limbs.

Intrathecal baclofen therapy for stiff-man syndrome and progressive encephalomyelopathy with rigidity and myoclonus

We report on eight patients with stiff-man syndrome (SMS) or its "plus" variant, progressive encephalomyelopathy with rigidity and myoclonus (PERM) receiving intrathecal baclofen via pump. In six of the patients, follow-ups continued for approximately 2.5 to 6.5 years after pump implantation. Intrathecal baclofen was an effective last-resort alternative for patients who responded poorly to or did not tolerate oral antispasticity medications. General mobility increased, and spasms and rigidity were reduced; however, no complete remissions were observed either before or after pump implantation. PERM patients showed more severe and rapid progression of symptoms and more attacks of autonomic dysregulation than SMS patients. They also required higher doses and more rapid dosage increases. Complications of intrathecal baclofen therapy included spasm-induced rupture of the catheter, catheter dislocation causing radicular symptoms, and pump malfunction resulting in inaccurate dosage administration. Patients suffered fewer side effects with intrathecal baclofen than with oral medication, but overdose resulted in a transient, comalike state in one patient and sudden dosage reduction due to pump failure was fatal in another.

Antibodies to the tyrosine phosphatase-like protein IA-2 are highly associated with IDDM, but not with autoimmune endocrine diseases or stiff man syndrome

Antibodies to the 40 kD antigen (identified as tyrosine phosphatase IA-2) and glutamate decarboxylase (GAD65) are strongly associated with insulin dependent diabetes mellitus (IDDM). However, antibodies to GAD (GADA) can appear in the absence of IDDM, particularly in stiff man syndrome (SMS) and in some individuals with autoimmune polyendocrine syndrome type II (APS II) and organ specific autoimmune diseases. The aim of this study was to compare the specificity of IA-2 antibodies (IA-2A) and GADA for IDDM by determining their frequency in different patient groups. IA-2A were present in 64/114 (56%) IDDM patients and 9/19 (47%) APS II patients with IDDM but in only 4/28 (14%) SMS patients. 1/24 (4%) APS II patients without IDDM and 1/113 (0.9%) patients with organ specific autoimmune disease had low level IA-2A. In contrast GADA were present in 77/114 (68%) IDDM patients and 17/19 (89%) APS II patients with IDDM, but also in 25/28 (89%) SMS patients, 5/24 (21%) APS II patients without IDDM and 22/113 (19%) patients with organ specific autoimmune diseases. Furthermore, within the group of new onset IDDM, IA-2A seemed to be associated with ICA and age: 63% of ICA positive IDDM patients had IA-2A (74% had GADA) increasing to 77% in the group below 20 years of age (69% for GADA). Our results demonstrate that IA-2A may be more specific for IDDM than GADA, as the latter are also present in patients with SMS, APS II without IDDM and organ specific autoimmune diseases. IA-2A were less frequent in older patients with IDDM than GADA or ICA. A combination of IA-2A and GADA detected 84% of total and 93% of ICA positive IDDM patients.

Myotonic dystrophy. The role of large triplet repeat length in the development of mental retardation

OBJECTIVE

To describe mental retardation and microcephaly as initial clinical signs in myotonic dystrophy (MD) with high trinucleotide repeats.

PATIENTS AND METHODS

Two patients with maternally inherited MD were examined. Southern blot analysis was performed and trinucleotide repeat expansions were related to the findings of clinical and magnetic resonance imaging investigations.

RESULTS

Both patients had the large CTG trinucleotide repeat expansions often seen in congenital MD, but they lacked the typical clinical signs. Mental retardation and microcephaly were the leading features present in infancy. Muscular weakness, in contrast, developed after age 35 years. Although there was no evidence for perinatal asphyxia or sleep apnea, magnetic resonance imaging disclosed reduced brain volume and subcortical demyelination.

CONCLUSIONS

Mental retardation preceding the development of muscle weakness suggests that the cerebral involvement in MD is a direct consequence of the genetic disorder and not mediated by muscle disease. Careful clinical examination of the parents for signs of MD should be considered in patients with cognitive deficits even without apparent muscular involvement.

Progressive cerebellar ataxia, proximal neurogenic weakness and ocular motor disturbances: hexosaminidase A deficiency with late clinical onset in four siblings

Tay-Sachs disease is a genetically determined neurodegenerative disorder, resulting from mutations of the hexosaminidase (Hex) A gene coding for the alpha-subunit of beta-D-N-acetyl-hexosaminidase. Clinically, there is severe encephalomyelopathy leading to death within the first few years of life. Hex A activity is usually absent in tissue and body fluids of these patients. Juvenile and adult Hex A deficiencies are less severe but rare variants with some residual Hex A activity. All these variants are most prevalent among Ashkenazi Jews. We describe a non-Jewish family in which four adult brothers and sisters had markedly reduced Hex A activities and onset of symptoms in the second decade of life. The phenotypical expression was remarkably homogeneous, consisting in a combination of slowly progressive motor neuron disease, ataxia and ocular motor disturbances. None of the patients were demented at this stage of their illness. Magnetic resonance studies showed severe cerebellar atrophy, but were otherwise normal. Hex A deficiency was established by biochemical measurements in the serum and skin fibroblasts using the fluorogenic substrates 4-MUG and 4-MUGS as well as by gel electrophoresis. Molecular genetic studies revealed that the patients are compound heterozygotes for the 'adult' mutation Gly269 --> Ser and the 'infantile' 4-base insertion in exon 11 of the Hex A gene.

Proximal myotonic myopathy with MRI white matter abnormalities of the brain

Proximal myotonic myopathy (PROMM) is an autosomal dominantly inherited multisystemic disorder characterized by myotonia, proximal muscle weakness, and cataracts. This disorder is not linked to the gene locus of myotonic dystrophy (DM). We describe three new families with PROMM. In all patients, CTG repeats of the DM gene in DNA from blood leukocytes were normal. MRI of the brain revealed a consistent pattern of marked white matter hyperintensity on T2-weighted images in four patients; two additional patients had similar but mild to moderate MRI abnormalities. The morphology of these abnormalities is unknown. Clinical symptoms of brain disease were not consistent and included mental changes with hypersomnia, parkinsonian features, stroke-like episodes, and seizures. The causative relationship of these clinical features with the MRI white matter abnormalities remains to be established. Our observations suggest that PROMM may involve the brain.

Meningeal involvement in Wegener's granulomatosis confirmed and monitored by positive circulating antineutrophil cytoplasm in cerebrospinal fluid

MRI and CSF investigations revealed meningeal involvement in a 29-year-old patient with biopsy-confirmed Wegener's granulomatosis. The intracranial manifestation of Wegener's granulomatosis was supported by the detection of pathologic circulating antineutrophil cytoplasm (c-ANCA) in the CSF. We monitored disease activity by c-ANCA measurement in the CSF. After repeated cycles of intrathecal administration of methotrexate and corticoids, progression of meningeal infiltration stopped, and CSF c-ANCA titers became negative.

Three familial cases presenting with an immobile spine. Rigid spine or Emery-Dreifuss syndrome?

A father and his two sons presented with slowly progressive muscular weakness, contractures of the spine, elbows and ankles, and cardiac conduction disturbances in the father. Clinical and histological findings are discussed in relation to the hitherto reported cases of autosomal dominant variant of the Emery-Dreifuss syndrome and the distinction from the rigid spine syndrome.

Psychological factors in the diagnosis and pathogenesis of stiff-man syndrome

Retrospective psychological evaluation of nine patients with stiff-man syndrome (SMS), seven of whom evidenced autoimmune disease, revealed a characteristic set of psychological symptoms or features: Major stressful life events preceded the development of permanent symptoms by 6 months or less (seven patients); transient motor symptoms occurred in emotionally distressing situations months or even years before the onset of a permanent motor deficit (five patients); after onset, similar situations specifically precipitated or augmented stiffness and spasms (five patients). We also found task-specific fear resembling agoraphobia (six patients) and loss or invalidation of one or both parents, or loss of home, in childhood (seven patients). Eight patients were initially misdiagnosed as having psychogenic movement disorder. We conclude that the common misdiagnosis of SMS as a psychogenic movement disorder is due to the compelling association of a set of salient psychological features, bizarre and fluctuating motor symptoms, and lack of approved neurologic signs.

Köbberling-Dunnigan syndrome: a rare cause of generalized muscular hypertrophy

A 36-year-old woman presented with muscle hypertrophy (particularly of the calves) since puberty, occasional muscle cramps, a musculine habitus, and a loss of subcutaneous fat on limbs and trunk sparing her face, neck, and vulva. Multiple lipomas were found on her trunk, and acanthosis nigricans on her neck. Laboratory testing revealed hyperlipidemia and pathological glucose tolerance with hyperinsulinemia. Physical and laboratory findings are consistent with Köbberling-Dunnigan syndrome, a rare inherited form of lipoatrophy. The patient's mother had the same body habitus and insulin-dependent diabetes mellitus. These cases suggest that partial lipodystrophy also affects muscle and is a cause of genuine muscular hypertrophy.

A GLRA1 null mutation in recessive hyperekplexia challenges the functional role of glycine receptors

Dominant missense mutations in the human glycine receptor (GlyR) alpha 1 subunit gene (GLRA1) give rise to hereditary hyperekplexia. These mutations impair agonist affinities and change conductance states of expressed mutant channels, resulting in a partial loss of function. In a recessive case of hyperekplexia, we found a deletion of exons 1-6 of the GLRA1 gene. Born to consanguineous parents, the affected child is homozygous for this GLRA1(null) allele consistent with a complete loss of gene function. The child displayed exaggerated startle responses and pronounced head-retraction jerks reflecting a disinhibition of vestigial brain-stem reflexes. In contrast, proprio- and exteroceptive inhibition of muscle activity previously correlated to glycinergic mechanisms were not affected. This case demonstrates that, in contrast to the lethal effect of a null allele in the recessive mouse mutant oscillator (Glra1 spd-ot), the loss of the GlyR alpha 1 subunit is effectively compensated in man.

A transgenic rat model of Charcot-Marie-Tooth disease

Charcot-Marie-Tooth disease (CMT) is the most common inherited neuropathy in humans and has been associated with a partial duplication of chromosome 17 (CMT type 1A). We have generated a transgenic rat model of this disease and provide experimental evidence that CMT1A is caused by increased expression of the gene for peripheral myelin protein-22 (PMP22, gas-3). PMP22-transgenic rats develop gait abnormalities caused by a peripheral hypomyelination, Schwann cell hypertrophy (onion bulb formation), and muscle weakness. Reduced nerve conduction velocities closely resemble recordings in human patients with CMT1A. When bred to homozygosity, transgenic animals completely fail to elaborate myelin. We anticipate that the CMT rat model will facilitate the identification of a cellular disease mechanism and serve in the evaluation of potential treatment strategies.

"Sunbath polyneuritis": subacute axonal neuropathy in perazine-treated patients after intense sun exposure

This article aims at drawing attention to the peculiar association of intense exposure to sunlight and subacute development of sensory neuropathy which was seen in 7 psychiatric patients treated with the phenothiazine derivative, perazine. Three patients additionally developed bilateral VII nerve palsy. Symptoms followed a monophasic course with almost complete remission. Routine neurophysiology suggested axonal neuropathy confirmed by sural nerve biopsy in 1 patient. A toxic origin of neuropathy is supposed, possibly induced by phenothiazine photoproducts, which may cause cell damage via lipid peroxidation.

Masseter inhibitory reflex threshold: a novel technique for electrophysiological investigation of trigeminal nerve lesions

The masseter inhibitory reflex was investigated in 60 healthy volunteers, in 38 patients with trigeminal nerve branch lesions in the majority due to dental surgery, and in 9 patients with facial sensory loss and weakness caused by brain hemisphere lesions. The reflex threshold (TR) was almost symmetric both in normal subjects and in the patients with hemisphere lesions. In peripheral trigeminal hypaesthesia, elevation of TR on the lesioned side proved the most sensitive electrophysiological parameter. There was, moreover, some correspondence between the degree of sensory loss in hypaesthesic skin areas and elevation of TR, and recovery from the lesion was associated with TR normalization. Supratentorial lesions, in contrast, may influence the reflex pattern rather than reflex excitability.

Two sisters with Escobar syndrome

We report on 2 sisters with an autosomal-recessive multiple pterygium syndrome, type Escobar, consisting of multiple pterygia with severe contractures, short stature, and minor facial and external genital anomalies. The striking finding was severe muscular atrophy. We speculate that a neuromuscular disorder is the underlying pathogenesis of Escobar syndrome.