Gert van Dijk

Defining and classifying syncope.

Abstract.There is no widely adopted definition or classification of syncope and related disorders. This lack of uniformity harms patient care, research, and medical education. In this article, syncope is defined as a form of transient loss of consciousness (TLOC) due to cerebral hypoperfusion. Differences between syncope and other causes of TLOC such as epilepsy, and disorders mimicking TLOC are described. A pathophysiological classification of syncope is proposed.

Development of weakness in patients with chronic inflammatory demyelinating polyneuropathy and only sensory symptoms at presentation: a long-term follow-up study.

Abstract This long-term follow-up study examined patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and only sensory symptoms at first presentation, with emphasis on the development of motor symptoms and long-term disability. From all CIDP patients referred to our Department between 1987 and 1995, seven had only sensory symptoms at first clinical presentation. These were investigated according to a standard protocol, including a quantified clinical neurological examination and nerve conduction studies. The mean duration of the disease before weakness developed was 3.1 years, but varied considerably (0.8–6.3 years). At follow-up, weakness developed in five patients and persisted in three of them. Five patients were not seriously incapacitated by their disease (Rankin 1 or 2), four of them being in remission now and one showing a very slow progression of disease. Two patients were moderately disabled (Rankin 3); one had severe persistent sensory ataxia and only weakness during relapses and one had stepwise progression and moderate weakness. Motor nerve conduction studies revealed that the most notable worsening in the entire group of patients was a decrease in distal compound muscle action potential amplitudes, indicating the development of distal conduction block or axonal degeneration. These findings show that CIDP with only sensory symptoms is a transient clinical stage that precedes the appearance of weakness in about 70% of patients. The long-term prognosis does not differ from that of patients with CIDP who have weakness at the beginning of the disease.

Sensory neuropathies including painful and toxic neuropathies

In most peripheral neuropathies, dysfunction of motor and sensory nerve fibres is present. However, in some of them either pattern may predominate or be exclusively present. In this review we describe the clinical characteristics of sensory neuropathies, with emphasis on their possible causes. Guidelines are given for the diagnostic approach in these patients and, where possible, suggestions are given for treatment, including symptomatic treatment of painful neuropathies.

Memory activation reveals abnormal EEG in preclinical Huntington's disease.

The EEG is potentially useful as a marker of early Huntingtons disease (HD). In dementia, the EEG during a memory activation challenge showed abnormalities where the resting EEG did not. We investigated whether memory activation also reveals EEG abnormalities in preclinical HD. Sixteen mutation carriers for HD and 13 nonmutation carriers underwent neurological, neuropsychological, MRI and EEG investigations. The EEG was registered during a rest condition, i.e. eyes closed, and a working memory task. In each condition we determined absolute power in the theta (4–8 Hz) and alpha (8–13 Hz) bands and subsequently calculated relative alpha power. The EEG during eyes closed did not differ between groups. The EEG during memory activation showed less relative alpha power in mutation carriers as compared to nonmutation carriers, even though memory performance was similar [F (1,27) = 10.87; P = 0.003]. Absolute powers also showed less alpha power [F (1,27) = 7.02; P = 0.013] but similar theta power. No correlations were found between absolute and relative alpha power on the one hand and neuropsychological scores, motor scores or number of CAG repeats on the other. In conclusion, memory activation reveals functional brain changes in Huntingtons disease before clinical signs become overt.

Ictal Asystole Life-Threatening Vagal Storm or a Benign Seizure Self-Termination Mechanism?

Ictal bradycardia and ictal asystole, although well known to neurologists, have received relatively little attention in the cardiology community. Consequently, in certain instances, the true pathogenesis for heart rate slowing (ie, epilepsy) may be missed, and the bradyarrhythmia incorrectly attributed to other causes. Technically, both ictal bradycardia and asystole are more precisely termed ictal-induced cardiac bradyarrhythmia or asystole. Most often the neurological trigger is a complex partial seizure, which may or may not become generalized. 1 Further, if sufficiently severe, the ictal-induced bradyarrhythmia temporarily impairs both cerebral perfusion and cortical function; the result has the dual effect of terminating the seizure, while at the same time triggering syncope with consequent loss of consciousness and postural tone. In essence, a complex partial seizure patient may manifest both seizure and syncope features during the same episode. Article see p 159

A case of bilateral medial medullary infarction demonstrated by magnetic resonance imaging with diffusion-weighted imaging.

Sirs: Infarction of the medial medulla is very rare [1]. Bilateral medial medullary infarction presents with acute-onset or slowly progressive quadriplegia, either isolated, or with weakness of the face and tongue, transient paraesthesias in all four limbs, and impaired deep sensation [2, 4]. The clinical course is often complicated by respiratory failure, and the prognosis is poor [2, 4]. The diagnosis can be difficult at times. We report the use of magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) in acute bilateral medial medullary infarction allowing an early diagnosis. A 56-year-old man with a previous history of hypertension experienced tingling sensations in both hands and feet. The following morning he awoke with weakness of the left arm and leg as well as with slurred speech. He was admitted to the hospital. On neurological examination he was alert and oriented, he had dysarthria, left-sided arm and leg weakness, bilateral Babinski signs, and intact sensation to all modalities. Computed tomography of the head was normal. In the hours following admission the left hemiparesis progressed to hemiplegia, and the patient gradually developed weakness of the right arm and leg as well, resulting in flaccid quadriplegia. There was no evident facial or hypoglossal weakness, and sensation remained intact. MRI of the brain obtained 10 h after admission showed no abnormalities on the T1-weighted, the T2-weighted and the fluid-attenuated inversion recovery sequences, whereas on DWI a hyperintense signal was seen in the anterior rostral medulla, consistent with acute ischaemia (Fig. 1A). The following day the patient developed respiratory insufficiency requiring assisted ventilation for 7 days.A repeat MRI of the brain 3 days later revealed bilateral medial medullary infarction (Fig. 1B). Both duplex ultrasonography and MRI demonstrated an abnormal flow signal in the right vertebral artery and normal flow in the left vertebral artery. The left vertebral artery was dominant and elongated, and located on the right side of the rostral medulla (Fig. 1B).After a week the patient was extubated. The quadriplegia became spastic over time.After 2 months he could make minimal movements with his digits, wrists and elbows. The patient was able to sit in a wheelchair and talk with his family. We attributed the bilateral medial medullary infarction in our patient to unilateral distal vertebral artery occlusion, probably against the background of an anatomical variant of the anterior spinal artery or the paramedian anterior spinal branches originating from a single vertebral artery, which occurs in approximately 10 % of persons [5]. Other causes of this type of infarction include an embolic or thrombotic occlusion of the anterior spinal artery itself, which usually leads to infarction in the caudal medulla [3]. In the patient reported here DWI detected signal abnormalities in the medulla shortly after symptom onset, allowing rapid confirmation of the location of infarction. Since early diagnosis may guide therapeutic strategies, our case illustrates the value of DWI in atypical presentations of uncommon cerebral infarctions such as bilateral medial medullary infarction. LETTER TO THE EDITORS

Indications for an immune-mediated etiology of idiopathic sensory neuronopathy.

To investigate immune mechanisms in the etiology of idiopathic sensory neuronopathy (ISN), we studied neurite outgrowth inhibition and antibody binding to neuronal tissue of serum from 4 patients with ISN. Rat dorsal root ganglion (DRG) cells were cultured in the presence of serum from ISN patients and controls. After 48 h of incubation, neurite outgrowth was quantified with a neurofilament ELISA. Serum from ISN patients significantly inhibited DRG neurite outgrowth compared to controls. ISN serum also strongly immunostained fixed cultured and cryostat rat DRG neurons (at dilutions up to 1:10,240), whereas serum from controls did not. Western blots showed unique binding patterns to DRG proteins in 3 ISN patients compared with controls, but a single band corresponding in all ISN patients was not found. The inhibitory effect of ISN serum on neurite outgrowth and the presence of circulating anti-DRG antibodies in the acute phase of the disease supports an immune-mediated pathogenesis of ISN.

Het ‘zwakke plekken’-eeg als voorspeller van de ziekte van Alzheimer?

SamenvattingIn Nederland wordt het aantal mensen met dementie geschat op meer dan 195.000. De prevalentie hangt sterk samen met leeftijd; slechts circa 10.000 patiënten zijn jonger dan 60 (www.alzheimer-nederland.nl). De verwachting is dat door de vergrijzing het aantal mensen met dementie de komende jaren fors zal toenemen. In dit kader is het van groot belang om de eerste verschijnselen zo vroeg mogelijk op te sporen, mogelijk zelfs in een voorstadium van dementie. Met deze kennis kan eerder worden begonnen met een (in de toekomst beschikbare) behandeling en kan de informatieverstrekking aan patiënten en hun gezinnen worden verbeterd. In dit artikel bespreken wij de mogelijke bijdrage van kwantitatieve elektro-encefalografie (eeg) aan de vroege detectie van de ziekte van Alzheimer. Het eeg is een veelgebruikte, non-invasieve techniek om hersenfuncties in kaart te brengen. Met het achterliggende idee dat afwijkingen pas aan het licht komen wanneer de ‘zwakke plek’ wordt gestimuleerd, onderzochten wij het eeg tijdens geheugentaken.

Kwantitatieve elektro-encefalografie als hulpmiddel bij de vroege diagnostiek van Alzheimer-type dementie

Het aantal mensen met Alzheimer-type dementie in Nederland wordt momenteel geschat op meer dan 175.000. De verwachting is dat dit aantal zal verdubbelen in minder dan 50 jaar. Het is van belang dat Alzheimer-type dementie zo vroeg mogelijk wordt vastgesteld, of mogelijk zelfs voorspeld in een voorstadium van de ziekte. Op deze manier kan zo vroeg mogelijk begonnen worden met behandeling en kunnen patiënt en verzorgers worden ingelicht over de aard en het beloop van de klachten. In dit artikel wordt de mogelijke rol van elektro-encefalografie (eeg) in de vroege diagnostiek van Alzheimer-type dementie besproken. Met behulp van het eeg kunnen vroege veranderingen in het functioneren van de hersenen in kaart worden gebracht. Bovendien is het eeg makkelijk uit te voeren, weinig belastend voor de patiënt, en goedkoop.