Description and analysis of 12 years of surveillance for Creutzfeldt-Jakob disease in Denmark, 1997 to 2008.

Prospective surveillance of Creutzfeldt­Jakob disease (CJD) was initiated in Denmark in 1997, following the observation of variant CJD in the United Kingdom. Demographic, clinical and diagnostic information was collected for each patient with clinical suspicion of CJD. Here we describe the methods for surveillance and the observed outcomes between 1 January 1997 and 31 December 2008. A total of 83 patients were classified as sporadic CJD, 47 were definite diagnoses, 34 probable and two possible. This resulted in a mean incidence of 1.26 patients with probable and definite sporadic CJD per million inhabitants. Two sporadic CJD patients were found to have a genetic variant of unknown significance: Thr201Ser and Glu200Asp. One patient was diagnosed with Gerstmann-Sträussler-Scheinker syndrome. No patients were classified as having variant, iatrogenic or familial CJD. The Danish surveillance system, like those in other countries, has a multidisciplinary approach, which is labour-intensive and time-consuming but ensures the most complete set of information possible. With this approach we think that patients with variant CJD would have been detected had they occurred in Denmark. Certain aspects of CJD surveillance need further discussion at European level and beyond, in order to find a balance between efficiency of the systems and accuracy of surveillance data.

Intraoperative hyperventilation vs remifentanil during electrocorticography for epilepsy surgery - a case report.

BACKGROUND: Traditionally, intraoperative intracranial electroen-cephalography-recordings are limited to the detection of the irritative zone defined by interictal spikes. However, seizure patterns revealing the seizure onset zone are thought to give better localizing information, but are impractical due to the waiting time for spontaneous seizures. Therefore, provocation by seizure precipitants may be used with the precaution that spontaneous and provoked seizures may not be identical. OBJECTIVE: We present evidence that hyperventilation induced and drug induced focal seizures may arise from different brain regions in the same patient. METHODS: Hyperventilation and ultra short acting opioid remifentanil were used separately as intraoperative precipitatants of seizure patterns, while recording from subdural and intraventricular electrodes in a patient with temporal lobe epilepsy. Two different ictal onset zones appeared in response to hyperventilation and remifentanil. Both zones were resected and the patient has remained essentially seizure free for 1 year. Furthermore, this is the first description of hyperventilation used as an intraoperative seizure precipitant in human focal epilepsy.

Remifentanil-induced spike activity as a diagnostic tool in epilepsy surgery.

OBJECTIVES: To assess the value of remifentanil in intraoperative evaluation of spike activity in patients undergoing surgery for mesial temporal lobe epilepsy (MTLE). MATERIALS AND METHODS: Twenty-five patients undergoing temporal lobectomy for medically intractable MTLE were enrolled in the study. Electrocorticography (ECoG) recordings were performed on the intraventricular hippocampus and from the anterior inferior temporal and lateral neocortex before and after a 300 microg intravenous bolus of remifentanil. Spike activity was quantified as spike-count per minute. RESULTS: A significant increase (P < 0.005) in spike activity was observed after administration of remifentanil in 23 of 25 patients (92%). Furthermore, two patients who did not have any spike activity on the baseline ECoG developed spikes after administration of remifentanil. CONCLUSIONS: The results suggest that remifentanil can enhance spike activity in the epileptogenic zone and reveal otherwise concealed epileptogenic tissue in patients with MTLE. Thus, remifentanil may prove to be an important diagnostic tool during surgical treatment for intractable focal epilepsy.

Electroencephalography in dogs with epilepsy: similarities between human and canine findings.

OBJECTIVES: To investigate the diagnostic value of electroencephalography (EEG) in dogs with epilepsy, applying human criteria for EEG abnormalities observed with this disorder. MATERIAL AND METHODS: Twenty-six dogs with a clinically established diagnosis of epilepsy were investigated with electroencephalography (EEG) in order to evaluate the diagnostic yield of EEG in canine epilepsy. RESULTS: Of 23 dogs with evaluable EEGs 15 (65%) demonstrated abnormal activity. The most common abnormalities were focal low frequency patterns without spikes (48%), followed by focal epileptiform activity (22%) and generalized epileptiform activity (17%). The distribution between focal and generalized activity were 73% and 27%, respectively. Consistency were demonstrated between the clinical- and the EEG-diagnosis in 13 dogs (87%). A relationship was demonstrated between the number of abnormal EEGs and the proximity of a seizure to the EEG examination. CONCLUSION: A marked consistency was demonstrated between the clinical diagnosis of seizure type and the type of abnormalities observed in the EEG, thus indicating that EEG is a valuable diagnostic aid in confirming the diagnosis of epilepsy in dogs. EEG findings in dogs with epilepsy and humans with this disorder were markedly similar.

ECG changes in epilepsy patients.

OBJECTIVES: To investigate the frequency of ECG abnormalities suggestive of myocardial ischaemia in patients with severe drug resistant epilepsy and without any indication of previous cardiac disease, assuming that these changes may be of significance for the group of epileptic patients with sudden unexpected death. MATERIAL AND METHODS: Twelve patients with medically intractable epilepsy were investigated with simultaneous long ECG and EEG recordings while attending either epilepsy surgery investigational procedures or the investigational programme for diagnostic purposes, and one while having an episode of status epilepticus. RESULTS: The ECG recording failed in 1 patient. This patient had chest pain and minor yet morphologically conspicuous changes in the ECG, suggestive of myocardial infarction. He died in heart arrest. Eight epilepsy patients had episodes of ST segment depression in the ECG, many of which coincided with video- and EEG documented epileptic seizures. Two patients experiencing simple partial seizures and 1 patient experiencing absence seizures had no ST segment depressions in the ECG. One patient had an episode of status epilepticus secondary to brain damage and no ST segment deviation was seen during the ECG recording which continued until 3 h before the patient died. CONCLUSION: Patients with severe drug resistant epilepsy have episodes of ST segment changes, some of which are closely related to epileptic seizures. Further studies are needed to confirm the present results and to investigate the nature of these changes and document the effect of prophylactic treatment with cardioactive drugs to reduce the risk of sudden death.

Interictal SPECT of rCBF is of clinical utility in the preoperative evaluation of patients with partial epilepsy.

Fifty-eight patients with drug-resistant partial epilepsy were studied preoperatively by interictal rCBF measurements using 99mTc-HMPAO and a dedicated brain SPECT camera (Tomomatic 64). Follow-up of seizure outcome, using the "Engel score", was at least 3 years. The data were analyzed in a blinded set-up, first visually and subsequently quantitatively by an automatic regional analysis. By visual analysis 95% of the patients were considered abnormal in one part of the brain, of whom 27% were abnormal on CT, 45% on MRI and 98% on scalp EEG. Using a quantitative regional analysis subdividing each hemisphere into 17 larger regions, 85% of the patients had an abnormal rCBF compared to an age-matched control population of healthy volunteers (using the Wilcoxon 2-sample test with Bonferroni's correction). The average number of abnormal regions of interest was 4.7. The percentage of patients with abnormal SPECT-CBF or the total number of abnormal regions of interest (ROIs) per patient showed no correlation to duration of epilepsy or seizure load (number of seizures per year x epilepsy duration) or seizure type. Neither were the rCBF changes prognostic for the outcome as measured by the Engel score. In 20 patients ictal SPECT of rCBF was additionally performed. In 2 cases it added further information to the patient evaluation.

Vigabatrin in childhood epilepsy: a 5-year follow-up study.

In an retrospective uncontrolled long-term study in 30 children with intractable epilepsy, it was found that treatment with vigabatrin resulted in a seizure reduction of more than 50% at 1-year follow-up in 40% of the children. The responders were all children with partial seizures. Side effects were mild and did not lead to discontinuation of the drug. Increased numbers of seizures were seen in three cases. A moderate weight increase was seen in 27% of the children. At 5-year follow-up 7 children (23%) still maintained a seizure reduction of more than 50%. Trials of monotherapy in three seizure-free patients were unsuccessful. No further side effects were observed. A study of evoked potentials in 12 children showed no alteration in latency and amplitudes of VEP following treatment with vigabatrin. Our results show that in children vigabatrin seems to have a stable effect even though a few children may experience a breakthrough of seizures. The presented results together with previous reports on MRI-scans seem to indicate that even in children with a still maturing CNS vigabatrin is a safe drug.

[3-year experiences with surgical treatment of epilepsy at the Hvidovre hospital]. / Tre års erfaringer med epilepsikirurgi på Hvidovre Hospital.

The results of a retrospective survey of 48 patients submitted to neurosurgery for medically intractable epilepsy are presented. Twenty-eight patients were treated with selective amygdalohippocampectomy, one with temporal lobe resection, 12 with anterior callosotomy and seven with a total callosotomy. Of the amygdalohippocampectomized patients and the one with temporal lobe resection (n = 29), 52% were seizure free, 17% experienced rare seizures, 7% had a worthwhile improvement while 24% observed no worthwhile improvement (follow-up time 6 to 36 months). Of the callosotomized patients, 11% were free from generalized seizures, 69% had a significant seizure reduction and 18% experienced no worthwhile improvement. The observed neurological complications were: one patient had hemianopia, one had superior quadrant anopia, four developed unilateral anosmia and one complete anosmia. The callosotomized patients, with two exceptions, were all mentally and physically handicapped. In the callosotomy group, two patients died, one from a intracerebral hematoma three months after the operation and another patient seven months postoperatively from unknown causes.

Penicillamin-induced neuropathy in rheumatoid arthritis.

A case of penicillamin-induced severe polyradiculopathy in rheumatoid arthritis is presented. The neuropathy was of demyelinating type, purely motor, proximal and clinically fully reversible when the drug ceased. In case of a progressive neuropathy, during penicillamin treatment, this adverse effect should be born in mind, and discontinuation of the drug considered.

Personality characteristics and epilepsy.

Patients with a long history of temporal lobe epilepsy or primary generalized epilepsy entered a questionnaire study of personality characteristics, based on a modification of the Bear-Fedio inventory for temporal lobe behavioural syndrome. Psoriasis patients and healthy volunteers served as controls. Four clinical meaningful dimensions of included personality traits were identified: ixoide, ideational, obsessive-compulsive and affective features. Analyses based on the Rasch model approved of all dimensions except for affective features. The epilepsy group obtained the highest scores on all 3 dimensions, healthy volunteers the lowest, while the psoriasis group repeatedly held an intermediate position in all sets of assessment (subjects, interviewers and relatives). A logistic regression analysis showed ixoide features being most important when the entire epilepsy group was compared with other study groups, while the dimension ideational features was significant when the temporal lobe epilepsy group was entered as target group and opposed to primary generalized epilepsy. The intermediate position of the psoriasis group, however, suggests that in addition to the presence of a cerebral dysfunction in the epilepsy group, the mere presence of a chronic disorder with potential social stigmatization influences personality.

Ego functions in epilepsy.

Two groups of epilepsy patients (28 patients with temporal lobe epilepsy and 15 patients with primary generalized epilepsy) entered a study of personality traits related to epilepsy, based on a modification of Bellak's semistructured interview for assessment of ego strength. Two groups of subjects served as controls: 15 patients with a non-neurological but relapsing disorder, psoriasis, and 15 healthy volunteers. Compared with the group of healthy volunteers, a decreased adaptive level of ego functioning was found in the epilepsy groups, regardless of seizure types and EEG findings, and, to a lesser extent, compared with the psoriasis group. Areas of ego functioning most affected were "reality testing", "cognitive functioning", "integrative functioning" and "regulation and control of drives". Patients with more than one type of seizure were the most affected, as were patients who were younger than 15 years when the disease began. The number of anticonvulsants administered did not influence the results. No difference on adaptive level of ego functioning was found between the group with primary generalized epilepsy and the group with temporal lobe epilepsy. Similarly, the temporal lobe epilepsy group with predominantly right-sided and left-sided EEG changes, respectively, showed similar adaptive levels of ego functioning.

Epilepsy after stroke.

Development of epilepsy was studied prospectively in a group of 77 consecutive stroke patients. Included were stroke patients less than 75 years old admitted within the first 3 days after the stroke. Excluded were patients with subarachnoid hemorrhage, vertebrobasilar stroke, and patients with other severe diseases. Cerebral angiography, CT, and EEG were performed in all patients. The patients were followed clinically for 2 to 4 years. Seven patients (9%) developed epilepsy. Of 23 patients with lesions involving the cortex, 6 (26%) developed epilepsy. Of 54 patients in whom the cortex was not involved, only 1 (2%) developed epilepsy. Patients with persisting paresis and cortical involvement seem to be at particularly high risk of developing epilepsy, as 50% of such patients (6 of 12) developed the disease.

Motor unit firing intervals and other parameters of electrical activity in normal and pathological muscle.

The analysis of the firing intervals of motor units has been suggested as a diagnostic tool in patients with neuromuscular disorders. Part of the increase in number of turns seen in patients with myopathy could be secondary to the decrease in motor unit firing intervals at threshold force of the motor units, as noted in previous studies. In the brachial biceps muscle we have studied the firing intervals of 164 motor units in 14 controls, 140 motor units in 13 patients with myopathy and 86 motor units in 8 patients with neurogenic disorders, and related the findings to those of the turns analysis and the analysis of properties of individual motor unit potentials. To ensure comparable conditions we have examined motor unit firing intervals and turns at a force of 10% of maximum. The average of motor unit firing intervals and of interval variability was the same in controls and in patients, and the diagnostic yield of the motor unit firing intervals analysis was none. Although the number of turns increased with decreasing motor unit firing intervals, this relation was physiological rather than pathophysiological. In patients with neurogenic disorders, interval variability indicated unstable firing in severely affected muscles.