[Pathogenesis of narcolepsy: from HLA association to hypocretin deficiency]

Narcolepsy is a rare and chronic sleep disorder, characterised by excessive daytime sleepiness. Frequently associated signs are cataplexy, sleep paralysis and hypnagogic or hypnopompic hallucinations. Advances in understanding the pathogenesis of the disease have essentially been elucidated during the last fifteen years. The most significant finding has been the discovery of hypocretin-1 and -2 in 1998. Hypocretin-containing cells have widespread projections throughout the entire CNS and play a crucial role in the regulation of the sleep-wake cycle. They also contribute to olefaction and to the regulation of food intake. Animal models and human studies concordantly show that the disturbed hypocretin system is the probable cause of narcolepsy. However, it remains unclear why there is neuronal death of hypocretin-producing cells in the lateral hypothalamus. As the HLA-allele DQB1*0602 is associated with narcolepsy and hypocretin deficiency, an autoimmune reaction against hypocretin-producing neurons has been vigorously discussed. Newly discovered gene polymorphisms as well as previously unknown pathogenetic mechanisms, linking the sleep-wake cycle with the immune system, may also contribute to the pathogenetic cascade. Worthy of mention in this context is, e.g., the "insulin-like growth factor"-binding protein 3 (IGFBP3), whose overexpression causes a down-regulation of the hypocretin production. Substitution of the deficient neuropeptides by hypocretin agonists may become the causal treatment strategy of the future, if an adequate administration route can be found. Presently, animal trials, including genetic therapy, cell transplantations or the administration of hypocretin receptor agonists, are underway.

Thalamic stimulation for essential tremor activates motor and deactivates vestibular cortex

BACKGROUND

The functional effects of deep brain stimulation in the nucleus ventralis intermedius (VIM) of the thalamus on brain circuitry are not well understood. The connectivity of the VIM has so far not been studied functionally. It was hypothesized that VIM stimulation would exert an effect primarily on VIM projection areas, namely motor and parietoinsular vestibular cortex.

METHODS

Six patients with essential tremor who had electrodes implanted in the VIM were studied with PET. Regional cerebral blood flow was measured during three experimental conditions: with 130 Hz (effective) and 50 Hz (ineffective) stimulation, and without stimulation.

RESULTS

Effective stimulation was associated with regional cerebral blood flow increases in motor cortex ipsilateral to the side of stimulation. Right retroinsular (parietoinsular vestibular) cortex showed regional cerebral blood flow decreases with stimulation.

CONCLUSIONS

Beneficial effects of VIM stimulation in essential tremor are associated with increased synaptic activity in motor cortex, possibly due to nonphysiologic activation of thalamofrontal projections or frequency-dependent neuroinhibition. Retroinsular regional cerebral blood flow decreases suggest an interaction of VIM stimulation on vestibular-thalamic-cortical projections that may explain dysequilibrium, a common and reversible stimulation-associated side effect.

[Late form with psychiatric presentation of Wilson's disease, with pseudo-compulsive stereotyped movements. Neuro-radiological correlations]

Wilson's disease rarely starts after the third decade and may present with misleading psychiatric signs. We observed a 39-year-old white male who developed hysterical behaviour followed by frank delusional psychosis. Secondary neurological symptoms like astasia and dyarthria were misinterpreted as drug-induced. Despite a treatment with D-penicillamine and zinc sulfate there was further deterioration with anarthria and pseudo-compulsive stereotypies. These latter signs cleared after five months, whereas astasia and abasia remained the same and MRI imaging showed further deterioration characterized by marked bilateral putaminal cavitation. SPECT imaging could not predict the clinical evolution. Our case emphasizes that Wilson's disease can have variable initial presentations, and confirms the relationship between pseudo-compulsive stereotypies and bilateral lenticular lesions, as already described in other diseases of the basal ganglia.

Genetic variability of the CYP 2D6 gene is not a risk factor for sporadic Parkinson's disease

Genetic studies of the frequencies of mutant alleles for coding cytochrome P-450 monooxygenase (CYP 2D6) in Parkinson's disease (PD) patients have been inconsistent. We studied the mutants A and B in 80 strictly defined sporadic PD patients divided into young age onset of the disease (< 40 years, N = 20), mid age onset (40-50 years, N = 12), and older age onset (> 50 years, N = 48). They were compared with 108 controls from the same geographic area. There were no significant differences in allele or genotype frequencies between PD patients and controls. Future genetic studies in PD should focus on other alleles or other areas of the genome.

[Clozapine in the treatment of mental manifestations of Parkinson disease]

BACKGROUND

Medical treatment of Parkinsonian syndromes is often complicated by psychiatric side effects such as confusional states, hallucinations and psychosis. Recent pilot studies report good clinical results with the atypical neuroleptic clozapine.

PATIENTS AND METHODS

We report on 15 patients with Parkinsonian syndromes: 11 with idiopathic Parkinson's disease (IPD), 3 with multiple system atrophy (MSA) and 1 with postencephalitic Parkinsonism (SPP). The mean age was 68.8 +/- 10 years; the mean duration of Parkinsonian symptoms was 6.8 +/- 5.7 years. The Hoehn & Yahr grade was: 3.5 +/- 0.8. Eleven patients were suffering from psychotic episodes, 10 from hallucinations, 8 from confusional states. Clozpine was introduced at nighttime and dosage was modified until the appearance of clinical effect or intolerable side effects.

RESULTS

We report on an observed cumulative duration of clozapine treatment of 13 patient-years. The average treatment duration was 10.5 +/- 10.4 months. The mean daily dose was 33.3 +/- 30 mg (range: 6.2-100). There was at least transitory improvement of psychiatric symptoms in all patients. There was constant and complete improvement in 7 patients (46%) and satisfactory improvement in 5 patients (33.3%). The levodopa dosage was unchanged (mean dosage 563 +/- 232 mg), and the dosage of dopamine agonists was significantly increased. None of our patients experienced motor deterioration. Side effects comprised sialorrhoea, sedation, orthostatic hypotension, and delirium tremens and an epileptic seizure in one patient each. Two patients died suddenly at the 63rd and at the 86th day of treatment respectively, outside the hospital. These deaths seemed to be unrelated to the treatment. There was no agranulocytosis.

CONCLUSION

Clozapine is an efficient antipsychotic drug in Parkinsonian patients with no motor side effects in the dosages used. The effective dosage is very low in comparison to psychiatric patients. However various side effects may occur and close monitoring is required.

[Functional significance of calcinosis of the basal ganglia via positron emission tomography]

Four patients with symmetrical basal ganglia calcification of different etiologies detected by cranial computed tomography (CT) were clinically evaluated and underwent positron emission tomography (PET) with (18F)-2-fluoro-2-deoxy-D-glucose (FDG). All patients were subjected to extensive laboratory investigation and neuropsychological testing. In two patients we found typical laboratory signs of hypoparathyroidism, the other two patients had no endocrinological alterations. Changes of glucose metabolism were mainly detected only in calcified tissues. Particularly in two patients with test psychologically confirmed psychomotoric retardation we did not find any cortical dysfunction. In conclusion, basal ganglia calcification in contrast to primary degenerative diseases has no influence on metabolic function in tissue that is not calcified.

Blinded evaluation confirms long-term asymmetric effect of unilateral thalamotomy or subthalamotomy on tremor in Parkinson's disease

In the past, stereotactic surgery was a regular treatment for prominent unilateral tremor in Parkinson's disease (PD), but follow-up studies were usually short-term and always unblinded. We examined 17 PD patients in long-term follow-up (mean, 10.9 years after surgery) and used videotapes and the Unified Parkinson's Disease Rating Scale to blindly compare tremor ipsilateral and contralateral to the side of surgery. Since the patients were specifically selected for stereotactic surgery because of asymmetric tremor, and the surgical side chosen was contralateral to the predominant tremor, a sign of long-term efficacy would be current postoperative reversal of tremor side predominance. Upper extremity tremor was significantly better contralateral to the surgery compared with the ipsilateral side. We conclude that stereotactic surgery improved the absolute magnitude of tremor or ameliorated its rate of progression. Since asymmetric bradykinesia and dyskinesia were not a prerequisite for the choice of surgical side, we cannot make any conclusion about long-term impact of surgery on these features.

New approaches in the treatment of the dystonias

At this point the treatment of dystonias remains highly empirical. Secondary dystonias, especially those related to specific drug treatment, have to be ruled out carefully. A few dystonic subgroups respond well to levodopa medication. In the other syndromes, anticholinergics are the usual first choice. In focal conditions botulinum toxin injections seem to be the most effective regimen, although there are only a few long-term studies. Surgical procedures are an ultimate option.

[Why does the human immunodeficiency virus (HIV) invade the nervous system?]

Human Immunodeficiency Virus (HIV) has neurotropic effects that are independent of the well-known lymphotropism. They have been proved by various techniques, but their pathogenesis is not clear. It is remarkable that the neuropathological features do not correlate with the degree of the clinical symptomatology. HIV antigens and antibodies are demonstrable within the central nervous system by immunological tests. The macrophages transport the virus across the blood-brain barrier and are responsible for its persistence in that location. Different cell types, especially of the subcortical areas, have HIV-receptive CD4 molecules. These markers may be identical with the receptors for endogenous neuropeptides and it is likely that viral proteins are causing a competitive inhibition of these mostly neurotrophic factors. This interference is discussed as one of the main reasons of HIV dementia.

[Symptomatic mania in HIV infection. 3 cases of classified euphoric psychoses as a sequela of the AIDS disease]

3 case histories of patients with acquired immune deficiency syndrome and acute organic psychoses are reported. Their psychoses can be classified as benefaction or blissfulness psychoses. A handfull of previous reports classify similar acute organic psychoses as symptomatic manias. The respective descriptions make obvious that these psychoses are homogenous among each other and that their contents represent a vivid reflection over a life situation which had been thoroughly changed by the AIDS illness.

[Psychopathologic pictures in HIV infection: AIDS lethargy and AIDS dementia]

The paper describes the psychiatric status on the basis of 76 patients with acquired immune deficiency syndrome. There is considerable difference between the different stages of the disease. The disorders are divided into groups following the German and French psychopathological tradition, where the incidence is dependent on the underlying complaint. 50% of the patients suffered from chronic psychoorganic disorders (34% organic personality disorders, 16% dementia). 9% suffered from an acute psychosis caused by complications and founded on substantial physical illness. 3 patients showed symptoms of a (under given circumstances) hitherto unknown endoform psychosis. In 9% of the patients, psychoreactive disturbances (anxiety and reactive depression) were observed. Two infants had congenital development deficiencies. 25% of the patients were without any psychopathology. Patients showing organic personality disorders mostly resemble each other to such a degree as to form a separate group. We suggest to name this group according to the most prominent psychopathology as "AIDS-lethargy". This status is characterised by a specific apathy, tiredness and indolence of the patients combined with the lack of emotional participation related to their own destiny. AIDS-lethargy is the first manifestation in appearance of the HIV infection of the brain itself. Another sequel of the brain infection is AIDS dementia which can be classified as "subcortical dementia" and differs from the more current forms of dementia clinically. Affected are mainly neuropsychologic functions like arousal, attention, mood and motivation, whereas the hallmarks of cortical involvement-aphasia, agnosia and apraxia-are not present. Supplementary findings (EEG, CCT, CSF): The group of patients with chronic psychoorganic disorders differs significantly from the group with psychoreactive disorders and normals. Pathological EEG and CCT are more frequent in psychoorganic disorders. CSF-test-including the intrathecally synthesized antibodies against HIV-does not show traceable variation in either group. There are four problems which may be combined in a given acute psychopathological HIV-syndrome: 1. Being member of a risk group with its reactive, psychosocial and personality problems. 2. Individual mental and emotional reaction to the fact of infection 3. Chronic psychoorganic disturbances. 4. Acute organic psychoses as a result of complications and other physical illness.

Human immunodeficiency virus (HIV)-related chronic relapsing inflammatory demyelinating polyneuropathy with multifocal unusual onion bulbs in sural nerve biopsy. A clinicomorphological study with qualitative and quantitative light and electron microscopy

This is obviously the first report on a case with a spontaneous sensu strictu relapsing variant of human immunodeficiency virus (HIV)-related polyneuropathy. Its manifestation preceded LAS. Intrathecal HIV-antibodies developed between the most severe third and fourth episode. Analysis of sural nerve biopsy was consistent with a multifocally accentuated chronic inflammatory demyelination, characterized by unusual onion bulb-like Schwann cell formations with irregular voluminous layers, electron density, aggregation of filaments, multiple indented nuclei, and numerous enclosed collagen pockets. A direct or immune-mediated indirect specific influence on Schwann cell morphology by HIV might be discussed. Virus-like particles and ultrastructural markers of HIV were not detectable.

Early involvement of the nervous system by human immune deficiency virus (HIV). A study of 79 patients

We report on 79 patients of different stages of human immune deficiency virus (HIV) infection according to the Walter-Reed staging classification (WR). Comparing the HIV antibody content per weight IgG in serum and cerebrospinal fluid (CSF), 54 patients (68%) showed higher antibody activity in CSF than in serum, indicating intrathecal antibody production and thus a local challenge with the virus. The percentage of patients with these antibodies in CSF increased from stage WR 1 (33%) to WR 5 (90%). It decreased again in WR 6 (68%). Twenty-one patients with intrathecally produced antibodies but without evidence for opportunistic or preexistent neuropsychiatric diseases were further analyzed. Even in stages WR 1 and 2 these patients showed distinct clinical signs. These consisted mostly in apathic personality change (n = 13), peripheral neuropathy (n = 8) or mild hemisyndrome (n = 9). Progression to severe dementia solely caused by HIV encephalitis seems to be possible. More often acceleration of the mental disorder indicates a synergistic action of other pathogens. Our study gives further evidence for very frequent, early and clinically active involvement of the nervous system by the HIV infection.

[Brain involvement in acquired immunodeficiency syndrome (AIDS): computed tomography (CT) and magnetic resonance tomography (MR)]

Involvement of the central nervous system in acquired immune deficiency syndrome (AIDS) is usually due to opportunistic infections; these frequently offer a difficult differential diagnostic problem. Imaging methods play an important part in the elucidation of symptoms. CT and MR findings were analysed in 13 patients with AIDS and neurological symptoms. Some infections of the central nervous system (encephalitis of unknown aetiology, cytomegalic encephalitis, meningitis) may show cerebral atrophy or even no morphological changes. Toxoplasmosis and PML are the most common opportunistic infections typical changes on CT and MR may lead to diagnosis. MR offers advantages compared with CT in its higher sensitivity for the demonstration even of small lesions.

Schizophrenia suspecta

We investigated what makes a Schneider-oriented psychiatrist diagnose "suspected schizophrenia" yet nevertheless stop short of a definitive diagnosis of schizophrenia. We compared the case records of 1208 patients hospitalised for schizophrenia for the first time in their life and all patients with discharge diagnosis "suspected schizophrenia" (n = 358). We found that the main factors for making the diagnosis of "suspected schizophrenia" are, as when using Bleuler's concept, intrasymptomatological ones, i.e. type, structure and constellation of symptoms. Hereby the non-committal character of the "expression symptoms in the wider sense" (Schneider), i.e. disorders of thought, of affect and behaviour, is of particular importance. Psychotic productive symptoms in the form of delusions or hallucinations alone are not always sufficient to confirm the diagnosis of schizophrenia. Even first rank symptoms cannot establish the diagnosis schizophrenia if certain factors reducing their pathognomonic value are present.

Cardiovascular reactivity to methacholine in normotensives with genetic risk of hypertension

Hemodynamic reactivity to methacholine (0,1 mg/kg bodyweight) was studied in 10 normotensives with genetic risk of hypertension (mean age: 25,4 +/- 2,6 years) in comparison with 8 controls (mean age: 25,0 +/- 2,3 yrs). Due to peripheral vasodilatation this substance led to an initial blood pressure fall which was the same in the investigated and in the control group. In the phase of counterregulation the secondary rise of blood pressure was higher in the group with family history of hypertension. As evidenced by correlation statistical analysis the increases of heart rate and cardiac output were responsible for the rise of systolic blood pressure. The hemodynamic response to methacholine in the group with genetic risk of hypertension has been attributed to a higher sympathetic reactivity.