Hans-Peter Ludin

Autonomic disturbances and cardiovascular reflexes in idiopathic Parkinson's disease

SummaryA total of 22 patients suffering from idiopathic Parkinsons disease and 20 age-matched volunteers were questioned about autonomic disturbances and all underwent four non-invasive tests examining cardiovascular reflexes. Significantly more autonomic disturbances were reported by the patients than by the controls. Resting blood pressure was significantly decreased in patients taking dopamine agonists, whereas it was normal in those patients who only received levodopa and anticholinergics. Resting heart rate and resting beat-to-beat variation were normal in the patients, as were the blood pressure response to standing and the postural heart rate response. No pathological response to the Valsalva manoeuvre could be detected. On the other hand, the heart rate variation evoked by deep breathing as well as the blood pressure response and the heart rate response to sustained isometric exercise were significantly diminished in the patients with idiopathic Parkinsons disease. These findings indicate a central disturbance of cardiovascular reflex control, whereas the corresponding peripheral pathways seem to be normal.

Visual evoked potentials in acute occipital blindness

SummaryPattern-evoked and flash-evoked responses were recorded from four patients with acute blindness due to occipital ischaemia. No responses could be obtained with pattern stimulation. Flash stimulation, however, yielded well-reproducible potentials in all four cases in spite of practically complete visual loss. In one patient vision recovered completely while the three others showed poor or minimal recovery in restricted visual field areas only. It is concluded that the flash method is not appropriate for differentiation of occipital blindness from psychogenic visual disorders. Furthermore, preserved flashevoked potentials in the acute stage of occipital blindness cannot be taken as a reliable prognostic sign for visual recovery, as has been postulated by others. A possible extrastriate origin of these flash responses is discussed in view of recent theories on a second visual system.ZusammenfassungVon vier Patienten mit akuter Erblindung infolge bilateraler occipitaler Ischämie wurden visuell evozierte Potentiale mit Schachbrettmuster-und Blitz-Stimulation abgeleitet. Während sich bei der Musterstimulation keine verwertbaren Potentiale ableiten ließen, ergab der Blitzreiz in allen vier Fällen eindeutig reproduzierte Antworten trotz praktisch vollständiger Blindheit. Bei einer Patientin bildete sich der Sehverlust vollständig zurück, die drei anderen zeigten nur geringe oder minimale Erholung in umschriebenen Gesichtsfeldbezirken. Aufgrund dieser Beobachtung scheint die Blitzmethode zur Abgrenzung kortikaler Blindheit von Psychogenen Sehstörungen ungeeignet. Zudem sprechen die Befunde gegen die von einzelnen Autoren vertretene Ansicht, daß erhaltene blitzevozierte Potentiale bei akut kortikal Erblindeten eine gute Prognose für die Erholung des Sehens erwarten lasse. Die Frage des Entstehungsortes von Blitz-VEP bei kortikaler Blindheit wird im Lichte neuerer Erkenntnisse über das visuelle System erörtert und eine mögliche extrastriäre Entstehung diskutiert.

The innervation of the trapezius muscle

SummaryIn 10 healthy subjects stimulation of the accessory nerve in the posterior triangle of the neck always elicited action potentials in all 3 parts of the trapezius muscle. Of 8 patients with a lesion of the accessory nerve 3 had no evoked potentials, while 5 showed evoked potentials in the 3 parts of the muscle. 7 of these patients had voluntary activity in the lower part of the trapezius muscle. 7 patients with lesions of the accessory nerve showed, by electromyographic investigation, no constant pattern of the neurogenic involvement in the 3 different parts of the muscle. Direct stimulation of the accessory nerve during neck dissection in 3 patients gave evoked potentials in the ascending and the horizontal part in all 3 cases and in the descending part in 2 cases.It is concluded that the accessory nerve normally supplies all 3 parts of the trapezius muscle. An additional cervical supply is very probable. The proportions of the two components probably show great variation; a reasonably accurate quantitative estimate cannot be made from the present material.ZusammenfassungBei 10 gesunden Versuchspersonen konnten bei supramaximaler Reizung des N. accessorius im hinteren Halsdreieck immer Summenpotentiale von allen 3 Anteilen des M. trapezius abgeleitet werden. Von 8 Patienten mit Läsionen eines N. accessorius zeigten 3 keine Summenpotentiale, während 5 Summenpotentiale in allen 3 Anteilen dieses Muskels hatten. Bei 7 dieser Patienten konnte Willküraktivität im unteren Anteil des M. trapezius registriert werden. Bei 7 weiteren Patienten mit Accessoriusläsionen wurden bei der elektromyographischen Untersuchung unterschiedliche Befunde in den 3 verschiedenen Teilen des Muskels erhoben. Bei der direkten Reizung des freigelegten N. accessorius während Halsoperationen bei 3 Patienten konnten in den 2 unteren Anteilen immer und im oberen Anteil in 2 Fällen Summenpotentiale abgeleitet werden.Die Befunde sprechen dafür, daß der N. accessorius normalerweise alle 3 Teile des M. trapezius versorgt. Eine zusätzliche Versorgung aus cervicalen Wurzeln ist aber sehr wahrscheinlich. Das Verhältnis der zwei Komponenten unterliegt wahrscheinlich großen individuellen Schwankungen. Die vorliegenden Befunde erlauben keine zuverlässige quantitative Schätzung.

Is Parkinson's disease of early onset a separate disease entity?

SummaryTwo groups of patients suffering from Parkinsons disease were studied. The first group consisted of 23 patients with an onset age before 40 years; in the second group of 21 patients the onset was after age 50. The clinical findings and the course of the disease were very similar in each group. In spite of a longer disease duration in the patients with early onset of the disease there was no difference in motor impairment; the younger patients did better in mental testing and they were taking less dopaminergic medication. These differences are thought to be due to the age difference rather than to the existence of different disease entities. In the early onset group more familial cases (mostly affecting siblings) were found than in the older ones. The points in favour of there being a hereditary subgroup of early onset Parkinsons disease or of environmental factors causing the disease are reviewed.

Subclinical visual field defects in multiple sclerosis

SummaryFourteen patients with definite but inactive multiple sclerosis (MS) and 17 normal controls were examined with the automated perimeter octopus. Most of the patients had subclinical visual field defects, typically consisting of patchy, shallow scotomata located mostly in an area of between 15° and 30° eccentricity. In 8 patients, more than 15% of the tested visual field of at least one eye was abnormal. The severity and extent of the defects was unrelated to a history of optic neuritis. When visually evoked potentials (VEPs) of these subjects were examined using a reversing pattern, no correlation was found in the MS patients between prolonged VEP latencies and the location, depth or extent of visual field defects. Since subclinical visual field defects may be found in MS patients with normal VEP latencies, automated perimetry can be helpful in diagnosing some cases.

Electrophysiological investigations in a case of cephalic tetanus

SummaryIn a case of cephalic tetanus the amplitudes and the latencies of the compound action potentials recorded from the facial muscles after stimulation of the facial nerve at the mastoid were not significantly different on the two sides. With repetitive stimulation at 30/sec a pathological facilitation was observed on both sides. The blink reflex bilaterally had normal latencies but the amplitudes of the reflex potentials were always significantly lower on the paretic side. It is concluded that facial palsy in cephalic tetanus is mainly due to a functional block of conduction in the course of the peripheral nerve whereas the disturbance of neuromuscular transmission probably has little importance in these cases.ZusammenfassungBei einem Fall von Kopftetanus mit rechtsseitiger Fazialisparese wurden bei Reizung des N.facialis am Mastoid von den Gesichtsmuskeln beidseits gleichhohe Summenpotentiale mit normaler Latenzzeit abgeleitet. Bei Reizung mit 30 Hz kam es beidseits zu einer pathologischen Fazilitierung der Potentialamplituden. Der Blinkreflex wies auf der paretischen Seite immer eine niedrigere Amplitude bei normalen Latenzzeiten auf als auf der Gegenseite. Aufgrund dieser Befunde und der Berichte in der Literature wird auf einen funktionellen Leitungsblock im Verlaufe des N. facialis als wichtigste Ursache der Parese geschlossen, die Störung der neuromuskulären Überleitung hat klinisch wahrscheinlich geringere Bedeutung.