P. De Bastiani

The risk of Parkinson disease in Mediterranean people

On the basis of previous epidemiologic studies, Parkinson disease was thought to be evenly distributed throughout the world. These studies, however, were conducted only on North European populations. The position with regard to the Mediterranean peoples was still unknown, and we therefore studied the frequency of Parkinson disease on the island of Sardinia, where some ethnic groups of the Mediterranean stock are represented. Based on 967 accepted cases, the prevalence per 100,000 population on January 1, 1972, was 65.6; the average annual incidence for the period 1961 through 1971 was 4.9. These figures are one-half of the figures established for North Europeans. Our findings suggest racial differences in predisposition to Parkinson disease. Some Negroid features are present in Sardinians. If, as seems likely, Africans prove to be relatively unsusceptible to the disease, the risk for Sardinians and other Mediterranean ethnic groups might be intermediate between North Europeans and Africans.

Systemic lupus erythematosus presenting with neurological disorders

SummarySix patients are described who developed a wide variety of neurological manifestations heralding systemic lupus erythematosus (SLE), which included epileptic seizures, stroke, peripheral polyradiculoneuro pathy similar to Guillain-Barré syndrome, transverse my elopathy and multifocal disorders with remitting course mimicking multiple sclerosis. The peculiarity of these cases was that the neurological disorders remained the only manifestations of SLE for many years and the nervous system appeared to be the main target even after the development of systemic SLE. In five patients the prognosis was favourable and corticosteroid treatment led to prolonged remission.

Clinical and audiological findings in a case of auditory agnosia

SummaryA case is reported of severe agnosia for verbal and non-verbal sounds without associated aphasic disorder. A CT scan revealed bilateral, temporal lobe lesions from two ischaemic accidents that had occurred 9 months apart. The search for subtle deficits in this patient showed normal sensitivity to changes in the intensity and frequency of simple sounds; in contrast, his ability to discriminate sound duration and musical note sequences was severely impaired. The simultaneous recording of the whole auditory-evoked response pattern revealed no abnormality in the early components, which reflect the activation of the auditory nuclei and pathways of the brain stem. However, the middle and late components were delayed and slowed. These results and others in the literature suggest that the neocortex in man, as in other mammals, plays an essential role in the temporal aspects of hearing. Also, the two main ingredients commonly recognized in auditory agnosia, i.e. word deafness and the inability to interpret non-verbal sounds, are caused by the disruption of elementary, bilaterally represented cortical functions which start the processing of every kind of auditory information.

Pure agraphia: a discrete form of aphasia.

A 62 year old, right handed man developed a pure agraphia as the result of a left temporal lobe stroke. Isolated writing disturbances persisted for seven months until he had a second cerebrovascular accident resulting in total aphasia and right hemiplegia. A CAT scan obtained four months after the first episode showed a localised dilatation of the posterior portion of the left Sylvian cistern and patchy areas of low absorption in the left temporal lobe. The report supports suggestions that localised damage to the language area can produce a pure agraphia as the sole detectable disorder of language organisation.

Alexia without agraphia: a study of a case of verbal alexia without accompanying colour-naming defect

SummaryA 47-year-old man developed a persistent form of alexia without agraphia as the result of a haemorrhagic intracerebral lesion in the left inferior temporo-occipital region, due to the rupture of an arteriovenous malformation. Surgical evacuation of the haematoma and excision of the malformation did not produce any modification of the reading deficit, which remained unchanged during a 4-year follow-up. The reading deficit was restricted to words and the patient was able to read only letter-by-letter, so that the whole words were reconstructed from the auditory names of the letters. So far, the disconnection explanation is the standard explanation of alexia without agraphia and the present case of verbal alexia may be regarded as being within this overall category. However, this explanation meets with unanswered questions that suggest more flexible interpretations. Neurolinguistic studies have questioned the unique character of alexia without agraphia as a clinical entity and, in contrast to the disconnection hypothesis, support the notion that the different varieties of alexia that are traditionally described represent distinctive syndromes, each with its own clinical features and pathophysiological basis. In this context, the reading properties in this case seem fully compatible with a deficit of the visual word-form system postulated by Warrington and Shallice, that is, the relatively early stage of the reading process through which a word-form or equivalent unit is attained. This system might be lateralized to the left hemisphere, as suggested by the fact that this case, like other cases of verbal alexia, had sustained damage to the left hemisphere and did not show any differential preservation of the reading of concrete words.ZusammenfassungBei einem 47jährigen Mann trat eine intracerebrale Blutung infolge Ruptur eines arteriovenösen Angioms der linken basalen Temporookzipitalregion auf. Dies führte zu einer persistierenden Alexie ohne Agraphie. Auch die chirurgische Ausräumung des Hämatoms und der Mißbildung bewirkte keine Veränderung der Leseschwierigkeiten, die während vier Jahren konstant blieben. Die Lesestörung beschränkte sich auf Wörter, und der Patient war lediglich fähig, Buchstabe um Buchstabe zu lesen, so daß das Gesamtwort lediglich rekonstruiert wurde. Bisher beruht die Standarderklärung der Alexie ohne Agraphie auf der Diskonektionstheorie und der vorgelegte Fall verbaler Alexie kann innerhalb dieser Kategorie gedeutet werden. Immerhin wirft dieser Fall eine Reihe von offenen Fragen auf, welche eine flexiblere Interpretation nahelegen. Neurolinguistische Studien haben den einmaligen Charakter der Alexie ohne Agraphie als klinische Entität in Frage gestellt und sprechen — im Gegensatz zu der Diskonektionshypothese — zugunsten der Annahme, daß unterchiedliche Arten von Alexie auch eigenständige Syndrome darstellen, jedes davon mit seinen eigenen klinischen Eigenheiten und pathophysiologischen Grundlagen. In diesem Zusammenhang scheinen die Leseeigentümlichkeiten im vorliegenden Fall kompatibel zu sein mit einem Defizit des visuellen Wort-Formsystemes, wie es von Warrington und Shallice postuliert wurde: das ist ein relativ frühes Stadium des Leseprozesses durch welches eine Wortform oder äquivalente Einheit erreicht wird. Dieses System könnte im Bereiche der rechten Hemisphäre lokalisiert sein, wofür ein Argument im vorliegenden Fall, wie auch in anderen Fällen von verbaler Alexie sprechen würde: hier war eine Läsion der linken Hemisphäre erzeugt worden, ohne daß irgend eine selektive Erhaltung der Fähigkeit zum Lesen konkreter Worte nachweisbar gewesen wäre.

UNITARY ATTENTION IN CALLOSAL AGENESIS

The interhemispheric organisation of two specific components of attention was investigated in three patients affected by partial or complete agenesis of the corpus callosum. A visuospatial component of attention was explored using a visual search paradigm in which target and distractors were displayed either unilaterally within a single visual hemifield, or bilaterally across both visual hemifields in light of prior work indicating that split-brain patients were twice as fast to scan bilateral displays compared to unilateral displays. A central component of attention was explored using a psychological refractory period (PRP) paradigm in which two visual stimuli were presented laterally at various stimulus onset asynchronies (SOAs), with each stimulus associated with a different speeded two-alternative choice task. The stimulus–response compatibility in the second task was systematically manipulated in this paradigm, in light of prior work indicating that split-brain patients exhibited a close-to-normal PRP effect (i.e., slowing of the second response as SOA is decreased), with, however, abnormally decreasing effects of the manipulation of the response mapping on the second task speed as SOA was decreased. The present results showed that, although generally slower than normals in carrying out the two tasks, the performance of each of the three acallosal patients was formally equivalent to the performance of a matched control group of normal individuals. In the visual search task, the search rate of the acallosal patients was the same for unilateral and bilateral displays. Furthermore, in the PRP task, there was more mutual interference between the lateralised tasks for the acallosal patients than that evidenced in the performance of the matched control group. It is concluded that the visuospatial component and the central component of attention in agenesis of the corpus callosum are interhemispherically integrated systems.

Uremic Neuropathy: Correlations between Electroneurographic Parameters and Serum Levels of Parathyroid Hormone and Aluminum

An electrophysiological investigation on 29 dialysis patients was performed with the aim of verifying whether serum parathyroid hormone (PTH) and aluminum (Al) levels may play a role in the pathogenesis of uremic neuropathy. All patients except 1 showed electrophysiological abnormalities. Both PTH and Al levels were found to be significantly correlated with the time on dialysis. On the contrary, the values of each single electroneurographic parameter did not show any correlation with the duration of dialysis, PTH levels and Al levels. The authors conclude that PTH and Al does not seem to play a role in the etiology of uremic neuropathy.

Voluntary lid closing inability

SummaryVoluntary lid closing inability has been observed in two patients with right-sided frontal ischemic damage. The patients developed a transient inability to close their eyelids voluntarily at the same time as a transient forced grasping in the left hand and left hemiparesis not affecting the face. Automatic and reflex lid closures were retained as well as the ability to keep the eyes closed and to reopen them readily on command. In previous reports, inability to close eyelids voluntarily has been attributed to apraxia, paralysis, or motor impersistence. The localization of the lesion observed in our patients suggests other pathogenetic hypotheses similar to compulsive gaze [19]. It is conceivable that the voluntary lid closing inability produced by frontal lobe lesions is due to the release of a compulsion to maintain the lids elevated in the waking state, because of the overactive effect of the visual stimuli.ZusammenfassungDie willkürliche Unfähigkeit zum Lidschluß wurde bei zwei Patienten mit rechtsseitig-frontalen Ischämieherden im Bereich der A. cerebri anterior beobachtet. Die Lidschlußapraxie war vorübergehend und entwickelte sich zusammen mit linksseitigem Zwangsgreifen und linker Hemiparese ohne Facialisbeteiligung. Der automatische und reflektorische Lidschluß war erhalten, ebenso wie die Fähigkeit, die Augen geschlossen zu halten und sie auf Kommando wieder zu öffnen. Bisher wurde die Fähigkeit zum Lidschluß meist als Apraxielähmung, motorische Impersistenz oder Zwangsblicken erklärt. Die Verbindung mit Zwangsgreifen und die Lokalisation der Läsion bei unseren Patienten spricht für eine pathogenetische Hypogenese mit Zwangscharakter. Es wird angenommen, daß die Unfähigkeit zum willkürlichen Lidschluß bei Frontalläsionen durch eine Enthemmung der forcierten Lidöffnung im Wachzustand bedingt ist mit überaktiver Wirkung visueller Reize, ähnlich dem „Zwangsblicken“ Zutts [19].