T. Kallanranta

Decreased driving ability in people with Parkinson’s disease

BACKGROUND Driving is a complex form of activity involving especially cognitive and psychomotor functions. These functions may be impaired by Parkinson’s disease. The relation between Parkinson’s disease and driving ability is still obscure and clinicians have to make decisions concerning the driving ability of their patients based on insufficent information. Until now no studies have compared different methods for evaluating the driving ability of patients with Parkinson’s disease. METHODS The driving ability of 20 patients with idiopathic Parkinson’s disease and 20 age and sex matched healthy control subjects was evaluated by a neurologist, psychologist, vocational rehabilitation counsellor, and driving instructor using a standard 10 point scale. The patients and controls also evaluated their own driving ability. Cognitive and psychomotor laboratory tests and a structured on road driving test were used for evaluating the subjects’ driving ability. RESULTS The patients with Parkinson’s disease performed worse than the controls both in the laboratory tests and in the driving test. There was a high correlation between the laboratory tests and driving test both in the patient group and in the control group. Disease indices were not associated with the driving test. The neurologist overestimated the ability of patients with Parkinson’s disease to drive compared with the driving ability evaluated by the structured on road driving test and with the driving related laboratory tests. Patients themselves were not capable of evaluating their own ability reliably. CONCLUSION Driving ability is greatly decreased in patients with even mild to moderate Parkinson’s disease. The evaluation of patients’ driving ability is very difficult to carry out without psychological and psychomotor tests and/or a driving test.

Early Neuropsychological Outcome after Carotid Endarterectomy

30 patients with a history of transient ischemic attacks (TIA) and 16 patients with cerebral infarcts were evaluated neuropsychologically 1-3 days before carotid endarterectomy, due to hemodynamically significant carotid artery stenosis, and again 2 weeks and 2 months after operation. Preoperatively, there were no differences between the groups, but postoperatively the neuropsychological outcome of the TIA patients was better than that of the infarction patients. Consequently, carotid endarterectomy patients cannot be studied as one group in neuropsychological examinations but various subgroups should be dealt with separately. In the TIA group 2 months after operation, the patients with left-sided operations had improved in verbal but not in visual tests, and the right-operated patients showed improvement also in visual tests. Therefore, the use of sum scores across neuropsychological tests is not preferable in the evaluation of the effects of carotid endarterectomy because after unilateral operation the cognitive improvement is greater in functions ipsilateral to the operation side.

Serial measurements of quantitative EEG and cerebral blood flow and circulation time after brain infarction

The quantitative EEG (QEEG), regional cerebral blood flow (rCBF) and circulation time of 17 patients were examined semisimultaneously thrice during the first 3 months after a cerebral supratentorial infarction. The EEG was quantified according to normalized slope descriptor technique in nine patients and by means of a combined period and amplitude analysis in eight patients. Intravenously injected isotopes 133Xenon and 99TcmO4 were used for blood flow and circulation time measurements. The QEEG‐values improved during the whole follow‐up period. Cerebral blood flow stayed low for all 3 months and did not alter during this period, while initially prolonged circulation time to some extent improved within 2 weeks remaining, however, prolonged even thereafter. A tendency for a positive correlation between QEEG and rCBF values in the infarcted hemisphere could be seen.

Evaluation of the driving ability in disabled persons: A practitioners' view

Purpose and methods. The purpose of this paper is to present, on the basis of four genuine cases from the Rehabilitation Research Unit of Oulu University, the theoretical frame in which evaluations of driving ability of disabled persons can be made. Results. First, it is not the operations with the control devices but the correct mental actions which the driver carries out with the help of the control devices which are crucial for safe driving. Second, driving ability is only partly a biomedical object of research and one ought to avoid an excessive medicalisation of an evaluation of driving ability. Third, the driver meets traffic situations not by his or her separate biological or psychological functions, such as vision, attention, memory, thinking, motives, but as an integrated whole, as a personality. Conclusions. By its complexity an evaluation of driving ability can be compared to an evaluation of working capacity where often a multidisciplinary team is needed. When evaluating driving ability we have to take a step from low-level motor operations towards high-level mental actions, from the measurement of acuity of eyesight towards the testing of the flexibility of perception, from the diagnosis-based evaluation to the patient-based evaluation, from using the common pencil – paper tests towards the traffic-related task-specific tests and from the testing of separate single general non-driving-related factors towards an evaluation of the theoretically based driving performance as whole.

ELECTRORETINOGRAM (ERG) AND VISUAL EVOKED RESPONSE (VER) STUDIES IN PATIENTS WITH OPTIC DISC DRUSEN

Non‐corneal ERGs, recorded from infraorbital skin electrodes to flash stimulation and mid‐occipital and parasagittal VERs to both flash stimulation and pattern reversal were performed in 26 patients with optic disc drusen. ERGs were normal in all patients. The mean VER amplitude was lower in the eyes with optic disc drusen than the mean amplitude of VERs in the normals but the interindividual variation was also so great in normals that the difference was not significant. The waveform of the major positive peak was quite often broad or split. VER latencies were usually in normal range although the visual field defects could be rather severe. Some other cause was present when the major positive peak was delayed.

Neurological findings in patients with pseudopapilloedema with and without verified optic disc drusen

ABSTRACT As part of a clinical examination of 200 patients with pseudopapilloedema with and without verified optic disc drusen, neuroophthalmological examinations were performed in 158, neurological examinations in 117 and electroencephalography in 109 patients. Headache and suspected papilloedema were the most frequent reasons for referral. Headache was one of the complaints in 102 patients. Migraine was diagnosed in 22 and suspected in 3 patients. Epilepsy was present in 9 patients and, in addition, 1 patient had had treatment for convulsions in childhood. 2 patients had a pituitary tumour and 1 had a tumour in the hypothalamic region. Various other neurological disorders appeared in small numbers. Abnormalities in electroencephalograms (EEGs) were found in 36 patients. Progressive loss of central visual acuity unexplained by retinal pathology as well as bitemporal and homonymous hemianopic visual field defects and also evidence of papilloedema warrant a neurological examination in patients with optic disc drusen.

Evaluation of cerebral infarctions of the carotid area by an intravenous 133Xenon and 99mTechnetium method.

Quantitative determinations of regional cerebral blood flow (rCBFf, rCBFm) and volume (rCBV), transfer time (rCTT) and fast compartmental weight (Wf) were performed in 34 patients with infarctions of the carotid area by a 133Xe and 99mTc intravenous injection method. The results were compared with clinical signs and electroencephalographic (EEG) findings.

Elimination of extracranial blood flow during dynamic cerebral perfusion studies using diffusible and non-diffusible radioisotope

The extracranial blood flow seriously complicates the interpretation of dynamic cerebral studies. To eliminate this, we used a blood pressure cuff placed around the head in 50 patients with no evidence of cerebrovascular disease. The pressure in the headband was increased to 30 mmHg above the patients systolic pressure, and the first 60 sec static scintigram was taken exactly 3 min after the injection of 99mTc‐pertechnetate. A second 60 sec static scintigram was taken without pressure in the headband at 6 min after injection. After correction for diffusion of tracer into extravascular compartments we could still show 13% reduction in counting rates over the hemispheric regions and 30% over the convexity regions during application of the pressure headband. With the Xenon method, the application of the headband appears to have insignificant influence on the results of cerebral perfusion. We thus recommend that a headband should be used for dynamic 99mTc‐isotope cerebral circulation studies.

PROSPECTIVE FOLLOW‐UP OF CAROTID ENDARTERECTOMY USING QUANTITATIVE EEG AND CEREBRAL CIRCULATION TIME

Cerebral blood flow tends to return to normal or near-normal values following internal carotid artery (ICA) endarterectomy (Engell et a1 1972, Obrist et a1 1975). In many instances the quantitative EEG (QEEG) is related to cerebral blood flow and metabolism (see Tolonen 1981). The present study prospectively evaluates the effect of an ICA endarterectomy in patients with hemodynamically significant symptomatic carotid stenosis clinically and by serial measurements of quantitative EEG (QEEG) and cerebral circulation time (CCT) during a half year follow-up time. The series consisted of 13 patients, their ages ranging from 45-70 years. Five of them Bad unilateral and two of them had bilateral carotid stenoses. Carotid stenosis on the operation side and old carotid occlusion contralaterally occured in six patients. Two of the patients had earlier suffered from supratentorial cerebral infarction. The EEG recorded from the occipital regions (s.c. alpha area) from-both hemispheres and also bilaterally corresponding to the lesionary area. It was off line quantified using power spectral density analysis. For the quantification of the EEG in cerebral ischemia the power spectral density method is superior to the many other generally used analysis techniques (Tolonen and Sulg 1981). CCT was measured by a multidetectgGmdevice brain helmet consisting of 32 detectors. 5-10 mCi of Tc was rapidly injected into an antecubital vein and the time activity curves were analysed by the modified gamma function fitting method. Interhemispheric differences of CCT instead of absolute values were used as an index because of variation of pertechnetate bolus dispersion due to changes in the systemic circulation and injection technique interand intraindividually. The method is presented in detail by Ahonen et a1 (1981). Both QEEG and CCT examinations were carried out preoperatively and thrice postoperatively (I day, 2 months, and 6 months after the endarterectomy).

INTRAVENOUS PERTECHNETATE CIRCULATION TIME CHANGES METHOD FOR ANALYSING OF GLOBAL AND REGIONAL CEREBRAL

Cerebral blood f low measurements have been g e n e r a l l y performed by d i f f u s i b l e i .sotopes such as by Xe-133 (Lassen e t a1 1978) . However d i f f u s i b l e i s o t o p e washout measurements are no t a p p l i c a b l e t o asymmetrical p a t h o l o g i c a l states where assumptions about tracer constancy of d i s t r i b u t i o n , volume and p a r t i t i o n c o e f f i c i e n t s cannot be he ld t o be v a l i d . Although t h e c l e a r a n c e of 133-Xenon have widely been used f o r measuring r e g i o n a l c e r e b r a l p e r f u s i o n hardly any r e g i o n a l c i r c u l a t i o n time measurements u s ing m u l t i d e t e c t o r dev ice and in t r avenous ly i n j e c t e d p e r t e c h n e t a t e have been performed.