Background: Neuropsychological studies of the pattern and extent of cognitive impairment in HIV-infected patients have mostly used deviations from control values and/or cut-off scores as criteria for classification of dementia. There is, however, no agreement as to how to define impairment, and classification is imprecise. Method: The current study used a dementia classification matrix, developed with a step-wise linear discriminant analysis of neuropsychological data from patients with primary neurodegenerative dementias, to classify symptomatic HIV patients as demented or non-demented, and further to differentiate cortical and subcortical dementia patterns. Thirty-two male and 2 female patients (mean age 39 ± 2) with symptomatic HIV disease (mean absolute CD4 count 195 ±41) participated in the study. Results: Thirty-five per cent of patients were classified as demented. Of these, 83% showed a subcortical pattern and 17% a cortical profile of deficits. Significant differences between patients classified as subcortically demented and those categorized as normal on neuropsychological measures associated with subcortical integrity further validated the classification. Measures of psychiatric status between subgroups were similar. Conclusion: Since certain treatments may delay or reverse cognitive deficits, the use of an objective classification method based on discriminant analysis may help to identify patients who may benefit from therapy.

Background: No clinical parameter other than “sufficient” dopamine denervation and exposure to exogenous levodopa has been unquestionably linked to dyskinesia in levodopa-treated Parkinson’s disease patients. Methods: We retrospectively analyzed data on 100 consecutive patients treated with levodopa for 1 to 18 years to identify clinical risk factors for dyskinesia. The cumulative dyskinesia-free survival probability in relation to levodopa therapy was assessed using the Kaplan-Meier method. Results: Overall, 56% of patients developed dyskinesia after a mean of 2.9 years, a figure similar to the average duration of levodopa treatment in the non-dyskinetic group. Dyskinetic patients were significantly younger at disease onset, but their mean latency to dyskinesia induction after levodopa initiation was not different from older dyskinetic individuals and the overall dyskinesia-free survival of younger subjects was not worse either. Dyskinetic patients were on a higher daily levodopa dose than non-dyskinetic subjects when dyskinesia emerged, but the cumulative levodopa dose used prior to dyskinesia did not discriminate dyskinetic from non-dyskinetic patients. A delay in initiating levodopa therapy of more than three years after disease onset and levodopa treatment initiation in Hoehn-Yahr stage II compared to stage I patients did not increase the probability of developing dyskinesia over time. Conclusions: Since withholding levodopa therapy did not increase the risk for dyskinesia in our patients and can delay the emergence of dyskinesia after onset of parkinsonian symptom, a trial with a dopaminomimetic agonist as initial treatment appears logical.

Background: We set out to determine whether separable visual and representational components underlie normal subjects’ upward and distal biases in bisecting vertical and radial lines under visual guidance. Methods: Thirty-four normal subjects were asked to bisect lines oriented horizontally, vertically, and radially. Human silhouette figures were placed at either end of each line. These figures were presented upright or upside down in order to pictorially define a “top” to each line independent of the actual top of the visual field. Results: Although subjects erred toward the top of the visual field, they also demonstrated a significant bias toward the heads of the figures for lines in all spatial orientations. Conclusions: This result supports the existence of two biases: one toward the upper visual field, and another toward an internally represented “top” as suggested pictorially. These findings provide further support for the hypothesis that normal subjects’ upward and distal biases on bisection of vertical and radial lines under visual guidance have both representational and visual-based components.

Objective: To quantify the performance of patients with Parkinson’s disease (PD) in incentive learning, or learning to respond to stimuli that signal the imminent presentation of a reinforcer, and in paired-associate learning, or learning of word associations. Methods: The performance of 32 patients with idiopathic PD was compared to that of 25 healthy control subjects, and 32 subjects suffering from arthritis, matched for age and education. The PD and arthritic groups were comparable on a self-report measure of physical disability. All subjects were physically capable of satisfying the contingencies of the incentive learning task. The avoidance task that quantified incentive learning used money loss as an aversive stimulus. The word paired-associate learning task was presented on a computer and feedback was not given on performance. Results: The normal and arthritic groups performed equally well on the avoidance task, whereas the PD group was impaired despite dopaminergic replacement therapy. The groups did not differ significantly in paired-associate learning. Conclusions: These findings are among the first to suggest that the nigrostriatal dopamine dysfunction associated with PD may play a role in incentive learning but not in paired-associate learning and are consistent with a role for dopamine in certain forms of learning and memory. The findings may highlight differences between tonic and modulated function in the nigrostriatal system.

In the last few years a number of new antiepileptic drugs ahve been introduced for the treatment of epilepsy. In addition to the standard antiepileptic drugs, clobazam, vigabatrin, gabapentin, and lamotrigine have been introduced. The choice of the best antiepileptic drug for an individual patient has become more complex. In this review the clinical benefits of the standard and the new antiepileptic drugs are presented.

Background: There is currently no consensus on the best way to localize muscles in the forearm for botulinum toxin (BTX) injection. We devised a study to compare electromyography (EMG) with local stimulation through a cannula for localizing forearm muscles for botulinum toxin (BTX) injection, and for predicting the risk of unwanted weakness in non-target muscles. Methods: In 12 patients with focal hand dystonia a single “target” muscle, determined by clinical examination to contribute most to the dystonic hand posture, was selected for botulinum toxin injection. The patients were randomized into 2 treatment groups, one in which the target muscle was localized by recording the EMG signals during voluntary contractions (8 patients) and the other in which the target muscle was localized by local electrical stimulation (4 patients). The target muscle was then injected with a standardized dose of BTX. Results: At follow-up 3 weeks after BTX injection the target muscle was weakened in 7/12 patients (4/8 of the EMG group, and 3/4 of the stimulation group). Additional non-injected muscles, adjacent to the target muscle, were weakened in 5 of these 7 patients, presumably from diffusion of the toxin. Conclusions: Localization by stimulation is probably at least as good as EMG. Each technique has certain advantages. Weakness of “non-target” muscles was not consistently predicted by either EMG or stimulation suggesting that BTX diffuses farther than the volume conduction of EMG signals or the spread of effective stimulus current.

Objective: To present guidelines on the use of apomorphine in combination with rectal domperidone in Parkinson’s disease (PD) patients undergoing abdominal surgery and to review the perioperative problems encountered in such patients. Background: PD patients undergoing abdominal surgery present a major therapeutic challenge. Because most antiparkinsonian medications must be withheld until the patient is able to resume oral intake, resulting rigidity and akinesia as well as alterations in gastrointestinal motility, respiratory function and swallowing mechanisms predispose these patients to numerous serious postoperative complications. We have found that parenteral apomorphine in combination with rectal domperidone markedly facilitates the care of these difficult patients. Methods: Presentation of two illustrative cases with review of the literature. Results: A standardized protocol using subcutaneous apomorphine and rectal domperidone was used in two PD patients who underwent abdominal surgery. Excellent control of parkinsonian symptomatology was obtained without side effects. The simplicity of the protocol was emphasized in our second patient who required urgent reoperation; the surgery nursing staff was able to restart the apomorphine immediately without having to wait for neurological follow-up assessment. Conclusions: The use of parenteral apomorphine with rectal domperidone in the immediate postoperative period for patients unable to take oral antiparkinson drugs increases patient comfort, facilitates nursing care and may reduce serious postoperative complications.

Background: The observation that resection of structural lesions of the frontal lobe provides an effective treatment of intractable epilepsy has been made by surgeons specializing in this field for over sixty years! However, the excellent results achieved when such resections are coupled with the use of modern diagnostic and operative technologies are not fully appreciated by the modern clinician. Methods: We review the results of resection of large post traumatic frontal lesions in six patients with intractable frontal seizures. No invasive EEG recording was required pre-operatively. Results: The imaging characteristics of the underlying lesions, usually due to depressed skull fractures are illustrated. Surgical treatment rendered five patients seizure free and the sixth had over 85% improvement in seizure frequency. Conclusions: Modern imaging permits ready visualization of the post traumatic lesions with cause intractable seizures. It is important to recognize that resection of these post traumatic scars usually leads to excellent seizure control.

Background and Objective: In preparation for analytic study we undertook to describe areas of relative excess and deficit of Parkinson’s Disease (PD) in Nebraska and tested two methodologic tools for inexpensive assessment of descriptive epidemiology of PD. Methods: In lieu of large-scale population screening and diagnosis, we obtained sales information of anti-PD drugs in the state in 1988 – 1990 as well as listings of all people dying from 1984 to 1993 who had Parkinson’s Disease mentioned anywhere on their death certificate. The anti-PD drug sales data are intended as a proxy for prevalence, while the death certificate data are intended as a proxy for incidence. Results: Sales divided by population over age 54 indicates where anti-PD drug sales differ from expected. We found high correlation of drug sales rates with several farming exposures. Age-adjusted death rates, however, showed a low degree of association with sales or farming variables. This may be attributable to differences in death certificate completion or in underlying incidence versus prevalence. Conclusions: These techniques provide a useful tool for delineating possible differences in incidence and prevalence. While not as accurate as full community survey with expert diagnosis, they are not as expensive, and can be followed by local cluster investigations and individual-level etiologic studies to test hypotheses resulting from the initial study.

Objective: The interactions between sleep, neck muscle activity, and cervical spinal pain were examined in a controlled study with nine patients suffering from idiopathic cervical dystonia (ICD; also referred to as spasmodic torticollis), and nine gender- and age-matched controls. Methods: From each participant, two all-night polysomnograms with additional electromyographic recordings from the sternocleidomastoid and upper trapezius muscles were obtained. The first night was for habituation to the laboratory environment; the second night for experimental data collection. Visual analogue scales were used to collect intensity and unpleasantness ratings of cervical spinal pain before and after the second sleep recording. Results: None of the standard sleep variables showed statistically significant differences between average values of both groups of participants. However, a significantly larger variance in sleep latency was obtained for the ICD patients. In general, abnormal cervical muscle activity decreased immediately when lying down without the intention to go to sleep. Subsequently, abnormal muscle contractions were gradually abolished in all ICD patients during the transition from relaxed wakefulness to light NREM sleep. Following this transition phase, no more abnormal EMG activity was found in any of our patients. Finally, cervical spinal pain intensity and unpleasantness were reduced by about 50% overnight. Conclusions: Both supine position and sleep can be associated with an improvement of symptoms of ICD, and this disorder does not induce any sleep perturbations.

Background: Brain tumors comprise more than 20% of all childhood malignancies, and constitute the greatest number of solid pediatric cancers. Incidence rates reported have varied from 2.4 to 3.5/100, 000 children, reflecting the impact of modern imaging techniques, the application of diverse investigative methodologies, and the accessibility of the community to health care. Methods: Material from patients < 18 years of age was collated from the Manitoba Cancer Foundation Tumor Registry, the personal records of Winnipeg pediatric neurologists, and autopsy data. Patient data were also obtained from hospital charts and operating room log books. Histological sections were examined and classified according to the American Cancer Society by a single neuropathologist. The chi-square test was used for statistical evaluation. Results: During the seven-year study period, the diagnosis of brain tumor was made in 89 pediatric patients, of which 88 were diagnosed premortem. The overall average annual incidence rate for both sexes was 4.03/100, 000 child-years, higher than that previously reported. The male and female average annual incidence rates were 4.2 and 3.7/100, 000 child-years, respectively. Tumor type and location were relatively unremarkable, with an expected peak of medulloblastoma occurring in young males. The yearly incidence of tumor occurrence was fairly stable, and the geographic distribution of cases within Manitoba, homogeneous. Conclusion: The highest incidence rates of pediatric brain tumors have been recorded in countries possessing sophisticated universal health care systems, possibly reflecting their efficacy in disease surveillance.