Jean E. Cibula

Conduction Aphasia and the Arcuate Fasciculus: A Reexamination of the Wernicke–Geschwind Model ☆

Wernicke, and later Geschwind, posited that the critical lesion in conduction aphasia is in the dominant hemispheres arcuate fasciculus. This white matter pathway was thought to connect the anterior language production areas with the posterior language areas that contain auditory memories of words (a phonological lexicon). Alternatively, conduction aphasia might be induced by cortical dysfunction, which impairs the phonological output lexicon. We observed an epileptic patient who, during cortical stimulation of her posterior superior temporal gyrus, demonstrated frequent phonemic paraphasias, decreased repetition of words, and yet had intact semantic knowledge, a pattern consistent with conduction aphasia. These findings suggest that cortical dysfunction alone may induce conduction aphasia.

A review of diagnostic techniques in the differential diagnosis of epileptic and nonepileptic seizures.

The diagnosis of psychogenic nonepileptic seizures (PNES) is complex. Long-term electroencephalogram monitoring with video recording (video EEG) is the most common method of differential diagnosis of epilepsy and PNES. However, video EEG is complex, costly, and unavailable in some areas. Thus, alternative diagnostic techniques have been studied in the search for a diagnostic method that is as accurate as video EEG, but more cost effective, convenient, and readily available. This paper reviews the literature regarding possible diagnostic alternatives and organizes findings into 7 areas of study: demographic and medical history variables, seizure semiology, provocative testing, prolactin levels, single photon emission computed tomography, psychological testing, and neuropsychological testing. For each area, the literature is summarized, and conclusions about the accuracy of the technique as a diagnostic tool are drawn. Overall, it appears unlikely that any of the reviewed alternative techniques will replace video EEG monitoring; rather they may be more successful as complementary diagnostic tools. An important focus for further investigations involves combinations of diagnostic techniques for the differential diagnosis of epilepsy and PNES.

Vagus nerve stimulation therapy for epilepsy in older adults

Article abstract The authors assessed the efficacy, safety, and tolerability of vagus nerve stimulation (VNS) for refractory epilepsy in 45 adults 50 years of age and older. They determined seizure frequency, adverse effects, and quality of life. At 3 months, 12 patients had a >50% decrease in seizure frequency; at 1 year, 21 of 31 studied individuals had a >50% seizure decrease. Side effects were mild and transient. Quality of life scores improved significantly with time.

Performance of Patients with Epilepsy or Psychogenic Non-Epileptic Seizures on Four Measures of Effort

Exaggeration of cognitive symptoms or poor effort on cognitive testing has been addressed primarily in the traumatic brain injury literature. The present investigation aims to extend the evaluation of effort to the epilepsy monitoring setting, where base rates of failure on effort testing remain unknown for patients with intractable epilepsy (ES), psychogenic nonepileptic seizures (PNES), or both conditions (ES+PNES). In addition, this investigation explores how well four measures of effort (DMT, LMT, TOMM, PDRT) distinguish between these diagnostic groups. Results show that 20% of the combined sample failed one or more effort measure. When examining failure rates for each diagnostic group, 22% of epilepsy patients, 24% of PNES patients, and 11% of ES+PNES patients performed suboptimally on one or more measure of effort. The utility of these effort measures to differentiate between these diagnostic groups appears limited. Further research is needed to clarify the base rate of poor effort in the epilepsy monitoring unit setting in general and in these three diagnostic groups specifically.

SECONDARY EPILEPTOGENESIS IN HUMANS

Secondary epileptogenesis as it applies to humans remains a controversial topic despite 40 years of investigation. Part of the controversy stems from disagreement about the definition of secondary epileptogenesis, and part of the controversy stems from the imperfect fit of animal models to the human epileptic syndromes. It may be that models of secondary epileptogenesis can be useful to describe specific epileptic syndromes such as bitemporal epilepsy and secondary bilateral synchrony, but other models may be required for remitting syndromes such as the Landau-Kleffner syndrome. The concept of secondary epileptogenesis may also provide a useful construct for evaluating patients with partial epileptic syndromes, especially those under consideration for epilepsy surgery, and for the evaluation of preventive strategies in epilepsy.

A Comparison of MMPI-2 Decision Rules in the Diagnosis of Nonepileptic Seizures

The differential diagnosis of epileptic seizures (ES) and psychogenic nonepileptic seizures (PNES) continues to be a common concern in epilepsy treatment centers. The MMPI/MMPI-2 is the most commonly studied psychological measure in the differential diagnosis of ES and PNES. Wilkus, Dodrill, and Thompson (1984) and Derry and McLachlan (1996) both developed decision rules for use with the MMPI and MMPI-2 to assist in this diagnostic discrimination. Both sets of decision rules were evaluated in a sample of ES (n = 58), PNES (n = 29) and epilepsy plus PNES (n = 19) patients. Validity of the epilepsy diagnosis was established with 24-hr video-EEG monitoring in all cases. The two sets of decision rules applied to the MMPI-2 showed sensitivities of 68% and 48% and specificity values of 55% and 58%. Calculation of positive and negative predictive power for both sets of rules at three different base rates suggests that use of these rules can result in a large number of false positive diagnoses of PNES.

Apraxia and motor-skill acquisition in Alzheimersdisease are dissociable

Many patients with Alzheimers disease (AD) are apraxic and the apraxia has been posited to be related to a loss of movement representations. Whereas patients with Alzheimers disease have been reported to demonstrate normal motor learning on a rotor pursuit skill acquisition task, it is unknown whether AD subjects who are apraxic demonstrate normal skill-learning. We tested subjects with probable AD and normal controls on a rotor pursuit task. We also tested the AD subjects for ideomotor apraxia. Subjects with AD who were apraxic had normal motor learning. In addition, praxis score did not correlate with performance on the skill-acquisition task. The results suggest that ideomotor praxis and motor learning are at least partly dissociable.

Emotional conversations in Parkinson’s disease

Objective: To learn how PD influences verbal description of emotional events. Background: Individuals with PD exhibit emotional processing deficits. Emotional experience likely involves several dimensions (e.g., valence, arousal, motor activation) subserved by a distributed modular network involving cortical, limbic, basal ganglia, diencephalic, and mesencephalic regions. Although the neurodegeneration in PD likely affects components in this network, little is known about how PD influences emotional processing. Because PD is associated with activation deficits, one could predict that the discourse of emotional experiences involving high activation would be reduced in patients with PD compared to control subjects. Alternatively, because patients with PD exhibit paradoxical sensitivity to externally evoked motor activation (kinesia paradoxica), it is possible that emotional stimuli may facilitate verbal emotional expression more so in patients with PD than in control subjects. Methods: The authors measured verbal descriptions of personal emotional experiences in subjects with PD and normal controls. Results: Compared with control subjects, individuals with PD showed a relative increase in the number of words spoken and in discourse duration when talking about emotional experiences that are usually associated with high levels of arousal and motor activation. Although the authors did not measure arousal or activation, prior research has shown that, when asked to recall an emotional experience, people will often re-experience the emotion previously experienced during that episode. Conclusions: Recalling emotional episodes induces verbal kinesia paradoxica in patients with PD. Although recall of these emotional episodes may have been associated with increased arousal and activation, the mechanism underlying emotional verbal kinesia paradoxica is unclear.

Anosognosia and confabulation during the Wada test

Feinberg et al. proposed that right-hemisphere-damaged stroke patients with anosognosia for hemiplegia (AHP) confabulate seeing stimuli on the left side but those without AHP admit to having inadequate visual information. This study examines the relationship between AHP and confabulation using selective anesthesia of the cerebral hemispheres. Seventeen patients with intractable epilepsy were tested during intracarotid methohexital infusion. For half of the trials, subjects were stimulated on their paretic hand with a material (sandpaper, metal, or cloth), and for the remaining trials they were not stimulated. The subjects were trained to use a pointing response to indicate if they been stimulated and the type of material they had felt. Admission of uncertainty was defined as pointing to a question mark. Confabulation was defined as any material response to a no-touch trial. During anesthesia of either hemisphere, subjects with and without AHP confabulated responses. The AHP and non-AHP groups did not differ in admission of uncertainty. Our results support the postulate that confabulation and AHP are independent disorders, and therefore confabulation cannot fully account for AHP.

Prior Podcast Experience Moderates Improvement in Electroencephalography Evaluation After Educational Podcast Module.

BACKGROUND:There is continued interest in using technology to enhance medical education and the variables that may affect its success. METHODS:Anesthesiology residents and fourth-year medical students participated in an electroencephalography (EEG) educational video podcast module. A 25-item evaluation tool was administered before any EEG education was provided (baseline), and the podcast was then viewed. Another 25-item evaluation tool was administered after podcast viewing (after podcast). Ten EEG interpretations were completed with a neurophysiologist with an additional 25-item evaluation tool administered after the interpretations (after 10 EEG interpretations). Participants were surveyed concerning technology and podcasting experience before the educational module and their responses to the podcast educational model. Multiple analyses were performed (1) to evaluate differences in improvement in EEG evaluation scores between the podcast module and the standard didactics (control group); and (2) to evaluate potential moderation by technology and the podcast experience on the change in mean EEG evaluation scores from after the podcast module to after 10 EEG interpretations. RESULTS:A total of 21 anesthesiology residents and 12 fourth-year medical students participated. Scores on the 25-item evaluation tool increased with each evaluation time (P ⩽ 0.001). Moderation analyses revealed that individuals with more podcast experience (≥4 previous podcasts) had greater increases in scores after a podcast and 10 EEG interpretations compared with individuals with less experience (⩽3 previous podcasts) (P = 0.027). Furthermore, compared with a control group with similar baseline characteristics that received only standard didactics without a podcast, those in the podcast group had greater increases in mean EEG evaluation scores between baseline and after 10 EEG interpretations. CONCLUSIONS:In reviewing the improvement in EEG evaluation after a podcast education module, those with more podcast experience achieved greater gains in EEG evaluation scores. For EEG education, those receiving the podcast education module showed greater increases in scores compared with those receiving didactic teaching without podcasting, as measured by change in a mean EEG evaluation scores.