Béatrice Leemann

Receptive amusia: temporal auditory processing deficit in a professional musician following a left temporo-parietal lesion

This study examined the musical processing in a professional musician who suffered from amusia after a left temporo-parietal stroke. The patient showed preserved metric judgement and normal performance in all aspects of melodic processing. By contrast, he lost the ability to discriminate or reproduce rhythms. Arrhythmia was only observed in the auditory modality: discrimination of auditorily presented rhythms was severely impaired, whereas performance was normal in the visual modality. Moreover, a length effect was observed in discrimination of rhythm, while this was not the case for melody discrimination. The arrhythmia could not be explained by low-level auditory processing impairments such as interval and length discrimination and the impairment was limited to auditory input, since the patient produced correct rhythmic patterns from a musical score. Since rhythm processing was selectively disturbed in the auditory modality, the arrhythmia cannot be attributed to a impairment of supra-modal temporal processing. Rather, our findings suggest modality-specific encoding of musical temporal information. Besides, it is proposed that the processing of auditory rhythmic sequences involves a specific left hemispheric temporal buffer.

Masticatory Function and Bite Force in Stroke Patients

Orofacial functions are frequently affected by stroke, but little is known on the nature and extent of the impairment of mastication, which is investigated in this observational study. Thirty-one stroke patients, aged 69.0 ± 12.7 yrs, presenting with a hemi-syndrome with facial palsy, were recruited. Chewing efficiency, maximum bite and restraining lip forces were tested. Stroke severity (National Institutes of Health Stroke Scale) and dental state were recorded. The control group was similar in age, gender, and dental state (n = 24). The chewing efficiency was significantly lower in the stroke group (p ≤ 0.0001) and was related to both the dental state and the lip forces measured with small and medium-sized labial plates. The maximum bite force proved to be not significantly different between sides or groups (n.s.), whereas lip force was significantly lower in the stroke group (p ≤ 0.05). Chewing efficiency is severely affected by stroke; thus, rehabilitation protocols should aim to restore the strength and co-ordination of the orofacial muscles.

Disorientation, Confabulation, and Extinction Capacity: Clues on How the Brain Creates Reality

BACKGROUND Disorientation and confabulation often have a common course, independent of amnesia. Behaviorally spontaneous confabulation is the form in which patients act according to a false concept of reality; they fail to abandon action plans (anticipations) that do not pertain to the present situation. This continued enactment of previously valid but meanwhile invalidated anticipations can be conceived as deficient extinction capacity, that is, failure to integrate negative prediction errors into behavior. In this study, we explored whether disorientation and behaviorally spontaneous confabulation are associated with extinction failure. METHODS Twenty-five patients hospitalized for neurorehabilitation after first-ever brain injury who either had severe amnesia (n = 17), an orbitofrontal lesion (n = 14), or both (n = 6) were tested regarding disorientation (questionnaire) and performed an experimental task of association learning and extinction. Five patients were also classified as behaviorally spontaneous confabulators. RESULTS Extinction capacity explained 66% of the variance of orientation in the whole group of patients (amnesics only, 56%; orbitofrontal group only, 90%), whereas association learning explained only 17% of the variance in the whole group (amnesics only, 7%; orbitofrontal group only, 16%). Also, extinction capacity, but not association learning, significantly distinguished between behaviorally spontaneous confabulators and all other subjects. CONCLUSIONS Disorientation and behaviorally spontaneous confabulation are strongly and specifically associated with a failure of extinction, the ability to learn that previously appropriate anticipations no longer apply. Rather than invoking high-level monitoring processes, the human brain seems to make use of an ancient biological faculty-extinction-to keep thought and behavior in phase with reality.

Neutral Functional Realignment Orthosis Prevents Hand Pain in Patients With Subacute Stroke: A Randomized Trial

OBJECTIVE To quantify the preventive effect of a neutral functional realignment orthosis on pain, mobility, and edema of the hand in subacute hemiparetic poststroke patients with severe motor deficits. DESIGN Randomized trial. SETTING Rehabilitation center. PARTICIPANTS Poststroke patients (N=30) with subacute hemiparesis and severe deficits of the upper limb were enrolled. Fifteen patients were randomized to a standard rehabilitation program without orthosis and 15 patients received an experimental orthosis in addition to their standard rehabilitation program. INTERVENTION The orthosis group wore the neutral functional realignment orthosis for at least 6 hours daily. MAIN OUTCOME MEASURES Hand pain at rest (visual analog scale), wrist range of motion (Fugl-Meyer Assessment subscale), and edema of hand and wrist (circumferences). Outcome measures were assessed at time of randomization and after 13 weeks between groups. RESULTS At baseline, 2 patients in each group complained about a painful hand. After 13 weeks, 8 subjects in the control group and 1 subject in the orthosis group complained of hand pain (P=.004). Mobility and edema evolved similarly in both groups. CONCLUSIONS Neutral functional realignment orthoses have a preventive effect on poststroke hand pain, but not on mobility and edema in the subacute phase of recovery.

Reality confusion in spontaneous confabulation

A woman produced spontaneous confabulations after rupture of an anterior communicating artery aneurysm. She confused currently irrelevant with currently relevant information in implicit memory; confabulations about people concerned only new acquaintances; false reality could be induced by an intensive 5-minute discussion; and in a recognition task, she confused false repetitions in another modality with real item repetitions. The findings support the theory that the defect causing spontaneous confabulation precedes conscious memory processing.

Crossover Trial of Subacute Computerized Aphasia Therapy for Anomia With the Addition of Either Levodopa or Placebo

Background. The effect of levodopa on recovery from aphasia is controversial. Objective. To determine whether levodopa enhances the effect of intensive computer-assisted therapy (CAT) of anomia in the postacute stage of aphasia. Methods. Double-blind multiple case study with intrasubject crossover design comparing the effect of levodopa (100 mg) versus placebo, each given for 2 weeks. Subjects. Twelve patients with onset of aphasia from 2 to 9 weeks after stroke or traumatic brain injury were compared on naming performance on items trained and not trained with CAT. Subjects were randomized to either levodopa or placebo first, separated by a 1-week washout, and then switched to the other drug intervention for the second 2-week CAT intervention. The subjects also received routine aphasia therapies during these periods. Results. All patients improved their naming performance for items trained by CAT in both periods (P = .001). No significant difference was found between the placebo and levodopa phases. Conclusion. Administration of levodopa for 2 weeks during the postacute stage of aphasia did not augment the positive effects of subacute intensive language treatment with CAT for a spoken naming task.

Carotid artery calcification in ischemic stroke patients detected in standard dental panoramic radiographs - a preliminary study

PURPOSE Examine the prevalence of carotid artery calcifications in standard dental panoramic radiographs (OPT), their association to gender, medical history and oral status. Assess the predictive value of a dental OPT in early diagnosis of carotid artery calcifications. MATERIAL AND METHODS Fourteen patients admitted to Geneva University Hospital for recent ischemic stroke and stenosis of the carotid artery confirmed by Duplex sonography. All OPTs were digitised and subsequently assessed independently by two operators. RESULTS From 21 carotid artery calcifications detected with Doppler sonography 15 were visible on the corresponding OPT, most of them on the right side (n=11). No correlation was found between the side of calcification and cerebral lesion. Hypertension and periodontal disease were the most prevalent cardiovascular risk factors. CONCLUSIONS Dentists who either detect carotid artery calcifications in OPTs or see patients with severe periodontitis should consider a prophylactic specialist examination.

The Role of the Cognitive Control System in Recovery from Bilingual Aphasia: A Multiple Single-Case fMRI Study

Aphasia in bilingual patients is a therapeutic challenge since both languages can be impacted by the same lesion. Language control has been suggested to play an important role in the recovery of first (L1) and second (L2) language in bilingual aphasia following stroke. To test this hypothesis, we collected behavioral measures of language production (general aphasia evaluation and picture naming) in each language and language control (linguistic and nonlinguistic switching tasks), as well as fMRI during a naming task at one and four months following stroke in five bilingual patients suffering from poststroke aphasia. We further applied dynamic causal modelling (DCM) analyses to the connections between language and control brain areas. Three patients showed parallel recovery in language production, one patient improved in L1, and one improved in L2 only. Language-control functions improved in two patients. Consistent with the dynamic view of language recovery, DCM analyses showed a higher connectedness between language and control areas in the language with the better recovery. Moreover, similar degrees of connectedness between language and control areas were found in the patients who recovered in both languages. Our data suggest that engagement of the interconnected language-control network is crucial in the recovery of languages.

Behaviorally spontaneous confabulation in limbic encephalitis: the roles of reality filtering and strategic monitoring

Behaviorally spontaneous confabulation is characterized by a confusion of reality evident in currently inappropriate acts that patients justify with confabulations and in disorientation. Here, we describe a 38-year-old woman lawyer hospitalized because of non-herpetic, presumably autoimmune, limbic encephalitis. For months, she considered herself at work and desperately tried to respect her falsely believed professional obligations. In contrast to a completely erroneous concept of reality, she did not confabulate about her remote personal past. In tasks proposed to test strategic retrieval monitoring, she produced no confabulations. As expected, she failed in tasks of reality filtering, previously shown to have high sensitivity and specificity for behaviorally spontaneous confabulation and disorientation: she failed to suppress the interference of currently irrelevant memories and she had deficient extinction capacity. The observation underscores the special status of behaviorally spontaneous confabulation among confabulatory phenomena and of reality filtering as a thought control mechanism. We suggest that different processes may underlie the generation of false memories and their verbal expression. We also emphasize the need to present theories of confabulation together with experimental tasks that allow one to empirically verify the theories and to explore underlying physiological mechanisms.

Iron-Deficiency Anemia as a Rare Cause of Cerebral Venous Thrombosis and Pulmonary Embolism

Cerebral venous thrombosis (CVT) is a relatively rare cause of stroke and has a wide spectrum of unspecific symptoms, which may delay diagnosis. There are many etiologies, including hematological disorders, trauma, infection, and dehydration. Iron-deficiency anemia (IDA) has been reported as an extremely rare cause of CVT, especially in adults.