RESUMO
Part 1 of this paper discussed several more general aspects of Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and offered a detailed, paradigmatic analysis of changes made to the chapter on depressive disorders. This second part focusses on several other disorders, including bipolar and schizophrenia spectrum disorders. The respective changes and their possible consequences are discussed under consideration of traditional psychiatric classification, particularly from the perspective of European traditions and on the basis of a PubMed search and review papers. The general conclusion is that even seemingly small changes such as the introduction of the mixed feature specifier can have far-reaching consequences. Contrary to the original plans, DSM-5 has not radically changed to become a primarily dimensional diagnostic system but has preserved the categorical system for most disorders. The ambivalence of the respective decision-making becomes apparent from the last minute decision to change the classification of personality disorders from dimensional back to categorical. The advantages and disadvantages of the different approaches are discussed in this context. In DSM-5, only the chapter on addictive disorders has a somewhat dimensional structure. Also in contrast to the original intentions, DSM-5 has not used a more neurobiological approach to disorders by including biological markers to increase the objectivity of psychiatric diagnoses. Even in the most advanced field in terms of biomarkers, the neurocognitive disorders, the primarily symptom-based, descriptive approach has been preserved and the well-known amyloid-related and other biomarkers are not included. This is because, even after so many years of biomarker research, the results are still not considered to be robust enough to use in clinical practice.
Assuntos
Manual Diagnóstico e Estatístico de Transtornos Mentais , Transtornos Mentais/classificação , Transtornos Mentais/diagnóstico , Transtornos Relacionados ao Uso de Substâncias/diagnóstico , Bases de Dados Factuais/estatística & dados numéricos , Humanos , Transtornos PsicofisiológicosRESUMO
DSM-5 was published in 2013 after about 10 years of preparation. Part 1 of this paper discusses several more general aspects of DSM-5 and offers a detailed, paradigmatic analysis of changes made to the chapter on depressive disorders. The background for the changes is analysed on the basis of a PubMed search and review papers on the classification of mental disorders in general and on empirical knowledge about individual disorders. Contrary to the original plans, DSM-5 has not introduced a primarily dimensional diagnostic system but has widely preserved the categorical system of disorders. Also, it has not adopted a more neurobiological approach to disorders by including biological markers to increase the objectivity of psychiatric diagnoses but has maintained the primarily symptom-based, descriptive approach. The criteria for some disorders have been changed, including affective, schizophrenic and addiction disorders, and a few new disorders have been added. A minimal version of the dimensional approach was realised through the introduction of several transnosological specifiers and the option to make symptom- or syndrome-related severity and dimensional assessments. These specifiers and assessments might allow a more individualised description of a patient's psychopathological state and more personalised treatment. However, most of the symptom- and syndrome-related assessments are not mandatory and therefore may not be used in clinical practice.
Assuntos
Transtorno Depressivo/diagnóstico , Manual Diagnóstico e Estatístico de Transtornos Mentais , Transtorno Depressivo/classificação , Humanos , Avaliação de SintomasRESUMO
Using the example of dementia in Alzheimer's disease, it is shown which opportunities but also risks are posed by newer methodological approaches of artificial intelligence (AI) for the diagnosis and treatment of Alzheimer's dementia (AD). In addition, AI is examined in the context of an ethical-philosophical critique of technology.
Assuntos
Doença de Alzheimer , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/terapia , Inteligência Artificial , Alemanha , HumanosRESUMO
High-frequency test stimulation for tremor suppression is a standard procedure for functional target localization during deep brain stimulation. This method does not work in cases where tremor vanishes intraoperatively, for example, due to general anaesthesia or due to an insertional effect. To overcome this difficulty, we developed a stimulation technique that effectively evokes tremor in a well-defined and quantifiable manner. For this, we used patterned low-frequency stimulation (PLFS), i.e. brief high-frequency pulse trains administered at pulse rates similar to neurons' preferred burst frequency. Unlike periodic single-pulse stimulation, PLFS enables one to convey effective and considerably greater integral charge densities without violation of safety requirements. In a computational investigation of an oscillatory neuronal network temporarily rendered inactive, we found that PLFS evokes synchronized activity, phase locked to the stimulus. While a stronger increase in the amount of synchrony in the neuronal population requires higher stimulus intensities, the portion of synchronously active neurons nevertheless becomes strongly phase locked to PLFS already at weak stimulus intensities. The phase entrainment effect of PLFS turned out to be robust against variations in the stimulation frequency, whereas enhancement of synchrony required precisely tuned stimulation frequencies. We applied PLFS to a patient with spinocerebellar ataxia type 2 (SCA2) with pronounced tremor that disappeared intraoperatively under general anaesthesia. In accordance with our computational results, PLFS evoked tremor, phase locked to the stimulus. In particular, weak PLFS caused low-amplitude, but strongly phase-locked tremor. PLFS test stimulations provided the only functional information about target localization. Optimal target point selection was confirmed by excellent post-operative tremor suppression.
Assuntos
Estimulação Encefálica Profunda/métodos , Tremor Essencial/fisiopatologia , Neurônios/metabolismo , Ataxias Espinocerebelares/fisiopatologia , Tremor/fisiopatologia , Adulto , Biofísica/métodos , Simulação por Computador , Tremor Essencial/diagnóstico , Humanos , Modelos Biológicos , Modelos Neurológicos , Modelos Estatísticos , Modelos Teóricos , Oscilometria , Ataxias Espinocerebelares/diagnóstico , Núcleo Subtalâmico/fisiologia , Tremor/diagnósticoRESUMO
This is a single case report of a patient with spinocerebellar ataxia type 2 (SCA2) and severe tremor. Whereas disease progression with prevailing ataxia and dysmetria was slow over the first symptomatic 6 years, 6 months prior to operation were characterized by the development of a severe, debilitating postural tremor rendering the patient unable to independently sit, stand, speak, or swallow. Deep brain stimulation (DBS) at a subthalamic-thalamic electrode position almost completely arrested her tremor. The patient regained the functional state prior to her rapid disease progression allowing a restricted range of daily activities. Her condition has remained approximately stable over the two postoperative years to date. In addition to the efficacy of DBS on cerebellar tremor, the results illustrate a remarkable improvement of the patient's general condition and independence.
Assuntos
Estimulação Encefálica Profunda , Ataxias Espinocerebelares/terapia , Núcleo Subtalâmico/fisiopatologia , Tremor/terapia , Núcleos Ventrais do Tálamo/fisiopatologia , Atividades Cotidianas/classificação , Adulto , Eletrodos Implantados , Feminino , Seguimentos , Humanos , Exame Neurológico , Ataxias Espinocerebelares/diagnóstico , Ataxias Espinocerebelares/fisiopatologia , Torcicolo/diagnóstico , Torcicolo/fisiopatologia , Torcicolo/terapia , Resultado do Tratamento , Tremor/diagnóstico , Tremor/fisiopatologiaRESUMO
In order to study the temporal activation course of visual areas V1 and V5 in response to a motion stimulus, a random dots kinematogram paradigm was applied to eight subjects while magnetic fields were recorded using magnetoencephalography (MEG). Sources generating the registered magnetic fields were localized with Magnetic Field Tomography (MFT). Anatomical identification of cytoarchitectonically defined areas V1/V2 and V5 was achieved by means of probabilistic cytoarchitectonic maps. We found that the areas V1/V2 and V5+ (V5 and other adjacent motion sensitive areas) exhibited two main activations peaks at 100-130 ms and at 140-200 ms after motion onset. The first peak found for V1/V2, which corresponds to the visual evoked field (VEF) M1, always preceded the peak found in V5+. Additionally, the V5+ peak was correlated significantly and positively with the second V1/V2 peak. This result supports the idea that the M1 component is generated not only by the visual area V1/V2 (as it is usually proposed), but also by V5+. It reflects a forward connection between both structures, and a feedback projection to V1/V2, which provokes a second activation in V1/V2 around 200 ms. This second V1/V2 activation (corresponding to motion VEF M2) appeared earlier than the second V5+ activation but both peaked simultaneously. This result supports the hypothesis that both areas also generate the M2 component, which reflects a feedback input from V5+ to V1/V2 and a crosstalk between both structures. Our study indicates that during visual motion analysis, V1/V2 and V5+ are activated repeatedly through forward and feedback connections and both contribute to m-VEFs M1 and M2.
Assuntos
Percepção de Movimento/fisiologia , Córtex Visual/fisiologia , Adulto , Idoso , Algoritmos , Mapeamento Encefálico , Cadáver , Potenciais Evocados Visuais/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Distribuição Normal , Estimulação Luminosa , Córtex Visual/anatomia & histologiaRESUMO
Pattern reversal stimulation provides an established tool for assessing the integrity of the visual pathway and for studying early visual processing. Numerous magnetoencephalographic (MEG) and electroencephalographic (EEG) studies have revealed a three-phasic waveform of the averaged pattern reversal visual evoked potential/magnetic field, with components N75(m), P100(m), and N145(m). However, the anatomical assignment of these components to distinct cortical generators is still a matter of debate, which has inter alia connected with considerable interindividual variations of the human striate and extrastriate cortex. The anatomical variability can be compensated for by means of probabilistic cytoarchitectonic maps, which are three-dimensional maps obtained by an observer-independent statistical mapping in a sample of ten postmortem brains. Transformed onto a subject's brain under consideration, these maps provide the probability with which a given voxel of the subject's brain belongs to a particular cytoarchitectonic area. We optimize the spatial selectivity of the probability maps for V1 and V2 with a probability threshold which optimizes the self- vs. cross-overlap in the population of postmortem brains used for deriving the probabilistic cytoarchitectonic maps. For the first time, we use probabilistic cytoarchitectonic maps of visual cortical areas in order to anatomically identify active cortical generators underlying pattern reversal visual evoked magnetic fields as revealed by MEG. The generators are determined with magnetic field tomography (MFT), which reconstructs the current source density in each voxel. In all seven subjects, our approach reveals generators in V1/V2 (with a greater overlap with V1) and in V5 unilaterally (right V5 in three subjects, left V5 in four subjects) and consistent time courses of their stimulus-locked activations, with three peak activations in V1/V2 (contributing to C1m/N75m, P100m, and N145m) and two peak activations in V5 (contributing to P100m and N145m). The reverberating V1/V2 and V5 activations demonstrate the effect of recurrent activation mechanisms including V1 and extrastriate areas and/or corticofugal feedback loops. Our results demonstrate that the combined investigation of MEG signals with MFT and probabilistic cytoarchitectonic maps significantly improves the anatomical identification of active brain areas.