Functional networks of motor inhibition in conversion disorder patients and feigning subjects.

The neural correlates of motor inhibition leading to paresis in conversion disorder are not well known. The key question is whether they are different of those of normal subjects feigning the symptoms. Thirteen conversion disorder patients with hemiparesis and twelve healthy controls were investigated using functional magnetic resonance tomography under conditions of passive motor stimulation of the paretic/feigned paretic and the non-paretic hand. Healthy controls were also investigated in a non-feigning condition. During passive movement of the affected right hand conversion disorder patients exhibited activations in the bilateral triangular part of the inferior frontal gyri (IFG), with a left side dominance compared to controls in non-feigning condition. Feigning controls revealed for the same condition a weak unilateral activation in the right triangular part of IFG and an activity decrease in frontal midline areas, which couldn't be observed in patients. The results suggest that motor inhibition in conversion disorder patients is mediated by the IFG that was also involved in inhibition processes in normal subjects. The activity pattern in feigning controls resembled that of conversion disorder patients but with a clear difference in the medial prefrontal cortex. Healthy controls showed decreased activity in this region during feigning compared to non-feigning conditions suggesting a reduced sense of self-agency during feigning. Remarkably, no activity differences could be observed in medial prefrontal cortex for patients vs healthy controls in feigning or non-feigning conditions suggesting self-agency related activity in patients to be in between those of non-feigning and feigning healthy subjects.

A structural MRI study of motor conversion disorder: evidence of reduction in thalamic volume.

OBJECTIVE: To investigate potential abnormalities in subcortical brain structures in conversion disorder (CD) compared with controls using a region of interest (ROI) approach. METHODS: Fourteen patients with motor CD were compared with 31 healthy controls using high-resolution MRI scans with an ROI approach focusing on the basal ganglia, thalamus and amygdala. Brain volumes were measured using Freesurfer, a validated segmentation algorithm. RESULTS: Significantly smaller left thalamic volumes were found in patients compared with controls when corrected for intracranial volume. These reductions did not vary with handedness, laterality, duration or severity of symptoms. CONCLUSIONS: These differences may reflect a primary disease process in this area or be secondary effects of the disorder, for example, resulting from limb disuse. Larger, longitudinal structural imaging studies will be required to confirm the findings and explore whether they are primary or secondary to CD.

Altered central somatosensory processing in chronic pain patients with "hysterical" anesthesia.

OBJECTIVE: The authors hypothesized that central factors may underlie sensory deficits in patients with nondermatomal somatosensory deficits (NDSD) and that functional brain imaging would reveal altered responses in supraspinal nuclei. BACKGROUND: Patients with chronic pain frequently present with NDSD, ranging from hypoesthesia to complete anesthesia in the absence of substantial pathology and often in association with motor weakness and occasional paralysis. Patients with pain and such pseudoneurologic symptoms can be classified as having both a pain disorder and a conversion disorder (Diagnostic and Statistical Manual of Mental Disorders-IV classification). METHODS: The authors tested their hypothesis with functional MRI (fMRI) of brush and noxious stimulation-evoked brain responses in four patients with chronic pain and NDSD. RESULTS: The fMRI findings revealed altered somatosensory-evoked responses in specific forebrain areas. Unperceived stimuli failed to activate areas that were activated with perceived touch and pain: notably, the thalamus, posterior region of the anterior cingulate cortex (ACC), and Brodmann area 44/45. Furthermore, unperceived stimuli were associated with deactivations in primary and secondary somatosensory cortex (S1, S2), posterior parietal cortex, and prefrontal cortex. Finally, unperceived (but not perceived) stimuli activated the rostral ACC. CONCLUSIONS: Diminished perception of innocuous and noxious stimuli is associated with altered activity in many parts of the somatosensory pathway or other supraspinal areas. The cortical findings indicate a neurobiological component for at least part of the symptoms in patients presenting with nondermatomal somatosensory deficits.

Functional neuroanatomical correlates of hysterical sensorimotor loss.

Hysterical conversion disorders refer to functional neurological deficits such as paralysis, anaesthesia or blindness not caused by organic damage but associated with emotional "psychogenic" disturbances. Symptoms are not intentionally feigned by the patients whose handicap often outweighs possible short-term gains. Neural concomitants of their altered experience of sensation and volition are still not known. We assessed brain functional activation in seven patients with unilateral hysterical sensorimotor loss during passive vibratory stimulation of both hands, when their deficit was present and 2-4 months later when they had recovered. Single photon emission computerized tomography using (99m)Tc-ECD revealed a consistent decrease of regional cerebral blood flow in the thalamus and basal ganglia contralateral to the deficit. Independent parametric mapping and principal component statistical analyses converged to show that such subcortical asymmetries were present in each subject. Importantly, contralateral basal ganglia and thalamic hypoactivation resolved after recovery. Furthermore, lower activation in contralateral caudate during hysterical conversion symptoms predicted poor recovery at follow-up. These results suggest that hysterical conversion deficits may entail a functional disorder in striatothalamocortical circuits controlling sensorimotor function and voluntary motor behaviour. Basal ganglia, especially the caudate nucleus, might be particularly well situated to modulate motor processes based on emotional and situational cues from the limbic system. Remarkably, the same subcortical premotor circuits are also involved in unilateral motor neglect after organic neurological damage, where voluntary limb use may fail despite a lack of true paralysis and intact primary sensorimotor pathways. These findings provide novel constraints for a modern psychobiological theory of hysteria.

Los medicamentos histéricos: Ignatia, Moschus, Nux moschata / Medicaments used for the hyteria: Ignatia, Moschus, Nux moschata

Se pretende realizar una ejercitación de materia médica comparada con los principales medicamentos de la HISTERIA, destacando sus caracteres diferenciales en un cuadro comparativo. Se describen los síntomas definitorios de Moschus y Nux Moschata los cuales junto con Ignatia son considerados como la "tríada de los histéricos". Nos referiremos a esta "tríada de histéricos", desarrollando las características más destacadas de MOSCH y NUX-M., presentando al final una sinopsis comparativa de los 3, por sus síntomas histéricos tal como figuran en el Moderno Repertorio de Kent del Dr. Francisco X. Eizayaga, con el agregado complementario de otros medicamentos afines. Previamente daremos un rápido repaso a los cuadros Histéricos e Histeriformes, clasificados como TRASTORNOS SOMATOFORMES por la American Psychiatric Association (DSM IV, Diagnostic and Statical Manual of Mental Disorders) (AU)

Los medicamentos histéricos: Ignatia, Moschus, Nux moschata / Medicaments used for the hyteria: Ignatia, Moschus, Nux moschata

Se pretende realizar una ejercitación de materia médica comparada con los principales medicamentos de la HISTERIA, destacando sus caracteres diferenciales en un cuadro comparativo. Se describen los síntomas definitorios de Moschus y Nux Moschata los cuales junto con Ignatia son considerados como la "tríada de los histéricos". Nos referiremos a esta "tríada de histéricos", desarrollando las características más destacadas de MOSCH y NUX-M., presentando al final una sinopsis comparativa de los 3, por sus síntomas histéricos tal como figuran en el Moderno Repertorio de Kent del Dr. Francisco X. Eizayaga, con el agregado complementario de otros medicamentos afines. Previamente daremos un rápido repaso a los cuadros Histéricos e Histeriformes, clasificados como TRASTORNOS SOMATOFORMES por la American Psychiatric Association (DSM IV, Diagnostic and Statical Manual of Mental Disorders)