Selective Emotional Dysregulation in Splenium Agenesis. A Case Report of a Patient With Normal Cognitive Profile.

Objective: Patients with lesions of the corpus callosum are rare and may present different symptoms of the disconnection syndrome. However, to-date studies on callosotomized patients have not been conclusive, likely because of the non-uniform nature of clinical features, the extent of resection, and methods used to investigate specific and related deficits. Agenesis of the corpus callosum (AgCC) may be asymptomatic and discovered incidentally or associated with very slight deficits diagnosed during neurological examinations. In this study, we reported a case of an apparently completely asymptomatic 23-year-old woman with appreciable agenesis of the splenium of the corpus callosum. Methods: She underwent a neurological evaluation, a comprehensive battery of neuropsychological tests to identify any subclinical dysfunction that may affect the functionality of the subject in the daily life. Specifically, the possible presence of emotion dysregulation was examined by using a self-report questionnaire. Results: She showed normal neuropsychological and emotional functioning, performing efficiently on tests measuring acquired brain impairment. Discussion: The present case is discussed in terms of neuroplasticity - with a focus on putative compensatory mechanisms - emphasizing the variegated clinical feature patterns of brain defects present from birth.

Impulse control disorder and response-inhibition alterations in Parkinson's disease. A rare case of totally absent functionality of the medial-prefrontal cortex and review of literature.

This report illustrates a Parkinson's disease (PD) patient with impulse-control disorder (ICD) and selective impairment in response-inhibition abilities as revealed by the performance in a functional magnetic resonance imaging (fMRI) anterior cingulate cortex - sensitive go-nogo task. In line with hypothesis on the role of response-inhibition disabilities in the arising of impulsivity in PD, the patient completely failed the go-nogo task. Moreover, fMRI acquisition revealed absent task-sensitive activity in the anterior cingulate cortex, medial prefrontal, and orbitofrontal cortices for the contrast nogo versus go, which signifying that a hypo-function of this network could be associated with ICD. A fronto-striatal and cingulo-frontal dysfunction may reflect impairment in metacognitive-executive abilities (such as response-inhibition, action monitoring, and error awareness) and promote compulsive repetition of behavior. Response-inhibition tasks may be useful in PD post-diagnostic phase, to better identify individuals at risk of developing ICD with dopaminergic medication.