Prof. Giuseppe A. Chiarenza, M.D., Ph.D.
Centro Internazionale Disturbi di Apprendimento, Attenzione e Iperattività (CIDAAI), Milano, Italy
Psychophysiology of reading
Reading and writing does not only consist in the ability to interpret and to correctly reproduce graphemes and phonemes but also require willingness to get in touch purposefully with one’s own interlocutors. The interest in the study of this function is documented by the fact that any new system of neuroimaging has been used to illustrate and understand the mechanics involved in both normal and dyslexic subjects. Another approach has been to validate neuropsychological models that have been proposed in recent decades, to explain the universe of dyslexia. Appropriate clinical and neuropsychological investigations have demonstrated the existence of clinical subtypes of dyslexia. Modern investigations of structural and functional connectivity were also able to demonstrate that there are different neural networks for these specific patterns of reading and writing. Self-paced tasks corroborated the current hypotheses of dyslexia as a disorder of network connections: in particular dyslexia can be explained as a deficit in the programming and integration of ideokinetic elements associated with an impairment of fast processing and integration of sensory information along with reduced functioning of the system involved in error analysis. During reading and writing, all these phenomena occur at different levels of the central nervous system and at different times.
Prof. Risto Näätänen, Ph.D.
Department of Psychology, University of Tartu, Tartu, Estonia
The mismatch negativity (MMN) - a unitary biomarker for predicting schizophrenia onset
Recently, clinical brain research using the mismatch negativity (MMN), an automatic brain response to any discriminable change in some repetitive aspect of ongoing auditory stimulation, has been rapidly expanding. One of the most important recent developments in the field highlights the utility of MMN in predicting psychosis onset in clinically at-risk individuals, usually adolescents or young adults. A low-amplitude MMN in particular to occasional duration increments in repetitive stimuli ("standards") in these individuals predicts psychosis onset within a relatively short time, usually 1-2 years. This predictive ability is further strengthened when deviant stimuli differ from standards both in duration and frequency in parallel. This time range with a considerably elevated psychosis risk is preceded by a years-long period with occasional psychiatric symptoms, accompanied by a slightly decreased MMN amplitude. When this MMN attenuation occurs together with psychiatric symptoms in the same individual, this should be taken as a serious warning signal, and treatment should be immediately started, either drug or behavioral treatment or both. This review deals with the MMN as as a biomarker for detecting individuals with an increased risk of psychosis onset early enough when irreversible pathological processes in the brain have not yet commenced.