[The neural networks of facial expression]

INTRODUCTION

Face perception involves a broad network of connections between cortical and subcortical regions for the exchange and synchronization of information using white matter fibers. This precise communication system can be affected by the structures and the pathways that connect them.

AIMS

To establish the neural substrate underlying the perception of facial expression and to analyze the different factors involved in modulating the integrity of this neural network, with the aim being to introduce improvements into rehabilitation programs.

DEVELOPMENT

When the complex neural network involved in the perception of facial expression is altered by trauma, neurodegenerative disorders, developmental disorders, social isolation or negative contexts, the adaptive capacity to interact with the environment also deteriorates.

CONCLUSIONS

Maintaining the neural network integrity responsible for processing facial expression requires considering different variables. To a greater or lesser extent, these variables modify the structure or function of neural networks, such as aerobic training, transcranial magnetic stimulation, transcranial electrical stimulation, and learning. These variables are affected by age, and the type and course of the condition or generator context, and raise the need for rehabilitation protocols that are adapted and designed to delimit the deficient neuronal substrate.

Oral reading fluency analysis in patients with Alzheimer disease and asymptomatic control subjects

INTRODUCTION

Many studies highlight that an impaired ability to communicate is one of the key clinical features of Alzheimer disease (AD).

OBJECTIVE

To study temporal organisation of speech in an oral reading task in patients with AD and in matched healthy controls using a semi-automatic method, and evaluate that method's ability to discriminate between the 2 groups.

SUBJECTS AND METHODS

A test with an oral reading task was administered to 70 subjects, comprising 35 AD patients and 35 controls. Before speech samples were recorded, participants completed a battery of neuropsychological tests. There were no differences between groups with regard to age, sex, or educational level.

RESULTS

All of the study variables showed impairment in the AD group. According to the results, AD patients' oral reading was marked by reduced speech and articulation rates, low effectiveness of phonation time, and increases in the number and proportion of pauses. Signal processing algorithms applied to reading fluency recordings were shown to be capable of differentiating between AD patients and controls with an accuracy of 80% (specificity 74.2%, sensitivity 77.1%) based on speech rate.

CONCLUSION

Analysis of oral reading fluency may be useful as a tool for the objective study and quantification of speech deficits in AD.