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The aim of the study was to identify a number of sonographic landmarks in the evaluation of the oral phase of swallowing. Forty non-dysphagic adults (average age 38 years) and 20 normal bottle-fed newborns (average age 13 days) were submitted to videorecorded sonographic examination using two types of transducers (5 and 7.5 MHz). The adults were asked to swallow a 20 ml bolus of water and the newborns were examined while sucking from a bottle containing milk. Preliminary transverse scans of the neck were obtained to evaluate laryngeal movements during swallowing. The mouth was examined through the submental window using sagittal and coronal scans. In the newborn, additional transbuccal scans were employed. In both adults and newborns highly significant and reproducible images of single-element motor events involved in swallowing were obtained. Normal sonographic images of the oral stage of deglutition form the baseline from which abnormal patterns may then be recognized.

In the human brain, aging is characterized by progressive neuronal loss, leading to disruption of synapses and to a degree of failure in neurotransmission. However, there is increasing evidence to support the notion that the aged brain has a remarkable ability to reorganize itself, with the aim of preserving its physiological activity. It is important to develop objective markers able to characterize the biological processes underlying brain aging in the intact human, and to distinguish them from brain degeneration associated with many neurological diseases. Transcranial magnetic stimulation (TMS), coupled with electromyography or electroencephalography (EEG), is particularly suited to this aim, due to the functional nature of the information provided, and thanks to the ease with which it can be integrated with behavioral manipulation. In this review, we aimed to provide up to date information about the role of TMS and TMS-EEG in the investigation of brain aging. In particular, we focused on data about cortical excitability, connectivity and plasticity, obtained by using readouts such as motor evoked potentials and transcranial evoked potentials. Overall, findings in the literature support an important potential contribution of TMS to the understanding of the mechanisms underlying normal brain aging. Further studies are needed to expand the current body of information and to assess the applicability of TMS findings in the clinical setting.

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