[Sense of smell, physiological ageing and neurodegenerative diseases: I. Anatomy and clinical examination].

INTRODUCTION

Different studies on normal and pathological ageing have shown structural and functional impairment by means of psychophysical measures, electrophysiological studies and brain imaging studies. Lower sensory perception from peripheral olfactory structures, together with alterations in the medulla oblongata and cortex, are the most frequent causes of olfactory impairment in ageing.

AIM

To outline the most important tests that can be applied in clinical evaluation.

DEVELOPMENT

The article begins by reviewing concepts involved in olfactory anatomy and physiology and then goes on to describe the different methods of examination and their applicability to medical diagnosis.

CONCLUSIONS

Incorporating olfactory tests into clinical practice makes it possible to study the presence of sensory and cognitive impairment in greater depth, especially in ageing and in neurodegenerative diseases; this will allow a possible diagnosis to be expanded and completed.