The natural process of aging affects a few very specific timing parameters such as swallow reaction time and hyoid one movement velocity.

Many swallow timing and bolus transit parameters appear to be unaffected by aging. We want to know the changes of kinematic variables according to the aging process.

First hypothesis: There are probably be a protection mechanism that blocks functional loss progressing to kinematic abnormality. Muscle activation sequence change (i.e duration or amplitude) of the oropharyngeal muscles play an important role.

Second hypothesis: Age-related differences in muscle activation patterns will also appear differently depending on the characteristics of swallowed food.

Inclusion criteria

Inclusion criteria of healthy older adults : Age > 60, without dysphagia, comorbidity

Inclusion criteria of young control group

: Age < 60, without dysphagia, comorbidity

No prior history of swallowing difficulty or history of central nervous system disease, and none were taking medication that are known to affect swallowing.

Surface EMG was performed at bilateral suprahyoid, thyrohyoid, sternothyroid and pharyngeal constrictors. The latency of activation and termination was checked.

Inclusion Criteria of old group

• Age > 60, without dysphagia, comorbidity

Inclusion Criteria of young control group

• Age < 60, without dysphagia, comorbidity

Healthy participants