Experimental evaluation of a common susceptibility to motion sickness and vasovagal syncope in children.

In children, vasovagal syncope (VVS) is the most common cause of syncope and motion sickness (MS) is also very frequent, with many symptoms of an autonomic nature. To study a possible relationship between VVS susceptibility and MS susceptibility in young patients, 21 children (10 boys, 11.3+/-2.6 years) with recurrent syncope or presyncope were explored with a questionnaire concerning their vasovagal symptoms, susceptibility to MS and familial history. A tilt-table test and a dynamic posturography with Equitest (Sensory Organisation Test (SOT), in six conditions) were performed. Children were divided into two groups: A with a positive tilt-table test and particular susceptibility to VVS (n=13/21, six boys) and B with negative tilt-table test. A control group of 30 healthy children (15 boys, 11.4+/-2.4 years) was studied for MS susceptibility and familial history. VVS susceptibility was related to MS susceptibility (MS susceptibility was 69.3% in Group A versus 12.5% in Group B (p=0.0237) and 16.7% in control group (p=0.0028)) and also to SOT scores which are related both to the role of vestibule in equilibrium and to MS susceptibility, with lower values in Group A than Group B (condition 5: 47.9+/-12.3% versus 66.0+/-13.8%, p=0.0189 and vestibular (ratio of conditions 5/1): 51.8+/-12.7% versus 71.3+/-13.5%, p=0.0147). Our study demonstrates, for the first time, a relationship between VVS susceptibility and MS susceptibility in a population of children with a particular susceptibility to VVS. This paradigm may prove useful in better understanding the mechanisms underlying the susceptibility to VVS and MS.