A friend recently sent me a video of her one-year old granddaughter proudly pointing to her nose or eyes or ears when asked by her encouraging parents to find each of these “sensory portals.” One of the head’s senses, though, went missing from the list – the eager young parents never queried, “Where’s your vestibular labyrinth?”
Out of sight and reach, the vestibular sensors in the inner ear remain out of mind, even as they provide sensory information essential to every step of little Emily’s development. The inner-ear sense of motion and gravity plays a role in the rhythmic pattern of her breathing, her sense of safety and security, her visual perception of the world, the development of neck muscles to hold her head up, her ability to navigate the world on all fours, and eventually in finding balance on two feet for those literal first steps.
Science, too, has long overlooked this “invisible” sense. In part, that’s due to the challenge of understanding sensory information that never stands alone. Interwoven with visual, proprioceptive (the feeling of the joints/muscles), and tactile input, the vestibular sense of motion/gravity contributes to our composite perception of moving in the world. We only consciously “sense” it when something’s not right.
At the other end of life, Emily’s great grandmother has become all too aware of her own vestibular sensors as their malfunction threatens her independence. Extreme vertigo, accompanied by nausea, has undermined her ability to sit up in bed let alone walk across a room or navigate a set of stairs. The cause remains undetermined, although simple movement exercises help hold symptoms at bay.
Scientific study of the vestibular system has made progress over the last decade, as this remarkable sensory system begins to get its due. Hopefully, growing understanding will provide improved solutions for people like Emily’s great grandmother. Meanwhile, the motion sensors in Emily’s vestibular labyrinth will continue to quietly help her find her way in life.