I've been dizzy before, Norbert, but what I experienced recently was debilitating.

It wiped me out for a week. Turns out, I had BPPV, or benign paroxysmal positional vertigo.

That can be scary, Dave. Someone we know who also had BPPV thought he was having a stroke when it happened to him. This is a common cause of vertigo which, though not serious, could cause you to fall.

Because while it's happening, you don't know up from down or left from right.

These brief episodes of dizziness can be mild or intense. And they're triggered by changes in the position of your head. So, moving your head up or down or suddenly rising from or turning over in bed can cause you to feel like the room is spinning.

Fortunately, the symptoms usually last less than a minute but it's possible the effect can linger, making you unsteady.

For people under fifty, the likely cause of BPPV is head injury. But in older people, there's probably degeneration to an organ inside the inner ear called the vestibular labyrinth.

Inside this organ are fluid-filled semi-circular canals with fine, hair-like sensors that monitor your head position. Another structure in the organ, called the utricle, contains crystals that monitor the position of your head in relation to gravity.

In BPPV patients, these crystals dislodge, enter one of the semicircular canals and begin to stimulate the sensors. This throws off the sensors' ability to gauge normal head position, which makes the person dizzy.

Fortunately, your doctor can teach you something called the canalith repositioning procedure. They're simple, slow head movements to shift the crystals out of the canals.

You can also learn which head positions to avoid to prevent the crystals from dislodging and literally turning your life upside down.