| Type 1 |
Sporadic MD (if concurrent migraine, autoimmune disease, or familial MD is observed, patients are out of this subgroup) |
| Type 2 |
Delayed MD (hearing loss precedes vertigo attacks in months or years) |
| Type 3 |
Familial MD (at least two patients in the first or second degree) |
| Type 4 |
Sporadic MD with migraine (temporal relationship not required) |
| Type 5 |
Sporadic MD plus an autoimmune disease |
|
Bilateral MD
|
|---|
| Type 1 |
Unilateral hearing loss becomes bilateral |
| Type 2 |
Sporadic, simultaneous hearing loss (usually symmetric) |
| Type 3 |
Familial MD (most families have bilateral hearing loss, but unilateral and bilateral cases may coexist in the same family) |
| Type 4 |
Sporadic MD with migraine |
| Type 5 |
Sporadic MD with an autoimmune disease |
