Spatial index type for mysql

I'm using doctrine and some of mysql's spatial functions. I need to specify spatial index for my tables.
My declaration looks like:

Geometry:
tableName: geometry
options:
type: MyISAM
collate: utf8_unicode_ci
charset: utf8
columns:
id:
type: integer(4)
primary: true
autoincrement: true
geometry:
type: geometry
notnull: true
indexes:
geometry:
fields:

• geometry
  type: spatial

Exporting this definitions throws an exception: Unknown type spatial for index geometry_idx