Do ability enhancing items (such as the headband of intellect, cloak of charisma, and periapt of wisdom) grant bonus spells to the appropriate spellcasters? The spells these items are based on would seem to prohibit it, but the only things specifically addressed in the item descriptions are skill points.
Yes, you can get extra bonus spells if you have an item that increases the ability score that governs your spellcasting. To get the extra bonus spells, you must wear the item while resting to regain spells and all through your initial daily preparations for spellcasting. (Even characters who don’t prepare spells need to meditate a little while at the beginning of the day; see Daily Readying of spells under the Sorcerers and bards section of Chapter 10 in the Player’s Handbook.) If you lose the item, you immediately lose the bonus spell slots the item gave you, starting with any uncast spells you have of the appropriate levels.