What is Synaesthesia?

Synaesthesia is the result of a specific cross-linking in the brain that occurs relatively infrequently. Due to the accumulation in families, heritability is assumed.
The word synesthesia is derived from the Greek words syn (together =) and aisthesis (= sense), according to Duden (the german Dictionary), the synergism of a sense to stimulation of another. Synaesthesia is based on an additional channel of perception. Some synaesthetes can feel letters or taste words. Others see sounds in bright colors ("color hearing").
Studies show that certain phenomena occur more frequently in synaesthetes. These include giftedness and creativity, as well as increased noise sensitivity and attention disorders.
(From www.synaesthesie.org/3synaesthesia/Syn_e4sthesie / Site of the Deutschen Synästhesie-Gesellschaft e.V. (DSG e.V.))

An article about Alexandra Kirschner in Psychology Today: The Shape and Color of Song in Germany

Radiointerview with Dr. Jasmin Rani Sinha and Christine Söffing on the 13th February 2012, Radio Corax, Halle: Welche Farbe hat der Montag?

23th March 2012 - 8:10 P.M. - (First broadcast) Deutschlandfunk, Feature by Heike Tauch
Ich sehe was, was du nur hörst. Über synästhetische Wahrnehmungen