Contact a Speech Language Pathologist.They will give voice therapy and teach vocal hygiene technique.As all investigation are normal your wife is an ideal candidate for voice therapy for her dysphonia
Few tips for vocal hygiene are:
Limit your intake of drinks that include alcohol or caffeine. These act as diuretics (substances that increase urination) and cause the body to lose water. This loss of fluids dries out the voice. Alcohol also irritates the mucous membranes that line the throat.
Drink plenty of water. Six to eight glasses a day is recommended
Don't smoke and avoid second-hand smoke. Cancer of the vocal folds
is seen most often in individuals who smoke.
Practice good breathing techniques when singing or talking. It is important to support your voice with deep breaths from the diaphragm, the wall that separates your chest and abdomen.
Talking from the throat, without supporting breath, puts a great strain on the voice.
Consult speech language Pathologist to learn vocal hygiene.
B.Sc. (Hons.) Speech and Hearing, AIIMS New Delhi
M.Sc. Speech Language Pathology, AIISH Mysore
Consultant Speech Language Pathologist,Speech Therapist, Voice Therapist, Audiologist