The voice is not affected in

Unilateral injury to recurrent laryngeal nerve results in ipsilateral paralysis of all the intrinsic muscles except the cricothyroid. The vocal cord thus assumes a median or paramedian position and does not move laterally on deep inspiration. Unilateral recurrent laryngeal paralysis may pass undetected as about one-third of the patients are asymptomatic. Others have some change in voice but no problems of aspiration or airway obstruction. The voice in unilateral paralysis gradually improves due to compensation by the healthy cord which crosses the midline to meet the paralyzed one. Ref: PL Dhingra Textbook of Ear, Nose and Throat, Edition 7, page - 339