Universal newborn hearing screening has allowed early diagnosis and, subsequently, early intervention in hearing loss. In 2020 the Food and Drug Administration candidacy criteria for cochlear implants (CI) expanded to include profound sensorineural hearing loss (HL) in children as young as nine months old. CI surgery is only recommended for children older than 12 months in British and Chinese guidelines. However, in France, CI surgery is proposed before 12 months of age for children with congenital bilateral profound HL, and the Australian guideline has removed the minimum age limit for children. Speech evaluation tools are unlikely to be sensitive enough for children younger than 12 months of age. Few studies have focused on neuropsychological development. The Gesell Development Diagnosis Scale (GDDS) is a neuropsychological development examination and widely used in children aged 0 to 60 months. It includes five domains: gross motor, fine motor, adaptability, language, and social skills. This study looked to investigate the value of GDDS in children with simultaneous bilateral CIs in a group of infants implanted at six to 12 months compared with a group implanted at 12 to 36 months. Sixty-two children receiving simultaneous bilateral CIs were enrolled. They were divided into two groups depending on the operative age. Simultaneous bilateral CIs in younger children improved adaptability and social skills at two years. The complication rates in the infants and children groups were 0% vs. 2.1%.