حَدَّثَنَا يُوسُفُ بْنُ مُوسَى، حَدَّثَنَا وَكِيعٌ، عَنِ الأَعْمَشِ، نَحْوَهُ وَقَالَ أَيْضًا حَتَّى يَعْقِلَ ‏.‏ وَقَالَ وَعَنِ الْمَجْنُونِ حَتَّى يُفِيقَ ‏.‏ قَالَ فَجَعَلَ عُمَرُ يُكَبِّرُ ‏.‏

A similar tradition has also been transmitted by al-A’mash through a different chain of narrators. He also said : “... . Till he reaches puberty , and a lunatic till he is restored to consciousness.” ‘Umar then began to utter: Allah is most great. Translation Not Available

Book Ref: Sunan Abi Dawud Book 40 Hadith 4400
Web Ref:  Sunan Abi Dawud Book 39 Hadith 4386