My uncle asked Messenger of Allah ﷺ about a person who imagined to have passed wind during the prayer. Allah' Apostle replied: "He should not leave his prayers unless he hears sound or smells something."  

أَنَّهُ شَكَا إِلَى رَسُولِ اللَّهِ ﷺ الرَّجُلُ الَّذِي يُخَيَّلُ إِلَيْهِ أَنَّهُ يَجِدُ الشَّىْءَ فِي الصَّلاَةِ فَقَالَ لاَ يَنْفَتِلْ أَوْ لاَ يَنْصَرِفْ حَتَّى يَسْمَعَ صَوْتًا أَوْ يَجِدَ رِيحًا  

He should not cease (to pray) unless he hears a sound or perceives a smell (of passing wind).  

شُكِيَ إِلَى النَّبِيِّ ﷺ الرَّجُلُ يَجِدُ الشَّىْءَ فِي الصَّلاَةِ حَتَّى يُخَيَّلَ إِلَيْهِ فَقَالَ لاَ يَنْفَتِلُ حَتَّى يَسْمَعَ صَوْتًا أَوْ يَجِدَ رِيحًا  

"A complaint was made to the Prophet about a man who sensed something (some doubt about his ablution) during prayer. He said: 'No (he does not have to perform ablution) unless he notices a smell or hears a sound.'"  

شُكِيَ إِلَى النَّبِيِّ ﷺ الرَّجُلُ يَجِدُ الشَّىْءَ فِي الصَّلاَةِ فَقَالَ لاَ حَتَّى يَجِدَ رِيحًا أَوْ يَسْمَعَ صَوْتًا  

[Machine] "He (the man) complained to the Messenger of Allah ﷺ that during his prayer, he feels that he has passed gas, so he said: It does not nullify the prayer until he finds a smell or hears a sound."  

أَنَّهُ شَكَا إِلَى رَسُولِ اللهِ ﷺ الرَّجُلُ يَجِدُ الشَّيْءَ فِي الصَّلَاةِ يُخَيَّلُ إِلَيْهِ أَنَّهُ قَدْ كَانَ مِنْهُ فَقَالَ لَا يَنْفَتِلُ حَتَّى يَجِدَ رِيحًا أَوْ يَسْمَعَ صَوْتًا  

"A complaint was made to the Prophet about a man who sensed something (some doubt about his ablution) during prayer. He said: 'No (he does not have to perform ablution) unless he notices a smell or hears a sound.'" (Using translation from Ibn Mājah 513)  

شُكِيَ إِلَى النَّبِيِّ ﷺ الرَّجُلُ يَجِدُ الشَّيْءَ فِي الصَّلَاةِ فَقَالَ «لَا يَنْصَرِفْ حَتَّى يَجِدَ رِيحًا أَوْ يُسْمَعَ صَوْتًا»