Assalamualaikum ustaz. What is the ruling of a prayer for a person who moves more than thrice because he’s suffering from Parkinson’s disease?
Waalaikumussalam wrt. wbt.,
Alhamdulillah, praise and gratitude to Allah SWT for His countless blessings for us all. Praise and salutations to our beloved Prophet Muhammad PBUH, his family, companions, and all those who follow his footsteps until the Final day.
Definition of Parkinson’s Disease
In answering the above question, we’ll first need to know what is the meaning of Parkinson’s disease. The 4th Edition of Kamus Dewan defines it as a neurological disease that characterizes less motion control, muscle stiffness and trembling limbs.
According to the Malaysian Ministry of Health’s MyHealth portal, Parkinson’s disease is a neurological disease that can occur in the elderly, which occurs due to brain cell damage that results in a reduction in a chemical called dopamine.
Among the signs and symptoms of this disease are:
- Trembling (in fingers, hands, feet, jaw and/or face)
- The rigidity of limbs (hands, feet and/or body – Rigidity)
- Slow body movements (Bradykinesia)
- Problems of imbalance of posture and body coordination can result in falls.
The initial symptoms that occur may not be obvious. However, when the disease becomes more serious, these symptoms will affect the activities of daily living. 
Moving More than Thrice in Prayer
Basically, movement more than thrice consecutively in prayer invalidates prayer according to madhhab Syafie, for it is considered a lot of movement.
Abu Isyak al-Syirazi said: “If a person steps three times successively or hit three times consecutively, then his prayer is invalidated.” 
Imam al-Nawawi in al-Minhaj stated: “If a person intentionally performs such an act in prayer, other than the movements originally in prayer, although the actions are from the actions of prayer (requisites and others), then his prayer is invalidated except if he forgets. If the action is not from the type of actions in prayer (requisites and others), then the prayer is invalidated if the action (movement) is more than the uruf and it doesn’t invalidate prayer if the action (movement) is less than the uruf. Two steps or two hits are included as a little movement, while thrice actions (movements) consecutively is a lot (hence, it invalidates prayer).” 
Al-Khatib al-Syarbini said: “And two matters that invalidate prayer is too many movements that are not from the actions of prayer according to uruf. What is considered the uruf as a little movement such as removing one’s khuf, wearing light clothing, then it is a little movement. Likewise, two moderate steps and two hits. Three or more movements are considered a lot (and invalidate prayer) if it is done consecutively. Whether the movement is from the type of movement such as three steps or mixed from any such movements such as one step, one hit and removing one’s slippers or three steps done in one large step. If he moves once with the intention of three moves, then his prayer is invalid.” 
Imam al-Nawawi stated: “The summary of what our ashab stated regarding movements which aren’t from the types of movements in prayer if it is a lot, then the prayer is invalidated without khilaf (regarding this matter). If the movement is a little, then it doesn’t invalidate the prayer.”
He further added: “As for what is considered by others a lot of movements such as steps and a lot of successive movements, then the prayer is invalid. Our ashab states: On this basis, one movement such as one step and hit is considered as a little movement and three movements is a lot.” 
Thus, basically, three movements consecutively are included as matters that invalidate the prayer.
Moves More Than Three Times Due to Parkinson’s Disease
Referring to the above-presented question, a person who experiences Parkinson’s disease and moves three times consecutively in prayer doesn’t invalidate his prayer. The reason is the movement or action is out of his control.
This is stated by Syeikh Ahmad bin Umar al-Syathiri in his book Nail al-Raja’: “A little movement is anything less than three actions (movements) even if it is done consecutively or the act is three times but it isn’t performed in succession. All of these must not be meant to be a joke and it is not included (the ruling of invalidation of prayer due to a lot of movement), for those who are in an exigent situation and aren’t able to not move a lot (can’t control their movements) such as a person who suffers from severe itchiness.” 
Severe itchiness can be analogically deduced with Parkinson’s disease for both matters are uncontrollable. Furthermore, movements due to Parkinson’s disease is an involuntary movements as stated by Allah SWT:
فَاتَّقُوا اللَّـهَ مَا اسْتَطَعْتُمْ
“So fear Allah as much as you are able.”
Syeikh ‘Abd al-Rahman al-Sa’di explained: “This verse shows that all the obligations of syarak of which one isn’t able to bear, then it is abrogated if he is capable to perform it. If he is capable to do parts of it and the other parts, he isn’t capable to do so, then it is obligated for him to perform the ones that he is capable of doing. This is as stated by the Prophet PBUH: “If you are commanded with a commandment, then fulfil it based on your capability.” 
Moreover, in madhhab al-Syafie, there is a discussion related to heavy and light body parts. For example, heavy parts are the hands, legs, head and others. While light body parts meant here are the movement of the fingers. This can also be seen explained in fiqh books of madhhab al-Syafie such as Nail al-Raja’ Syarah Safinah al-Naja’ regarding matters that invalidate the prayer.
May Allah SWT grant us all health so that we can worship Him the best we can. Amin.
 See http://www.myhealth.gov.my/penyakit-parkinson/
 See al-Tanbih Fi al-Fiqh al-Syafie, pg. 76
 See Minhaj al-Thalibin, pg. 53-54
 See al-Iqna’ Fi Hill al-Alfaz Abi Syuja’, 2/268
 See al-Majmu’ syarh al-Muhazzab, 4/25-26
 See Nail al-Raja’, pg. 142
 See Taisir al-Karim al-Rahman fi Tafsir Kalam al-Mannan, 1/237