We have been making the argument that we have to #thinkhand, notably when we do clinical trials in MS. This is based on the idea that the problems in MS are related to thelength of the nerve tracts, so if you ge lesions anywhere in the nervous system, the longer nerve tracts are more likely to get a lesion and the more lesions you get in a tract the more likely that disability occurs. Eventually the tract gets so many lesions that the compensatory capacity to accomodate damage is lost. The legs are more likely to accumlate damage quicker than the hands and so if you base your trials on hand function, you are more likely get a positive result.
The study looks at tapping of the hands and the foot and concludes that if you look at hand function there is worse performance betweeen MS and health and this reflects damage to the nerve tracks but this has not taken on so much damage that you can spot a difference between progressive and relapsing MS. Whereas foot tapping in progressive MS is worse than in relapsing MS, becuse of accumulation of more damage, supporting using hand function as an outcome. Will we ever get to find out…After the CoVID crisis I hope.
P.S. Hand Foot co-ordination is important to be a druumer
Rapid foot-tapping but not hand-tapping ability is different between relapsing-remitting and progressive multiple sclerosis. Sato S, Lim J, Miehm JD, Buonaccorsi J, Rajala C, Khalighinejad F, Ionete C, Kent JA, van Emmerik REA.Mult Scler Relat Disord. 2020 Feb 27;41:102031. doi: 10.1016/j.msard.2020.102031. [Epub ahead of print].
BACKGROUND:Rapid tapping tests have been shown to be reliable measures of upper motor neuron disease, and effectively examine motor function differences between multiple sclerosis (MS) and non-MS controls (CON), and between relapsing-remitting and progressive MS subtypes. To successfully perform rapid repetitive movements such as tapping, a person must be able to consistently turn on and off motor units to switch between the up and down movement phases. However, it is not clear which specific movement phase that occurs during tapping is different between MS subtypes. The objective of this study was to quantify and characterize performance differences during rapid hand- and foot-tapping tests between relapsing-remitting (RRMS) and progressive (PMS) forms of MS, as well as how both subtypes differ from non-MS controls.
METHODS:Participants in this study included 30 non-MS controls, 32 RRMS, and 31 PMS. Participants wore inertial sensors on all hands and feet and were instructed to tap as fast as possible for 10 seconds.
RESULTS: Inter (between)-tap interval for both hand- and foot-tapping differed between controls and MS, but only foot tapping was different between RRMS and PMS (RRMS = 286.7 ± 83.0 ms; PMS = 379.5 ± 170.9 ms; mean difference (d) = -92.8 ms). Foot-tap interval but not hand-tap interval has the potential to distinguish between RRMS and PMS . Both up- and down-movement duration differences were consistent with the results for inter-tap interval, but up-movement duration showed larger mean group differences than down-movement differences. Up-movement foot-tapping variation (CON = 18.7 ± 6.1; RRMS = 25.5 ± 11.2; PMS = 23.3 ± 8.6; CON vs RRMS d = -6.8; CON vs PMS d = -4.7), but not down-movement variation was different between controls and MS. Up- and down-peak angular velocity during foot-tapping were different between controls and PMS (CON Up = 1.4 ± 0.5 rad/s; PMS Up = 1.0 ± 0.4 rad/s; Up d = 0.4 rad/s; CON Down= 1.5 ± 0.6 rad/s; PMS Down = 1.2 ± 0.5 rad/s; Down d = 0.3 rad/s), and up-movement peak angular velocity differences showed larger mean group differences than the down-movement peak angular velocity between controls and PMS.
CONCLUSION:Foot-tapping differs between MS disease subtypes and has greater potential than hand-tapping to distinguish between subtypes. Performance in the up-movement showed larger group differences than the down-movement, suggesting that the anti-gravity up-movement during tapping may be more important diagnostically. Future studies should be conducted on the nature of the physiological mechanisms underlying impairments in anti-gravity movements in people with MS.