Journal of Rehabilitation Medicine 51-4inkOmslag | Page 18

R. Stock et al.
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Fig 3. Recovery of maximum force in key grip (A), 3-finger grip (B) and 2-finger grip (C) during the first year after stroke. Maximum force was
measured with a pinchmeter at 2, 4, 28, 30 and 54 weeks after stroke. Values are mean and error bars 95% confidence interval (95% CI). Note
that the assessment intervals are upscaled to improve readability. Closed circles represent the non-affected side and open circles the affected side.
and there was no difference between the hands at W28
and W30 (p ≥ 0.19 for all comparisons). At W54, rate
of force development was 21% lower for the affected
hand than for the non-affected (p = 0.30).
The pinchmeter recordings for the 0–500 ms interval
(Fig. 4B) showed a similar pattern, but a lower rate of
force development compared with the dynamometer
recordings. Rate of force development on the affected
side was 46% of the non-affected side at W2 (p = 0.001)
and 88% at W54 (p = 0.43). Most increase in rate of
force development on the affected side occurred bet-
ween W2 and W28.
Sustainability of grip force
At W2, there was a similar decrease in the ability to
maintain hand grip MVC during the 12-s sustained
period when measured in absolute values (p = 0.68).
However, when the force curve was normalized to %
maximum force (e.g. expressed as % of initial force),
the affected side decreased to 44% of maximum
force during the 12-s interval at W2, while the non-
affected side decreased only to 74% of maximum force
(p < 0.001, Fig. 5A). At W54, the ability to sustain
relative hand grip MVC was still lower on the affected
side (p = 0.004).
Pinchmeter recording showed a similar pattern,
with no difference in deficit between the affected and
non-affected side when measured in absolute values
at W2 (p = 0.22). Fig. 5B shows the normalized key
pinchmeter values. At W2, the affected side decreased
to 47% of the maximum force and the non-affected
side to 67% (p = 0.009). At W54, the ability to sustain
relative key grip MVC no longer differed between the
affected and non-affected hand (p = 0.24). Furthermore,
as Fig. 5A and 5B show, there was a marked drop in
sustainability of grip force at W2 during the first 2–2.5
s on the affected side compared with the non-affected
side. This drop decreased during the 1-year follow-up
period, but was still visible at W54.
Fig 4. Recovery of rate of force development for (A) dynamometer (position 2) and (B) pinchmeter (key grip) recordings during 0–500 ms during
the first year after stroke. Rate of force development was measured at 2, 4, 28, 30 and 54 weeks after stroke. Values are mean and error bars
95% confidence interval (95% CI). The assessment intervals are upscaled to improve readability. Closed circles represent the non-affected side
and open circles the affected side.
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