Introduction: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative
disease, that causes motor neuron degeneration, resultin in atrophy, muscle weakness and
the appearance of the split-hand syndrome. Abductor pollicis brevis (APB) and firs dorsal
interosseous muscle (FDI) are more affected compared to abductor digiti minimi (ADM).
Split-hand syndrome can be demonstrated by the split hand index (SHI). Purpose: The
purpose of master's thesis was to examine the differences between electrophysiological
measurements and nine hole peg test within ALS patients and healty controls, and determine
whether there is correlation between SHI and repetitive nerve stimulation (RNS) with nine
hole peg test. Methods: 42 ALS patients and 45 healthy controls were included in the study,
who performed measurements of the CMAP and its amplitude decline in RNS on median
and ulnar motor nerves. Using electrophysiological measurements, SHI was then calculated
by the product of CMAP of APB and FDI muscle, divided by the CMAP of the ADM muscle.
RNS index was calculated by the product of CMAP decrement of APB and FDI muscle,
divided by the CMAP decrement of the ADM muscle. In addition, all subjects completed 10
repetitions of the nine hole peg test. Results: There was statistically significatn differences
between ALS and control group in CMAP amplitude, SHI, RNS index and absolute times
of nine hole peg test performance. A cutoff value -1,7 of RNS index poorly discriminates
between ALS patients and healthy controls with 62 % sensitivity and 71 % specificty.
Correlation of SHI with repeated nine hole peg test was high, correlation of SHI with RNS
index and amplitude decline with repeated nine hole peg test was low. Discussion and
conclusion: ALS patients have higher RNS decrement and repeated nine hole peg test time
values and are therefore more susceptible to the phenomenon of performance fatigue. SHI is
still a more accurate method in identifying split-hand syndrome compared to the RNS index,
but in combination they can help to diagnose ALS more quickly.
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