Evidence map›Paper›PMID 42469515›Full record

ArticleJournal of neurology2026

Beyond ALS: split-hand syndrome in immune-mediated motor neuropathies.

Luisa Kreß, Mai Abuzant, Daniel Zeller, Claudia Sommer

Abstract read
In one paragraph

Article in Journal of neurology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Luisa KreßDepartment of Neurology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany. Kress_L@ukw.de.ORCID http://orcid.org/0000-0003-4369-3866
Mai AbuzantDepartment of Neurology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany.ORCID http://orcid.org/0000-0002-9857-1818
Daniel ZellerDepartment of Neurology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany.ORCID http://orcid.org/0000-0003-3393-5657
Claudia SommerDepartment of Neurology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany.ORCID http://orcid.org/0000-0002-7064-5002

Funding

Interdisziplinäres Zentrum für Klinische Forschung, Universitätsklinikum Würzburg Z-2/AdvCSP-4Interdisziplinäres Zentrum für Klinische Forschung, Universitätsklinikum Würzburg Z-2/CSP_22Interdisziplinäres Zentrum für Klinische Forschung, Universitätsklinikum Würzburg Z-3 BC-18
6 · The paper itself

Abstract

BACKGROUND AND

aimsSplit-hand syndrome describes selective wasting and weakness of the abductor pollicis brevis (APB) or first dorsal interosseous (FDI) muscles with relative preservation of the abductor digiti minimi (ADM). Beyond clinical definition, two neurophysiological ratios and one index have been proposed to quantify this pattern. It is considered a potential diagnostic criterion for amyotrophic lateral sclerosis (ALS). Its occurrence in immune-mediated neuropathies, as differential diagnoses, remains unclear. We aimed to investigate clinical and electrophysiological manifestations of split-hand syndrome in multifocal motor neuropathy (MMN) and multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) compared to ALS.

methodsWe prospectively examined 26 MMN, 16 MADSAM, and 22 ALS patients. All underwent neurological examination and neurophysiological measurements of compound muscle action potentials (CMAP) from the APB, FDI, and ADM bilaterally after median (APB) and ulnar nerve (FDI, ADM) stimulation. Split-hand ratios (APB/ADM; FDI/ADM) and split-hand index (SI) were calculated.

resultsClinical split-hand syndrome was present in 16/26 (62%) MMN, 7/16 (44%) MADSAM, and 12/22 (54%) ALS patients. Electrophysiological criteria (abnormal split-hand ratios or SI; ≥ 1 parameter fulfilled) were similarly frequent across groups (MMN 17/26, 65%, MADSAM 11/16, 69%, and ALS 16/22, 73%). CMAP ratios and SI did not differ between groups in the overall analysis and showed no correlation with disease duration or severity. Diagnostic models showed limited discriminatory power (area under the curve ≤ 0.61).

interpretationSplit-hand syndrome occurs in MMN, MADSAM, and ALS at comparable frequencies and lacks robust or consistent diagnostic discrimination across disease groups.

Indexed as

Amyotrophic Lateral SclerosisHandMuscle, SkeletalAdultAgedDiagnosis, DifferentialFemaleHumansMaleMiddle AgedNerve Conduction StudiesProspective StudiesAmyotrophic lateral sclerosisMultifocal acquired demyelinating sensory and motor neuropathyMultifocal motor neuropathySplit-hand syndrome

Identifiers

PMID42469515
PMCPMC13379438

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.