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INTRODUCTION: In the arms of patients with Amyotrophic lateral sclerosis (ALS) two peculiar patterns of dissociated muscular atrophy have been described: the split-hand sign (with predominant atrophy of the lateral aspect of the hand, compared to hypothenar eminence) and the split-hand-plus sign (SHPS), a predominant abductor pollicis brevis (ABP) atrophy with sparing of flexor pollicis longus (FPL). AIMS: In this case-control study, we evaluated the diagnostic utility of a neurophysiological indicator of SHPS and assessed its association with clinical features. METHODS: We prospectively studied 59 incident ALS patients, 61 patients with ALS-mimic disorders (OND) and 61 non-neurological controls (NNCs). ABP and FPL compound muscle action potentials (CMAP) amplitudes were obtained by supramaximal stimulation of median nerve at elbow. Split-hand plus index (SHPI) was calculated according to the formula: APB-CMAP/FPL-CMAP. RESULTS: SHPI was significantly lower in ALS compared to OND patients and NNCs (p < 0.0001). SHPI value < 1 was observed in 2% of NNCs and 9% of OND patients and demonstrated an accuracy of 71% in differentiating ALS from OND and an accuracy of 74% in differentiating ALS from NNC. SHPI was associated with higher LMN score, and higher disease severity as quantified by the ALSFRS-r. CONCLUSION: Our results indicate that SHPI is a reliable indicator to distinguish ALS patients from ONDs and NNCs. SHPI was significantly associated to the degree of lower motor neuron impairment but showed no association with upper motoneuron impairment.
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Background: Split phenomena (SP) are characterized by patterns of differential muscle wasting and atrophy, which are highly prevalent in amyotrophic lateral sclerosis (ALS) patients. Several neurophysiological indicators, including the split-hand index (SHI), split-leg index (SLI), and split-elbow index (SEI), have been proposed to assess SP. Nevertheless, their cutoff values and the impact of age and sex on these measures remain unclear. Methods: We prospectively collected neurophysiological data from 300 healthy adult subjects. The following indices were measured from compound muscle action potentials (CMAPs): SHI [abductor pollicis brevis (APBcmap) x first dorsal interosseous (FDI)cmap/adductor digiti minimi (ADMcmap)], SEI (BICEPScmap/TRICEPScmap), SLI (extensor digit brevis (EDB)cmap/abductor Hallucis (AH)cmap), and the neurophysiological ratios APBcmap /ADMcmap and FDIcmap/ADMcmap. Multiple linear regression analysis was used to investigate the association between age, sex, CMAPs, and neurophysiological indicators. Results: The median SHI was 10.4, with a median APBcmap/ADMcmap ratio of 0.9 and a median FDIcmap/ADMcmap ratio of 1.2. The median SEI was 1.6 (IQR:1.1-2.4) and the median SLI was 0.7 (IQR:0.5-1.0). Negative associations were observed between age, most of the CMAPs, and all the neurophysiological indices, except for SLI. The male subjects exhibited significantly higher CMAP values for the first dorsal interosseous (FDI), biceps, and SHI compared to the female participants. Conclusion: Our findings highlight the importance of age- and sex-adjusted normative data for SP indices, which could enhance their diagnostic accuracy and clinical utility in patients with ALS. The SL index appears to be the most reliable indicator, as it showed no significant association with age or sex.
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BACKGROUND: Hepatis C virus infection is presently an exclusion criterion to classify Sjögren's syndrome; however, there are distinct clinicopathologic and biologic similarities between HCV-related and SS-related chronic inflammation of mucosa-associated lymphoid tissue and lymphoproliferation that suggest common pathogenetic pathways. OBJECTIVES: To determine whether a subset of patients with sicca syndrome and HCV infection may present a true primary SS rather than a distinct clinicobiologic entity. METHODS: We extensively characterized 20 consecutive patients with positive anti-HCV antibodies and heavy subjective dry eye and/or dry mouth symptoms, plus positive unstimulated sialometry and/or Shirmer's test. We then compared these features with those in HCV-negative primary SS controls (classified according to the latest American-European Consensus Group Classification Criteria for SS). RESULTS: Of the 20 HCV-positive patients with sicca manifestations, 12 (60%) had positive anti-SSA/SSB antibodies (3/12 by enzyme-linked immunosorbent assay and 6/12 by immunoblot) and/or positive salivary gland biopsy (at least 1 focus/4 mm2), which met the strict classification criteria for SS, as in the case of HCV-negative SS controls. Comparing the HCV-positive SS subset with HCV-negative SS controls showed similar female to male ratio (11/1 vs. 46/4), major salivary gland swelling (17% vs. 26%), positive antinuclear antibodies (75 vs. 94%) and positive rheumatoid factor (58 vs. 52%). Significant differences (P < 0.05) were seen in mean age (69 vs. 56 years), liver disease (50 vs. 2%), lung disease (25 vs. 0%), anti-SSA/SSB positivity (25 vs. 90%), and low C3 or C4 (83 vs. 36%). HCV-positive SS patients exhibited a trend for more frequent chronic gastritis (50 vs. 22%), fibromyalgia (33 vs. 14%), peripheral neuropathy (33 vs. 18%), purpura (33 vs. 19%) and cryoglobulinemia (33 vs. 6%). CONCLUSIONS: A major subset of HCV-positive patients with definite subjective sicca symptoms and positive objective tests may indeed present a true, though peculiar, subset of SS. There are strict similarities with key clinical, pathologic and immunologic findings of definite HCV-negative SS. Other features appear more characteristic of HCV infection. When also considering that HCV is sialotropic and may be treated, HCV-related chronic sialadenitis represents a unique opportunity to clarify key pathogenetic events occurring in the large majority of HCV-negative SS; and similarities to typical primary SS, rather than differences, should be taken into account.
