Anterior cruciate ligament reconstruction is associated with increased corticospinal excitability and rate of force development Stefano Scarano, Antonio Caronni, Alessandra Menon, Viviana Rota, Maurizio Amadei, et al. BMC Sports Science Medicine and Rehabilitation, 2026 Background After anterior cruciate ligament reconstruction, asymmetries in central activation are suspected to prevent complete functional recovery. This cross-sectional study investigated the motor function of both lower limbs in ACLR patients using morphological, mechanical, and neurophysiological measures after surgical repair with a semitendinosus-gracilis graft. Methods Ten male patients (age 20–31 years; 6/4 right/left knee surgery; 6–12 months after ACLR) were recruited. Muscle trophism was quantified through ultrasound estimates of quadriceps volume and mid-thigh circumference; knee extensors’ rate of force development (RFD), maximum torque and voluntary activation (interpolated twitch technique, ITT) were assessed through dynamometry during maximal isometric effort; spinal excitability was measured with the Soleus H-reflex; transcranial magnetic stimulation was used to assess corticospinal excitability (resting motor threshold (rMT) and recruitment curve of motor evoked potentials (MEP) during submaximal contraction) and intracortical excitability (short-interval intracortical inhibition (SICI)) of the Vastus medialis (VM) and Tibialis anterior (TA) muscles. Results The quadriceps muscle on the operated side showed significant volume loss (mean [SD] of 2264.6 [345.1] cm³ and 2082.9 [386.2] cm³ for the non-operated and operated sides, respectively; p = 0.035) and mid-thigh circumference (52.2 [2.7] cm and 50.2 [3.3] cm; p = 0.035). In the VM recruitment curves, the increase in MEP amplitude with increasing stimulation intensity was steeper on the operated side ( p = 0.001). The operated limb also showed a higher RFD ( p = 0.026). No inter-limb differences were found for the remaining outcomes. Conclusions The steeper rise of knee extensor torque, paralleled by an increased corticospinal excitability of the operated side VM muscle, suggests that an increased drive from the motor cortex is needed to engage the quadriceps in fast contractions following ACLR. This may represent a compensatory phenomenon aimed at counteracting the decline in muscle power associated with reduced muscle mass and altered quadriceps morphology. Trial registration ClinicalTrials.gov NCT04837417 (submitted On 2021-03-31).
Validity of the Arabic Version of the PROMIS Anxiety and PROMIS Depression in Cancer Questionnaires: Measuring Depression and Anxiety in Oncologic Patients in Saudi Arabia—A Rasch Analysis Study Hadeel R. Bakhsh, Bodor Bin sheeha, Luigi Tesio, Anna Simone, Stefano Scarano, et al. Journal of Clinical Medicine, 2025 Background/Objectives: The cancer experience has a significant affective impact on patients, often causing anxiety and depression. Given the importance of this condition, there is a true need for psychometrically valid and culturally appropriate assessment tools for anxiety and depression in this condition. This is also true for Arabic-speaking populations. This study evaluates the measurement properties of the PROMIS Depression in Cancer (PROMIS-Ca-D) and Anxiety in Cancer (PROMIS-Ca-A) questionnaires, part of the Patient-Reported Outcomes Measurement Information System® (PROMIS®), for assessing depression and anxiety in Saudi Arabian cancer patients. Methods: The PROMIS-Ca-D was translated into Arabic and subsequently tested with 30 participants from five Arabic-speaking countries. The PROMIS-Ca-A had been previously translated into Arabic. The second phase recruited 213 cancer patients in Riyadh, Saudi Arabia, who completed the PROMIS-Ca-D and PROMIS-Ca-A. Rasch analysis (rating scale model) was used to assess category functioning, item fit, unidimensionality, differential item functioning, and measures reliability. Results: The translation process confirmed the cultural appropriateness of the Arabic PROMIS-Ca-D. In the validation cohort (N = 213), Rasch analysis indicated excellent reliability for both scales. Although disordered modal thresholds and signs of multidimensionality were observed, control analyses confirmed that these features did not compromise the item calibrations or the person’s measures. Item fit was adequate, and Differential Item Functioning was negligible. However, suboptimal item-person targeting was noted. Conclusions: The Arabic PROMIS-Ca-D and PROMIS-Ca-A are psychometrically sound instruments for evaluating psychological distress in Arabic-speaking cancer patients. Future research should focus on assessing responsiveness and evaluating metric equivalence with legacy measures.
Generalisability of the Barthel Index and the Functional Independence Measure: robustness of disability measures to Differential Item Functioning Antonio Caronni, Stefano Scarano Disability and Rehabilitation, 2025 PURPOSE Differential Item Functioning (DIF), an item malfunctioning, causes Differential Test Functioning (DTF), thus biasing questionnaire measures. The current study evaluates the relationship between DIF and DTF for the Barthel Index and the Functional Independence Measure, likely the most used disability measures. The aim is to understand under which conditions DIF can be ignored as its DTF is negligible. METHODS A simulation study was run. Disability measures were obtained for the Barthel Index and FIM motor domain using Rasch analysis with previously published item calibrations. Several DIF scenarios have been assessed. DTF was tolerable if ≤0.50 logits. RESULTS Simulations showed that the larger the DIF, the larger the DTF and that, keeping the overall DIF constant, the total number of items with DIF does not affect DTF. DIF of the items with the lowest or highest calibrations is the most dangerous. The DIF of central items should be so massive to matter in DTF terms that it is unlikely to happen in practice. The FIM robustness to DIF is better than that of the Barthel Index. CONCLUSIONS The FIM and the Barthel Index show remarkable robustness to DIF. Thanks to this feature, sample invariant, generalisable disability measures are available.
Plantar flexors are the main engine of walking in healthy adults Viviana Rota, Antonio Caronni, Stefano Scarano, Maurizio Amadei, Luigi Tesio Frontiers in Sports and Active Living, 2025 IntroductionThe plantar flexors contribute to the uniqueness of man's walking across bipeds (including apes). This role is achieved in late infancy through neural maturation. This may explain why this mechanism is lost with all corticospinal lesions despite the spared power of plantar flexors in segmental motions. During adult human walking, the plantar flexor muscles at the rear limb, during double stance, are suspected to provide most of the work and power required to translate the body system, which can be represented mechanically by its centre of mass (CoM). However, direct evidence of the dominant role of the ankle muscles in CoM translation is scarce. Experimental evidence requires synchronously assessing the lower limb joints’ and CoM's power.MethodsIn this work, ten healthy adults were requested to walk on a split-belt force treadmill at speeds ranging from 0.3 to 1.2 m s−1. A series of eight subsequent strides was analysed at each different speed. The synchronous analysis of ground reaction forces (through force platforms) and joint rotations (through an optoelectronic system) allowed us to simultaneously measure the CoM and the lower limb joints’ power.ResultsThe dominant role of the ankle plantar flexors, suggested by previous studies focusing on speeds above 0.9 m s−1, was confirmed by observing that changes in ankle power during the push-off phase (end of single stance and initial double stance) mirror the changes in power of the CoM. In the double support phase, the amplitude of the increments in ankle joint power was a strong predictor of the increments in CoM power (R2 = 82%).DiscussionLow walking speeds have been included to foster the interpretation of pathologic gaits, and clinical correlates of these findings in motor impairments are highlighted.Clinical Trial RegistrationClinicalTrials.gov, identifier NCT05778474.
Implementation of the sensory organization test with the CAREN system: a pilot study Paolo De Pasquale, Augusto Ielo, Cristiano De Marchis, Daniele Borzelli, Antonino Casile, et al. Frontiers in Bioengineering and Biotechnology, 2025 IntroductionThe Sensory Organization Test (SOT) is a clinical and instrumental tool designed to assess postural stability by measuring body sway during standing under different sensory feedback conditions. This study explores the implementation of the SOT using the Computer Assisted Rehabilitation Environment (CAREN) system, aiming to enhance balance assessment and extend the diagnostic applications available for CAREN.MethodsA software application (CAREN-SOT) was developed to implement the SOT using the CAREN, which features a six degrees of freedom motion platform, force sensors, a 3D motion capture system, and an immersive visual environment. Eight healthy participants (ages 23–40, four males) underwent the SOT across six conditions, using either optic motion capture or force plate inputs to estimate the sway of the body center of mass. A generalized linear mixed model was employed to analyze equilibrium scores (ESs) from both modalities, considering system’s latency and responsiveness.ResultsCAREN-SOT implementation was possible using both input modalities. No statistically significant differences were found between the optoelectronic and force plate modalities in measuring postural stability across conditions. Comparison with normative data from the NeuroCom™ EquiTest™ system suggested equivalence in key SOT metrics, despite minor variations in ESs likely due to methodological differences and sample size.DiscussionBy integrating advanced technological and customization capabilities, CAREN-SOT provides an immersive, controlled environment for postural stability assessment. While findings must be validated on a larger sample, they support CAREN-SOT’s utility in diagnostic and rehabilitative settings. Future research directions include expanding normative datasets and exploring mediolateral sway to increase our understanding of postural control mechanisms.
Minimal detectable change of gait and balance measures in older neurological patients: estimating the standard error of the measurement from before-after rehabilitation data thanks to the linear mixed-effects models Antonio Caronni, Michela Picardi, Stefano Scarano, Viviana Rota, Giacomo Guidali, et al. Journal of Neuroengineering and Rehabilitation, 2024 Background Tracking gait and balance impairment in time is paramount in the care of older neurological patients. The Minimal Detectable Change (MDC), built upon the Standard Error of the Measurement (SEM), is the smallest modification of a measure exceeding the measurement error. Here, a novel method based on linear mixed-effects models (LMMs) is applied to estimate the standard error of the measurement from data collected before and after rehabilitation and calculate the MDC of gait and balance measures. Methods One hundred nine older adults with a gait impairment due to neurological disease (66 stroke patients) completed two assessment sessions before and after inpatient rehabilitation. In each session, two trials of the 10-meter walking test and the Timed Up and Go (TUG) test, instrumented with inertial sensors, have been collected. The 95% MDC was calculated for the gait speed, TUG test duration (TTD) and other measures from the TUG test, including the angular velocity peak (ωpeak) in the TUG test’s turning phase. Random intercepts and slopes LMMs with sessions as fixed effects were used to estimate SEM. LMMs assumptions (residuals normality and homoscedasticity) were checked, and the predictor variable ln-transformed if needed. Results The MDC of gait speed was 0.13 m/s. The TTD MDC, ln-transformed and then expressed as a percentage of the baseline value to meet LMMs’ assumptions, was 15%, i.e. TTD should be < 85% of the baseline value to conclude the patient’s improvement. ωpeak MDC, also ln-transformed and expressed as the baseline percentage change, was 25%. Conclusions LMMs allowed calculating the MDC of gait and balance measures even if the test-retest steady-state assumption did not hold. The MDC of gait speed, TTD and ωpeak from the TUG test with an inertial sensor have been provided. These indices allow monitoring of the gait and balance impairment, which is central for patients with an increased falling risk, such as neurological old persons. Trial registration NA.
In Myotonic Dystrophy Type 1 Head Repositioning Errors Suggest Impaired Cervical Proprioception Stefano Scarano, Antonio Caronni, Elena Carraro, Carola Rita Ferrari Aggradi, Viviana Rota, et al. Journal of Clinical Medicine, 2024 Background: Myotonic dystrophy type 1 (DM1) is a rare multisystemic genetic disorder with motor hallmarks of myotonia, muscle weakness and wasting. DM1 patients have an increased risk of falling of multifactorial origin, and proprioceptive and vestibular deficits can contribute to this risk. Abnormalities of muscle spindles in DM1 have been known for years. This observational cross-sectional study was based on the hypothesis of impaired cervical proprioception caused by alterations in the neck spindles. Methods: Head position sense was measured in 16 DM1 patients and 16 age- and gender-matched controls. A head-to-target repositioning test was requested from blindfolded participants. Their head was passively rotated approximately 30° leftward or rightward and flexed or extended approximately 25°. Participants had to replicate the imposed positions. An optoelectronic system was adopted to measure the angular differences between the reproduced and the imposed positions (joint position error, JPE, °) concerning the intended (sagittal, horizontal) and unintended (including the frontal) planar projections. In DM1 patients, JPEs were correlated with clinical and balance measures. Static balance in DM1 patients was assessed through dynamic posturography. Results: The accuracy and precision of head repositioning in the intended sagittal and horizontal error components did not differ between DM1 and controls. On the contrary, DM1 patients showed unintended side-bending to the left and the right: the mean [95%CI] of frontal JPE was −1.29° [−1.99°, −0.60°] for left rotation and 0.98° [0.28°, 1.67°] for right rotation. The frontal JPE of controls did not differ significantly from 0° (left rotation: 0.17° [−0.53°, 0.87°]; right rotation: −0.22° [−0.91°, 0.48°]). Frontal JPE differed between left and right rotation trials (p < 0.001) only in DM1 patients. No correlation was found between JPEs and measures from dynamic posturography and clinical scales. Conclusions: Lateral head bending associated with head rotation may reflect a latent impairment of neck proprioception in DM1 patients.
