Matteo Francesco Lauriola

Cognition and emotional decision-making in chronic low back pain: an ERPs study during Iowa gambling task

Previous reports documented abnormalities in cognitive functions and decision-making (DM) in patients with chronic pain, but these changes are not consistent across studies. Reasons for these discordant findings might include the presence of confounders, variability in chronic pain conditions, and the use of different cognitive tests. The present study was aimed to add evidence in this field, by exploring the cognitive profile of a specific type of chronic pain, i.e., chronic low back pain (cLBP). Twenty four cLBP patients and 24 healthy controls underwent a neuropsychological battery and we focused on emotional DM abilities by means of Iowa gambling task (IGT). During IGT, behavioral responses and the electroencephalogram (EEG) were recorded in 12 patients and 12 controls. Event-related potentials (ERPs) were averaged offline from EEG epochs locked to the feedback presentation (4000 ms duration, from 2000 ms before to 2000 ms after the feedback onset) separately for wins and losses and the feedback-related negativity (FRN) and P300 peak-to-peak amplitudes were calculated. Among cognitive measures, cLBP patients scored lower than controls in the modified card sorting test (MCST) and the score in this test was significantly influenced by pain duration and intensity. Behavioral IGT results documented worse performance and the absence of a learning process during the test in cLBP patients compared to controls, with no effect of pain characteristics. ERPs findings documented abnormal feedback processing in patients during IGT. cLBP patients showed poor performance in the MCST and the IGT. Abnormal feedback processing may be secondary to impingement of chronic pain in brain areas involved in DM or suggest the presence of a predisposing factor related to pain chronification. These abnormalities might contribute to the impairment in the work and family settings that often cLBP patients report.

The Association between Serum Cytokines and Damage to Large and Small Nerve Fibers in Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is a frequent complication of type 2 diabetes mellitus (DM) and may involve small and large peripheral nerve fibers. Recent evidence suggests a role of cytokines in DPN. The paper is aimed at exploring whether the serum concentration of cytokines is associated with small and large nerve fiber function and with neuropathic pain (NP). We recruited a group of 32 type 2 DM patients who underwent serum cytokines (TNF-α, IL-2, IL-4, IL-6, and IL-10) dosage as well as electrodiagnostic and quantitative sensory testing (QST) assessment to explore damage to large and small nerve fibers. Raised serum levels of IL-6 and IL-10 correlated with markers of large nerve fiber sensory and motor axonal damage. Raised IL-10 serum level was associated with signs of motor nerve demyelination. No differences were found in pain characteristics and electrodiagnostic and QST markers of small nerve fiber function in relation to cytokines serum levels. IL-6 and IL-10 serum levels were associated with large nerve fiber damage but not to small fibers function or NP. IL-6 and IL-10 cytokines might play a role in the pathogenesis of nerve fiber damage or represent a compensatory or neuroprotective mechanism.

An electrodiagnostic technique for assessing palmar proper digital nerves of the hand: Normative data and clinical application

Introduction: There is no standard electrodiagnostic technique for palmar proper digital nerves (PaPDNs). In this study we investigated sensory nerve action potentials (SNAPs) to PaPDN stimulation in normal subjects and patients. Methods: SNAPs of PaPDNs were recorded in response to selective antidromic stimulation at the web space and mixed nerve stimulation at the wrist in 14 controls. The selectivity of PaPDN stimulation and the effect of recording electrode position on SNAP amplitude were studied. The technique was tested in 2 patients with PaPDN lesions. Results: The technique yielded selective PaPDN stimulation at the web space. SNAP amplitude to PaPDN stimulation was influenced by age and was larger than SNAP amplitude to wrist stimulation. The recording electrode positions influenced SNAP amplitude. In patients, we documented PaPDN lesions, which were confirmed at surgery, whereas conventional wrist mixed nerve stimulation yielded negative findings. Conclusions: Selective PaPDN stimulation at the web space is feasible and may be helpful for electrodiagnosis of PaPDN lesions. Muscle Nerve 52: 972–980, 2015

Isolated musculocutaneous nerve injury in a kickboxer.

Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d’Hebron, Institut de Recerca, Universitat Aut onoma de Barcelona, Barcelona, Spain Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain Universidad Europea, Madrid, Spain Instituto de Investigaci on Hospital 12 de Octubre, Madrid, Spain Hospital Universitari de Bellvitge, Hospitalet del Llobregat, Spain Department of Neurosciences, Institut d’Investigaci o en Ciències de la Salut Germans Trias i Pujol I Campus Can Ruti, Universitat Aut onoma de Barcelona, Badalona, Spain

Damage to the Median and Ulnar Nerves After a Snake Bite.

About 5 million people are bitten by snakes every year, resulting in more than 2 million cases of envenoming and 20,000–125,000 deaths. Most of these cases occur in Asia, Africa, South America, and the Indo Pacific. Muscle weakness caused by preor postsynaptic toxins acting on the neuromuscular junction and rhabdomyolysis and ischemic or hemorrhagic strokes are the most common neurological complications of snake bite. Local signs of envenomation are more prominent after viper and colubrid bites, but may also occur in cases of elapid bites and include swelling, blister formation, and necrosis of the skin and subcutaneous tissue. Peripheral nerve damage is a rare complication of snake bite. Neuroma-in-continuity represents one of the worst complications of peripheral nerve lesions because of pain and poor recovery. We report a case of median and ulnar nerve necrosis leading to ultrasound feature of a double neuroma-incontinuity after cobra snakebite to the forearm.

Nerve ultrasound findings differentiate Charcot-Marie-Tooth disease (CMT) 1A from other demyelinating CMTs

OBJECTIVE Ulnar/median motor nerve conduction velocity (MNCV) is ≤38 m/s in demyelinating Charcot-Marie-Tooth disease (CMT). Previous nerve high resolution ultrasound (HRUS) studies explored demyelinating CMT assuming it as a homogeneous genetic/pathological entity or focused on CMT1A. METHODS To explore the spectrum of nerve HRUS findings in demyelinating CMTs, we recruited patients with CMT1A (N = 44), CMT1B (N = 9), CMTX (N = 8) and CMT4C (N = 4). They underwent nerve conduction study (NCS) and HRUS of the median, ulnar, peroneal nerve, and the brachial plexus. RESULTS Median, ulnar and peroneal MNCV significantly differed across CMT subtypes. Cross sectional area (CSA) was markedly and diffusely enlarged at all sites, except entrapment ones, in CMT1A, while it was slightly enlarged or within normal range in the other CMTs. No significant right-to-left difference was found. Age had limited effect on CSA. CSAs of some CMT1A patients largely overlapped with those of other demyelinating CMTs. A combination of three median CSA measures could separate CMT1A from other demyelinating CMTs. CONCLUSIONS Nerve HRUS findings are heterogeneous in demyelinating CMTs. SIGNIFICANCE Nerve HRUS may separate CMT1A from other demyelinating CMTs. The large demyelinating CMTs HRUS spectrum may be related to its pathophysiological variability.

Sunderland's median nerve fascicular anatomy revisited by ultrasound

The internal anatomy of the upper-limb nerves was investigated with microdissection by the seminal work of Sunderland.1 More recent autopsy studies further explored the fascicular anatomy of the median nerve (MN) and confirmed a radial-to-ulnar sensory and motor arrangement of nerve fascicles at the wrist.2 ,3 We report two patients with partial MN damage, in whom sensory neurography and ultrasound (US) documented asymmetrical involvement of the nerve involving its ulnar and radial sectors, respectively. Patient 1 was a 22-year-old man with a penetrating lesion of the wrist because of a glass fragment. He reported sensory loss and paraesthesia involving the ulnar side of the index, middle and radial side of the ring finger with no motor symptoms. Median sensory neurography showed markedly reduced ring finger sensory nerve action potential (SNAP), absent middle finger SNAP and slightly reduced, but still in …

Electrodiagnosis of Lesions of Median and Ulnar Nerve Hand Sensory Branches: A Case Series

Introduction: The authors have recently tested a new electrodiagnostic technique for palmar proper digital nerves sensory nerve action potentials in normal controls. Here the authors explored whether it may offer additional information in comparison to mixed nerve wrist stimulation in a series of patients. Methods: The authors recorded palmar proper digital nerves sensory nerve action potential to selective antidromic webspace stimulation in a group of 19 patients with suspected lesions of median and ulnar nerve hand sensory branches. Coexistent carpal tunnel syndrome was present in 11 patients. Results: The webspace stimulation technique offered additional information in 89% patients when compared with mixed nerve wrist stimulation. Webspace stimulation was informative even when carpal tunnel syndrome coexisted with damage to hand sensory branches and biased the interpretation of conventional wrist nerve conduction study. Conclusions: Webspace PaPDN stimulation is feasible in patients with lesion of median and ulnar nerve hand sensory branches and offer additional information in comparison with wrist-mixed nerve conduction study, also in patients with coexisting carpal tunnel syndrome.

Unexpected Inching Explained by an Ulnar Nerve Anatomic Variant Documented by Sonography.

Ulnar neuropathy at the elbow is the most common upper limb entrapment neuropathy after carpal tunnel syndrome, and its diagnosis is usually straightforward. The inching technique may help document the site of ulnar nerve entrapment and help decide the site of surgical release.1 A 69-year-old man with paresthesia involving the fourth and fifth fingers and clumsiness of the right hand was sent for suspected ulnar neuropathy. An examination showed mild hypoesthesia in the fourth and fifth fingers and slight weakness of the ulnar and innervated intrinsic hand muscles on the right side. His clinical history was unremarkable except for mild hypertension. An ulnar nerve electrodiagnostic study, which was performed according to current guidelines,1 documented a reduced sensory nerve action potential amplitude, a reduced motor nerve conduction velocity from above to below the elbow (37.5 m/s; below the elbow to wrist: 52 m/s), and a 40% decrease in the compound muscle action potential amplitude from below to above the elbow. An ulnar nerve inching study1 documented a 49% reduction and a further 54% decrease in the compound muscle action potential amplitude across the distal and proximal segments of the cubital tunnel, respectively (Figure 1A). A surprising 241% increase in the ulnar compound muscle action potential amplitude in comparison to the above-the-elbow value was found in the distal arm (Figure 1A). The presence of MartinGruber anastomosis or other anomalous medianulnar communications was ruled-out.2 The patient underwent sonography imaging,3 which showed that when the elbow was extended, the right ulnar nerve, instead of coursing in the cubital tunnel between the olecranon and the medial epicondyle, was located anterior to the medial epicondyle, and its cross-sectional area was increased (29.4 mm2; normal values4: 8.0 ± 3.2 mm2; Figure 1B and Video 1). No changes in the ulnar nerve position were found with the elbow flexed. On the opposite side, sonography showed a normal course of the left ulnar nerve, with a cross-sectional area (12.8 mm2) in the normal range. The inching study was repeated, taking into account the abnormal course of the right ulnar nerve, and nerve entrapment was found in the area corresponding to the site of ulnar nerve enlargement (Figure 1C). The left upper limb was asymptomatic, and a left ulnar nerve electrodiagnostic study yielded normal values. CLINICAL LETTERS

Painful Legs and Moving Toes Syndrome: Putative Underlying Pathophysiology as a Hint for Combined Pharmacological Treatment?

Painful legs and moving toes (PLMT) syndrome is a rare movement disorder. PLMT is characterized by pain to one or more limbs associated with involuntary movements of digits or near segments. Involvement of the lower limbs is more common than that of the upper limbs. An underlying lesion in the peripheral or central nervous system is identified in some cases, although many of them remain idiopathic. There is no agreement on PLMT treatment, and response to drugs is usually poor. We report on a case of idiopathic PLMT syndrome. Based on electrophysiological evidence of central hyperexcitability and the temporal correlation with peripheral trauma, the patient was treated with combined treatment to reduce spinal excitability and block peripheral afferents.