Background/Objectives: Ulnar nerve neuropathy at the elbow (UNE) is the second most common focal neuropathy of the upper extremity and often results from entrapment of the ulnar nerve as it traverses the elbow with insidious onset and gradual progression. This study describes the clinical, electrodiagnostic (EDX), and ultrasound (US) findings in a cohort of patients presenting with acute UNE. Methods: This is a review of 103 patients with clinical features of UNE with acute onset who underwent EDX and US studies over a 25-year period (2010–2026) at our Neurodiagnostic Center. Results: Of the 103 patients with acute UNE, all experienced paresthesia in the ulnar nerve distribution. A total of 27 (26.2%) patients had elbow pain, and 99 (96.1%) had decreased pinprick sensation in the ulnar nerve distribution. Weakness of the following muscles was detected: abductor digiti minimi (ADM) (94 [91.3%]), FDI (first dorsal interosseous) (91 [88.3%]), and FDPu (flexor digitorum profundus—ulnar) (76 [73.8%]). Most patients had a clinical grade of 3 (severe: sensory and motor abnormalities as well as atrophy of the FDI and ADM muscles) (93 [90.3%]). Perioperative injuries were the most common etiology of acute UNE, consisting of 65 (63.1%) patients. The perioperative injury was noted after surgical procedures at varied locations, most frequently at the shoulder in 23 (35.4%) followed by coronary artery bypass in 9 (13.8%) and knee joint surgery in 8 (12.3%). Non-iatrogenic injuries affected 11 (10.7%) patients. The US study revealed cysts and tumors such as a Schwannoma in 14/76 (18.4%) patients. Focal demyelination was observed by EDX studies in 95 (92.2%) patients, and a conduction block was detected in 24 (23.3%). Motor and sensory axonal involvement was identified in 81 (78.6%) and 86 (83.5%) patients, respectively. Of the 76 patients who underwent an US study, 68 (90.6%) had an increase in the cross-sectional area of the ulnar nerve and 51 (68.0%) had a hypoechoic ulnar nerve at the elbow. Conclusions: In this study, the most common cause of acute UNE was periprocedural injury, most frequently following shoulder surgery. Acute UNE may also occur without a history of antecedent trauma or a surgical procedure. EDX and US studies provide complementary data to determine the severity and the etiology of acute UNE and guide further management.

Background and objective Herpes zoster infection is due to reactivation of the varicella zoster virus, usually at the dorsal root ganglia, leading to classic skin lesions and neuralgic pain. Concurrent involvement of motor axons/cells may cause segmental paralysis. We sought to describe the clinical and electrodiagnostic (EDX) findings in a cohort of patients with zoster segmental paralysis (ZSP). Methods This is a retrospective study of 17 patients with historical and clinical evidence of ZSP of the upper extremities (UE) or lower extremities (LE), confirmed by EDX studies. The clinical metrics collected included (1) demographics; (2) relevant history, including herpes zoster and/or herpes zoster vaccination; and (3) clinical findings (sensory, motor, and reflexes) and localization of the motor deficit. The EDX protocol included motor and sensory nerve conduction studies and needle electromyography (EMG). Metrics collected included motor and sensory conduction velocity, alterations in compound muscle action potentials (CMAP) and sensory nerve action potentials (SNAP), and signs of denervation in muscles detected by needle EMG, as well as their topography for precise localization. Results In our study, of the 17 patients with ZSP by history, the UE were involved in 15 (88.2%) patients and the LE in two (11.8%). All patients had weakness of specific muscles of the UE or LE corresponding to the dermatomal location of the skin eruptions. Of the 15 patients who had symptoms of the UE, the most frequent clinical localization of the motor deficit was the C8 and T1 nerve roots (8 (53.3%)). Of the two patients who had symptoms of the LE, the localization of the motor deficit was the L5 and S1 nerve roots in one and the L5 nerve root in the other. Fifteen (88.2%) patients had sensory abnormalities of either the UE or LE, which consisted of either decreased pinprick sensation or allodynia. The EDX studies revealed abnormal motor conduction in 15 (88.2%) patients, displayed by diffuse slowing of motor conduction and/or low amplitude or absence of the CMAP. Sensory conduction was abnormal in 16 (94.1%) patients, with either decreased or absent SNAP. Thirteen (76.5%) patients demonstrated abnormal spontaneous activity suggestive of denervation. Of the 15 patients with UE symptoms, the EDX localization was most frequently at the C8-T1 ventral root/horn cell (V) and dorsal root ganglion (D) in 8 (53.3%) patients. In the two patients with LE symptoms, the EDX location was at the L5-S1 ventral root/horn cell and dorsal root ganglion in one, and the L5 ventral root/horn cell and dorsal root ganglion in the other. Conclusions ZSP is a rare complication of herpes zoster infection. Physicians should consider ZSP in the differential diagnosis when patients present with acute onset of muscle weakness in a radicular distribution and should look for skin lesions suggestive of herpes zoster in the corresponding dermatome. EDX studies are highly useful in confirming the radicular/segmental topography of muscle denervation. In this study of a large cohort of patients with ZSP confirmed by EDX, we describe the clinical and EDX findings to improve clinical detection of this uncommon condition.

Background/Objectives: Atrophy of the thenar muscles (abductor pollicis brevis [APB], opponens pollicis [OP], and flexor pollicis brevis [FPB]) is most commonly caused by carpal tunnel syndrome (CTS). It may also occur following injury to the recurrent motor branch of the median nerve, proximal median nerve neuropathy, medial cord/lower trunk plexopathy, T1 radiculopathy, ventral horn cell disorder at C8 or T1, disuse atrophy, or congenital aplasia. Clinical observation of flattening of the thenar eminence coupled with electrodiagnostic (EDX) and ultrasound (US) studies is valuable in determining the etiology of thenar atrophy. This study describes clinical, EDX, and US findings in a large cohort of patients with thenar muscle atrophy. Methods: This is a review of 197 patients (226 hands) with thenar atrophy who underwent EDX and US studies. Patients were divided into those with total thenar atrophy (all three thenar muscles were atrophic) or partial thenar atrophy (atrophy of one or two thenar muscles) based on clinical and US findings. Results: Of the 226 hands, 174 (77.0%) had partial thenar atrophy, 217 (96.0%) had sensory loss, and all hands demonstrated weakness of the APB and OP muscles on examination. A total of 220 (97.3%) hands had EDX evidence of severe median nerve entrapment at the carpal tunnel. The compound muscle action potentials (CMAPs) of the APB muscle and sensory nerve action potentials (SNAPs) were absent in 186 (82.3%) and 212 (93.8%) hands, respectively. US study showed hyperechoic APB and OP muscles in 225 (99.6%) hands. The Heckmatt grade, determined by US, was 3 in 152 (67.3%) hands, showing increased muscle echogenicity with loss of architecture and reduced bone reflection. Conclusions: In patients with thenar muscle atrophy, EDX studies were not always conclusive for confirming CTS due to an absence of SNAP and CMAP over the APB and second lumbrical muscles. In these cases, US is important to confirm the cause of thenar atrophy.

Background/Objectives: The Wartenberg sign is a diagnostic feature of ulnar nerve neuropathy. It results from unbalanced activity of the abductor digiti minimi (ADM) and extensor digiti minimi (EDM) muscles secondary to weakness of the third palmar interosseous muscle. Rarely, this sign may occur in the absence of an underlying ulnar neuropathy, which we refer to as the “pseudo Wartenberg sign” (PWS). Methods: This is a retrospective review of 10 patients manifesting an inability to adduct the little finger towards the ring finger with no evidence of an ulnar neuropathy. We describe the clinical and electrodiagnostic (EDX) findings in these patients and discuss the pathophysiologic basis of PWS. Results: The most common cause was an injury in five (50.0%) patients: avulsion of the third volar interosseous muscle in two (20.0%), contracture of the ADM muscle in one (10.0%), and trauma-related dystonia in two (20.0%). The most frequent mechanism of PWS was focal dystonia of specific hand muscles in seven (70.0%) patients. Needle electromyography (EMG) demonstrated no denervation changes in ulnar nerve-innervated hand muscles; the motor and sensory conduction was normal in the ulnar nerve in all patients. Four (40.0%) patients underwent ultrasound studies, with a hyperechoic, avulsed third volar interosseous muscle in one, a hyperechoic and atrophic ADM muscle in one, normal hypothenar and extensor muscles in one, and a normal hypothenar muscle in one. Conclusions: Neurologists, neurosurgeons, and hand and orthopedic surgeons should be aware of the rare cases in which the inability to adduct the little finger may occur in the absence of ulnar neuropathy and look for other causes like avulsion of the third palmar interosseus muscle or focal hand dystonia.

Vascular disruption is an early and critical event in spinal cord injury (SCI), but its contribution remains poorly understood. Using novel in vivo two-photon dual-dye imaging, we found simultaneous blood-spinal cord barrier (BSCB) leakage and venous dilation in both the injury epicenter and adjacent transitional segment after cervical SCI in rats. Notably, vascular permeability in the transitional zone preceded axonal and neuronal loss, revealing a therapeutic window. Systemic delivery of ferulic acid-glycol chitosan (FA-GC) nanoparticles, a membrane-sealant, rapidly stabilized the compromised vasculature, reduced neuronal loss in the transitional region, and improved forelimb muscle strength. These findings identified acute vascular leakage beyond the injury epicenter as a driver of secondary pathology and highlight early vascular stabilization as promising therapeutic strategy.

Background/Objectives: This is a retrospective review of 36 patients with electrodiagnostic (EDX) confirmation of carpal tunnel syndrome (CTS) and ultrasound (US) detection of marked median nerve enlargement (defined as a cross-sectional area [CSA] of 40 mm2 or greater) at the wrist. Methods: We describe the clinical, electrodiagnostic (EDX), and US findings in these patients and discuss the pathophysiologic basis of a markedly enlarged median nerve. Results: The markedly enlarged median nerve was detected by US in a total of 39 hands (36 patients, with 3 bilateral). Of the 39 hands, thenar atrophy was observed in 15 (38.5%) hands, and pinprick loss in the median nerve distribution was noted in all hands. Moderately severe or severe median nerve entrapment at the carpal tunnel (CT) was confirmed by EDX studies in 21 (53.8%) and 16 (41.0%) hands, respectively. A total of 12 (30.8%) hands had no compound muscle action potentials (CMAPs) over the abductor pollicis brevis muscle, and sensory nerve action potentials (SNAPs) were not detected in 31 (79.5%) hands. The wrist CSA was between 40 and 44 mm2 in 20 (51.3%) hands, between 45 and 49 mm2 in 13 (33.3%) hands, and 50 mm2 or greater in 6 (15.4%) hands. Conclusions: The implications of the markedly enlarged median nerve for surgical management of CTS are unknown, and future prospective studies are needed.

Background/Objectives: Elderly patients with carpal tunnel syndrome (CTS) have more severe clinical, ultrasonic, and electrodiagnostic (EDX) findings compared to younger patients. Thenar weakness and atrophy are more common at initial presentation in the elderly population with CTS. Methods: This is a retrospective review of 187 very elderly patients (aged 80 years and older) with EDX confirmation of CTS. We describe the clinical, EDX, and US features in these patients and compare the severity of the median nerve entrapment at the carpal tunnel (CT) by EDX findings to a middle-aged cohort (ages 40–50 years). Results: The total number of very elderly hands with CTS was 289 (187 patients total, with bilateral symptoms in 102 patients). Of the 289 hands, thenar atrophy was observed in 75 (26.0%) hands, weakness of the abductor pollicis brevis (APB) muscle was detected in 178 (61.6%) hands, and pinprick decrease/loss was noted in 265 (91.7%) hands. Of the total 289 hands, 57 (66.3%) hands’ median nerve stimulation did not evoke compound muscle action potentials over the APB and second lumbrical muscles. Sensory nerve action potentials were not detected in 211 (76.2%) hands. Comparing the sensitivities of various US measurements in diagnosing CTS, the cross-sectional area at the CT inlet had the highest sensitivity among the various measurements. As the CSA at the CT inlet increases, the odds of a greater CTS severity by EDX studies also increase (OR = 1.109, p-value = 0.001). The very elderly patients with CTS more frequently had more severe CTS compared to the middle-aged patients with CTS (chi-squared = 102.653, p-value < 0.001). Conclusions: The very elderly patients appear to seek medical care only when the CTS has become severe. The primary care physicians should look for signs and symptoms of CTS in the very elderly and encourage prompt treatment. Surgeons should be cognizant of the differences in the clinical, EDX, and US studies in the very elderly patient cohort with CTS. US is highly useful in evaluating CTS when the EDX studies become non-localizing in severe CTS, as often seen in the very elderly patients.

Dr Roy Glenwood Spurling (1894-1968) is a foundational figure in modern neurosurgery whose leadership and ingenuity transformed the discipline. A graduate of Harvard Medical School and deeply influenced by Harvey Cushing, Spurling pioneered the first dedicated neurosurgical service at the University of Louisville in 1926. The establishment of the university's neurosurgical residency program in 1946 became a model for training neurosurgeons and set benchmarks for surgical education. His vision extended nationally as a co-founder of the Harvey Cushing Society in 1932 (later called the American Association of Neurological Surgeons) and served as inaugural secretary and later president. During World War II, Spurling's tenure as Assistant Chief of Surgery at Walter Reed Hospital revolutionized military neurosurgery. He introduced new standards of care for disk surgery and peripheral nerve injuries in the Military and Veterans Affairs Hospital. In 1945, his management of General George Patton's cervical spine injury and quadriplegia highlighted neurosurgery's growing role in trauma care. Spurling served as neurosurgical consultant for the Veterans' Administration (1946-1953) and remained in charge of the neurosurgical services at the University of Louisville until his retirement in 1960. He collaborated with Michael E. DeBakey to disseminate knowledge through the American Lecture Series. Colleagues worldwide celebrated his leadership in neurosurgical education. Spurling's legacy continues to define neurosurgical excellence today.

Gorham-Stout disease (GSD), also known as vanishing bone disease or massive osteolysis, is a rare entity characterized by destruction of the osseous matrix and proliferation of vascular structures resulting in bone resorption. While neurological complications such as cerebrospinal rhinorrhea secondary to cranial involvement and paraplegia from spinal involvement have been reported, peripheral nerve complications are not known. We describe a case of radial nerve palsy that was an iatrogenic complication of shoulder replacement surgery with bone loss of the humerus resembling GSD. A 71-year-old male with a history of left total shoulder arthroplasty followed by a revision reverse total shoulder arthroplasty noted a "bone protruding" and pain in the left upper arm 12 years later. X-rays showed that the proximal portion of the humerus was not detectable. CT scan of the left upper extremity revealed loosening of the humeral component with prominent osteolysis most pronounced around the distal stem. The patient underwent a revision of the reverse total shoulder arthroplasty with replacement of the humeral head and shaft. He experienced numbness, pain, and weakness of the left shoulder and arm with wrist drop postoperatively. Physical exam revealed marked weakness of the dorsiflexors of the wrist and digits, wasting and weakness of the brachioradialis muscle, and loss of pinprick sensation of the superficial radial nerve distribution. Needle EMG showed denervation changes in the extensor digitorum communis, brachioradialis, and extensor carpi radialis longus muscles. An ultrasound (US) study showed enlargement of the left radial nerve at the spiral groove. The EDX and US findings suggested a left radial nerve palsy at the spiral groove. There were minimal EMG abnormalities in the deltoid and triceps muscles suggesting additional involvement of the posterior cord of the brachial plexus. This case illustrates the potential for iatrogenic radial nerve palsy following shoulder replacement surgery with significant bone loss of the humerus resembling GSD.

Alterations in the gut-microbiome-brain axis are increasingly being recognized to be involved in Alzheimer’s disease (AD) pathogenesis. However, the functional consequences of enteric dysbiosis linking gut microbiota and brain pathology in AD progression remain largely undetermined. The present work investigated the causal role of age-associated temporal decline in butyrate-producing bacteria and butyrate in the etiopathogenesis of AD. Longitudinal metagenomics, neuropathological, and memory analyses were performed in the 3×Tg-AD mouse model. Metataxonomic analyses showed a significant temporal decline in the alpha diversity marked by a decrease in butyrate-producing bacterial communities and a concurrent reduction in cecal butyrate production. Inferred metagenomics analysis identified the bacterial acetyl-CoA pathway as the main butyrate synthesis pathway impacted. Concomitantly, there was an age-associated decline in the transcriptionally permissive acetylation of histone 3 at lysines 9 and 14 (H3K9/K14-Ac) in hippocampal neurons. Importantly, these microbiome-gut-brain changes preceded AD-related neuropathology, including oxidative stress, tau hyperphosphorylation, memory deficits, and neuromuscular dysfunction, which manifest by 17–18 months. Initiation of oral administration of tributyrin, a butyrate prodrug, at 6 months of age mitigated the age-related decline in butyrate-producing bacteria, protected the H3K9/K14-Ac status, and attenuated the development of neuropathological and cognitive changes associated with AD pathogenesis. These data causally implicate age-associated decline in butyrate-producing bacteria as a key pathogenic feature of the microbiome-gut-brain axis affecting the onset and progression of AD. Importantly, the regulation of butyrate-producing bacteria and consequent butyrate synthesis could be a significant therapeutic strategy in the prevention and treatment of AD.

ObjectivesProximal median nerve (PMN) neuropathies are caused by lesions proximal to the carpal tunnel, which include the forearm, elbow, upper arm, and brachial plexus. Differentiating between carpal tunnel syndrome and PMN neuropathies is important to guide management and is based on clinical, electrodiagnostic (EDX), and ultrasound (US) findings. This study describes the clinical, EDX, and US features in 62 patients with PMNs.MethodsAll patients underwent EDX studies, and 52 (83.9%) had a US study. The patients were assigned to one of the following four localization zones of PMN neuropathies based on clinical and EDX criteria: Zone 1: extends from the fascicles in the brachial plexus contributing to the median nerve to the innervation of the pronator teres (PT); Zone 2: distal to the branch to the PT and proximal to the origin of the anterior interosseous nerve (AIN); Zone 3: involves the origin of the AIN; and Zone 4: distal to the origin of the AIN and proximal to the carpal tunnel. The localization was based on the pattern of muscle weakness, topography of EMG abnormalities, and US study findings.ResultsThe anatomical locations of the PMN neuropathies based on clinical, EDX, and US findings were as follows: Zone 1 in 38 patients (61.3%), Zone 2 in 6 patients (9.7%), Zone 3 in 7 patients (11.3%), and Zone 4 in 11 patients (17.7%). The most common etiology among all 62 patients was iatrogenic injury (30 [48.4%]), followed by non-iatrogenic trauma (20 [32.2%]). The following EDX findings were noted: prolonged distal motor latency (29 [46.8%]), decreased motor nerve conduction velocity in the forearm (22 [35.5%]), low amplitude or absent compound muscle action potentials (50 [80.6%]), and abnormal or absent sensory nerve action potentials (50 [80.6%]). Of the 52 (83.9%) patients who underwent US studies, a total of 22 (42.3%) patients showed an increased cross-sectional area of the median nerve. A neuroma was observed in 9 patients (17.4%).ConclusionIt is often possible to localize the site of the median nerve involvement and gain insight into the underlying cause based on clinical and EMG findings, but in certain cases, a US study may be necessary to confirm the location.

ObjectivesGunshot wounds of the upper extremities may cause permanent neurovascular injuries, leading to significant morbidity, chronic pain, functional loss, and disability. While there are many reports on the incidence and intraoperative findings in gunshot-related nerve injuries (GSNI) sustained during wars, there is a paucity of details pertaining to GSNI of the upper extremities in civilians. The goal of this paper is to provide the clinical, electrodiagnostic (EDX), and ultrasound (US) findings in 22 patients with GSNI of the upper extremities.MethodsThis is a retrospective study of patients referred for EDX studies to evaluate the presence of nerve injury after sustaining GSWs to the upper extremities. All patients underwent EDX studies, and 16 patients had US evaluations. Numerous metrics were documented including presenting symptoms, neurological abnormalities, EDX findings, and US features.ResultsThe forearm was the most frequent location of injury (8 [36%] patients). The ulnar nerve was the most common injured nerve (10 [45%] patients), followed by the brachial plexus (7 [32%] patients). All patients complained of muscle weakness; the most frequently affected muscles were the first dorsal interosseous (FDI) (14 [64%] patients) and abductor pollicis brevis (APB) (11 [50%] patients). Muscle atrophy was noted in 19 (86%) patients, 15 of whom had atrophy of the FDI. Axonotmesis was the type of nerve injury in all patients based on EDX studies. Of the 16 patients who underwent US studies, a neuroma in continuity was noted in 4 (25%) patients and neurotmesis in 1 (6.2%) patient. Eleven (69%) patients had enlarged and/or hypoechoic nerves.ConclusionsAxonotmesis of the ulnar nerve was the most common finding among patients sustaining gunshot injuries to the upper extremities. EDX and US studies provide valuable insight into the underlying pathophysiology and guidance for management of patients with GSNI of the upper extremities.

Hirayama disease (HD) is a rare disorder characterized by insidious asymmetric neurogenic atrophy primarily involving the upper extremities. HD most commonly affects adolescent males and has a favorable prognosis for arrest of progression. Electrodiagnostic (EDX) studies show chronic denervation changes in the distal upper extremity muscles. A cervical spine MRI in neck flexion may reveal compression of the cervical ventral spinal cord. We report clinical, EDX, and MRI findings in two cases of HD. The first case involved a 15-year-old male with a six-month history of progressive weakness, wasting, and tremulous movements of the left hand without pain or paresthesia. A physical exam revealed marked wasting of the left intrinsic hand muscles with polyminimyoclonus. Needle electromyography (EMG) revealed fasciculations (simultaneous with the polyminimyoclonus) while at rest and recruitment of 1-2 large polyphasic units in the left C8, T1, and, to a lesser extent, the C7 distribution. A T2-weighted flexion cervical spine MRI revealed narrowing and anterior displacement of the posterior dura of the cervical cord, leading to cord compression at C5-6 and C6-7. At last contact 11 years following symptom initiation, the patient continued to complain of profound weakness of the left hand without pain or numbness. The second case involved a 17-year-old male who was found to have wasting of the intrinsic muscles of the non-dominant left hand on a routine physical examination. The left first dorsal interosseus, abductor digiti minimi, abductor pollicis brevis, and extensor pollicis longus muscles were found to be clinically weak. Polyminimyoclonus involving all fingers of the left hand was also observed. A needle EMG demonstrated fasciculations with large amplitudes and wide duration motor unit potentials in the left C8, T1, and, to a lesser extent, C7 distribution. An ultrasound study showed frequent fasciculations in the left intrinsic hand muscles and the distal forearm muscles simultaneously with the polyminimyoclonus. A T2-weighted cervical spine MRI scan in the flexed sagittal position revealed anterior displacement of the dura and an enlarged epidural space from C4-C7. At last follow-up 11 months later, the findings were unchanged. The EDX studies and cervical MRI findings were consistent with HD in both cases. The role of EDX studies and cervical spine flexion MRI in diagnosing HD and the correlation between polyminimyoclonus and fasciculations are highlighted.

Background: The inability to extend the fingers at the metacarpophalangeal and interphalangeal joints leads to finger drop. While wrist drop and foot drop are well recognized, the causes of finger drop are poorly understood. Aims: This study describes the clinical, electrodiagnostic (EDX), and ultrasound (US) features in patients with finger drop. Materials and methods: This is a retrospective study of 87 patients presenting with finger drop and referred for EDX studies during the past 10 years. We analyzed the clinical picture, EDX data, and US findings. The patients were categorized into global (all five digits) or partial (limited to 1-4 digits) finger drop. Results: Fifty-six (64%) patients had global finger drop, while 31 (36%) had partial finger drop. The frequent cause of finger drop was Parsonage-Turner syndrome (PTS) (29 [33%]), followed by trauma (23 [26%]), cervical radiculopathy (16 [18%]), extensor tendon rupture (four [4%]), and compression/entrapment (two [2%]). In 13 (15%) patients, no cause was identified. A total of 13/16 (81%) patients with cervical radiculopathy and four of the patients with tendon rupture had partial finger drop, while 52/64 (81%) with posterior interosseous nerve (PIN) neuropathy had global finger drop. Of the 16 patients who experienced cervical radiculopathy as the cause of the finger drop, 15 patients had C7 and C8 radiculopathy and one patient had C7 radiculopathy. EDX studies of patients with PTS revealed partial axon loss in 18 (62%) patients, conduction block in eight (28%), and total axon loss in four (14%). Enlarged fascicles were observed by US in 40% of patients with PTS. EDX studies of patients who sustained iatrogenic nerve injury causing finger drop demonstrated total axon loss in six (46%) patients, partial axon loss in four (31%), demyelination in two (15%), and conduction block in two (15%). Conclusions: PIN neuropathy is the most common cause of finger drop, however, lesser-known causes such as cervical radiculopathy and extensor tendon rupture should also be considered. Global finger drop is suggestive of PIN neuropathy, while partial finger drop occurs more often in cervical radiculopathy and tendon rupture. EDX and US studies provide valuable information for localizing the lesion site and may reveal the cause of the finger drop.

Unilateral calf atrophy may result from several medical conditions, such as lumbar radiculopathy, asymmetric myopathy/dystrophy, a Baker’s (popliteal) cyst leading to tibial nerve compression, and disuse atrophy. We present a case series of four patients with unilateral calf atrophy, including chronic neurogenic atrophy (benign focal amyotrophy, one patient), tibial nerve compression at the popliteal fossa by a Baker’s cyst (one patient), and disuse atrophy (two patients). All four patients underwent electrodiagnostic (EDX) studies, and two of them had denervation changes of the gastrocnemius. One patient underwent an ultrasound (US), which revealed a large cyst in the popliteal fossa causing compression of the tibial nerve. The differential diagnosis of unilateral calf atrophy as well as diagnostic techniques to confirm the underlying pathology are described. EDX and US studies are useful in differentiating between the varied conditions that may cause asymmetric calf muscle wasting.

Background: The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve and is rarely entrapped or injured. This study describes the electrodiagnostic (EDX) findings and etiologies of LACN neuropathy. Methods: This is a review of 49 patients with pain and/or paresthesia of the forearm who underwent EDX studies. The diagnosis of LACN neuropathy was based on clinical and sensory conduction abnormalities. Results: The most common etiology of LACN neuropathy was iatrogenic injury in 30 (61.2%) patients, primarily due to biceps tendon repair at the elbow (11 [36.7%]) and phlebotomy (5 [16.7%]). Fifteen (30.6%) patients sustained a non-iatrogenic injury at the proximal forearm/elbow, consisting of six (60%) laceration injuries and five (33.3%) stretch injuries. Four (8.2%) patients comprised the “other” etiology category, including two mass lesions causing LACN compression. Pain, paresthesia, and/or numbness in the LACN distribution were reported in 33 (67.3%), 27 (55.1%), and 23 (46.9%) patients, respectively. Hypoesthesia was detected in 45 (91.8%) patients, and dysesthesia in 7 (14.3%). The sensory nerve action potentials (SNAPs) of the LACN on the symptomatic side were absent in 44 (89.8%) patients. Of the five patients whose SNAPs of the LACN were detected, all had a decreased amplitude, and two had increased sensory latency. Conclusions: The most common etiology for LACN neuropathy in this series was iatrogenic injury; repair of biceps tendon at the elbow was the most frequent provoking cause. Protection of the LACN during surgical procedures at the elbow and forearm is vital to prevent iatrogenic injury.

Dysbiosis of the gut microbiome is associated with various diseases, including Alzheimer’s Disease (AD). A decrease in intestinal butyrate-producing bacteria has been indicated by pre-clinical and clinical studies in AD; therefore, we assessed the effects of long-term oral administration of tributyrin (TB: a butyrate pro-drug) on the development of memory and neuromuscular deficits, and CNS pathology in 3xTg-AD (3xTg) mice. Oral gavage with tributyrin (2 mg/kg) was given twice weekly to female 3xTg mice between 6- and 17-months of age. Treatment was stopped and mice were tested for spatial memory (Y-maze and novel object recognition test-NORT) and neuromuscular function (RotaRod and grip tests). Brains from untreated (2-, 12-, or 18-month-old untreated or TB treated 18-month-old mice were formalin-fixed, paraffin-embedded for microscopic analysis of AD-associated pathology, neuroinflammation, and oxidative stress markers. Short-term, episodic memory and spatial memory along with balance and coordination and grip strength were all significantly decreased in untreated 3xTg mice at 17-months of age compared to 2- or 10-month-old mice. TB treatment, however, attenuated these effects in 17-month mice. TB treatment did not affect the accumulation of either Aβ or Tau in the subiculum at 18-months. However, pTau hyperphosphorylation—as indicated by co-staining with both pTau(Ser404) and AT-8 pTau (Ser202/Thr205) mAb—was effectively prevented with TB treatment. Similarly, significant age-dependent neuroinflammation indicated by IBA1 (microglia) and GFAP (astrocytes) staining was increased in the hippocampus of 18-month 3xTg mice and was effectively prevented by TB treatment. Additionally, markers of oxidative stress, 4-HNE and acrolein adducts, were also increased in the molecular layer of the hippocampus and attenuated in TB treated mice. These studies demonstrate that TB treatment after initiation of Aβ deposition in the subiculum dramatically abrogates the loss of neurologic function in 3xTg mice as demonstrated by increased memory, cognition, and neuromuscular function. Moreover, these increases coincide with attenuated AD-associated pathology in the hippocampus of TB-treated 3xTg mice. Importantly, these data indicate that treatment with a butyrate pro-drug can be integrated into treatment strategies to preserve cognitive and neuromuscular functions in patients in the prodromal phase of AD.

Osteopontin is a proinflammatory cytokine associated with systemic vascular, inflammatory, and autoimmune diseases. It has been recently implicated in neuroinflammation and neurodegeneration. We hypothesized that plasma osteopontin is a deleterious neuroinflammatory marker increased in people with dementia and cerebral small vessel disease (CSVD). We conducted a pilot study in participants in the longitudinal multi-ethnic Northern Manhattan Study (NOMAS). Three groups were selected based on their dementia status and evidence of subclinical CSVD, and chosen to be similar in age, sex, and education attainment: No Dementia/No CSVD (n = 19), Dementia/No CSVD (n = 22), and Dementia+CSVD (n = 21). Dementia (any type) was diagnosed by consensus adjudication following a series of comprehensive neuropsychological assessments and a review of medical history. CSVD was indicated by silent brain infarcts, perivascular spaces, cerebral microbleeds, and white matter hyperintensity volumes on MRI. Osteopontin was measured by quantitative solid-phase ELISA. Multinomial logistic regression was used to examine the difference in osteopontin levels across groups, adjusting for key determinants of CSVD and neurodegeneration in NOMAS, including age, race/ethnicity, BMI, and brain volume. Osteopontin levels were substantially elevated in the Dementia+ CSVD group (mean = 70.69±39.00 ng/ml) and only slightly increased in the Dementia/No CSVD group (mean = 45.46±19.11) compared to the No dementia/No CSVD group (mean = 36.43±15.72). Osteopontin was associated with dementia+CSVD (Odds Ratio (OR) per ng/ml = 1.06, 95%CI 1.02-1.11) in unadjusted analysis, and this remained consistent and significant after adjusting for covariates, including brain volume. Osteopontin was strongly correlated with WMHV (Pearson r = 0.46, p = 0.0001), but not with other components of CSVD. In this pilot study, we observed a significant relationship between increased levels of osteopontin and dementia. This link is predominately driven by vascular contributions to dementia through the presence of CSVD, specifically through the burden of white matter lesions on MRI. Brain volume, a marker of neurodegeneration, does not seem to influence this relationship. Our study provides further evidence to suggest that underlying white matter disease and CSVD are likely targets of deleterious osteopontin expression in dementia.

Background: Isolated neuropathy of the dorsal cutaneous branch of the ulnar nerve (DCBUN) is rare and most cases are secondary to trauma, often iatrogenic. The topography of sensory abnormalities and abnormal electrodiagnostic (EDX) findings are crucial in confirming DCBUN neuropathy. Materials and methods: This is a retrospective study of patients with isolated involvement of the DCBUN from among patients referred for EDX studies for upper extremity symptoms. All patients underwent a focused neurological examination followed by EDX studies. Ultrasound (US) studies were performed in two patients. Results: Of the 14 patients with DCBUN neuropathy, decreased pinprick sensation in the distribution of the DCBUN was noted in 11 (78%) patients. DCBUN sensory nerve action potential (SNAP) was not recordable in 13 (92%) patients. In one patient who had a recordable SNAP, the latency was prolonged, and the amplitude was decreased. Four (28%) patients had incidental EDX abnormalities suggestive of entrapment of the median nerve at the carpal tunnel. The most common cause of DCBUN neuropathy was trauma in 13 (92%) patients, of which eight were iatrogenic. No specific etiology was detected in one patient (7%). Of the two patients who underwent US studies, one had increased cross-sectional area (CSA) at the wrist with prominent fascicles and hyperechoic scar tissue, while the CSA was normal in the other patient. Conclusions: Although rare, DCBUN neuropathy can be readily confirmed by typical clinical features and EDX findings. Surgeons should be aware of the anatomy and clinical features of DCBUN neuropathy and avoid injuring the nerve during surgical procedures at the wrist and forearm.

Charcot-Marie-Tooth (CMT) disease is the most common hereditary neuropathy.Duplication of the peripheral myelin protein-22 (PMP22) gene is the most frequent genetic abnormality in CMT disease.Although rare compared to PMP22 gene mutations, many different myelin protein zero (MPZ) gene mutations have been described in patients with CMT disease.MPZ gene mutations are known to cause hereditary neuropathies with heterogenous phenotypes ranging from early-onset severe demyelinating to adult-onset axonal forms.MPZ, the major protein component of peripheral nerve myelin, is important for myelin compaction.We report a family in which a mother and her son, both with adult-onset CMT disease, showed a newly described mutation p.Glu37Lys of the MPZ gene.The clinical features of the mother provided insight into the progression of the disease over decades, while features in the early stage of the disease could be studied in the son.Clinical, electrodiagnostic, and sonographic findings are described in the early and late stages of the disease.The MPZ gene mutation p.Glu37Lys is associated with clinical features of a progressive axonal type of adult-onset CMT disease.