Regeneration of starfish radial nerve cord restores animal mobility and unveils a new coelomocyte population.

The potential to regenerate a damaged body part is expressed to a different extent in animals. Echinoderms, in particular starfish, are known for their outstanding regenerating potential. Differently, humans have restricted abilities to restore organ systems being dependent on limited sources of stem cells. In particular, the potential to regenerate the central nervous system is extremely limited, explaining the lack of natural mechanisms that could overcome the development of neurodegenerative diseases and the occurrence of trauma. Therefore, understanding the molecular and cellular mechanisms of regeneration in starfish could help the development of new therapeutic approaches in humans. In this study, we tackle the problem of starfish central nervous system regeneration by examining the external and internal anatomical and behavioral traits, the dynamics of coelomocyte populations, and neuronal tissue architecture after radial nerve cord (RNC) partial ablation. We noticed that the removal of part of RNC generated several anatomic anomalies and induced behavioral modifications (injured arm could not be used anymore to lead the starfish movement). Those alterations seem to be related to defense mechanisms and protection of the wound. In particular, histology showed that tissue patterns during regeneration resemble those described in holothurians and in starfish arm tip regeneration. Flow cytometry coupled with imaging flow cytometry unveiled a new coelomocyte population during the late phase of the regeneration process. Morphotypes of these and previously characterized coelomocyte populations were described based on IFC data. Further studies of this new coelomocyte population might provide insights on their involvement in radial nerve cord regeneration.

Muscle responses during radial nerve-biased upper limb neurodynamic test in asymptomatic individuals: a cross-sectional study.

This laboratory cross-sectional study aimed at explore the muscle response (MR) of the upper trapezius, infraspinatus, biceps brachii and extensor carpi radialis brevis (ECRB) during the radial nerve-biased upper limb neurodynamic test (RN-ULNT) in healthy participants. Myoelectric activity was stage-by-stage recorded during two sequencing variants of the RN-ULNT: S1, in which elbow extension was the last movement; and S2, in which wrist flexion was the last movement. Final elbow and wrist joint angle and sensory response (SR) in five zones (Z1-Z5) were also registered. MR was qualitatively categorized as 'absent' (No-MR), 'true' (TMR) or 'uneven' (UMR). In both sequences, significant increases in muscle activity occurred mostly during shoulder abduction and elbow extension (p ≤ 0.009). Also, elbow extension but not wrist flexion increased the activity of the ECRB muscle (p ≤ 0.009). S2 showed significantly higher upper trapezius (p = 0.04) and biceps brachii (p = 0.036) muscle activity during wrist flexion, and higher report of SR in Z1 and Z4 (p < 0.001) compared to S1. Only the ECRB muscle showed significant differences in the MR type between S1 and S2 (TMR, p = 0.016; UMR, = 0,012). Our results may be useful in the assessment of upper limb musculoskeletal disorders.

A novel method to measure sensory nerve conduction of the posterior antebrachial cutaneous nerve.

INTRODUCTION/AIMS: Posterior antebrachial cutaneous (PABC) nerve conduction studies could be useful for distinguishing PABC neuropathy from C7 radiculopathy. In the conventional method using an antidromic method, the sensory nerve action potential (SNAP) is sometimes followed by a large volume-conducted motor potential. In this report we describe a reliable nerve conduction study using an orthodromic method for recording SNAPs of the PABC nerve. METHODS: Thirty-six healthy volunteers participated in this study. PABC SNAPs were recorded by placing a surface-active electrode 2 cm anterior to the lateral epicondyle. The PABC nerve was stimulated 10 cm distal to the active recording electrode along a line from the recording point to the mid-dorsum of the wrist, midway between the radial and ulnar styloid processes. We also performed PABC nerve conduction studies using an antidromic method and compared the findings. RESULTS: PABC SNAPs were recorded bilaterally from all subjects. The mean peak-to-peak amplitude for SNAPs was 13.4 ± 4.8 µV. Mean maximum conduction velocity was 62.7 ± 3.9 m/s and mean negative peak conduction velocity was 51.2 ± 2.6 m/s. The mean side-to-side difference in amplitude was 22.1 ± 16.0%. The mean amplitude of SNAPs obtained by our method was 48.9% higher than that of SNAPs obtained by the conventional method (13.4 vs 9.0 µV; P < .001). In contrast to the conventional method, our method enabled SNAPs to be recorded without a volume-conducted motor potential. DISCUSSION: The higher mean amplitude of SNAPs with our method enables them to be obtained easily.

A topographical and physiological exploration of C-tactile afferents and their response to menthol and histamine.

Unmyelinated tactile (C-tactile or CT) afferents are abundant in arm hairy skin and have been suggested to signal features of social affective touch. Here, we recorded from unmyelinated low-threshold mechanosensitive afferents in the peroneal and radial nerves. The most distal receptive fields were located on the proximal phalanx of the third finger for the superficial branch of the radial nerve and near the lateral malleolus for the peroneal nerve. We found that the physiological properties with regard to conduction velocity and mechanical threshold, as well as their tuning to brush velocity, were similar in CT units across the antebrachial (n = 27), radial (n = 8), and peroneal (n = 4) nerves. Moreover, we found that although CT afferents are readily found during microneurography of the arm nerves, they appear to be much more sparse in the lower leg compared with C-nociceptors. We continued to explore CT afferents with regard to their chemical sensitivity and found that they could not be activated by topical application to their receptive field of either the cooling agent menthol or the pruritogen histamine. In light of previous studies showing the combined effects that temperature and mechanical stimuli have on these neurons, these findings add to the growing body of research suggesting that CT afferents constitute a unique class of sensory afferents with highly specialized mechanisms for transducing gentle touch.NEW & NOTEWORHY Unmyelinated tactile (CT) afferents are abundant in arm hairy skin and are thought to signal features of social affective touch. We show that CTs are also present but are relatively sparse in the lower leg compared with C-nociceptors. CTs display similar physiological properties across the arm and leg nerves. Furthermore, CT afferents do not respond to the cooling agent menthol or the pruritogen histamine, and their mechanical response properties are not altered by these chemicals.

Relationship between the Branching Patterns of the Radial Nerve and Supinator Muscle.

The posterior interosseous nerve (PIN) innervates the posterior compartment muscle of the forearm and is a continuation of the deep branch of the radial nerve. The anatomic descriptions of PIN vary among different authors. This study investigated the distribution patterns of PIN and its relationships to the supinator muscle. This study investigated which nerves innervate the posterior compartment muscles of the forearm, the radial nerve, and the PIN, using 28 nonembalmed limbs. Also, the points where the muscle attaches to the bone were investigated. The measured variables in this study were measured from the most prominent point of the lateral epicondyle of the humerus (LEH) to the most distal point of the radius styloid process. For each specimen, the distance between the above two points was assumed to be 100%. The measurement variables were the attachment area of the supinator and branching points from the radial nerve. The attachment points of the supinator to the radius and ulna were 47.9% ± 3.6% and 31.5% ± 5.2%, respectively, from the LEH. In 67.9% of the specimens, the brachioradialis and extensor carpi radialis longus (ECRL) were innervated by the radial nerve before superficial nerve branching, and the extensor carpi radialis brevis (ECRB) innervated the deep branch of the radial nerve. In 21.4% of the limbs, the nerve innervating the ECRB branched at the same point as the superficial branch of the radial nerve, whereas it branched from the radial nerve in 7.1% of the limbs. In 3.6% of the limbs, the deep branch of the radial nerve branched to innervate the ECRL. PIN was identified as a large branch without divisions in 10.7% and as a deep branch innervating the extensor digitorum in 14.3% of the limbs. The anatomic findings of this study would aid in the diagnosis of PIN syndromes.

Location of the radial nerve along the humeral shaft between the prone and lateral decubitus positions at different elbow positions.

Identification of the radial nerve is important during the posterior approach to a humerus fracture. During this procedure, the patient can be placed in the prone or lateral decubitus position depending on the surgeon's preference. The distance from the radial nerve to the osseous structures will be different in each position. The purpose of this study was to identify the safety zones in various patient and elbow flexion positions. The distances from the olecranon to the center of the radial groove and intermuscular septum and lateral epicondyle to the lateral intermuscular septum were measured using a digital Vernier caliper. The measurements were performed with cadavers in the lateral decubitus and prone positions at different elbow flexion angles. The distance from where the radial nerve crossed the posterior aspect of the humerus measured from the upper part of the olecranon to the center of the radial nerve in both positions at different elbow flexion angles varied from a mean maximum distance of 130.00 mm with the elbow in full extension in the prone position to a minimum distance of 121.01 mm with the elbow in flexion at 120° in the lateral decubitus position. The mean distance of the radial nerve from the upper olecranon to the lateral intermuscular septum varied from 107.13 to 102.22 mm. The distance from the lateral epicondyle to the lateral edge of the radial nerve varied from 119.92 to 125.38 mm. There was not significant contrast in the position of the radial nerve with osseous landmarks concerning different degrees of flexion, except for 120°, which is not significant, as this flexion angle is rarely used.

Anatomical variations of the superficial branch of the radial nerve and the dorsal branch of the ulnar nerve: A detailed electrophysiological study.

INTRODUCTION: In this study we evaluated anatomic variations of the superficial branch of the radial nerve (SBRN) and the dorsal branch of the ulnar nerve (DBUN) electrophysiologically. METHODS: Antidromic nerve conduction studies (NCS) of the SBRN and DBUN were performed on healthy individuals. To identify individual responses from the distal branches of the SBRN and DBUN, sensory nerve action potentials of each finger (lateral side/medial side) were recorded. RESULTS: NCS were performed in 50 hands of 27 healthy control subjects. The thumb and the index finger were supplied by the SBRN in all cases. The lateral and medial sides of the third finger were supplied by the SBRN in 94.0% and 74.0% of the cases, but the lateral and medial sides of the fourth finger were supplied by the SBRN in only 10.0% and 2.0% of cases. The fifth finger and the medial side of the fourth finger were always supplied by the DBUN. The lateral side of the fourth finger was supplied by the DBUN in 98.0% of cases, but the lateral and medial sides of the third finger were supplied by the DBUN in 40.0% and 70.0% of cases. Dual innervation by the SBRN and DBUN was found in 34.0% and 46.0% of the lateral and medial sides of the third finger, but in only 8.0% and 2.0% of the lateral and medial sides of the fourth finger. DISCUSSION: There are considerable anatomic variations of the SBRN and DBUN in healthy individuals.

Optimal recording electrode placement for radial motor nerve conduction study using extensor indicis muscle: Cadaver and electrophysiological studies.

INTRODUCTION/AIMS: The aim of this study was to determine the optimal combination of active (E1) and reference (E2) recording electrode placements for the radial motor nerve conduction study recording over the extensor indicis muscle using surface electrodes. METHODS: Thirty-six upper limbs from 18 fresh frozen cadavers were dissected to determine the midpoint of the extensor indicis muscle. Radial nerve conduction study was performed in 112 arms of 56 healthy subjects. Six combinations of three E1 and two E2 sites were studied. The stimulation site was 8 cm proximal to the E1 electrode. RESULTS: The optimal combination of placement sites for the E1 and E2 electrodes to provide the largest amplitude is E1 electrode at the distal 1/4 point of the forearm length and E2 electrode at the extensor indicis tendon point in the wrist. DISCUSSION: Optimal recording electrode placement may increase the accuracy and reproducibility of radial motor nerve conduction studies.

Need for early exploration of radial nerve in humeral shaft fractures with radial nerve palsy.

INTRODUCTION: Radial nerve palsy (RNP) associated with humeral shaft fracture (HSF) is the most common nerve complication in long bone fractures. There is still controversy over the need for immediate exploration of the radial nerve (RN) in HSF with RNP. The purpose of the current study was to determine which situations of HSF with RNP require early exploration of the RN. MATERIALS AND METHODS: This is a retrospective study that included 55 patients who had visited the emergency department of the current authors' hospital and had been diagnosed with HSF between March of 2005 and September of 2015. Of these 55 patients, 14 (25.4%) had been diagnosed with HSF with RNP. We reviewed the medical records of those 14 patients and their radiographs to evaluate each fracture's type, location, pattern, energy of trauma, status of RN injury, and time until recovery from RNP. RESULT: All the 14 RNP patients had suffered high-energy trauma. Three had fractures in the proximal third (21.4%), six in the middle third (42.9%), and five in the distal third (35.7%). The three patients (21.4%) with incomplete recovery of RNP all had proximal third fractures; two of these three patients had RN transection. CONCLUSION: Early exploration of the radial nerve should be considered in patients with radial nerve palsy associated with proximal third humeral shaft fracture, regardless of the fracture patterns caused by the high-energy trauma.

Outcomes of surgery for schwannomas of the upper extremity.

<b>Introduction:</b> Schwannoma is a nerve tumor originating from Schwann-cells of the nerve sheath. It is found in all body regions, the most frequent in the head, neck and in the extremities. </br></br> <b>Aim:</b> The objective of this study was analysis of outcomes of surgery for these lesions in the authors' institution. </br></br> <b>Materials and methods:</b> Results of the treatment of 12 patients, 7 women and 5 men, aged a mean of 40 years with shwannomas localized in the upper limb are presented. The follow-up assessment was performed in a form of telephone interview at a mean of 4.2 years post-operatively. </br></br> <b>Results:</b> The tumors were located in the hand in 5 patients, in the forearm in other 5 and in the wrist in 2. In 3 patients the tumors originated form the median, in 2 from the ulnar and in 2 from the radial nerves; in 5 cases it grew from small nerve branches. All lesions of the median, ulnar and radial nerves were encapsulated without damage of the nerve fascicles, while in the hand they were resected in total. At a mean of 4.2 years of follow-up, two recurrences (17%) occurred, both following resection of the tumor located in the hand. Complications were noted in 5 patients: two felt parasthesiae in the operated finger, two were disappointed due to unaesthetic scar and one patient following tumor resection from posterior interosseous nerve had incomplete finger extension. </br></br> <b>Conclusion:</b> Outcomes of surgery for these rare tumors are generally good, but functional deficits should be considered in cases of lesions involving motoric nerves.

Unique age-related transcriptional signature in the nervous system of the long-lived red sea urchin Mesocentrotus franciscanus.

The red sea urchin, Mesocentrotus franciscanus, is one the earth's longest-lived animals, reported to live more than 100 years with indeterminate growth, life-long reproduction and no increase in mortality rate with age. To gain insight into mechanisms associated with longevity and negligible senescence, age-related transcriptional profiles were examined in tissues of the red sea urchin. Genome-wide transcriptional profiling using RNA-Seq revealed few age-related changes in gene expression in muscle and esophagus tissue. In contrast, radial nerve showed an unexpected level of complexity with the expression of 3,370 genes significantly altered more than two-fold with age, including genes involved in nerve function, signaling, metabolism, transcriptional regulation and chromatin modification. There was an age-related upregulation in expression of genes involved in synaptogenesis, axonogenesis and neuroprotection suggesting preservation of neuronal processes with age. There was also an upregulation in expression of positive regulators and key components of the AMPK pathway, autophagy, proteasome function, and the unfolded protein response. This unique age-related gene expression profile in the red sea urchin nervous system may play a role in mitigating the detrimental effects of aging in this long-lived animal.

Sensory enhancement amplifies interlimb cutaneous reflexes in wrist extensor muscles.

Interlimb neural connections support motor tasks such as locomotion and cross-education strength training. Somatosensory pathways that can be assessed with cutaneous reflex paradigms assist in subserving these connections. Many studies show that stimulation of cutaneous nerves elicits reflexes in muscles widespread across the body and induces neural plasticity after training. Sensory enhancement, such as long-duration trains of transcutaneous stimulation, facilitates performance during rehabilitation training or fatiguing motor tasks. Performance improvements due to sensory stimulation may be caused by altered spinal and corticospinal excitability. However, how enhanced sensory input regulates the excitability of interlimb cutaneous reflex pathways has not been studied. Our purpose was to investigate the effects of sensory enhancement on interlimb cutaneous reflexes in wrist extensor muscles. Stimulation to provide sensory enhancement (2-s trains at 150 Hz to median or superficial radial nerves) or evoke cutaneous reflexes (15-ms trains at 300 Hz to superficial radial nerve) was applied in different arms while participants (n = 13) performed graded isometric wrist extension. Wrist extensor electromyography and cutaneous reflexes were measured bilaterally. We found amplified inhibitory reflexes in the arm receiving superficial radial and median nerve sensory enhancement with net reflex amplitudes decreased by 709.5% and 695.3% repetitively. This suggests sensory input alters neuronal excitabilities in the interlimb cutaneous pathways. These findings have potential application in facilitating motor function recovery through alterations in spinal cord excitability enhancing sensory input during targeted rehabilitation and sports training.NEW & NOTEWORTHY We show that sensory enhancement increases excitability in interlimb cutaneous pathways and that these effects are not influenced by descending motor drive on the contralateral side. These findings confirm the role of sensory input and cutaneous pathways in regulating interlimb movements. In targeted motor function training or rehabilitation, sensory enhancement may be applied to facilitate outcomes.

Elicited Finger and Wrist Extension Through Transcutaneous Radial Nerve Stimulation.

Individuals with neurological disorders, such as stroke or spinal cord injury, often have weakness and/or spasticity in their hand and wrist muscles, which can lead to impaired ability to extend their fingers and wrists. Functional electrical stimulation can help to restore these motor functions. However, the conventional stimulation method can lead to fast muscle fatigue and limited movements due to a non-physiological recruitment of motor units and a limited recruitment of deep muscles. In this paper, we investigated the feasibility of eliciting various hand opening and wrist extension movement patterns through a transcutaneous electrical stimulation array, which targeted the proximal segment of the radial nerve bundle proximal to the elbow. The wrist and finger joint kinematics were used to classify the different movement patterns through a cluster analysis, and electromyogram signals from the wrist and finger extensors were recorded to investigate the muscle activation patterns. The results showed that the finger and wrist motions can be elicited both independently and in a coordinated manner, by changing the stimulation intensity and stimulation location. H-reflex activity was also observed, which demonstrated the potential of recruiting motor units in a physiological order. Our approach could be further developed into a rehabilitative/assistive tool for individuals with impaired hand opening and/or wrist extension.

Increased angiogenesis by the rotational muscle flap is crucial for nerve regeneration.

BACKGROUND: The gold standard surgical treatment of nerve injury includes direct repair, nerve graft, and neurolysis. The underlying effects (either beneficial or detrimental) of angiogenesis during nerve regeneration by rotational muscle flap have not yet determined. We assess the neurological outcome and angiogenesis of nerve injury following a rotational muscle flap. METHODS: We retrospectively analyzed the outcome of the patients with severe radial nerve injury by neurolysis and rotational muscle flap; we also mimicked the clinical situation by nerve crush followed by rotational muscle flap in animals to assess associated angiogenesis factor expression. RESULTS: Twenty-three out of 25 (92%) cases of severe radial nerve injury underwent neurolysis assisted by muscle flap rotation and eventually reached their preinjury neurological outcome. In the animal study, both FITC-dextran and Dil infusion showed a remarkably increased vascular structure in the crushed nerve integrated by the muscle flap and abolished by Avastin injection. The rotational muscle flap significantly increased angiogenesis factor expression, and this was attenuated by Avastin injection. The increased angiogenesis factor expression paralleled the improvement seen in neurobehavioral and electrophysiological studies as well as the significant expression of nerve regeneration markers and the restoration of denervated muscle morphology. CONCLUSION: Based on the clinical and animal data analysis, we conclude that muscle flap rotation provides a platform for angiogenesis in the acceleration of nerve regeneration. It appears that the muscle flap rotation augmented the nerve regeneration process which may be beneficial for nerve repair in clinical application.

Age-dependent Reliability of Semmes-Weinstein and 2-Point Discrimination Tests in Children.

BACKGROUND: Objective sensory testing is a critical component of the physical examination in children as they may be unable to communicate whether or not numbness is present. The purpose of this study was to determine at what age objective sensory tests could reliably be performed. METHODS: Normal, uninjured participants aged 2 to 17 years were enrolled in the study. Monofilament and static/moving 2-point discrimination tests were performed bilaterally assessing the median, ulnar, and radial nerves. Performance scores were recorded using the monofilament size and 2-point discrimination distance. Statistical analysis was performed utilizing univariable linear regression, 1-way ANOVA, and Welch t test. RESULTS: A total of 396 hands were tested utilizing the Semmes-Weinstein monofilament and static/moving 2-point discrimination tests. For the monofilament test, 27% of 3-year-olds, 83% of 4-year-olds, and all participants 5 years of age and older were capable of performing the monofilament test. The average monofilament scores were 2.874, 2.868, and 3.043 for the ulnar, median, and radial nerves, respectively, with no correlation with advancing age present. The ulnar and median nerve distributions were more sensitive than the radial nerve distribution (P<0.001).For 2-point discrimination tests, 33% of 4-year-olds, 61% of 5-year-olds, 88% of 6-year-olds, 95% of 7- and 8-year-olds, and all participants 9 years and older were capable of performing the static/moving 2-point discrimination tests. The average static 2-point discrimination scores were 3.348, 2.806, and 9.637 mm for the ulnar, median, and radial nerves, respectively. The average moving 2-point discrimination scores were 2.977, 2.483, and 8.506 mm for the ulnar, median, and radial nerves, respectively. There was no correlation between advancing age and performance scores. Children are the most sensitive in the median, then ulnar, and then radial nerve distribution (P<0.001). Better discrimination is present between 2 moving points than static points (P<0.001). CONCLUSIONS: Objective threshold testing utilizing a monofilament can reliably be performed in the vast majority of children aged 4 years and above, whereas density testing utilizing 2-point discrimination can reliably be performed in the vast majority of children aged 6 years and above. LEVEL OF EVIDENCE: Level II.

Radial Nerve F-wave reference values with surface electrodes from the anconeus muscle.

INTRODUCTION: We sought to obtain normative values for radial nerve F-wave variables, recording with surface electrodes from the anconeus muscle. METHODS: We tested 30 healthy participants (17 women, 13 men) and measured the following variables: number of F waves/40 traces (F%); minimum, maximum, and mean F-wave latency (FMIN, FMAX, FMED, respectively); F-wave chronodispersion (FCHR); interside differences of F% and FMIN (DF% and DFMIN, respectively). RESULTS: The mean F% was 41.3%; the normative values of FMIN, FMED, FMAX, and FCHR were < 21.2, <22.1, <23.3, and < 4.0 ms, respectively; and normative values of DF% and DFMIN were < 16.6% and < 1.1 ms, respectively. Height was the sole independent predictor in a regression model of FMIN, FMED, and FMAX; this explained 37%-44% of the variability. DISCUSSION: We identified a feasible and useful technique to record radial nerve F waves from the anconeus muscle and obtained normative values of F-wave variables. Muscle Nerve 59:244-246, 2019.

High frequency repetitive transcranial magnetic stimulation to the left dorsolateral prefrontal cortex modulates sensorimotor cortex function in the transition to sustained muscle pain.

Based on reciprocal connections between the dorsolateral prefrontal cortex (DLPFC) and basal-ganglia regions associated with sensorimotor cortical excitability, it was hypothesized that repetitive transcranial magnetic stimulation (rTMS) of the left DLPFC would modulate sensorimotor cortical excitability induced by muscle pain. Muscle pain was provoked by injections of nerve growth factor (end of Day-0 and Day-2) into the right extensor carpi radialis brevis (ECRB) muscle in two groups of 15 healthy participants receiving 5 daily sessions (Day-0 to Day-4) of active or sham rTMS. Muscle pain scores and pressure pain thresholds (PPTs) were collected (Day-0, Day-3, Day-5). Assessment of motor cortical excitability using TMS (mapping cortical ECRB muscle representation) and somatosensory evoked potentials (SEPs) from electrical stimulation of the right radial nerve were recorded at Day-0 and Day-5. At Day-0 versus Day-5, the sham compared to active group showed: Higher muscle pain scores and reduced PPTs (P < 0.04); decreased frontal N30 SEP (P < 0.01); increased TMS map volume (P < 0.03). These results indicate that muscle pain exerts modulatory effects on the sensorimotor cortical excitability and left DLPFC rTMS has analgesic effects and modulates pain-induced sensorimotor cortical adaptations. These findings suggest an important role of prefrontal to basal-ganglia function in sensorimotor cortical excitability and pain processing.

Artificial tactile and proprioceptive feedback improves performance and confidence on object identification tasks.

Somatosensory feedback of the hand is essential for object identification. Without somatosensory feedback, individuals cannot reliably determine the size or compliance of an object. Electrical nerve stimulation can restore localized tactile and proprioceptive feedback with intensity discrimination capability similar to natural sensation. We hypothesized that adding artificial somatosensation improves object recognition accuracy when using a prosthesis. To test this hypothesis, we provided different forms of sensory feedback-tactile, proprioceptive, or both-to two subjects with upper limb loss. The subjects were asked to identify the size or mechanical compliance of different foam blocks placed in the prosthetic hand while visually and audibly blinded. During trials, we did not inform the subjects of their performance, but did ask them about their confidence in correctly identifying objects. Finally, we recorded applied pressures during object interaction. Subjects were free to use any strategy they chose to examine the objects. Object identification was most accurate with both tactile and proprioceptive feedback. The relative importance of each type of feedback, however, depended on object characteristics and task. Sensory feedback increased subject confidence and was directly correlated with accuracy. Subjects applied less pressure to the objects when they had tactile pressure feedback. Artificial somatosensory feedback improves object recognition and the relative importance of tactile versus proprioceptive feedback depends on the test set. We believe this test battery provides an effective means to assess the impact of sensory restoration and the relative contribution of different forms of feedback (tactile vs. kinesthetic) within the neurorehabilitation field.