Designing for Disability: Making Activities of Daily Living more Manageable through 3D Printing

While there have been many innovations developed for those with physical disabilities in recent years, a multitude of unmet needs still remain. This review seeks to highlight designs, public policies, and other initiatives that have been established to assist this population thus far. Information has been curated from databases including, but not limited to, Pubmed and Policymap. With the advent of new and affordable technologies such as 3D printing, it is now more possible than ever before to bring one’s ideas to life; from creating customized prosthetics to wheelchair attachments for water bottles and umbrellas, we are able to quickly realize potentials otherwise unlikely - and in turn, we have the capacity to make the activities of daily living more manageable for those with physical disabilities. In accordance with the principles of appreciative inquiry, first-hand discussions with those having physical disabilities have allowed for some insight into the current challenges they face. Their stories have inspired the following proposed design(s) presented in this review, some of which can be 3D printed, with the hope that these developments can help them navigate the world we live in just a little bit easier

Designing for Disability: Making Activities of Daily Living more Manageable through 3D Printing

Introduction: While there have been many innovations developed for those with physical disabilities in recent years, a multitude of unmet needs still remain. With the advent of new and affordable technologies such as 3D printing, it is now more possible than ever before to bring one’s ideas to life; from creating customized prosthetics to wheelchair attachments for water bottles and umbrellas, we are able to quickly realize potentials otherwise unlikely - and in turn, we have the capacity to make the activities of daily living more manageable for those with physical disabilities. Objectives: By personally hearing from individuals with physical disabilities about what challenges they face on a daily basis, it is possible to develop 3D printed items that can address their unmet needs. This work seeks to propose design(s) that can be conveniently created via an FDM 3D printer, in response to their expressed concerns. Methods: In accordance with the principles of appreciative inquiry, first-hand discussions with those having physical disabilities have allowed for some insight into a few of the current struggles they endure. Their stories have inspired the following proposed design(s) which can be 3D printed, with the hope that these developments can help them navigate the world we live in just a little bit easier. Results: Presented design(s) have been drafted in Autodesk Fusion 360 and initial prototypes are to be printed in ABS plastic with an Affinia FDM printer. Conclusions: 3D printing is an affordable, convenient, and promising means of developing items that can assist those with physical disabilities as they navigate our often inaccessible-world. While many changes require advocacy and intervention at the level of public policy, some impactful means of assistance can instead be constructed in this manner

A Review of Applicable Materials for 3D Printing a Biomechanically Accurate Cervical Spine Model for Surgical Education & Case Preparation

Objectives: The authors review the literature to compare biomechanical properties of the human cervical spine as determined by cadaveric and finite elemental model (FEM) studies, with commercially available three-dimensional (3D) printing materials to aid in the development of 3D-printed cervical spines that can be used as biomechanically accurate educational tools. Specifically, 3D printing materials for fused deposition modeling (FDM) printers were explored. Methods: A literature review of biomechanical specifications such as Young’s Modulus and Poisson’s ratio of certain anatomical aspects of the cervical spine was performed by searching the databases PubMed, MEDLINE via Ovid, Wolters Kluwer, ClinicalKey, and EMBASE via Elsevier for keywords. The anatomical features that were investigated included cortical and cancellous bone, facet joints, intervertebral discs, and ligaments. Additionally, datasheets from companies Stratasys, Fillamentum, NinjaTek, SD3D, Polymakers, Lubrizol and BASF were compiled to review the specifications and mechanical properties of their 3D printing materials. Results: Suggested FDM 3D printing materials were assigned to anatomical features of the cervical spine according to their respective biomechanical properties, namely: cortical and cancellous bone, facet joint articular cartilage and the synovial membrane, both the ground substance and fibers of the annulus fibrosus, nucleus pulposus, anterior and posterior longitudinal ligaments, ligamenta flava, interspinous ligaments, and capsular ligaments. Conclusions: FDM 3D printing can improve development of cervical spine models for educational use and surgical case preparation. Commercially available materials and techniques exist to simulate all of the major anatomical components of the cervical spine

An exploration of grip force regulation with a low-impedance myoelectric prosthesis featuring referred haptic feedback

Abstract Background Haptic display technologies are well suited to relay proprioceptive, force, and contact cues from a prosthetic terminal device back to the residual limb and thereby reduce reliance on visual feedback. The ease with which an amputee interprets these haptic cues, however, likely depends on whether their dynamic signal behavior corresponds to expected behaviors—behaviors consonant with a natural limb coupled to the environment. A highly geared motor in a terminal device along with the associated high back-drive impedance influences dynamic interactions with the environment, creating effects not encountered with a natural limb. Here we explore grasp and lift performance with a backdrivable (low backdrive impedance) terminal device placed under proportional myoelectric position control that features referred haptic feedback. Methods We fabricated a back-drivable terminal device that could be used by amputees and non-amputees alike and drove aperture (or grip force, when a stiff object was in its grasp) in proportion to a myoelectric signal drawn from a single muscle site in the forearm. In randomly ordered trials, we assessed the performance of N=10 participants (7 non-amputee, 3 amputee) attempting to grasp and lift an object using the terminal device under three feedback conditions (no feedback, vibrotactile feedback, and joint torque feedback), and two object weights that were indiscernible by vision. Results Both non-amputee and amputee participants scaled their grip force according to the object weight. Our results showed only minor differences in grip force, grip/load force coordination, and slip as a function of sensory feedback condition, though the grip force at the point of lift-off for the heavier object was significantly greater for amputee participants in the presence of joint torque feedback. An examination of grip/load force phase plots revealed that our amputee participants used larger safety margins and demonstrated less coordination than our non-amputee participants. Conclusions Our results suggest that a backdrivable terminal device may hold advantages over non-backdrivable devices by allowing grip/load force coordination consistent with behaviors observed in the natural limb. Likewise, the inconclusive effect of referred haptic feedback on grasp and lift performance suggests the need for additional testing that includes adequate training for participants.http://deepblue.lib.umich.edu/bitstream/2027.42/116041/1/12984_2015_Article_98.pd

Automated Subfield Volumetric Analysis of Amygdala, Hippocampus, and Thalamic Nuclei in Mesial Temporal Lobe Epilepsy

Purpose: Identifying relationships between clinical features and quantitative characteristics of the amygdala-hippocampal and thalamic subregions in mesial temporal lobe epilepsy (mTLE) may offer insights into pathophysiology and the basis for imaging prognostic markers of treatment outcome. Our aim was to ascertain different patterns of atrophy or hypertrophy in mesial temporal sclerosis (MTS) patients and their associations with postsurgical seizure outcomes. To assess this aim, this study is designed in 2 folds: (1) hemispheric changes within MTS group and (2) association with postsurgical seizure outcomes. Methods and materials: 27 mTLE subjects with mesial temporal sclerosis (MTS) were scanned for conventional 3D T1w MPRAGE images and T2w scans. With respect to 12 months post-surgical seizure outcomes, 15 subjects reported being seizure free (SF) and 12 reported continued seizures. Quantitative automated segmentation and cortical parcellation were performed using Freesurfer. Automatic labeling and volume estimation of hippocampal subfields, amygdala, and thalamic subnuclei were also performed. The volume ratio (VR) for each label was computed and compared between (1) between contralateral and ipsilateral MTS using Wilcoxon rank-sum test and (2) SF and not seizure free (NSF) groups using linear regression analysis. False Discovery rate (FDR) with significant level of 0.05 were used in both analyses to correct for multiple comparisons. Results: Amygdala: The medial nucleus of the amygdala was the most significantly reduced in patients with continued seizures when compared to patients who remained seizure free. Hippocampus: Comparison of ipsilateral and contralateral volumes with seizure outcomes showed volume loss was most evident in the mesial hippocampal regions such as CA4 and hippocampal fissure. Volume loss was also most explicit in the presubiculum body in patients with continued seizures at the time of their follow-up. Ipsilateral MTS compared to contralateral MTS analysis showed the heads of the ipsilateral subiculum, presubiculum, parasubiculum, dentate gyrus, CA4, and CA3 were more significantly affected than their respective bodies. Volume loss was most noted in mesial hippocampal regions. Thalamus: VPL and PuL were the most significantly reduced thalamic nuclei in NSF patients. In all statistically significant areas, volume reduction was observed in the NSF group. No significant volume reductions were noted in the thalamus and amygdala when comparing ipsilateral to contralateral sides in mTLE subjects. Conclusions: Varying degrees of volume loss were demonstrated in the hippocampus, thalamus, and amygdala subregions of MTS, especially between patients who remained seizure-free and those who did not. The results obtained can be used to further understand mTLE pathophysiology

Amplitude Synchronization of Spontaneous Activity of Medial and Lateral Temporal Gyri Reveals Altered Thalamic Connectivity in Patients With Temporal Lobe Epilepsy

In this study, we examined whether amplitude synchronization of medial (MTL) and lateral (LTL) temporal lobes can detect unique alterations in patients with MTL epilepsy (mTLE) with mesial temporal sclerosis (MTS). This was a retrospective study of preoperative resting-state fMRI (rsfMRI) data from 31 patients with mTLE with MTS (age 23-69) and 16 controls (age 21-35). fMRI data were preprocessed based on a multistep preprocessing pipeline and registered to a standard space. Using each subject\u27s T1-weighted scan, the MTL and LTL were automatically segmented, manually revised and then fit to a standard space using a symmetric normalization registration algorithm. Dual regression analysis was applied on preprocessed rsfMRI data to detect amplitude synchronization of medial and lateral temporal segments with the rest of the brain. We calculated the overlapped volume ratio of synchronized voxels within specific target regions including the thalamus (total and bilateral). A general linear model was used with Bonferroni correction for covariates of epilepsy duration and age of patient at scan to statistically compare synchronization in patients with mTLE with MTS and controls, as well as with respect to whether patients remained seizure-free (SF) or not (NSF) after receiving epilepsy surgery. We found increased ipsilateral positive connectivity between the LTLs and the thalamus and contralateral negative connectivity between the MTLs and the thalamus in patients with mTLE with MTS compared to controls. We also found increased asymmetry of functional connectivity between temporal lobe subregions and the thalamus in patients with mTLE with MTS, with increased positive connectivity between the LTL and the lesional-side thalamus as well as increased negative connectivity between the MTL and the nonlesional-side thalamus. This asymmetry was also seen in NSF patients but was not seen in SF patients and controls. Amplitude synchronization was an effective method to detect functional connectivity alterations in patients with mTLE with MTS. Patients with mTLE with MTS overall showed increased temporal-thalamic connectivity. There was increased functional involvement of the thalamus in MTS, underscoring its role in seizure spread. Increased functional thalamic asymmetry patterns in NSF patients may have a potential role in prognosticating patient response to surgery. Elucidating regions with altered functional connectivity to temporal regions can improve understanding of the involvement of different regions in the disease to potentially target for intervention or use for prognosis for surgery. Future studies are needed to examine the effectiveness of using patient-specific abnormalities in patterns to predict surgical outcome

Automated subfield volumetric analysis of amygdala, hippocampus, and thalamic nuclei in mesial temporal lobe epilepsy

Purpose: Identifying relationships between clinical features and quantitative characteristics of the amygdala-hippocampal and thalamic subregions in mesial temporal lobe epilepsy (mTLE) may offer insights into pathophysiology and the basis for imaging prognostic markers of treatment outcome. Our aim was to ascertain different patterns of atrophy or hypertrophy in mesial temporal sclerosis (MTS) patients and their associations with post-surgical seizure outcomes. To assess this aim, this study is designed in 2 folds: (1) hemispheric changes within MTS group and (2) association with postsurgical seizure outcomes. Methods and materials: 27 mTLE subjects with mesial temporal sclerosis (MTS) were scanned for conventional 3D T1w MPRAGE images and T2w scans. With respect to 12 months post-surgical seizure outcomes, 15 subjects reported being seizure free (SF) and 12 reported continued seizures. Quantitative automated segmentation and cortical parcellation were performed using Freesurfer. Automatic labeling and volume estimation of hippocampal subfields, amygdala, and thalamic subnuclei were also performed. The volume ratio (VR) for each label was computed and compared between (1) between contralateral and ipsilateral MTS using Wilcoxon rank-sum test and (2) SF and not seizure free (NSF) groups using linear regression analysis. False Discovery rate (FDR) with significant level of 0.05 were used in both analyses to correct for multiple comparisons. Results: Amygdala: The medial nucleus of the amygdala was the most significantly reduced in patients with continued seizures when compared to patients who remained seizure free. Hippocampus: Comparison of ipsilateral and contralateral volumes with seizure outcomes showed volume loss was most evident in the mesial hippocampal regions such as CA4 and hippocampal fissure. Volume loss was also most explicit in the presubiculum body in patients with continued seizures at the time of their follow-up. Ipsilateral MTS compared to contralateral MTS analysis showed the heads of the ipsilateral subiculum, presubiculum, parasubiculum, dentate gyrus, CA4, and CA3 were more significantly affected than their respective bodies. Volume loss was most noted in mesial hippocampal regions. Thalamus: VPL and PuL were the most significantly reduced thalamic nuclei in NSF patients. In all statistically significant areas, volume reduction was observed in the NSF group. No significant volume reductions were noted in the thalamus and amygdala when comparing ipsilateral to contralateral sides in mTLE subjects. Conclusions: Varying degrees of volume loss were demonstrated in the hippocampus, thalamus, and amygdala subregions of MTS, especially between patients who remained seizure-free and those who did not. The results obtained can be used to further understand mTLE pathophysiology. Clinical relevance/application: In the future, we hope these results can be used to deepen the understanding of mTLE pathophysiology, leading to improved patient outcomes and treatments