PINCHPHONE : An exertoy for kids affected by Cerebral Palsy

The therapy treatment of CP can be painful and boring resulting in lack of compliance. How can we rethink this to improve compliance using playful interventions?
Photo of morphological chart
Pinchphone is an exertoy that introduces playful and sensorial elements to the pinch exercise performed by kids affected by Cerebral Palsy. The pinching action is very important as it helps kids pick up things and eat food. The exercise routine of cerebral palsy kids is very boring and repetitive . This seems to affect their compliance to the treatment and moreover impact their sensorial and social growth.
Further, the perception of the condition seems to affect the treatment as parents and society treat the children in a 'specific' way. This, although, may seem good from a humane point, but in long run affects their and their family's social development. Due to the 'specific' way of treating, the field of therapy has been slow on picking on newer and research validated alternatives to conventional therapy. The demand is less and hence, there are very few 'playful experiences' designed specially for CP affected kids. Pinchphone tries to make the boring routine of picking beans by using :
  • Audio notes activated by plucking each bead which hits a xylophone key
  • Color that can help in basic identification and a means to improve engagement
  • Shape that helps in learning and basic cognition
  • Size that makes kids understand variation
  • Physicality of the overall form
The toy has been developed with physiotherapist and developmental psychologists using co-design methods. The feedback received from therapists and parents motivated me to open-source the toy and work on easy reproducibility of the toy. The plans allow any maker-space with a CNC to replicate the toy easily.

More than the project, I would like to stress two things that the project contributes to :
  • It is to suggest a newer way to include designers in therapy processes so they can design toys in a grounded manner and further the possibilities.
  • A novel method to design for CP kids by thinking therapy patterns in terms of International Classification of Functioning (ICF) model with evidence based practices.


My siblings suffer from cerebral palsy. I have seen their therapy program ever since I was a child. In many ways, the therapy is experimental and may not be research-backed. Most therapists use a mix of stroke-centric approach with orthopedic rehabilitation to understand and improve the state of life. But, things are changing now as more and more people become aware of the condition. I started my work by going through the taxonomy of disease and various terms and concepts that would help me talk to doctors well. The major thing to understand is CP is treated from a point of rehabilitation, while in actual sense of the disease it is habilitation. So, I tried to understand :
  • What is Cerebral Palsy?
  • What are it effects? on kids, their parents?
  • What is the "state of the art" in CP research?
  • What is the diagnostic process?
  • What are the treatment options?
  • What are the means of measure progress of treatment?
  • What is the prevalence of CP in India?
  • What are the efforts by HCI community in the CP or related conditions?


The goals of the project were to design something :
  1. Useful in therapy centers and homes
  2. Improves playfulness of existing therapy
  3. Low Tech, easy to deploy, limited adult supervision needed
  4. Positively affects social participation
  5. Affordable ( < 2000 INR )
Photo of morphological chart Effects of Cerebral palsy
I made a therapy map to understand what therapy practices are being used and which of those are proven to be helpful in randomized control tests (RCTs) conducted by various researchers. This made me more aware of the current and suggested therapies in the domain.
Photo of therapy map Evidence based practice in CP treatment

However, I was unable to think from the point of view of a CP child. What would be his/her struggles? What would be their desires and goals? How did they see themselves and why? These emotional layers may not be easy to see via interviews. It may be said in pop design lingo, I sought to develop empathy. But, it was not empathy, it was a feeling of being. I researched a lot on what could be possible and came across acquired behavior methods used in marketing to develop a sense of nostalgia.
Even more, reading made me learn about the process of learning without doing but just seeing/feeling/experiencing things done - Vicarious Learning. I tried some of the experiments mentioned in the paper by Bandura I read books and saw movies narrated by the person who is suffering from CP. I read – "Out of my mind" by Sharon Draper and "My left foot" by Christy Brown. There is a good movie on the latter book as well.

Photo of therapy map How would a CP person feel? Vicariously learning effects of CP.

This helped me a bit about the various things a CP child may think of. Further, I moved on by visiting therapy centers. I visited centers in Delhi and Mumbai. I tried to divide the centers on the basis of speciality offered. I started with a government hospital, then to a wide range development disorder clinic and finally to a CP specific one. When I went there, I saw the ways therapy was being conducted and sat in the corner, just listening and taking notes. I made architectural plans of the centers to understand the structure and layout of various places.
Only once, I had developed enough confidence and rapport, I was able to talk to parents. We talked about how they feel about therapy, things they wished or missed in the past. Further, I learned about the routines of children who attend therapy and their life’s in general.

The doctors were very helpful. They helped me improve my therapy map and we discussed improvements and most relevant areas of the problem. In the research, I found that fine motor skills are sometimes more important compared to locomotion. There are several options available in the area of locomotion like crutches, walkers and wheelchairs that can assist but none in fine motor. So, I decided to work on fine motors skills of hands. But, I decided to still explore possibilities in areas like gait correction and walking as well.

Photo of therapy map Papers published per disability in design/HCI community. There is obvious under-representation as CP is the most common condition.


This was the most difficult part of the process for me. I had a few ideas all from my bag of electronics. I knew from my research that batteries and electronics won’t go well with the users as it needs care and maintenance. The research on interventions performed in cerebral palsy seems to discount the maintenance factor often. Frankly, it’s like “hit and runs”. That got me stuck for a long time. I was in a block.
Whatever ideas I came with were like, lets put an LED here, a sensor and we shall be good. But alas! I feel this is a problem with me. I have been working on it as I move. Otherwise, I shall always suggest, what I can build. This does not play well in long run it seems.

I was more concerned with coming with a model based on the surveyed knowledge. Then use this model to come up with many different possibilities. With all the pieces in front of me, the therapy map, the ICF model and the "F-words for CP", I started to ideate.

Photo of morphological chart WHO ICF Model tries to understand the effects of a disease on an individual.
Photo of morphological chart "F words" is an approach by Rosenbaum to interpret ICF for CP
How about we interpret each therapy in the map from the point of F-words model? In that case, the more F words we can incorporate in a current therapy , the more we could contribute towards the wellness of the individual. This was based on effectiveness studied by Novak in their review of CP therapies.
Photo of Novak's paper. Novak analyzing therapy from ICF point of view.
Ideation The idea is to expand each therapy found in the field studies and understand it from ICF point of view. Then adding ICF values by design better therapies around the central therapy proven to be effective . So, if CIMT lacks a participation element, we generate ideas to make CIMT sessions more participation. Voila !

With this direction in mind, I created low fidelity mockups of concepts. They were then presented in a session to parents and doctors. These concepts were :

Photo of Dial a dice. Sketched by Vivek Dial a dice is a toy that replaces a dice with a wrist movement. The child puts her hand on the hand cutout and rotates it. The number appears on the rotating disk. It is helpful in incorporating therapy elements in normal board games. This could lead to more social participation.
Photo of Exerchunk. Exerchunk allows kids to practice gripping exercises. The two "nun-chuck" like batons have bending sensors that sense the grip and communicate via BT to a computer moving the character. The game learns from the force and increases the activation force to improve the child's grip.
Cardboard toys. In this concept, the phone slides into a cardboard case and allows specific games to be played. Parents can download those games and plans to make the simple structure of cardboard. The approach aims at using the sensors and capabilities of phones to come up with low cost but fun interventions.
Photo of flipbooks Flipbooks are fun. They are used for animation and playing random games. These allow children to play board games like snakes and ladder, Ludo, Book cricket etc. They allow a particular motion of the hand in the process.
Photo of mockups Exages (Exer Pages) are a set of modular toys that a therapist can prescribe the patient based on her condition. They provide a set of interactions that are fun as well as therapeutic. They concept is based on the observed habit of children to be attached to a single object that they carry from home to clinic and back.
Photo of mockups Pinchphone is one of the prototyped exages. It allows using the gripping/pinching action to trigger xylophone like notes.
Photo of therastairs Therastairs brings the concept of piano stairs into therapy domain. This concept explores the idea of using a staircase as an interactive medium to play games. The aim is to allow CP children to move up and down the staircase and remove the fear by incorporating playful elements.

Participatory Design Sessions

The mock-ups were shown to the experts (physiotherapists, dev psychologists, and child orthopedics) and users (Parents and Occupational therapists). The aim was not to get a number but rather to engage in a discussion around these prototypes. It was great. I got superb feedback and I moved into the next stage of prototyping. I did ask the experts to rate the mock-ups. They were also asked to consider aspects like maintenance, novelty, ease of use and the most important, safety.
Photo of results of Participatory design session The results of participatory session with 4 doctors and 3 parents.
The final idea was to build a wide spectrum toy to assist in pinching motion. It had these different shapes, size, and color that could help in cognitive development. The pick and grab motion hit a key on the xylophone that helped in creating a distinct sound. The idea was to come up with an ExerToy which could conform to a socially acceptable norm of products designed for CP affected kids. This could make the device non-alien to normal kids and acceptable to CP kids. This conformity could result in an increased social collaboration around the object.

Prototyping and Fabrication

A digital first approach was adopted. The toy was modelled in Alias. We tested the affordances in the digital model. Once, the digital model was finished. We rendered it to understand the final look and feel. These models were then processes with Fusion 360 for CAM process. They were then milled on a 3 axis CNC machine.
Photo of mockups Things look better in renders.
Photo of mockups The CAM preview from Autodesk Fusion 360
Photo of mockups The final milled pieces. I made four to present it to all participating users. A thing my guide, Prof. Girish taught me. I was happy to second this view. “No, Hit and Run” design.


I have wounds that remind me of this stage. I spent days in the wood studio sanding the parts of the CNCed wood, which were milled on the wrong surface and along the wrong grain. This is typical to the things when they are in sent to fab status.

The goal was to not use Dremel as much as possible and achieve a surface finish good enough for a toy. Samarth Sir, helped a lot. He even taught me how to lathe wood even though it was not required, but I just wanted to learn. But the process went like, sanding the 4 prototypes from 80, 100, 150, 220, 500, 700, 1200 grit papers. I learned a lot about materials too. The grain, texture, and curves of the wood. The next step was polishing. I did not want to use synthetic polish as they are usually not child safe. I was also not very confident of my spraying powers and hence, resorted to just using a wax polish on the wood. It worked very well. I would recommend this process if one is looking for a quick child and environment-friendly surface finish.
Photo of mockups The groves to guide the elasticord.

Design Details

This section discusses the design decisions taken while design the physical toy.
  • Material and Texture: Wood toys are robust, look great and last longer. Offer a better feel compared to plasticky ones. No polish to avoid use of harmful chemicals. High degree of hand buffing to achieve good surface finish.
  • Shape and Size : Shape is rounded in accordance with many kids toys available. The fillet edge is smooth to avoid injury if the toy falls on barefoot, edge downwards. The size fits easily in a CP Chair.
  • Audio feedback : Xylophone keys were used to construct the sound board.
  • Grips/Beads: There are different grips to simulate common objects like coins and food. The parameters were size, color, material and shape.
  • Elastic String : The toy uses an easy to replace elastic string whose tension can be changed by moving the knot on one side, this makes one arm harder to pull compared to another.
Photo of product The completed product - Top
Photo of product The completed product - Bottom


The evaluation involves testing using empirical methods. The prototypes of Pinchphone was constructed as per suggestions of the experts. Out of the three centers approached, only one agreed to participate in the evaluation of the product. Hence, the prototype was designed, as discussed, based on the measurements of the participating center with scope of modularity.
The hypothesis are :
H 0: There is no effect of interventions on the overall interest and playfulness of the therapy.
H 1 : The introduction of playful elements via the designed intervention positively overall interest and playfulness of the therapy.
I used Null Hypothesis Testing as the basis of our evaluation.
Photo of product Experiment Design
Explanation of evaluation stages :
  • A1 : This is the baseline stage. The children will be asked to perform the required motion using current therapy methods. In this case, the child will perform the fingerpicking exercise using a peg-board or beads transfer from one bowl to another.
  • B1 : The is first intervention stage. The designed interventions will be presented to the children. 10 minutes will be given for the child to explore and then a 15 minute session will begin to allow the child to play with the device.
  • A2 : At this stage the intervention will be removed and the child will do the therapy as before in stage A1.
  • B2: This is the final intervention stage. The designed interventions will be presented to the kids and they will be asked to perform actions as in B1 but this time no training will be provided.
The prototypes were presented to Adapt, RML Hospital and Dr. Mansoor for their feedback. I was not able to get permissions to test on the kids and hence, I resorted to the judgment of doctors and their experience to provide feedback. They could include it in the therapy, but that was not required. The feedback received from them was good. They wanted to know when they could buy it. Further, they advised to increase the size and improve the sound volume.
There are also certain limitations with respect to the long term use and deployment. These were not studied during the project. They include issues like distribution, maintenance and repair.


In the project, I presented Pinchphone and Therastairs, interventions to improve playfulness of existing therapy of children affected by cerebral palsy. I presented a process to understand the elements of therapies and using models like ICF expand the domain of the current practices to incorporate elements of fun, play and social interaction. These formed the theoretical basis of the project. Using the same approach, I designed two interventions. The Pinchphone is a toy that aids in finger-picking exercise. This fine motor action is required while eating of picking things. It form the basis of movement when writing. The designed intervention provides audio feedback and may assist in cognitive development by teaching concept of color, shapes and sequencing.

Further Information

I would like to acknowledge the support my family and friends - Siva, Prabal, Malay. My supervisor, Prof. Girish Dalvi and Prof. Ravi Poovaih, Doctors involved in the study - Dr. Sudha, Dr. Rohit, Dr. Alam, Dr.Deepak and Dr. Saurab.
The project can be downloaded here. If this has piqued your interest and you would like to read more. Check out my project report here.
Made by Rohit using Tachyons, Vuejs, and some "Pipas con café". Check out the Colophon to know more.