This article provides an email interview with Mark Goldstein, computer input device designer. His Goldtouch Mouse is new on the market and shows promise in reducing hand and arm strain related to mouse use.
Send Mark queries at firstname.lastname@example.org
Mark: Thank you for taking the time to ask these important questions. There are many issues considered and implemented into the Goldtouch Mouse design which I think would be of interest for many people. We welcome an ongoing dialogue.
TIFAQ: Based on the information that you provided, there are a few questions to be asked: The accommodation of several different hand positions, and hands of different sizes, in using the mouse . . . are there any drawings or photos of the different hand positions?
Mark: Currently, we are making just the right hand version of the mouse. The mouse is designed to be gripped in a multitude of ways with the right hand. I believe that it is not possible or advisable to predict or dictate how the individual will grip any mouse, there are too many variables. Handsize, physiology, mousing technique, the work-station and the software interface are the main factors. Mousing technique and the software interface are very important factors which will alter the way in which the mouse is gripped. These two factors may over-ride hand size in determining mouse comfort as they can pre-determine how the mouse is gripped. There are two main techniques people use with mice:
The software will determine how fast the cursor moves as you move the mouse. Fine movements are difficult to perform with the larger, less dexterous muscles of the wrist and shoulder and so users of this technique generally slow the cursor speed to gain accuracy. Users of the finger technique will generally speed the cursor movements as the hand stays mostly fixed on the desk and the finger movements are relatively small and sufficiently accurate to move the cursor a few pixels or covering most of the screen, the hand pivoting from the wrist in ulnar and radial deviation. This works in reverse also. If you speed the mouse up in the set-up, the increased speed will force you to anchor the hand and use the fingers for accuracy. Conversely, slowing the mouse will necessitate grasping the entire mouse and moving it from the elbow and shoulder, this time, the finer control coming from the wrist. So, with the Goldtouch mouse, we cater for both techniques: the shape allows a very comfortable grasping and resting position as well as providing "fingers only" grasping on the gently curving surfaces.
In these grips, we allow the reduction of pronation with the left to right slope in the resting position and also a reduction of pronation in the fingers only position. The latter position being facilitated by the tall left surface which can be gripped at the bottom of the mouse or on top of the ridge, providing a variable range of pronation angles from an open, thumb non-coplanar to hand posture, to an almost vertical joy-stick posture. This is where some mouse designs go awry, other designs may force a particular posture on to the user and keep it in a fixed, static position for the entire time it's being used. This constant contraction potentially fatigues the muscles involved and may also decrease blood flow as a consequence of the contraction. Mice which compel a fixed, no-finger movement posture, (such as the ones which compel only a fixed gripping position) will also restrict fine control of the fingers. This latter problem has several consequences: it forces a bracing of muscles and therefore more contraction to achieve fine control, and also it induces more movement at the wrist in ulnar and radial deviation.
With regard to buttons, we bring the buttons to meet the fingers in a non-pronated posture rather than having the left button slope away to the left. This latter position in most mice, coupled with a palm support will only lever the hand into pronation. The buttons are curved to reduce finger extension. If you prop the hand up with a palm support, the fingers will naturally curl over as the flexor tendons will tend to close the hand. Some mouse designs have this shape and also require a straight finger (or extended) posture setting up a conflict of postures and stressing the finger extensors.
TIFAQ: The ability to fit multiple hand sizes, is a good marketing point for larger purchasers. Contour mice are probably your largest competitor in the ergonomics market, but they have to be fit to the hand and size. Contour mice also lack a good anchor point for the little finger vs. thumb when raising the mouse.
Mark: Because the mouse is a continuous curve, it will facilitate a large range of hand sizes. Again, this is mostly relevant to a resting, grasping posture. The long buttons provide positions for a small hand to hold it towards the front of the mouse or further back, depending on grip preference. The larger hand can envelop the entire curve of the mouse. The Goldtouch mouse is designed to be grasped between the thumb and both ring and little fingers, providing a better grip for lifting. The ridge on the right side helps the ringer finger opposing the thumb. We have two main buttons with an auxiliary third button, the primary button and secondary buttons use the index and middle fingers allowing the ring finger to be used for gripping. Other three button mice leave only the weak little finger to oppose the much stronger thumb.
TIFAQ: The marketing material you provided mentioned that the design improves fine positioning by the fingers - what is the improvement and is there a particular method to use to receive this benefit?
Mark: The ring finger surface on the right side of the mouse allows the finger to be used in a straight position, rather than having the right button forcing it around to the side. This releases all the fingers for more movement and greater fine control. Try drawing circles with the ring finger in these two positions, the released finger will allow larger circles to be drawn.
TIFAQ: Reduced EMG - is this attached to any specific holding pattern with the mouse, hand size, right or left hand, or is the benefit for any/all?
Mark: Right hand only.
TIFAQ: The engineering model had a very slick surface and one would think that a lightly roughed-up, etched surface would be better as the user might feel the need to grasp a slippery surface harder than one with a light texture to it.
Mark: Interestingly, we found that a textured surface provides less grip than a glossy surface and so our mice are now smooth. The greater surface area of plastic interacting with lipids on the skin may be the reason. Perhaps like race cars getting better traction with racing slicks on than with treads. We initially had texture on the pre-production samples, then removed it to achieve better grip.
TIFAQ: Very interesting indeed. Thank you for your time and considered effort in answering these questions regarding the Goldtouch Mouse.
You can send Mark queries at email@example.com
Last Updated: 02/18/98