Seating and Positioning Series
Time To Tilt!
- By Laurie Watanabe
- Feb 01, 2010
How Tilt Works, Why It Works, & The Clients It Can Help
When discussing positioning options for seating & mobility
clients, you can’t get far without considering tilt. While
tilt is perhaps most immediately and commonly associated
with pressure relief — especially when justifying tilt to funding
sources — it’s also useful in a number of other clinical and lifestyle
situations. The bigger question: Can those situations be justified to
payors’ satisfaction?
Mobility Management asked several positioning experts about the
mechanics of tilt, its potential benefits and applications, which seating & mobility clients it can typically help, and of course — what the
funding situation is like. — Ed.
What Is Tilt?
Q: What are the physical logistics of tilt, i.e., what
happens to the physical orientation of a person’s
body when he moves from sitting upright to tilting? How
does tilt differ from recline?
As its name suggests, tilt repositions a client by moving the seated
client “backward,” so his head is lowered as his feet rise at the
same time.
“Simply put, tilt causes you to shift from your bottom to your back,” says Cody Verrett, ATP, national sales director of Quantum Rehab. “You
can imagine if you were in a sitting position in a chair, and a friend
slowly tilts your backrest backwards, which shifts your weight almost
entirely to your backrest. That’s essentially what tilt does. It uses an
actuator to lift the person in that fashion, shifting their weight from
their ITs or ischial tuberosities to their back, and displaces that pressure
evenly across their entire back and redistributes it from their behind.”
Motion Concepts’ Stephanie Tanguay, OTR, ATP, clinical education
specialist, described tilt as “a shift in weight-bearing — a transfer
of weight-bearing from one part of the body to another. In an upright,
seated posture, the majority of the body’s weight is at the seat surface
interface — not all of the weight, of course, as a percentage of the
body’s weight is on the forearms, if they are in weight-bearing contact
with the armrests. As the system moves through the tilt range, that
weight distribution is shifted onto the back support surface — in a
traditional posterior tilt-in-space.”
Tilt and recline are often mentioned in the same breath, but there
is an important difference, says Invacare Custom Manual Product
Manager Jud Cummins.
“Although the recline function of a wheelchair has its benefits —
comfort, eating, function — (recline) differs primarily from today’s tiltin-
space chairs because it changes the consumer’s center of gravity,”
Cummins says. “Modern tilt-in-space chairs provide those same benefits,
plus pressure relief without changing the consumer’s center of
gravity, which has a number of benefits to the consumer, caregiver and
the engineer designing the chair.”
While moving even slightly in that “backward” direction is technically
a form of tilting, Sunrise Medical’s VP of Clinical Content& Research, Tom Whelan, says that for tilt to effectively relieve pressure
— the benefit perhaps most commonly associated with tilt, at least in
the minds of funding sources — the degree of tilt has to be significant.
“The biggest justification for tilt is pressure relief,” he says. “But
there’s been some work done, some studies done, on how far you
have to tilt to get any significant pressure relief. And there’s still
some debate on that. Some studies indicate that you have to pass 45
(degrees of tilt) to get significant pressure relief for off-loading of the
ischial tuberosities. Clearly, you’ve got to at least approach 45 to get
anything significant, and there’s plenty of evidence that says you’ve got
to pass 30. There’s still some debate as to how meaningful is the relief
and at what degree does it occur. But there’s no debate that you have
to pass 30 to be able to get there.”
More later on those 30- to 45-degree tilt thresholds.
Which Clients Can Benefit from Tilt?
Q: What mobility-related diagnoses can typically benefit
from tilt?
“We see a wide range of diagnoses utilizing tilt systems,” says
Tanguay. “SCI, muscular dystrophy, multiple sclerosis, cerebral palsy (CP), spina bifida to name a few.” But Tanguay and the other positioning
experts cautioned against
using a diagnosis as the sole criterion
when evaluating a client for tilt.
“More important to consider
are the symptoms or conditions
that tilt is prescribed to address,”
Tanguay explains. As an example, she says, “Recline may be contraindicated
for limitations of hip range of motion.”
“A diagnosis is less significant to justifying technology than a functional
presentation,” Whelan says. “If I have a mild case of CP, I could
be ambulatory, but I still have CP. Or I can be a quadriplegic (with CP): I
could have neuromuscular involvement that prevents me from using my
trunk, my arms, my head and my legs. I could be completely non-functional
as a result of that diagnosis of CP.”
Assuming that wheelchair users, by definition, all have some degree
of mobility limitation, Whelan says the vast majority of them could
benefit from tilt.
“When you think about the mobility-related presentations that
benefit from tilt: Everybody benefits from tilt,” he says. “There is no
person that doesn’t benefit from tilt except the (paraplegic client) that
is the super para who can sit anywhere. That para can literally do what
(able-bodied people) do.” Whelan says that if a client’s functional
presentation shows that he’s retained the ability to move and control
his posture and change it, “then you don’t need tilt. If that’s not true,
you’re going to benefit from tilt.”
Whelan also uses the innate behaviors of an able-bodied person as
a baseline when addressing whether a seating & mobility client could
benefit from tilt.
“Now we’re back into the ‘How bad does it have to be before
you can justify tilt?’” he explains. “’How much do you have to suffer
before you need tilt?’ In my mind, it’s real simple: If you can’t do what
an able-bodied person can do to relieve the effects of sitting, you are
justified for tilt. It has nothing to do with if you’ve ever had skin-integrity
issues.”
And finally, Verrett notes that it’s important to consider the
progressive or non-progressive nature of a diagnosis while assessing a
client for tilt.
“If it’s progressive in nature, it’s important that a provider prepare
that product to meet that individual’s needs as time goes on,” he says.
“So they kind of have to pull out their crystal ball and know that with
an individual with a particular diagnosis, if it’s ALS or multiple sclerosis,
depending on how they present today, there could be a significant
change over just a short period of time.”
That assessment, Verrett says, should include how well the client is
able to function not just during the relatively brief evaluation, but also
throughout the day.
For instance, he says, if a provider is observing as a client repositions
himself, performs pressure relief or transfers from a commode to a wheelchair, the provider has “to really assess how well are they doing
it. Is it exhausting? What kind of fatigue level is created by that one
particular instance in that evaluation? Would they really be able to do
that functionally all day long, every day?”
What Other Clinical Benefits Does Tilt Offer?
Q: What other clinical or medical benefits can result
from employing tilt?
“Tilt can have a dramatic impact on respiration,” Tanguay notes.
“Even minimally kyphotic postures can restrict excursion and limit lung
capacity. Posterior tilt can create a sagittal shift in the body. In this
position, gravity can create some extension of the upper body and
position the trunk for greater lung inhalation.”
Posterior tilt — with the client tilting “backward” as his feet rise
simultaneously — is usually what we envision when we think of tilt
systems. But Tanguay points out that tilting laterally — i.e., to one side
or the other — can also offer clinical benefits.
“Lateral tilt and posterior tilt have been successfully utilized to
address respiration (J. Sparacio) and dysphagia (K. Hardwick& R. Handley),” Tanguay says, adding that tilt can enable “positioning
to improve visual field, head righting/positioning, reducing fatigue,
gravity assist for positioning after transfers, (and) increasing footrest
clearance while navigating some obstacles or curbs. Tilt is utilized for
postural stability.”
In fact, Whelan believes postural relief is, practically speaking,
probably the most common benefit of tilt.
“There’s research that shows very few people tilt past 30 (degrees),
and people don’t tilt to any great degree with any great frequency,”
Whelan says.
“So my argument is that the biggest use of tilt, if you talk about not
the justification, but the actual use by end-users, is what I refer to as
postural relief. If you’re in a wheelchair, there’s a very good likelihood
that you’ve either lost the ability to use the muscles in your trunk to
control your posture, or you have neuromuscular issues that challenge
that: could be low tone, could be high tone. So what that means is you
can’t sit and maintain your trunk posture by using your muscles. And in
fact, even if you look at able-bodied people, they can’t do it.”
If you’re sitting in a chair as you read this, Whelan says, “I guarantee
that you are moving, changing your position subtly, no less
than every minute or two. You’re changing the muscle that’s fatigued
so the muscle that’s holding your trunk up is a different muscle
because that muscle can’t just stay in a constant state of stress
for that long. Or you change your posture so you’re not using your
muscles at all; you’re just resting on the ligamentation that’s holding
your posture and your spine.”
That constant need to move and shift is no different for wheelchair
users, Whelan says. “For the person in a wheelchair, they can’t do that,
so they have to take a different path…. Comfort isn’t a medical necessity but sitting tolerance is, which is exactly the same thing.”
Verrett points out that respiration and digestion can be improved in
some clients by tilting them to achieve a specific position, and there are
other potential benefits as well.
“For someone who may be visually impaired in one particular field,
if they can tilt back, they can have better vision depending on their
body position, things like that,” he says. “But one that isn’t mentioned
that I think is really important: A newly injured individual recovering
from spinal cord injury (SCI) may absolutely require tilt just to be seated
in a functional capacity. The tilt system combined with their body
weight and gravity can hold them in a position of security, as opposed
to sitting in a normal, parallel-to-the-floor kind of seated position. Tilt
really maximizes body weight and gravity, and allows them to remain
seated, upright and engaged for functional activities.”
SCI patients, Verrett notes, have “lost certain trunk control functions
that they had prior to the injury” and have to “relearn their
balance, and their core strength has to rebuild itself to some degree.
What tilt will offer is the ability to adjust to that new strengthening of
the core while allowing them to still be engaged and functional. If we
didn’t have tilt, their backrest would have to be opened up very far into
a reclined position, which doesn’t always lend itself to function.”
Verrett recalls working as a provider with hospitals that had SCI
patients: “That was always a really big deal, the ability to get an individual
with a new injury up and moving and reoriented to their power
mobility surroundings. The faster, the better.”
And using tilt, along with the patient’s body weight and gravity,
could make the patient feel more secure and stable in his wheelchair,
which encouraged the patient to use the wheelchair more. “You’re
readjusting to this new world, and that’s got to be incredibly frustrating
and devastating,” Verrett says. “But the ability to be able to see other
people, smile and interact can really bring that person full circle and make huge strides in their recovery.”
Without tilt to help secure the new SCI patient in his wheelchair,
“they would be bedridden,” he says.
RESNA Provides Tilt
Justification Support
Looking for justification for tilt from an entity that your referral
sources and/or payors are likely to listen to?
RESNA has a position paper called “RESNA Position on
the Application of Tilt, Recline and Elevating Legrests for
Wheelchairs.” The paper begins with the history and definitions
of tilt, then discusses physiological effects ranging from
spasticity to contractures and orthopedic deformities.
It also explains how repositioning can facilitate or improve
other critical activities, such as transfers, feeding, speaking
and bowel/bladder management. And yes, significant space
is devoted to pressure relief, including the practicality of
expecting wheelchair users to effectively perform pressure
relief via pushups or forward/side leaning. Contact RESNA
(resna.org) for more information on the position paper.
The Many Evolutions of Tilt
Q: What technologies have improved or enhanced tilt in
seating systems?
While tilting or reclining a client to relieve pressure, improve posture,
improve comfort, enhance stability, etc., is a relatively simple concept,
it has not historically been a simply executed one.
“Manual and power tilt systems were originally pivot-style systems,
which required longer mobility bases,” Tanguay says.
“With the first tilt-in-space chairs, the center of gravity of the person
moved dramatically,” Whelan explains. “Your center of gravity in a
seated posture is generally just in front of and just above your navel.
That’s about where your center of gravity is. Now, picture a chair, and
I’ve tilted you back: You can see that center of gravity is moving rearward
substantially because you’re pivoting at a point that’s somewhere below
that, which means that center of gravity is traveling on an arc posteriorly.
The problem is that that center of gravity over your wheelbase defines
your stability. So in order for a wheeled system to be stable, the center
of gravity has to stay between the caster wheels and the rear wheels. If
it moves posterior or anterior to either of those, the chair falls over. So
when you tilt, you have to deal with that.”
Initially, Whelan says, industry wheelchair designers dealt with
that issue in a simple way: “We just moved the rear wheels rearward
to increase the base of stability, so it could move without becoming
unstable.” But what those longer wheelbases gained in stability,
they sacrificed in maneuverability. The wheelchairs required more
room to make turns, which could cause big accessibility problems,
especially indoors.
That challenge led to “sliding tilt” systems, “which move forward
over the base as the seat system tilts rearward,” Tanguay says. That
strategy could shorten the wheelbase required of wheelchairs that
incorporated tilt systems. But even with sliding tilt designs, there
was still another factor to consider, one that’s “a little harder to deal
with and less well known because it’s clinical as opposed to technical,”
Whelan says. “A lot of people in tilt-in-space chairs have an
abnormal neuromuscular system. They have an abnormal development
of balance.”
In those cases, Whelan explains, mobility limitations have
prevented the wheelchair-using client from developing a sense of
balance that able-bodied people take for granted.
“When we were kids,” Whelan says, “we rolled down hills on
purpose. When I was a kid, I would do everything I could to upset my
balance. It’s part of our normal development. We’re trying to develop
our vestibular system, so we stimulate it to develop it.”
Wheelchair users, however, may never have walked and therefore
may have had far less opportunity
to develop a sense of balance.
Or traumatic brain injury may have
affected that vestibular system.
“So,” Whelan says, “you put
that kid in a tilt-in-space chair, you
tilt him back, and as (his) head’s
moving backward, (his) center of
gravity is disturbed.” That can cause a physical reaction, Whelan says:
“You see these kids in wheelchairs, especially kids with CP. You start
tilting them and they go crazy. That’s because you’re disturbing their
innate sense of stability, and they react to that.
“If you can design a system where that sense of stability is less
disturbed during repositioning, you’ll get a clinical benefit. You’ll have
less episodes of tone and less reaction from the client in the chair. If
you’re conscious (of impending tilt) and you have the ability to control
it, if you have a normal intellect, then you can rationalize ‘I’m not going
to fall.’ But if I came up behind you and tilted back your chair, your
feet would fly out and your arms would fly out, and you’d try to extend
yourself to gain stability. That’s a normal reaction of the body.”
So the next evolution of tilt goes by a couple of different names,
including center-of-gravity (CG) tilt or in Sunrise Medical’s case,
Rotation In Space (RIS).
Verrett describes CG tilt this way: “As the chair tilts backwards, the
pivot point there at the back-and-seat intersection begins to slowly
come forward toward the area where the knees were. You can imagine
it tilting back, but kind of rotating a little bit. That can make a huge
difference in the overall size of the base that is necessary to keep it
stable. So that’s been a big additional improvement to the industry, the
advancement toward CG systems over single-pivot products.”
The end result of CG tilt, Verrett says, is the ability “to make the
overall footprint of the product much smaller as the innovation of CG
became much more readily acceptable. Essentially, as the weight’s
shifting, by bringing that center of gravity forward, it minimizes the
amount of stress and dynamics on the chair because all the weight isn’t
just tipping out the back of the product.”
Whelan describes the idea behind Rotation In Space tilt as “very
simple in concept and very difficult to develop. The idea is you
pivot around the individual’s center of gravity. If the whole chair
moves around that center of gravity, it never moves. It stays in one
place. That’s what we refer to as Rotation In Space, because now
you’re not tilting — tilting infers that you’re moving that center of
gravity, where rotation infers that you’re moving about that center
of gravity.”
Other tilt innovations, Verrett says, include lower seat-to-floor
height options, as well as electronics that can be programmed to
“remember” specific positions or certain functions, such as drive
inhibits or limitations while tilt is being used.
“A provider can program a product specifically for that individual’s
needs,” he explains. “A couple of good examples are individuals that use vans. (For) vehicle entrances, (they) may have to tilt back and
still drive into the vehicle. Being able to do that electronically to the
specific degree needs of that individual — that’s a big advantage for
providers today.”
Thanks to today’s electronics, providers can work with the client
to determine, then “lock in” certain tilt positions so the client automatically
“can go back to that position each and every time,” Verrett
says. “It takes all that guesswork out and makes life a lot better for
consumers.”
When Is Tilt Appropriate?
Q: When should a provider consider recommending
or including tilt in a seating system? What clinical
considerations, diagnoses and other factors typically indicate
that tilt should be considered?
“The inability to perform pressure relief, or to reposition oneself with
frequency throughout the course of the day, would be very common
reasons for the prescription of tilt in space,” Tanguay says. “Tilt is also
utilized in combination with lower-extremity elevation for positioning
to decrease lower-extremity edema.”
In addition to benefiting clients who need help with postural
relief, Whelan says, “Respiratory and digestion benefit from posture
more than they do from tilt. What tilt gives you is the ability to get an
ideal posture to facilitate normal respiration and to facilitate digestion.
You get this normal alignment of the trunk and body, but still
allow for change of position. It’s really to some extent the result of
the posture, and the tilt is just enabling you to control the posture
and still get the repositioning.”
He adds that tilt can have a more direct impact for some clients
who have trouble swallowing: “There are people that, as a result of
their disability, may only be able to swallow at a very specific position
of the head and neck and trunk. Tilt becomes a nice way of doing
it. You can do it with recline, but there are people that require tilt just
because they have to get to a very specific position for swallowing.”
And now another discussion of those 30- to 45-degree tilt thresholds.
Earlier, it was mentioned that according to research studies, a
significant amount of tilt is needed to adequately relieve pressure —
that is, to redistribute body weight from mainly the pelvis to mainly the
back. The actual numbers vary per study, but the consensus seems to
be that clients need to tilt more than 30 degrees — and 45 degrees
or more is better — to achieve pressure relief that will make a clinical
difference. Not only that, but clients need to hold that tilted position
AND tilt into that position frequently.
“If you think about the guidelines for pressure relief, they want you
to completely lift your buttocks,” Whelan says. “They teach people
that are spinal cord injured that you’re supposed to do a complete
pressure relief every 15 minutes. So if you follow medical best practice,
you’re supposed to (achieve) complete relief of the loading of the
pelvis. That’s a lot of tilt. To completely offload the pelvis, you’ve got
to go a long way, and you have to stay there a bit, and you’ve got to
come back up, and you’ve got to do that with a frequency that very few
people do.”
Compliance may be even more difficult for SCI clients who are
attempting to relieve pressure without using tilt. “You’ll often see
paraplegics lean forward and put their elbows on their knees,”
Verrett says. “That kind of picks up the pressure from their ITs, as
well. Those are ways that you can relieve that pressure without
necessarily tilting.”
That being said, performing “push-ups” or other forms of pressure
relief without the benefit of tilt can be very challenging, even for SCI
patients with good upper-body strength. For SCI patients whose injuries
are at a higher level, “if the individual doesn’t have that strength,
like a high-level SCI or somebody who’s got a progressive situation
with muscular dystrophy or multiple sclerosis or ALS, they’re unable to
do that,” Verrett notes. “So tilt replaces that function.”
Tilt vs. Recline: Or When Are Both Appropriate?
Q: When could tilt be used in conjunction with recline?
What clinical conditions, diagnoses, etc., would indicate
that this combination could be helpful?
“Tilt can be used in conjunction with recline when the client can
tolerate the change in hip angle — if it doesn’t cause repositioning
or other impacts,” Whelan says. “For some people, a specific hip
angle is indicated to reduce spasticity, so if you put them in recline
and you change the hip angle, their spasticity increases, and recline
is not indicated.”
In choosing between tilt and recline, Tanguay notes, “Spasticity
may be a consideration. The change of hip flexion angle with recline
can illicit a spastic response, which can alter the consumer’s posture/
position. This can result in shearing issues and can alter the orientation
of positioning components like lateral thoracic supports or
positioning-style headrests. This change can also alter functional
access to switches.”
She adds, “There are certainly consumers who cannot off-load
seat surface pressure with only tilt (or only recline). The combination
of perhaps 150-plus degrees of recline with some tilt, or full posterior
tilt (45-55 degrees) with some recline can be the solution. Pressure
mapping with a tilt-and-recline system is a great way to determine
the most effective pressure relief position, and it’s also a wonderful
training tool for teaching consumers what positions achieve offload of
seat surface pressure.”
In some cases, says Cummins, “combining tilt with recline can
improve function, breathing, feeding and comfort. Though an appropriate
degree of tilt might provide pressure relief and support for
a consumer, it may not provide optimal peer interaction, which a
reclining back could do.”
Is Tilt Being Funded?
Q: What is the funding climate currently like for tilt
systems?
Given all the clinical and social benefits of tilt — from postural and
pressure relief to facilitating respiration and digestion to encouraging
interaction and eye contact with peers — are funding sources seeing
the values of this positioning option? And are they opening their pocketbooks
to pay for tilt?
“From the acute-care standpoint, I would say the climate is status
quo,” Cummins says, “though when it comes to complex rehab, status
quo means there are still states that have slashed reimbursement and/
or made the process harder for tilt-in-space reimbursement.”
He adds, ”It’s a different story altogether from the standpoint of a
provider servicing long-term care facilities with tilt-in-space systems. It
comes down to a lack of understanding, where certain Medicaids don’t
see the clinical benefit of a tilt-in-space system as a complex, custom
product unique to an individual needing postural support, pressure
relief, all-day comfort.”
Whelan says, “There’s been a lot of challenges in the nursing home
environment. It’s (been) fairly traditional in the Medicaid program that
the minute you needed a tilt-in-space chair, Medicaid would pay for it
because it was considered not a chair that the nursing home should
have to provide. It was a ‘custom’ chair.”
But as states slash their health-care budgets, some Medicaid
programs are rethinking their funding habits. “So with all the reimbursement
pressures on the Medicaid system,” Whelan says, “You’ve
seen more of a battle of ‘Wait a minute, we don’t want to have to pay
for it anymore.’”
As tilt systems become more and more common — and tilt systems
and wheelchairs become increasingly adjustable — Medicaid administrators
began questioning whether it’s still their responsibility to pay for
tilting chairs in long-term care settings.
“We went through a discussion with a Medicaid program on that
very point,” Whelan says. “They stopped reimbursing tilt-in-space
chairs for nursing home residents. (The tilt systems) didn’t fit the technical
description of ‘custom’ anymore. Their big argument was the
minute (the chairs) become adjustable where they can be changed and
used by another client, it’s not custom anymore.
“In reality, it’s not like (the chairs) change themselves. They require
a significant amount of adjustment, so they really still are custom. The
language is the argument: You see language (such as) ‘Can’t be used
by another resident.’ Well, how do you interpret that? If I buy $400
worth of parts and I change the chair, it CAN be used by another resident.
So there are some states that have language that states, ‘Can’t
be used by another resident at the same time.’ I can’t take this person
out (of the chair) and put another person in it and (have them be able
to) use the chair. Therefore, it’s a custom chair. Whereas, in other
states it says, ‘Can never be used by another resident’ as the definition
of ‘custom.’ So we’re working our
way through that.”
Excluding certain long-term care
issues caused by Medicaid semantics,
Whelan says, “In general,
funding for tilt in space, like any
other technology in our industry, is
becoming more routine and more
recognized. I think the clinical prescription is driving the payors.”
Says Verrett, “The funding climate for tilt is relatively straightforward
and regularly paid for by Medicare, Medicaid and private
insurances. The ramifications of not funding tilt are astronomical
compared to the associated costs. So funding sources readily fund
and support tilt as a preventative measure to skin breakdown, which
ultimately leads to costly hospital stays and surgeries, all of which
dwarf the cost of tilt.”
Providers who do have problems getting tilt claims paid are “typically
not justifying it appropriately,” Verrett says, but he adds that
those scenarios are relatively uncommon.
“Most clinicians that operate in this space, in this industry, and
most providers have perfected justification and the appropriate documentation
necessary to justify and support tilt in space,” he says.
As for securing funding for tilt and recline systems together, Verrett
says, “Technically speaking, the requirement for tilt and recline to be
combined includes coverage criteria that the patient must first (1) meet
the requirements for a PWC (power wheelchair) described in the Power
Mobility Device LCD and (2) have a specialty evaluation completed by
an OT, PT or physician with specific training and experience in rehabilitation
wheelchair evaluations. In addition, (3) justification must include
that the patient is at risk for development of a pressure ulcer and is
unable to perform a functional weight shift or (4) the patient utilizes
intermittent catheterization for bladder management and is unable to
independently transfer or (5) the power seating system is needed to
manage increased tone or spasticity.”
Given those requirements, he adds, “Individually justifying each
component — tilt and recline separately — is an ideal approach for
funding sources and will give the provider the best opportunity to
secure funding. So for example, you would justify tilt based on the fact
that the person is at risk for pressure ulcers and can’t perform weight
shift independently. And then recline can be justified through their
bladder management program or increased spasticity and tone.”
Time for Tilt!
For all the clinical, social and even long-term financial benefits of incorporating
tilt into seating systems, the most common-sense one, Whelan
suggests, is that tilt works to compensate for a very natural, very
necessary ability that seating & mobility clients often lack.
“More repositioning and more change of posture more closely
reflects the normal human condition,” he says. “Why deny it to people
with disabilities when we wouldn’t deny it to ourselves?”
This article originally appeared in the February 2010 issue of Mobility Management.