 I come from the Victoria Institute of Forensic Medicine and people might ask what's a forensic doctor got to do with fitness to drive and coming to talk about impairment, but in fact we have a lot to do with not just analysing crashes after they happen and with the unfortunate consequences of them, but we do a lot of work with VicRoads and other organisations which I'll talk about a bit later on this afternoon in assessing fitness to drive and trying to make sure that the fitness to drive of people on our roads is optimal. Well when Joe asked me to come and talk about impairment and about the nature of impairment I actually had to sit back and think well what does this actually mean, what does the impairment mean? And went and did a little bit of looking into what definitions of impairment means, I suppose in the broader sense they mean deviation from normal. The World Health Organisation obviously went to great lengths to provide a definition of impairment I was quite surprised to see how tiny it was when you think about what an enormous amount of consultation and important people jetting around the world must have gone into producing this, but they say that impairment means a problem in body function or structure which is really about as general as you can possibly get and could really apply to just about anything including indigestion after a bad meal a night before or almost anything. In a medical dictionary I found that impairment really does have a more general definition than really any abnormality of anything and there are various different ways of looking at impairment which I'll talk about and the way that we consider them when we're thinking about fitness to drive on the road or what the effects of the impairment might be on driving performance. So why does impairment have an impact and you know I can sort of be a bit trite and say that we want to actually avoid impacts meaning impacts on the road but it's important to think about what the relationship between impairment and the driving task might be. Now the driving task is a really artificial situation you know up until the turn of the last century nobody had ever driven before. People on horseback might have done you know 20, 30 Ks an hour whatever velocity a horse does and people in trains might have gone a bit faster but it was only from about the early 1900s that people actually began driving and when you think about it it's a really artificial man-made environment, very dangerous environment. You put people of sort of arbitrary ability and health behind the wheel of a machine with a big chunk of hot metal up the front and a tank of explosive fluid up the back and you let them loose pretty well and they're surrounded by other people in the same sorts of vehicles and they're on roads of indifferent quality they might be really good quality roads or they might be terrible roads with poor signage and bad lighting and capricious signals and in this totally artificial environment we expect people to work to their optimal ability and to preserve safety and to perform an accordance to those rights that Richard talked about. In an ideal sense I guess we would have evolved to do this but 100 years is really nothing in the spectrum of human evolution and the way that the road system has evolved has perhaps been a bit faster than that and people have begun to appreciate the difficulties of coping with this unnatural environment but I think we're a long way from perfection yet. I have a background as an engineer as well as a doctor and I can very well remember in my engineering days seeing a picture of a person that had been designed to fit into a holden so taking a holden car as being natural if you like some engineer had sat down and tried to engineer a man to actually work to his optimal ability in such a car and in those days perhaps cars weren't designed as well as they are today but you know the person that came out of this design study looked like an alien more than any of us in this room today so they had eyes out on stalks and they had one longer than the other and you know very unusual looking body proportions because the car had been designed by some engineers somewhere and really there hadn't been much consideration about fitting it into the human interface hopefully things have improved a bit since then but the correlation is still capricious and imperfect and the correlation between you know the fragile chunk of sort of gooey wet material inside the metal cage is still not perfect and so we have to cope with trying to understand the way in which people function in relation to this very artificial environment it is an unnatural act you know we deal with all sorts of unnatural acts in forensic medicine but this is probably the most common of them things that people have to do when they drive are often aren't natural all these things that I've listed here basically have to do with how fast we're traveling and we have to take in a vast amount of information was very interesting to hear about the the particular demands of racing and rallying but being on on sort of domestic roads perhaps not quite as as difficult as that but similar sorts of skills people have to take in vast amounts of information mostly visual they have to think about them really quickly they have to be able to respond to the unexpected you know is there a pedestrian stepping off the side of the road is has someone else done something silly in a car have the lights changed so they've got to be able to do all that really really rapidly they've got to be able to plan in their mind where they're going they don't have the luxury of a co-driver telling you where to go unless it's a GPS these days and they can be a distraction on their own and then you know do all these things at once and then translate them into movements of the arms and legs to control the vehicle road trauma as a result of these things not going right is in fact the greatest non-homicide cause of traumatic death that we see at the Institute is about six times as many people end up in our pathology department from road trauma that end up from homicide and for every one of those that's killed there's a very large number that are injured and have all sorts of other effects on society so it is an important issue and it's important because of legal implications I'll talk about a bit later on today there's issues of culpability if people have a crash whose fault was it was it the there because there was a medical condition that wasn't properly recognised is there an issue with the responsibility of health professionals also a very vexed question and of course driving essential in the 21st century it's very hard to leave in the 21st century unless you can drive and especially here in regional areas where people can be quite isolated if they can't be mobile well what's the evidence base for driving fitness we'll hear a little bit about this I guess from myself and other speakers the evidence base is not perfect it's getting better all the time and it's been embodied as best it can be in the new guidelines there's a lot of research still happening especially to do with chronic conditions and this is quite important as the population ages the baby boomer generation as they've gone through life have been responsible for a lot of great medical advances for whichever particular ages they were at now that they're getting to the geriatric stage there's a lot of interest in older drivers and the effect of chronic conditions as they affect people and this reflects on the way that assessment methods are developed for driving fitness and some can be appropriate and some can not and there's the example of whether or not visual fields have an effect or can sorry whether the effective visual fields on driving fitness can be measured easily by other methods of testing and I'll talk about that a bit later on as well there was some reference to the Muac review this was a study that was done by a group of us at Muac that's been done twice now the most recent review was in 2010 and had a bit of input into the formulation the most recent guidelines it was basically a meta-analysis of the current scientific literature about various sorts of conditions and disabilities and their effect on crash risk and was divided into acute problems which cause sudden disability and chronic illnesses which affect fitness again I'll talk a little bit more about those later on we have a lot of experience in both of these things at the Institute because of both our rollers Vic Rhodes medical reviewers and also because we get to analyze crashes so when things go wrong we get to see what's happened when things go wrong and we get to see the sorts of cases that can happen when medical conditions might be a factor and I've got to say over about the last 20 years the number of nasty you know death crashes that the police have asked us to look into that have involved medical conditions has increased and this may be a reflection of the greater population but perhaps also the aging population certainly in the last year or so I've probably myself dealt with about three or four of these and this would have been unheard of 20 years ago and in those days just about every death crash involved alcohol and perhaps some other extraneous issues now there are crashes that are before the corona based on epilepsy and diabetes and all sorts of other medical conditions there is actually one case the first one in my experience and of any of my colleagues there is one case before the court at the moment here in Victoria that involves hearing so it's not thought to be a really big issue but it can happen so how do we classify impairments and I like to think of them this way there's the issues of sort of cognitive and intellectual abilities does a person have the capacity for learning and can they learn to drive in the first place whether it's it's an off-road test or doing a knowledge test or has a perception test or whether they can perform and actually have the capacity to learn from their mistakes when they've got all plates and then there's conditions that have episodic disability where people are okay in between physical deformities a situation that I call deceptive fitness that I'll elaborate on a bit later on and of course the thing that concerns most of us here I guess which is the effect of chronic conditions which can be physical and psychological or mental or a combination of all of those things intellectual disability occasionally crops up as a question in people's fitness to drive and it's more than just the capacity to learn the capacity to intellectual quotient or IQ is sometimes defined as the capacity to learn and you know there are people that can learn to drive and we we find it hard to assess fitness purely on a number as to a person's IQ I don't think anybody's ever been able to show a really good correlation between the actual number on an IQ test and the risk of crashing we usually give big roads a sort of advice that if a person can pass a driving test there's really no basis to deny them a license even though they might appear to be intellectually disabled if they've got the capacity to learn enough to pass the driving test that's assuming that a driving test is a good gateway into into being able to drive then there's no reason not to let them drive but there are people sometimes that are outside that frame and sometimes it's very hard to know you know you can't really assess them before they actually get on the road there's a particular patient I'll call Miss T who is an intelligent person this is based on a case that's been before us who was an intelligent person you know had a university qualification and all but sustained some brain damage and this person could pass any test you liked as far as driving and driving instructors thought she was wonderful but she lacked the ability to have insight into driving behaviour and if something went wrong she'd panic at one point you know things went wrong she just left her car parked somewhere with the engine running and ran away because she couldn't cope with the stress of an unfamiliar situation so intelligence and ability to learn is not necessarily something which is the Bill and end all. Episodic impairment is an exercise in risk assessment there are conditions like epilepsy, diabetes and the things I've listed here where people are completely okay most of the time and then they have something that happens to them if it's for instance epilepsy it's a transient unpredictable impairment caused by the disease and then there's conditions like diabetes where the impairment being a low blood sugar is caused by the treatment but whichever way you go people are disabled transiently and in between they might be totally okay they go and see their doctor they're totally okay and doctors or other health professionals have to rely on the history you can't do a test in many cases you have to rely on the history and you have to rely on the person being truthful to give you a good history as to how frequently these things are happening in some cases for instance in diabetes or you know conditions where people fall asleep for instance it's possible to modify these things by treatment in some cases it's not. Epilepsy is really interesting condition because it's so variable and it was the basis of the beginning of our driving clinic which I'll describe a bit later on today highly variable condition lots of different sorts of seizures some of which totally disabled people and some of which don't you know some people just have a funny feeling which is classed as a seizure without really losing awareness and they can still continue doing all sorts of things including driving some people get a warning some people don't some people respond well to treatment some people don't investigations can be illusory sometimes there's another patient I'll call miss S who came before us who you know had totally normal investigations had a normal MRI had an EEG even though there's a history of epilepsy years before had a had an EEG that was normal when she wasn't having a seizure and on the basis of those tests they reassured her to the point where she thought well I'm cured I don't have epilepsy anymore got a driver's license unfortunately that wasn't the case so you know some investigations might not necessarily be the appropriate ones for these sorts of conditions then of course there's other issues of compliance there's a there was a lady jailed a few years ago for culpable driving Victoria that hadn't taken her doctor's advice about compliance with medication killed somebody as a result so there's an overall risk assessment is not simple it's not as simple as just picking a disease and saying yes there's this disease this is this is what we need to do we have to take into account the whole clinical picture diabetes is a classic example high-posed may be preventable totally for persons on an adequate regime but there are competing treatment priorities endocrinologists if you talk to them they love to run people with low blood sugar as low as possible because that has the best outcome for the long-term health of the patient but on the other hand that almost assumes that they're going to have a high power at some stage during the day and we of course don't like that behind the wheel if we see a report from an endocrinologist saying this person's got terrible diabetic control we actually feel quite reassured even though we know even though we know that at some time in the future they might get some of the long-term effects most of which can be dealt with in one way or another deceptive fitness is a condition that that that I think about when the assessment method is really not sensitive to the impairment so I talked about the lady with the EEG and the MRI before which really didn't tell us whether she was going to have a seizure or not another other other classic examples might be people that have got visual fields now you know these are people that have lost part of their visual field and you know they can drive perfectly well in a lovely bright sunny day down a dead straight highway where there's no other vehicles or no pedestrians or no bits of road furniture on the side but it's the unpredictable that's the issue they can't see the whole visual field and I was interested to hear about the fact that rally drivers need to be able to take in the whole field everywhere and you know you sort of do it subconsciously and you know get a picture in your mind of it these people can't do that so you can test them on the road till a couch come home but you can't predict what the effect of that visual field loss is going to be so there are certain conditions like that where people appear to be fit but aren't necessarily so chronic impairments of those where there's really no prospect for improvement and there's lots of different ways of classifying those as well they can be something someone's born with and people might have actually made an adjustment to it people are born with visual problems there are certain visual conditions that look terrible you know there's a particular condition where people where people's eyes dance around and they can only see well out of the side of their vision but they can drive perfectly well because they've had this ever since they were little kids and they've learned to live with it whereas if something like that happened to an older person they might have great difficulty there are conditions that you know once you get a disability it's always going to be there for instance a person might lose a limb thing you know that's not going to change and and there's also chronic conditions that gradually get worse a lot of these people require individual assessment and I'm pleased to see that we'll be hearing from occupational therapists about that later on today there's also problems of you know whether or not a person had a pre-existing impairment and then as they get older the significance of that impairment might change so the sorts of chronic impairments that I guess you're all familiar with are these and I don't really need to go into great detail about a lot of these I suppose except to say that some of them are going to be the fairly static and some of them are going to get worse as time goes on older drivers are a sort of a special case and they're causing a lot of concern now as the population ages all of these problems can be there in general you saw that bath type that bathtub shaped curve that Richard showed about you know crash sorry about death risk going up as people get older that's part of the combination of the onset of chronic conditions and partly because older people are more fragile and tend to have a lot more trouble surviving injuries that might not necessarily hurt a younger person or at least keep them disabled for very long the most difficult issue that people always worry about in older drivers is cognitive decline that people are getting demented or they have trouble coping with complex conditions on the road and we've heard a little bit about the intersection problem that is something that hopefully will be coped with by better road designers things develop in the future but it's a problem that is going to be with us for a long time and it's hard to assess across a desk it's hard to do a pure medical assessment in a consulting room that will give you a clue as to how much this is going to be a factor for people's on road performance dementia well that's the condition that once is diagnosed the decline is inevitable and that's one of the reasons why the new guidelines have have put in mandatory regular review the idea being that they're lost to follow up otherwise if they're not followed up doesn't mean they have to have complicated OT assessments every year means that somebody who knows them needs to cast an eye over them regularly and just raise a flag if they're getting worse and anybody who's worked with people with this condition will know that there's enormous amount of variability in dementia there's different sorts of dementia some people go downhill very quickly some people grumble along for a long time they have ups and downs and hopefully most of them tend to self limit things themselves but along with dementia comes a lack of insight and sometimes there comes a time when difficult decisions have to be made for people and families have to get involved often because by the nature of the condition they can't actually understand the difficult decisions that have to be made so actually testing very helpful for things that are required where a person has something happened to them and they're not the same person after that so they've been quite okay and then they've had a stroke or something's happened to them or they've got a condition where they're deteriorating these sorts of things they're classic conditions any of the people here that are OTs will certainly know this but there are conditions where no T assessment is not appropriate you probably guess from what I've said before that some of these unpredictable impairment conditions or deceptive fitness conditions you can test them forever and you know they'll come up perfectly because you're not testing them at a time when they're disabled or you're not testing them appropriately for the problem they've got we think it's very important that people are fit to have driving tests if they're going to have OT assessments or on-road tests of one way or another they do need to be tested first of all to make sure that they can play with the driving guidelines on-road testing is no substitute for medical fitness so people need to have adequate vision their diabetes epilepsy what have you needs to be properly controlled before they're allowed out on the road because otherwise they're putting the testers at risk as well as themselves just a bit of a word about visual disabilities or visual impairments some of the guidelines have been relaxed for car drivers the amount of visual field that people need according to the new guidelines is less than it used to be for the old guidelines and that's going to make life easier for a lot of people but it's important to realize that visual defects can be associated with other problems especially if they've happened as a result of a stroke there are certain kinds of strokes that affect visual fields and they affect other things as well so other people's cognitive abilities and other things of that sort might also be affected at the same time so it's not purely an issue of visual fields there's also a lot of new technology coming out to plot visual fields now years ago a visual field was a visual field you put a person in a dark room or got them looking into a big white bowl and your flashed little lights to see what they could see and it was easy to do a plot these days there's an almost infinite number of devices on the market that'll plot visual fields in all sorts of different ways there are ones that use large targets little targets ones with moving targets ones with both eyes open you know some with only one eye open some with the eye fixed on a target and some where people are allowed to look anywhere they like so visual field plotting is not as easy as it used to be and the interpretation of them is not as easy as it used to be either and we put a tremendous amount of time into thinking about this and we have an expert committee that helps us try and make sense these aren't all the same patient but it's not uncommon to get a whole swag of these on a single patient they all look different and you've got to try and understand why they look different and actually what this means for what happens when they're behind the wheel just to put these sorts of risk into perspective everybody knows about alcohol it's been around for a long time and everybody knows about point oh five being the legal limit for driving if you're not on a probationary license and the relative risk of a crash at point oh five so that's the risk of having a just the pure risk of having a crash compared to if you're at zero if you're point oh five somewhere between three and five times and that's the risk that society has decided is unacceptable so this is not science really I mean the science tells you what the risk is but the government or the parliament picked point oh five because you know they have to let people have a little bit of social drinking but at about three to five times it's considered to be unacceptable and if you're at about point one then you've got about a ten times risk and that's the level at which the courts really give people a very penalty if they've had a nasty crash if you're in that central part of that bathtub curve if you're if you're a if you're a safe experienced driver aged 40 and and you take alcohol to make you as dangerous as an 18 year old you have to get up to about point oh six and it's illegal to drive at point oh six but it's not illegal to drive when you're 18 that people have the same risk but to compare that to medical conditions some of those don't have enormous risks compared to drink driving you know the relative risks the overall relative risks of treated people with these conditions not high but there's a lot more of them and and so that's why we have such an emphasis on trying to do something about them because every little bit incrementally reduces the overall risk on the road many of the concerns and sometimes of people who work in areas like social work and actually have to deal with families and so forth have to do with preserving people's lifestyles and mobility for as long as possible and I've got to say that's also one of our aims and I'm talking again later on this afternoon and I'll be talking about trying to put licensing conditions on to people that maximises those opportunities you know the aim of medical review of drivers well it's partly to take unsafe drivers off the road but it's to keep people mobile for as long as possible because you know it's certainly known that there are major public health implications if you take people off the road that shouldn't be taken off well look it's a bit hard to know about cost benefit analyses in a formal sense you did hear also in a previous talk that some of the Monash research has shown that Victoria's got the lowest rate of of all the driver crashes and deaths compared to places where there are different regimes now Victoria has got the most lenient fitness laws in that it's not compulsory to have medical review as you get older but Victoria does have the most thorough medical review system so that once people are known to the medical review system action is taken probably more than it is in other jurisdictions in Australia now the cost of a of a death on the road has been variously estimated as being at least a million dollars to society it's probably even more than that when you think about other sort of hidden intangibles so you know at the moment in Victoria there's about 260 deaths a year so that's a quarter of a billion dollars every year in direct costs associated with death and I'm not sure what the you know what the whole medical review industry an assessment industry costs but it couldn't possibly be as much as that certainly health professionals you know such as OTs, physios, doctors etc deal with lots of other things it isn't the only thing they do isn't the only thing I do either but there is a cost in doing all of this and you know I guess the only positive indicator I can say of the fact that it's money well spent is that we have the lowest death rate of older drivers in the country