Paul Greenberg (Expert Witness)

 

 

Interview Transcript

 

PG: Hi, I’m Dr. Greenberg with the Gait Analysis Research Group. We’re a group of podiatrists that are NHTSA-certified in standard field sobriety testing, and each of us have approximately 20 to 30 years of experience in Gait evaluation. The Gait evaluation that we do constitutes an evaluation of a client - the vascular evaluation, neurological evaluation, orthopedic evaluation – a review of the information that supplied to us – past medical history and the arrest report – and then an examination of the client to ascertain under controlled circumstances that individual would be able to accomplish the NHTSA-standard field sobriety testing.

 

RJ: So what is forensic gait analysis?

 

PG: Forensic gait analysis encompasses the evaluation of how someone walks, both visually and computerized, and through use of video, and comparing that gait, that walking pattern of the individual to films that you may have, to observations that were made of an individual during the course of an event. What my group does is we evaluate an individual on how they walk, correlate it with the historical data that we have to ascertain whether the initial evaluation of how someone walks is either the normal for that indivual or was purely the gait that the person had at the time they were observed or videoed. This is very relevant especially in DUI because in many instances the police officer’s observations of an inidivudal are relatively accurate. That person does walk a certain way. They do stumble to the right a little bit. They cannot maintain their balance. They have difficulty getting out of a car. They hold on to the car when they walk to the back. And these are all significant items in the interpretation of whether that person should be arrested for DUI. By our evaluation of the client, we ascertain whether or not this is the normal pattern for this individual.

 

RJ: So what you do is, let’s say I’ve been arrested for DUI. I walked the line, I touched my finger to my nose, I do all these tests that people do by the side of the road, and I’ve been arrested. You come in, and you’ll say – you’ll bring me into your lab and you’ll recreate all these tests that I did at the side of the road under controlled conditions, is that what you do? Is that right?

 

PG: What we do is first review a lot of the paperwork information we have on the client. We’ll review the medical history. We’ll review any surgical reports that we may have upon the client. And then we’ll do an evaluation of that client. We’ll focus, of course, on their gait patterns. We’ll correlate it with their medical conditions. There are easily a hundred medical conditions that can affect someone’s gait. So the medical history gives us an idea of directions that we should look. We’ll do a neurological evaluation. We’ll do a vascular evaluation. As an example, if a person is a diabetic, or they have a gout problem, or they have a peripheral neuropathy – a loss of sensation in their feet – it does affect their gait. And it can affect their gait in a way that could have an arresting officer interpret this as a person who was under the influence of alcohol. So we evaluate that client via the history, via an evaluation of their vascular, their neurologic, and then we repeat the standardized field sobriety tests, the same tests that were given road-side. Basically the one-leg stand, the walking turn, the horizontal gaze, and the stagmus. We get documentation under controlled circumstances in our laboratory situation. Flat ground, well-lit, essentially a controlled situation, and we have our set of results. In many instances those results will mimic what the police officer found. In many instances they will not.

 

RJ: So I come into your lab and we’re going to recreate all these tests that I had to take on the side of the road. How do you know if I’m intoxicated in your lab? Maybe that’s funny but do you breathalyze me in the lab? Do you sample my blood to know if I haven’t drank before I came into your lab?

 

PG: Well, actually, yes, I do. We’ll see a client and in that initial history, I’ll ask them if they’ve had anything to drink that day prior to seeing me. When I first speak to them by telephone, I also tell them that that’s very important that they consume no alcohol. And I’ll ask them that question, and I’ll do observations. Similar observations to what the police officer would do roadside. Is there an odor of an alcoholic beverage? Are the eyes watery? Are the eyes glassy? But I will also do a presumptive breathalyzer evaluation upon the client. And I do this once, and then I do it a second time twenty minutes later, so that I will have two readings of 0.00, essentially I breathalyzer them to make sure.

 

RJ: Okay, so when you do these analyses, you watch how I walk, are you just eyeballing me? Do you use a computer to do it? How do you know if I’m doing things the right way or the wrong way?

 

PG: Well, observation is very important. We watch the way you’re walking, because that observation really is a very, very important key just like the arresting officer observed the client or when they rolled down their window, and when they got their license and registration from their glove box, and when they exited the car and walked to the back. We observe our client from the moment they’re walking in the door through the time we’re evaluating them. When we do the gait evaluation, I’m observing them the same way I observe patients during 30 years of practice so that we can ascertain what their gait pattern is and whether they have any pathology or does it correlate with the pathology that we already know they have. Once we’ve done the observation of their gait and how they walked, then I do a computerized analysis. That computerized gait analysis is very important. The reason for that when you observe someone walking, you get a subjective analysis. Hopefully, it’s a good analysis. But it’s subjective. It’s what you visually see. When you get a computerized gait analysis, you’re getting objective, reproducible data. That objective, reproducible data should correlate with your subjective visual evaluation. That’s what is most important.

 

RJ: So what would you say are the top 3, or 5, or 10 medical conditions that affect a person’s gait? And how do they affect it?

 

PG: There are so many that affect a person’s gait. What we see of primary importance, diabetic patients. In today’s society, half of the diabetics are still undetected. Many people don’t know their diabetic. Of the people who are diabetic, we see sensory loss. They have what we call peripheral neuropathy. They don’t feel the sensation in their feet or in their hands like you or I would. Their feet, sometimes they’ll say, feel like balsawood. They don’t place their feet appropriately often when they are walking. They don’t feel the terrain like it should. Concerning feeling the terrain, many people, especially as they age, will have arthritic problems. Far and away, we see this in so many people. And those arthritic problems, whether it’s osteoarthritis, rheumatoid arthritis, or gout will cause pain when they walk. They may have limitation of motion because their joints aren’t working properly so they don’t flex or extend their feet, or their knees, or their hips adequately. This of course will change the way they walk, make them hold onto the car when they walk, especially if they’ve been sitting in the car for any period of time. We’ll see that limitation of motion that extends not just to their joints and lower extremity. They will have disc disease, and we see that in a large number of people where they’ll have sciatic, where they’ve had a herniated disc, where they’ve had a sports injury, where because of aging, they don’t have the motion in their back any longer so they walk with a guarded pattern. Their shoulders may be that way also, so that they don’t have the normal arm swing. They can’t move their neck to the right or the left, a full range of motion, so they will shift their whole body when the police officer asks them to roll down their window. Oftentimes they can’t turn their head enough, and they won’t be able to reach over adequately to the glove compartment. And this can be interpreted as a problem related to them drinking when in fact it may be a limitation of motion. We also see people with neurologic diseases, neurologic problems, people who’ve recovered from strokes, people who are on medications where it has affected them. Eyesight, particularly cataracts in an aging population, a lot of people do not see the signs well. When they see oncoming headlights, they’ll see a halo. Their cataracts may be getting worse but not bad enough yet for surgery. Somebody in their 60s, there are so many things that affect the way we walk, the way we talk, and the way we move, so many medical conditions.

 

RJ: So after you’ve spoken about all the medical conditions and factors that go into somene’s gait, it sounds like you probably have a pretty extensive intake form that tells you all the possible things that could be going on with someone that could affect their gait.

 

PG: Yes, most definitely.

 

RJ: And it sounds like, for an attorney, this kind of form, this kind of intake, could be very helpful to have because then it would open their eyes to a lot of things they may not have considered that could open holes in the case that they could use to defend their client.

 

PG: Yes, many times during our interview of the clients, we pull out information that was missed on the initial intake by the attorney. The attorneys who are sending me clients are generally sharp attorneys who know what they’re doing, but oftentimes the nuances of some of these diseases the medical side of it gets missed because the client doesn’t tell the attorney. As we do our medical evaluation and intertwine that history, we pull things out that nobody was aware of, and some of these are very significant, and have very significant impact on the direction of the case.

 

RJ: So other factors that can affect a person’s gait. What if they’re heavyset versus skinny? Do you see any differences there? And also men versus women, do you see any differences there?

 

PG: Yes, we do. Concerning weight, one has to only go to the NHTSA manual on standardized field sobriety testing to see what the regulations are. We all have our separate opinions on whether the field sobriety tests are accurate, inaccurate, good or bad, but they are the law of the land. So everyone operates within the law of the land, and using that one has to recognize also that if a person is overweight, if they’re morbidly obese, if they’re more than 50 lbs overweight, if they have lost more than 30 lbs or gained more than 30 lbs within a few months prior to their stop, that will affect their gait pattern. If they have a back problem, if they have a hearing or balance problem, if they have a joint problem in their hips, in their knees, in their ankles, in their feet. These are things that will affect their gait and these are things that are documented in the NHTSA manual. So besides our large base of knowledge and expertise, we have to refer back to what is the law of the land, and by referring back to the manual and pulling those things out to the forefront, that in fact, disqualify the tests that were done roadside. You’re pulling one of the legs of the table out which then in many instances causes that table to collapse.

 

RJ: So can you tell if someone comes in, if they are faking how they move?

 

PG: Yes, it’s very easy to tell that, and on occasion, I’ve had someone who not so much has faked the way –

 

RJ: So have you ever had anyone come in and fake how they walk, and could you tell?

 

PG: I’ve had people come in and try to, not fake how they walk, but dramatize how they walk, and it’s easily discernable. Years of visual analysis in private practice we get to see this all the time. But most important when you do a computerized gait analysis, and you do multiple repetitions, we can see what we call outliers. We can see what the gait pattern is. You can fool someone on the subjective side some of the time, but on the objective computerized side, you can’t. You just can’t do it. We do enough repetitions that we can see it on the graphs and on the numbers. So the short answer is, do they try to fool us? Sometimes, yes. Can they? No.

 

RJ: How often have you seen that roadside conditions affect someone’s gait substantially? You know, if the road is curved or rough or uneven, if there’s cars speeding by, if it’s nighttime, if it’s cold, hot, those kind of things?

 

PG: Roadside conditions definitely will affect the way someone walks. Every report that I have read has said that the ground was dry, the road was flat, there were no obstacles in the way, and it was a perfect condition. I’ve never read a report that said it was done at a significant angle. It was raining, there was a little bit of ice, or whatever. Or the gravel was loose. I’ve never seen that on a report. But of course, I’ve heard that from many clients. It’s important that you have a flat surface. It’s important that you have a controlled surface. And on the side of a car, with between the headlights of the police car, on an evening where it’s foggy and the ground is slippery and wet, and the grave may be loose, and the road may be canted as all highways all. It’s difficult to get a consistent accurate gait evaluation.

 

RJ: So when someone comes in and they do all these tests with you in controlled conditions, if the results are the same versus them being different, is that good or bad and why?

 

PG: Well, if the results are the same, what we’re showing is that this is the normal gait pattern for the client. And that being the normal gait pattern, it’s good for the client. In that, this is how they walk, and oftentimes this is very important for a judge to understand.

 

RJ: Are there any factors that would disqualify someone from getting any kind of valid result from a field sobriety test?

 

PG: Yes, there are several factors, and those factors are well-documented in the NHTSA -- National Highway Traffic and Safety Administration – standardized field sobriety test manual. If a person is above a certain age, if their weight is more than a certain number of pounds overweight, if they have any ear balance problems, if they have any arthritic problems, if they have any back disease, if they have any joint problems, if they have any problems in their lower extremities, these are all disqualifying factors that speak to the test being inaccurate.

 

RJ: Can you go into more detail into what the computerized gait analysis does, and what the benefit of it is?

 

PG: Yes, the computerized gait analysis takes the walking pattern, that same pattern we observe when you are walking, and takes the subject of the evaluation of visual analysis and converts it to a reproducible, electronic, numerical evaluation. And the advantage of that is that it’s reproducible. When a client walks and we observe them visually, we write down our findings. When we do a computerized analysis, they walk across a mat or pad, and that pad is similar to a sawed grass with 5,000 blades of grass, but instead of blades of grass, it’s 5,000 pixels or little dots, and those dots measure downward force or pressure, they measure rotation torc, and they measure direction. This is done from very beginning of heel strike to the very end of toe off throughout the gait cycle, and through this we get reproducible data, and that data is correlated to our visual exam to essentially determine that our visual evaluation is correct or not correct. It’s a great tool.

 

RJ: So how did you come to use the computer in the first place for DUI gait analysis?

 

PG: It was very interesting. I came to use this technology for DUI analysis because in the surgical side of my practice when I would be doing corrections, whether it be bunions or hammertoes, or metatarsal surgery in the podiatry practice that I actively participated in. I would fix a problem, sometimes put in an artificial joint, sometimes move a bone, sometimes straighten a toe, and I would follow up with that patient for years afterwards on an annual basis, but even though they were discharged for the problem, the academic and research side of me wanted to make sure that the surgical procedures that I was doing, that were common in the profession, were holding up adequately, so I started to use computerized gait analysis so that I could get the data, so that I could compare before I did a surgery, immediately after I did a surgery, and 1 year, 2 year, and 5 years later, what was happening to my patients’ gait pattern. Was it improving, was it staying the same, was the procedure I was doing, even though it may have looked better and the patient said it felt better, was it holding up? And computerized gait analysis offered me a very strong way – again, just like we do with DUI – get objective, reproducible data rather than just the subjective data of a patient saying yeah, I’m feeling pretty good. And the doctor seeing the client walk and saying, yeah, they’re walking okay now. Yeah, they’re walking okay now, while it sounds nice, isn’t good enough. I wanted hard data so I could analyze it. Computerized gait analysis gives that to me.

 

RJ: So why would you be called in a DUI case in the first place?

 

PG: There are a few reasons. First if a person has an abnormal gait, if they have pathology, then I’ll b called to evaluate that client to ascertain whether that gait exists all the time, or whether it only existed during the time of their stop. I will go to court – well, my report will go to court, and in many instances, my report being handed to prosecution will be strong enough for a better look at that case, but if that case does go to court, I’ll be called to testify. I represent another battleship in the harbor. When we’re able to show the court that the person’s gait was in fact their normal gait, it weakens the prosecution’s case. Oftentimes the written report will be enough. If not, I’ll be in court to testify. The other reason I am called is that oftentimes for the client is both knowledgeable and has the desire to have every aspect of their defense looked into. The client will speak to the attorney about it, and the attorney will want to make sure that everything has been discovered. Oftentimes I’ll be sent a client for evaluation where there’s only minor pathology. In many instances there will not be enough there that I can help in the case, and in those cases, I’ll let the attorney know that in fact my evaluation will not be helpful and that there was no pathology there. I measure, I test, and we tell the truth, and by doing that, we have reproducible data. Most of time, yes it does help the client because my clients are prescreened and oftentimes they are clients that the attorney knows are having a problem. I’m the person who can ascertain what that problem is and the significance of it. And in some instances, I’ll be able to ascertain that I can be of no benefit to the client.