Cognitive Domains Commonly Impacted by TBI
Keep in mind as we review these impairments, that this is just a guide as to what you might see cognitively, post-TBI. No two patients with traumatic brain injury will present the same way. I've been doing this for 17 years and I found that each case that I'll work on is always a little bit different. The brain injury is just as individual as the brain that was injured itself. Just as we're as individual people, the presentation of the traumatic brain injury is individual and thus, our treatment plans need to be individualized as well.
I know most of you are PTs or PTAs, if not all of you, and so you may not be doing actual cognitive therapy. However, in TBI, you cannot take out the cognitive piece of treatment and just do the physical piece in isolation with these patients. Cognition informs how the patients participate in your treatment session. It informs how they understand what you're telling them to do. It informs what they do outside of treatment. So it's all interrelated as Kelly referred to earlier. I've been really fortunate enough in my career to work on interdisciplinary teams and to be able to co-treat frequently. I've learned a lot from physical therapists, especially, and I think that you, as PTs, are in a perfect position, actually, to incorporate cognitive tasks into your treatment, either as a distractor to how badly you're hurting them when you're doing what you have to do to them physically or to increase the complexity of your treatment if you're working in a post-acute setting.
Those cognitive domains commonly impacted by TBI include
- Language and communication
- Visual spatial skills.
- Executive functioning which includes attention, organization, planning, reasoning, problem-solving, mental flexibility, and self-awareness.
Post-traumatic Amnesia (PTA)
Post-traumatic amnesia is the period following emergence from coma. Patients have had a traumatic brain injury and they are not mentally unconscious anymore. They are no longer in a coma, but they may have several of the below symptoms:
- Disorientation to time, place, person. They may not know who they are, where they are, and/or what happened to them at all.
- Delusions. I have definitely heard some crazy things. For example, people thinking they're in yachts on the beach and while we wish they could continue to think that, we eventually want them to move out of this phase.
- Agitation. Physical agitation may occur during this phase which is related to more frontotemporal injuries.
- Disrupted sleep/wake cycle
- Poor attention and concentration
- Retrograde and anterograde amnesia are the hallmark characteristics. They cannot lay down new memories during this period of time (PTA). They may have islands of memory, but they can't process the passage of time and hold on to memories in any sequential order while they're in post-traumatic amnesia.
These patients may or may not be physically aggressive, but they may be wanderers. They may thrash around in their rooms and may have a 24-hour sitter with them. They will likely be globally cognitively impaired with deficits in perception, speech intelligibility, language impairment, executive function, and processing speed.
The goal for all of us, whatever discipline we're in, is to be able to have them engage safely, be calm in therapy, be oriented, and have some attention and concentration to therapy, so they can get some benefit out of it. A few guidelines about treatment in post-traumatic amnesia are:
- Avoid restraint. I'm sure if you work in inpatient rehab or even seeing agitated patients in acute care, your facilities have protocols regarding this. You want to minimize the use of restraint if at all possible while keeping the patients and yourself safe.
- Avoid over-stimulation. Watch their environment. You may need to dim the lights, have a quiet, consistent environment. If you can manage to have them have the same nursing staff, have the same therapy team, the same caregivers, that's the best.
- Allow rest as needed. Evaluate the effectiveness of your treatment. So if they're more agitated in your therapy session because they're becoming fatigued, then you might want to end your session early.
- Establish a means of communication. If they are not verbal, you want to establish a means of communication such as asking them yes/no questions. You can make use of your SLP coworkers to help you if your patients are nonverbal.
- Frequent reassurance and comforting words to the patient
- Presenting familiarizing information as tollerated by the patient. That maybe about yourself and as well as the patient. Use their name and tell them where they are. Tell them you're there to help.
- Family education is going to be important. So while this is not normal per se, it is a pretty typical part of the recovery in traumatic brain injury. It can be pretty scary for all of those involved but family education is helpful during this time.
Kelly talked a lot about the GCS score which I think is the first information that we get in a post acute setting. I can easily get the GCS score, but if you can manage to get the duration of their PTA that is a very strong predictor of outcomes of those with TBI. Different studies out there have different variables of prediction but below is an example of the markers.
- PTA < 18 days: Strong likelihood of good recovery at 1 year
- PTA <4 weeks: Good recovery more likely
- PTA> 56 days: Less than 10% chance of a good recovery
- PTA of 48 days indicative of poor employment outcome
- PTA of 54 days a predictor of supervision need at 1-year post injury
Less than 18 days, you're going to have a good recovery at a year. 54 days of PTA is a predictor of requiring supervision at one-year post injury. So that timeline can also help with expectations for the patient as well. Of course, you don't want to use this as saying, "well, it's been a year, I'm gonna give up". It is just a pretty strong indicator of the severity of TBI. Most of the time, you're going to see patients in PTA in acute care, inpatient rehab, and long term acute care hospitals (LTACHs). But, I have found that as the landscape of healthcare has changed and people are not qualifying for the lengths of stay that they used to in inpatient rehab, I have had patients who are ambulatory with PTA and don't qualify for any impatient rehab or post acute admissions so they may home. Again, the hallmark characteristic of PTA is not being able to lay down new memories.
Memory and Learning
Memory impairment is one of the most prevalent cognitive impairments in traumatic brain injury. We're going to review both the types of memory as well as the process of what happens in our brain during memory and learning.
Types of Memory. There are three primary types of memory. Those three types are declarative or explicit, procedural or implicit and then prospective. Declarative memory is our general knowledge, names, what's happened to us, and events in our life. It's encoded in the hippocampus, the entorhinal cortex, perirhinal cortex, which is all within the medial temporal lobe, which is that gray section right there under the white section. Prospective memory is the memory of what we have to do in the future. So knowing that you have to go to a doctor's appointment, that's using your prospective memory. Procedural or implicit memory is starred in your handout because I want you to remember that this is going to be key for you guys in your treatment sessions and how you work with memory. Procedural or implicit memory is the knowledge of how to do something. It's motor memory. It's muscle memory. It's knowing the physical sequences that you go through. It is encoded and stored in the cerebellum, the basal ganglia, and the motor cortex.
Process of Memory and Learning. The first thing we do when we want to commit something to memory is we encode the information. Encoding is the most important part of the memory process, specifically in traumatic brain injury. We take in or encoded information visually, acoustically (what we hear), and semantically (anything that is word-related, either written or verbal). The process of encoding or taking in the information and organizing it so that it can be stored is the processing part. That occurs in the left lateral prefrontal cortex and the left medial temporal lobe. So I want you guys to just make note. It might come up again, that memory occurs in the temporal lobe. So encoding is taking it in. Then the next step is called consolidation which is storage. The process of putting it into your brain happens again in the medial temporal lobe structures, the hippocampus, and left hemisphere for verbal memory. So again, language and memory are in the temporal lobe, as well as the medial temporal lobe structures including the hippocampus.
The hippocampus is a subcortical structure that's part of the limbic system that is very sensitive to lack of oxygen and is damaged very easily, so that is why patients with anoxic brain injury have such severe memory impairment. They're not able to store the memory very well. So the process of encoding and consolidation is what we call learning. Encoding and Consolidation is the initial part of memory and the retrieval is the recalling it at a later date and that occurs in the right prefrontal cortex. It is not unusual for TBI patients to have memory impairment. There is a prevalence of 54 to 85%. Typically, what gets in and gets encoded and consolidated stays in and so it's easier to retrieve than it is to get in.
I highlighted procedural memory earlier for you guys because your patients are going to be able to remember the physical things that you are having them do because it is stored and consolidated and encoded in a different area. The literature suggests that chronic TBI associated memory and impairment is more related to the encoding and the consolidation part. So that informs your therapy techniques. Your learning procedures should enhance their ability to encode the information. So to focus how it's going in, as well as how they are processing that information but the other option is to reduce the demand of the memory and tap into their procedural memory. That's why I kind of wanted to highlight this a little bit more for you specifically because that is what you do.
Impact on Treatment
How does this impact treatment? How do memory impairments impact treatment? Well, that's kind of easy. They don't remember you. They don't remember your therapy session. They don't remember that they have a therapy session today or tomorrow. They can't remember what you worked on (including any new skills) and they certainly aren't going to be able to remember your home exercise program that you're asking them to do. So it's pretty easy to see how memory and learning deficits impact your treatment.
Evidence Based Memory/Learning Treatment
I'm going to provide you with evidence-based memory and learning treatment strategies, though you're not actually going to be treating the memory impairment. I'm not trying to convert everybody to be a speech therapist. You are not going be treating these deficits but these strategies are things that you can use, just as much as speech therapists can use, to be able to make your therapy more effective.
These are best used with a mild TBI population because they have a little bit more memory capability, a little bit better encoding and consolidation.
Internal Strategies (mild TBI) include:
- Mnemonic Device such as
- Word pneumonic (ROY G BIV)
- Expression mnemonic (Please Excuse My Dear Aunt Sally-You can make these up with your patients if you have maybe a list of exercises you want them to do, that's how you can incorporate those.
- Association- pairing something you want them to do with a task that they are already doing. One of the PTs that I work with was giving me an example of how she recognized that the patient's bathroom counter was at the right height for them to do their sit to stand exercises. So they associated brushing their teeth every morning and every night with doing their sit to stands at that particular time. So you can look at what else is going on in their routine and associate your exercises or what you want them to do.
- Organize in chunking-Pair two or more things together.
- Music- I starred music on your handout because I don't know if you use music in your treatment sessions. You may use for gait or coordination, but music, either making up a song or incorporating memory strategies to a song or playing it while you're doing your treatment session is one of the most effective ways that you can get your patients to remember what you need them to.
- Self-generated. This is at the top of your handout, but all of the literature says that you can't just give somebody a mnemonic device and have them remember it without it really being self-generated. It is more effective if it's functional. So rather than you making up the sentence or you making up the rhyme, you want to try to have them make it up.
External Memory Aids (Moderate to Severe TBI)
The second type of memory treatment is using external memory aids. So this is more for the moderate to severe TBI population. They must be personalized and have a functional application. If you're working with the TBI population, hopefully, you are working with a team and your speech therapist is working on their external memory aids. Meet with your SLP to find out what they're using and what they recommend.