Development of an integrated conceptual model of multiple sclerosis spasticity

Figures & data

Figure 1. Steps in developing the integrated conceptual model of multiple sclerosis spasticity.

PwMS = people with multiple sclerosis.

Table 1. Multistep process for developing the integrated conceptual model of multiple sclerosis spasticity^a.

Key concept	Step 1: Literature review	Step 2: Clinician Interviews N = 3	Step 3: Patient Interviews/Final Conceptual Model^b N = 20
Moderators
Sex	✓	✓	✓
Age	✓	✓	✓
Duration of MS	✓	✓	✓
Type of MS	✓	✓	✓
Disability due to other underlying conditions		✓	✓
Other MS symptoms that may influence  spasticity^c	✓	✓	✓
Triggers
Temperature/humidity	✓	✓	✓
Excessive physical activity			✓
Fatigue	✓^d	✓	✓
Stress	✓^d		✓
Other environmental factors			✓
Pain	✓	✓	✓
Physical dysfunction^e		✓	✓
Infection	✓	✓	✓
Menstruation	✓	✓	✓
Objective manifestations
Increased muscle tone (velocity dependent)	✓	✓	✓
Spasms	✓	✓	✓
Clonus	✓	✓	✓
Hyperreflexia	✓	✓	✓
Altered voluntary movement pattern		✓	✓
Subjective experience
Spasms	✓	✓	✓
Tightness	✓	✓	✓
Pain	✓	✓	✓
Stiffness	✓	✓	✓
Difficulty moving or bending		✓	✓
Muscle cramping	✓	✓	✓
Weakness	✓^f	✓	✓
Heaviness		✓	✓
Muscle jerks		✓	✓
Slowness of movement		✓	✓
Muscle tension		✓	✓
Physical impacts
Fatigue	✓	✓	✓
Limited range of motion	✓^g	✓	✓
Abnormal posture or gait		✓	✓
Bladder dysfunction	✓	✓	✓
Pain	✓	✓	✓
Sleep impairment		✓	✓
Functional limitations and impacts
Daily activity/functioning impairment	✓	✓	✓
Walking impairment	✓	✓	✓
Balance impairment/postural instability	✓	✓	✓
Reduced dexterity	✓	✓	✓
Difficulty with transfers	✓^h	✓	✓
Reduced swallowing	✓	✓	✓
Sexual dysfunction	✓	✓	✓
Social impacts
Reduced time with family and friends			✓
Work limitations		✓	✓
Emotional/psychological impacts
Fear of falling		✓	✓
Frustration		✓	✓
Depression	✓	✓	✓
Anxiety	✓	✓	✓
Sense of helplessness	✓	✓	✓
Limited ability to relax		✓	✓
Embarrassment			✓
Long-term consequences
Loss of driving ability		✓	✓
Falls/injuries	✓	✓	✓
Increased burden of care for ADL	✓	✓	✓
Loss of employment		✓	✓
Loss of mobility		✓	✓
Pressure injuries	✓	✓	✓
Loss of leisure and physical activities		✓	✓
Contractures	✓	✓	✓
Loss of independent living		✓	✓

Note: Abbreviation: ADL = activities of daily living.

^aAt each step of model development, six multidisciplinary experts on spasticity were consulted (JB, JRS, JMW, FB, MC, and EFF).

^bMultidisciplinary experts on spasticity were consulted, and some concepts were removed based on their feedback (see Supplemental Table 3 for more detail).

^cOther MS symptoms included: increased disability/motor impairment, pain, musculoskeletal symptoms, orthopedic symptoms, urinary and bowel dysfunction, balance disorders, fatigue/deconditioning, weakness, ataxia, sensory abnormalities.

^dFatigue and stress were identified in the literature review only as impacts of spasticity.

^ePhysical dysfunction included gastrointestinal problems, such as constipation, and skin lesions.

^fWeakness was identified in the literature review only among other MS symptoms that may influence spasticity.

^gLimited range of motion was identified in the literature review as a descriptor of spasticity.

^h“Transfers” was identified in the literature review as an impact of spasticity.

Table 2. Demographic and self-reported clinical characteristics.

Characteristic	N = 20
Age, years
Mean ± SD	47.3 ± 9.6
Sex, n (%)
Male	2 (10.0)
Female	17 (85.0)
Other	1 (5.0)
Ethnicity, n (%)
Hispanic or Latino ethnicity	1 (5.0)
Not Hispanic or Latino	17 (85.0)
Missing	2 (10.0)
Race, n (%)
White	16 (80.0)
Black or African American	3 (15.0)
Other^a	1 (5.0)
Highest Level of Education, n (%)
Secondary/high school	4 (20.0)
Some college	8 (40.0)
Four-year college degree	4 (20.0)
Postgraduate degree	3 (15.0)
Other^b	1 (5.0)
Duration Since MS Symptoms First Noticed, years
Mean ± SD	16.3 ± 11.1
Median (range)	16.0 (1.3-36.7)
Duration Since Spasticity First Experienced^c, years
Mean ± SD	12.3 ± 9.5
Median (range)	10.0 (0.6-36.7)
Self-Reported Duration Since MS Diagnosis, years
Mean ± SD	11.6 ± 8.8
Median (range)	9.9 (1.3-36.0)
Current Treatment for Spasticity^d, n (%)
Stretching	16 (80.0)
Oral baclofen	12 (60.0)
Massage	11 (55.0)
Spasticity Numeric Rating Scale
Mean (SD)	5.4 (1.6)
Median (range)	5.5 (3.0-8.0)
Patient Determined Disease Steps^e, n (%)
Normal (0)	0
Mild disability (1)	1 (5.0)
Moderate disability (2)	4 (20.0)
Gait disability (3)	3 (15.0)
Early cane (4)	3 (15.0)
Late cane (5)	0
Bilateral support (6)	4 (20.0)
Wheelchair/scooter (7)	4 (20.0)
Bedridden (8)	1 (5.0)

Note: Abbreviation: SD = standard deviation.

^aOther race: ‘‘’mixed’ (n = 1).

^bOther education: ‘‘General Educational Development’ (n = 1).

^cOne patient had an incomplete date entered. It was set to missing.

^dNot mutually exclusive.

^eLearmonth et al. 2013 [9].

Table 3. Summary of interview information from PwMS.

Spasticity triggers^a	Quantitative assessment	Qualitative representative quotes
Temperature or humidity	17/20 (85%) reported temperature (both hot and cold) or humidity as a trigger for spasticity	“Yeah. And I—to say I absolutely love the heat and I am a bikini advocate. Um, but this has been a bit of a stretch for me and that’s when I just—it, it really—the heat does warrant how long I can enjoy. I mean there’s no boating now. It’s I’ll watch you from the beach kind of thing. Um, but I definitely, um, think that it does impact me a little bit.” “the cold definitely makes [spasticity] so much worse… the heat is not great either…but the cold makes it so much worse.” “the quick weather changes is enough to just kind of give me a little kick me down.”
Physical activity	12/20 (60%) reported physical activity as a trigger for spasticity	“Certain exercises where I’ve had PT and I’m trying to stretch it out, it just draws back up even tighter.”
Fatigue, exhaustion, or feeling tired	9/20 (45%) reported fatigue as a trigger for spasticity	“I think it just wears down my body overall. So, I mean I’m extremely fatigued. I have to be very careful about how I spend what energy I have. It makes me really fatigued and also, I think maybe since I was using those muscles more or something, they’re more, more prone to have spasticity.” “When I’m having chronic fatigue, then I have more issues with spasticity.” “If I walked up the driveway too many times a day, I would be hunched over [from spasticity]… getting into the house, go lie down, and kick for a minute….”
Stress	5/20 (25%) reported tension as a trigger for spasticity	“when I’m stressed out or I’ve done too much, that’s when I get more spasms with my spasticity.”
Other environmental factors	4/20 (20%) reported other environmental factors as a trigger for spasticity	Examples included loud sounds, atmospheric pressure, temperature changes
Pain	3/20 (15%) reported pain as a trigger for spasticity	“Because I think that if it’s just not, like I was describing before, if it’s something that’s just not where it’s just a spasm and it doesn’t come with very much pain, it goes away quicker. If it’s coupled with pain that makes it harder, more intense, then it lasts longer.”
Physical dysfunction^b	3/20 (15%) reported physical dysfunction as a trigger for spasticity	“Um, like I mean so I mentioned intestinal issues. So I recently—they sent me to the ER two separate times because of the pain involved in that. And I mean it just seemed like the pain—like the excruciating pain from my stomach, it seemed to—I don’t know. My legs got worse and, you know, it just seemed more miserable.”
Subjective experience^c	Quantitative assessment	Qualitative representative quotes
Spasms	20/20 (100%) reported spasms Spasms most frequently occurred in the legs (n = 12/20, 60%).	Spasms were often described as “twitching,” “jerking,” “jumping,” or “kicking.” “Um, to me it’s when my muscles twitch and that’s what they do. Like my fingers will twitch. My toes will twitch. You can see in my arms and legs. You can literally see them to where it looks like, um, it’s jumping inside. Like my arm may not actually move, but you can see the muscle, um, twitch in the arm. And then there’s times where you can actually see the arm move, like, like someone is moving it, but it’s not me. It—that’s when it gets really bad.”
Tightness	20/20 (100%) reported tightness	“Um, like, kind of like, um, I’ve got the tightest jeans on in the world and feel like I’m having to walk very carefully, you know. Like when I’m just trying to move it’s just like everything is tightened up.” “…tightness [was] in my knee, but I think stiffness would be more in my leg.”
Pain	19/20 (95%) reported pain	“It’s like a tightness that tightens up, it’s almost like taking a rope and tying it around one of your limbs and just squeezing the rope.” “If the spasm is coupled with pain…then it lasts longer.” “I get a lot of spasms…and they burn and hurt really bad.” “muscles are aching and so tight that you’re just miserable… and it’s hard to function and walk.”
Stiffness	17/20 (85%) reported stiffness Most participants (n = 11/17, 65%) experienced stiffness in their legs, followed by their arms or hands (n = 4/17, 24%).	“Um, stiffness. It’s almost like having rubber bands in your body parts that are over stretched and if you don’t loosen them up, they’re going to snap in half.” “I function a lot slower…because I’m stiff or I can’t move as quickly as somebody might want me to.” “when I’m experiencing spasticity, I cannot bend the knee at all.”
Difficult to move or bend	15/20 (75%) reported difficulty moving or bending	Muscle spasms were considered to be “like ‘charley horse’ spasms, or the inability to move…my leg.”
Muscle cramping	10/20 (50%) reported muscle cramping	“So what I had to do was sit back down on the bed and try to like do a massage at that knotted-up muscle until such time as the muscle relaxed and then the pain of the charley horse went away, but during that time, I know 15 min probably doesn’t sound like that long of a time, but when your muscle is cramping and you’re in a huge amount of pain, it is a long time, so yeah.”
Weakness	10/20 (50%) reported weakness	“And, um, but, uh, sometimes it hits me as weakness. Um, my—I’d describe it like this. Sometimes my muscles feel like spaghetti noodles, you know.”
Heaviness	10/20 (50%) reported heaviness	“It’s like they’re like heavy like I can’t—like the same—the place where my leg gets like I told you like a voodoo doll is getting stabbed and not—feels like that. It’s just offline. Like as far as lifting up the leg to do whatever, but just on and that.”
Muscle jerks	9/20 (45%) reported muscle jerks	Muscle jerks were described as causing “twitches, spasms, contracting, tapping, kicking, and shakes.” “Or that’s more when like the jerking—like my muscles sit there and like contract and keep going and my leg will start literally like jerking and—or like you can look at the muscle and you can see the muscle twitching and stuff, and that has woken me up. That usually happens during the night when I’m sleeping.” “when my legs shake, my whole leg shakes. When my arms shake, my whole arm shakes. It jerks, yeah, it’s big jerks.”
Slowness of movement	5/20 (25%) reported slowness of movement	“Or if somebody—you know, your daughter watching you get in the car. "Come on. Let’s go." I just function a lot slower. And again if that’s because I’m stiff or I can’t move as quickly as somebody might want me to. That’s, that’s what causes anxiety, is that external, uh, thing.”
Physical impacts of spasticity	Quantitative assessment	Qualitative representative quotes
Fatigue	14/20 (70%) reported fatigue as a physical impact of spasticity	“[fatigue from spasticity] will wipe me out…from 45 min to two hours…you’re trying so hard to move and do normal everyday things.”
Limited range of motion	12/20 (60%) reported limited range of motion as a physical impact of spasticity	“I’ve had severe cricks in my neck, which I can’t really attribute to anything other than potential spasticity.”
Abnormal posture or gait	10/20 (50%) reported abnormal posture or gait as a physical impact of spasticity	It seems like I’m a little bit more slumped over lately and I have a lot of back pain like in my side, in my ribs it hurts. I’m a leaning a little bit to the left side and I have a hard time coming back over to the right because that’s all just tight, and I seem a little bit more slumped over and not as upright. I can’t go back, you know, like a bridge, like we used to back in the day, like make a bridge with your body, arch your back, yeah. "I’m hunched over…getting into the house [and I need to] go lie down…”
Bladder dysfunction	9/20 (45%) reported bladder dysfunction, which was described as being unable to hold their bladder and difficulty urinating, as a physical impact of spasticity	“you can feel it…twitching or tremoring when I do go [to the bathroom].”
Pain	8/20 (40%) reported pain as a physical impact of spasticity	“It, well, it hurts, you know, it’s like when you get a cramp, it hurts and then it hurts usually if I have one in my calves, sometimes they feel bad. My calves hurt several days after because it’s been pushing, it spasms, yeah, I have it like three or four days after, like I’ve been working out but I haven’t.” “I’m in pain every single day. I have a pain in my hip, but I experience pain in other areas every single day…The spasticity will make the back pain worse from jerking.”
Sleep impairment	8/20 (40%) reported sleep impairment as a physical impact of spasticity 3/8 (38%) reported having difficulty falling asleep 3/8 (38%) reported being awakened after falling asleep	“I wake up from those full body jerks…and I toss and turn all night."
Functional limitations/Impacts	Quantitative assessment	Qualitative representative quotes
Daily activity/ functioning impairment	17/20 (85%) reported daily activity and functional impairments 8/17 (47%) reported difficulty carrying out housework, such as cooking and cleaning 4/17 (24%) found self-grooming difficult	“I’d be getting ready and if I had to shave my pits, um, I could lift my left arm and I could shave…but then if I had to lift my right arm I had to use my left arm to lift the right arm and then pin it on the wall in order to keep the arm up because it just wouldn’t function.” “if I have spasticity between the shoulder blades, my arms are just useless…I’m not going to be able to unload my dishwasher or do anything.”
Walking impairment	16/20 (80%) reported walking impairment as a functional impact of spasticity	“You know, everything is just tight and so I can’t, I can’t undo my legs so that they will move. Um, I remember other times like walking and then you just stop because I can’t—my hip and my upper thigh, thigh are too—so tight that I can’t move at like a regular walk and I have to swing it around.” “[it] feels like [my legs] get tightened…and it hurts to walk.”
Balance impairment/ postural instability	16/20 (80%) reported balance impairment/postural instability as a functional impact of spasticity	Of the participants with balance impairment, most believed it was due to spasticity only. Participants who struggled to walk because of spasticity reported this was due to muscle spasms and cramping in their lower extremities. “when your feet want to cramp up, and it can be like in the awkwardest of places, like it can be like the side of my ankle or something and it kind of turns my foot in a little bit, you know, it’s hard to straighten out that foot and take a step or put your foot down flat because it just wants to bring it in.”
Reduced dexterity	15/20 (75%) reported reduced dexterity as a functional impact of spasticity	“I can’t reach and grasp things like I used to. They will slip out of my hand or my hand will get locked around it where I have to almost pry my fingers off of it.”
Difficulty with transfers	14/20 (70%) reported difficulty with transfers as a functional impact of spasticity	e.g., getting in and out of the bed, the car, the tub, standing up from a seated position, and getting on and off the toilet “Oh, sometimes it’s just a matter of, you know, I can’t get in and out of my bed myself so he’ll [help] me and sometimes just do it really. There are times that I’ve literally just gotten stuck because I can’t get off the toilet so he’ll help me with that.”
Reduced swallowing	12/20 (60%) reported reduced swallowing as a functional impact of spasticity	“I have noticed it a couple of times. I have gotten choked up. And, um, like my drink actually—I had to spit it back out. And then, um, like as like swallowing certain pills, like I can’t get those down.” “it feels like muscle cramps in my throat… Sometimes it happens when I’m eating. Sometimes it happens when I’m swallowing.”
Sexual dysfunction	5/20 (25%) reported sexual dysfunction which was related to pain from spasticity (3/5, 60%) and/or an inability to move their lower limbs (3/5, 60%)	.:"…suddenly something that should have been so enjoyable was so painful and I couldn’t move and I said, no, I need to stop now… And there was no being able to finish, no anything. It embarrassed me and made me feel awkward."
Social impacts	Quantitative assessment	Qualitative representative quotes
Reduced time with family/friends	14/20 (70%) reported that their spasticity has social impacts 6/14 reported that their spasticity (like pain, slowness of movement, or spasms) kept them from participating in social activities with family and friends)	“Um, it limits my ability to participate in social activities. And it also limits my ability in terms of scheduling because there are only certain parts of the day where I’m fairly sure that it’s—I’m going to have less impact. So, for example, I don’t typically schedule things early in the morning and I don’t typically schedule things in the late afternoon or evening.”
Work limitations	4/20 (20%) were employed at the time of the interview. 3/4 (75%) of those who were employed had work limitations due to spasticity	One had to modify the type of desk they used in the office and be more conscious of their slow movement while seated. Delegation of tasks to their employees when experiencing spasticity. Falling at work.
Emotional/ Psychological impacts	Quantitative assessment	Qualitative representative quotes
Fear of falling	16/20 (80%) reported a fear of falling	“Yes, I do. That is a big fear of mine ‘cause it, it has happened. Um, yeah. I mean it is—yeah. It’s just one of my series of falls can result in injuries and I don’t have time to be injured right now.” One participant explained the concern that standing up after a fall could be daunting because their legs could stiffen or “lock up.”
Frustration	14/20 (70%) reported frustration	“Just the spasms themselves. They’re so frustrating when I can’t stop them. If—I wish there was a medication that would—I could take during the day that wouldn’t put me to sleep”
Depression	13/20 (65%) reported depression	“I mean it all over kind of could be depressive period, you know, because it limits your life in so many ways, like grandchildren, playing with your grandkids.” “I went through a bad bout of depression… in December because my legs had gotten so bad that [I had] to lie around and everybody was out doing all the fun things.”
Anxiety	13/20 (65%) reported anxiety	“Yeah. I think that’s again when I can’t get up from the floor or when I can’t get into the car. Or here that’s a good question. If there’s other people around, right. And if I’m stuck on the floor and somebody wants to try to help me get up and I can’t figure it out and my leg won’t move, then that makes you feel anxious, right.” “when I [have gotten] muscle cramps at night that wouldn’t release, should I call 911?”
Sense of helplessness	10/20 (50%) reported a sense of helplessness	“Yeah, when they’re happening, like I said, I can’t use my right arm, so the thought of not being able to use your arm is a little discouraging and a little scary …very much during you do feel helpless and you’re like, oh my gosh, how long are these going to go on?”
Limited ability to relax	8/20 (40%) reported a limited ability to relax	“Yeah. Like still this right foot, I mean you can’t—it’s hard not to, um—like I’m focused on our interview, this interview. But a portion of my mind is still focused on what feels like that rock in the—in my foot…you can’t fully relax when you’re hurting.” “[it’s] difficult when it comes to relaxing because…my lower back… and my hip gives me trouble.”
Embarrassment	3/20 (15%) reported embarrassment	“it’s hard…when you have friends or family…that want to do things and I don’t think my legs will let me do that.”
Long-term consequences	Quantitative assessment	Qualitative representative quotes
Loss of driving ability	15/20 (75%) reported loss of driving ability as a long-term consequence of MSS	“Um, it’s not, not great and it’s not—in those moments, I try not to like drive at night…I get very, very achy and so I try to kind of keep it pretty simple.” “Yeah, yeah. Yeah, it was, I loved driving but you know, when you get to the point you’re afraid, you know, what if I kill somebody because I make a bad judgment call.” “I can still drive, but I will not drive when I don’t feel good. I won’t put other people in danger.”
Falls/injuries	14/20 (70%) reported falls/injuries as a long-term consequence of MSS	Have you…fallen as a result of your spasticity? “Yeah. I was carrying a bucket of potatoes that I was growing in a bucket and I fell in the grass and broke my—like the part of my left knee carrying.” “I don’t know if it was spasticity or imbalance. I don’t know. I, I ended up falling down my stairs and I don’t even know exactly what happened, but yeah, I fell down and broke my tailbone.”
Increased burden of care for activities of daily living	12/20 (60%) reported increased burden of care as a long-term consequence of MSS	“Carrying certain things, sometimes getting up out of the chair or something, balancing myself sometimes, yeah, stuff like that.” “Um, so stuff that would require me to move around a whole bunch or move around like say mowing the lawn or something like that, like there’s no way I can do that. And so I do have to have my husband do that or different things like that. I couldn’t go out and do that.” “Um, sometimes I feel like I put too much on my husband. That crosses my mind. Um, I do worry about it.”
Loss of employment	8/20 (40%) reported loss of employment as a long-term consequence of MSS	“I have not worked in over 10 years…the work limitations were not being able to walk up and down stairs…lift more than 10 pounds… stand for more than five minutes… sit for more than 10 min without shifting position… I realize now that it was MS.”
Loss of mobility	8/20 (40%) reported loss of mobility as a long-term consequence of MSS	“Well, right now I can’t walk so yes, and it’s not because of weakness or anything, it’s because of spasticity that I cannot walk very well, because my knees will not straighten out.” “Well I—yeah. I guess that’s the whole walking. I just do thing—everything is slower. Um, I, I don’t—I only use—in the house I have a three-wheeled walker, just to try to help me keep my head off the ground.”
Pressure injuries	6/20 (30%) reported pressure injuries as a long-term consequence of MSS	“I had a stage 1 decub years ago on my foot, so I’m very cautious. Of course no matter how cautious you are, it can happen.”
Loss of leisure activities/physical activities	5/20 (25%) reported that they had lost their ability to be physical active due to spasticity	“I like to go on long walks…and I’ve never been a very sportsy person, but like just doing different things like that and now I’m just thinking, oh gosh even a walk around my neighborhood is going to be very—it’s painful. And so I do limit myself on different things like that because of it.”
Contractures	4/20 (20%) reported contractures as a long-term consequence of MSS	“Yes. My right foot will turn inward. And the toes will also curl up.”
Loss of independent living	3/20 (15%) reported loss of independent living as a long-term consequence of MSS	“Um, I have always been a really independent person. I have reached a point because of the fall risk, um, and my fatigue level, um, and my mobility issues, I can’t do things like housework. So I can’t vacuum. I can’t, um, put groceries away. I can’t do laundry. Things like that, I just, I can’t do. I cannot independently live on my own and that, that is frustrating for me.”

Notes: Abbreviations: ER = emergency room; MSS = multiple sclerosis spasticity; PT = physical therapy; PwMS = people with multiple sclerosis.

^aTwo spasticity triggers (infection and menstruation) were not specifically probed in the participant interview and were not mentioned by participants; however, they were endorsed by targeted literature search, clinician interviews and the spasticity expert input and were therefore kept in the final model.

^bIn the model, physical dysfunction includes gastrointestinal problems, such as constipation, and skin lesions.

^cMuscle tension was included in the final model based upon input received from the clinician interviews and the spasticity experts.

Figure 2. Integrated conceptual model of multiple sclerosis spasticity.

*Variable not identified in literature review.

^†Variable not identified in clinician interviews.

^‡Variable not identified in patient interviews.

Abbreviations: ADL = activities of daily living; GI = gastrointestinal; MS = multiple sclerosis.

Triggers, MS Spasticity - Subjective Experience, Functional Limitations/Impacts, Social Impacts, Emotional/Psychological Impacts, and Long-term Consequences are listed in order of decreasing percentage of patients reporting the variable, as in Table 3.

Learmonth YC, Motl RW, Sandroff BM, et al. Validation of patient determined disease steps (PDDS) scale scores in persons with multiple sclerosis. BMC Neurol. 2013;13:37. doi: 10.1186/1471-2377-13-37.

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