[ resident’s case problem ]

SHANE MCCLINTON, PT, DPT, OCS, FAAOMPT, CSCS1 • BRYAN HEIDERSCHEIT, PT, PhD2

Diagnosis of Primary Task-Specific Lower Extremity Dystonia in a Runner

ystonia is a dynamic neurological syndrome associated secondary dystonia are catego- with involuntary and sustained muscle contraction rized based on the extent of the 5,13 SUPPLEMENTAL body regions affected, to include that causes abnormal postures and movement. One VIDEO ONLINE focal (involvement of only 1 body of the key distinguishing characteristics of dystonia is region), segmental (involvement D 5 the dynamic nature of its presentation. Examination findings may of continuous body regions), or general appear inconsistent because specific (focal) or general movement/ (involvement of multiple body regions).5 postural abnormalities can present differently depending on posture, Task-specific dystonia is a form of focal dystonia that results in abnormal move- position, or the intended task. studies (including structural abnormali- ments and postures exclusively within the The 2 types of dystonia, based on clini- ties in the central nervous system) that context of a specific task. Most reported cal and genetic epidemiological studies, can identify a cause. Conversely, second- cases of task-specific focal dystonia in- are primary and secondary. Most docu- ary dystonia is believed to result from volve the upper extremity, including syn- mented cases of dystonia are of primary physical or neurological trauma, medici- dromes such as writer’s cramp, musician’s etiology,27 where there is no evidence in nal or environmental toxicity, or psycho- dystonia, and golfer’s yips.39 In each of the history, examination, or laboratory genic factors.5 Furthermore, primary and these syndromes, the altered movement pattern is specific to a task that has been performed repetitively and often plays a TTSTUDY DESIGN: Resident’s case problem. final confirmed diagnosis of primary task-specific dystonia with first onset during running (ie, run- substantial role in the affected individu- BACKGROUND: A 56-year-old man was TT ner’s dystonia). al’s livelihood. The distinguishing feature referred to physical therapy for analysis of of runner’s dystonia from other task-spe- unusual gait, first noticed 3 years previously when TTDISCUSSION: Idiopathic, task-specific dystonia running. Prior to this evaluation, the patient had of the lower extremity is documented as a very cific dystonias is that the individual first seen multiple orthopaedic, sports medicine, and rare occurrence, yet increasing trends in running develops symptoms during running.41 neurological specialists while undergoing repeated participation may result in a higher incidence of Although the overall prevalence of and extensive testing. Ten months of testing and this condition. Improved awareness of runner’s runner’s dystonia is unknown, isolated dystonia in the present case might have enhanced treatment, including conservative and surgical population estimates of primary focal management, did not provide an explanation for the clinical decision-making process and resulted dystonia in the United States are 295 per the gait abnormality or result in improvement of in more timely and effective treatment solutions. 27 the patient’s condition. Clinical examination findings, including computer- million persons. Available data from ized gait analysis and electromyography, in con- the same population provide a relative DIAGNOSIS: The patient’s physical examina- TT junction with imaging, blood, and genetic testing, appreciation of the prevalence of focal tion was relatively unremarkable, considering the can aid in the diagnosis of runner’s dystonia. severity of the gait abnormality. Distinct abnormali- dystonia compared to more commonly ties were apparent with computerized gait analysis TTLEVEL OF EVIDENCE: Differential diagnosis, known movement-related disorders such level 4. J Orthop Sports Phys Ther 2012;42(8):688- and dynamic electromyography, and, when com- as Parkinson’s disease (1569 per million), 697, Epub 20 April 2012. doi:10.2519/ bined with the physical examination findings, led to amyotrophic lateral sclerosis (64 per mil- a suspicion of the task-specific disorder of runner’s jospt.2012.3892 lion), and convulsive disorders (6500 per dystonia. The patient was referred to a neurologist KEY WORDS: differential diagnosis, electromy- TT 27 specializing in movement-related disorders, with a ography, gait analysis, runner’s dystonia million). Outside of the United States, the prevalence of individuals with pri-

1Physical Therapist, Des Moines University Clinic, Des Moines, IA. 2Associate Professor, Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, WI. Following evaluation and prior to presentation of this case, approval was obtained from the Des Moines University Institutional Review Board, and the individual in this case provided consent for presentation of his medical information and videos. Address correspondence to Dr Shane McClinton, Des Moines University Clinic, 3200 Grand Avenue, Des Moines, IA 50312. E-mail: [email protected] Copyright ©2012 Journal of Orthopaedic & Sports Physical Therapy t

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42-08 McClinton.indd 688 7/18/2012 3:19:19 PM mary focal dystonia who presented to initial onset, the symptoms progressed bowel, bladder, diet, or weight changes. outpatient clinics ranges between 61 and over the following 2 years until he could His Lower Extremity Functional Scale 137 per million persons.9,11,16,26,31 Whereas no longer run, followed by similar pro- (LEFS) score indicated a clinically sig- primary focal dystonia is relatively rare, gressive decline in walking. He first pre- nificant decline in function since his visit task-specific lower extremity dystonia is sented to his primary care physician, with the first physical therapist (PT1) even less prevalent. Within a specialized describing the left-sided awkwardness 10 months prior (from 51/80 to 40/80; movement-disorder clinic, only 4 (0.7%) during walking and running without pain 80 is no disability). At present, he did of 579 individuals with primary focal and without further problems in other not report any disability (0/100; 0% is dystonia had lower extremity dystonia,21 daily or recreational tasks. The dysfunc- no disability) on the Modified Oswestry and none of these individuals presented tion during walking involved minimal Low Back Pain Disability Questionnaire. with the specific movement pattern de- deviation for the first few steps, with The patient did not complete a question- scribed in this case. With growing num- progression to excessive left knee flexion naire specific to psychosocial status, but bers of runners, including participants at terminal swing that persisted through interactions with the patient and fam- in high-mileage events (marathons and the following left midstance phase, re- ily indicated that there was a significant ultra-marathons), a higher prevalence sulting in reduced stride length (ONLINE amount of stress related to his work and of lower extremity dystonia, including VIDEO). His gait pattern would continue a busy family schedule outside of work. runner’s dystonia, is likely. Epidemio- to degrade with walking continuously The family reported that the patient often logical investigation to accurately define for slightly more than 1 minute, when he had difficulty getting away from work or the prevalence of lower extremity dys- would need to stop for fear of falling. Af- relaxing during family vacations. tonia is hindered by the perception that ter only a few minutes of rest, he could Physical examination included muscle dystonia is rare and the heterogeneous walk again with minimal deviation until strength, range of motion, movement co- presentation of the condition.9 A lack of his gait pattern progressively deterio- ordination, functional movement, and current epidemiological data specific to rated. The patient relayed that the only neurological testing (TABLE 2). Functional runner’s dystonia contributes to a lack of factor that improved his gait was walking movement testing following observation awareness and consideration in clinical on the beach, as observed while he was on of gait included bilateral deep squat, diagnostic decisions. This may result in vacation, and applying pressure with his single-leg squat, single-leg step-up/ missed diagnosis and inappropriate or hand to his hip. step-down, and isolated demonstration ineffective treatment recommendations. Prior to the initial evaluation by PT2, of each phase of the gait cycle from mid- In this case report, we will describe the patient underwent multiple and re- swing through midstance (fractionation). the circuitous diagnostic path and ini- peated orthopaedic, cardiovascular, and The patient demonstrated sufficient tial treatment of an individual who was neurological diagnostic testing, involv- strength, coordination, and isolated func- ultimately determined to have runner’s ing evaluation by 3 different physician tional movement to ambulate normally. dystonia. The purpose is to increase orthopaedic specialists, a sports medi- All basic neurological testing was nega- awareness of runner’s dystonia such that cine physician, a neurologist, and another tive, including cranial nerve screen, deep it may be more readily recognized and physical therapist (TABLE 1). He had failed tendon reflexes, sensation, Babinski, managed efficiently. to respond to cortisone injection, manual Hoffmann, and ankle clonus. It was ap- therapy, exercise, and orthopaedic sur- parent that the dysfunction was specific DIAGNOSIS gery directed primarily at the hip on the to the task of walking and not explained involved side. by the historical and initial physical ex- History amination findings. 56-year-old man was referred Examination Three-dimensional motion analysis to physical therapy (PT2) by his Review of the patient’s medical history was conducted while the patient walked A family practice physician for 3-D and review of systems was unremark- at his preferred speed of 1.07 m/s (nor- motion analysis with a diagnosis of able, except for perceived muscle weak- mal, 1.32-1.33 m/s)35 repeatedly across a gait dysfunction. The patient’s gait dys- ness, difficulty walking, and recent left 6-m laboratory walkway. Motion analy- function was first noted almost 3 years hip offset osteotomy performed to cor- sis included collection of joint kinematics prior when the left lower extremity be- rect the gait dysfunction. Subjectively, he and kinetics, as well as surface electromy- came clumsy and awkward during his reported 0/10 pain during walking and at ography (EMG) of bilateral medial ham- usual running routine. The patient was rest. The patient did not indicate any his- strings, vastus lateralis, gastrocnemius, a consistent runner and had logged ap- tory of neurological or medical red flags, and tibialis anterior (TABLE 2, FIGURES 1 proximately 121,000 km (approximately including headaches, visual disturbanc- and 2). Two-dimensional video analysis 75,000 mi) throughout his lifetime. After es, loss of consciousness or balance, or was also conducted from the sagittal and

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Timeline of Patient Testing and Management Prior TABLE 1 to Evaluation by the Second Physical Therapist (PT2)

Time, mo Event Testing/Intervention Significant Findings/Results Recommendations 0 Left leg first felt clumsy/awkward with ...... running 22 Forced to stop running ...... 22.5 PCP consult Physical exam Observational gait abnormalities Referral to Neuro1 22.75 Neuro1 consult Neurological exam; radiographs: B hips No abnormalities to explain gait distur- None and knees bance; no bony abnormality 23.25 Ortho1 consult Physical exam Observational gait abnormalities Referral to Ortho2 23.5 SportMed1 consult Physical exam Observational gait abnormalities; sus- Referral to PT1 pected dynamic leg weakness 23.75 PT1 consult Physical exam; 2-D video gait analysis Positive Ober test L; L hip abductor MMT MRI of the hip; PT 2 times per wk for 4+/5; L hip IR ROM, 13° (R, 20°); 30° 4 wk knee flexion at L heel strike 24 SportMed1 follow-up Inguinal hernia examination Negative MRA of the hip 24.03 Rad1 consult MRA L hip L hip labral tear ... 24.25 Vascular consult Vascular study Normal ... 25 Ortho2 consult Radiographs: B hips and pelvis B cam–type femoral acetabular Referral to Ortho3; continue PT; radio- impingement, lateral femoral head graphs and MRI of lumbar spine prominences, decreased femoral head/neck offset; B early DJD, R acetabular rim fracture 25 to 26 PT1 appointments Manual therapy, therapeutic exercise, No change in gait abnormality ... and gait training 26.3 Rad2 consult Radiographs and MRI (with and without Mild disc space narrowing at L5-S1; ... contrast) of lumbar spine normal MRI 26.5 Ortho3 consult Physical exam; review imaging tests No new findings L hip cortisone injection; NCS/EMG study; surgery pending outcome of above 26.75 Ana1 consult L hip cortisone injection No improvement of gait ... 28.25 PMR1 consult Static NCS and EMG Normal studies ... 29.5 Surgery by Ortho3 L hip offset osteotomy and debridement ...... 32 Follow-up by Ortho3 Repeat radiographs Normal healing from osteotomy proce- 3-D motion analysis dure; no improvement of gait 32.25 PCP follow-up ...... 3-D motion analysis with PT2 33 PT2 consult 3-D kinematic/kinetic motion analysis See TABLE 2 Referral to Neuro2 with dynamic EMG; physical exami- nation 34 Neuro2 consult Blood work; brain scan Idiopathic task-specific dystonia Botox injections; Parkinson’s medication Abbreviations: Ana, anesthesiologist; B, bilateral; DJD, degenerative joint disease; EMG, electromyography; IR, internal rotation; L, left; MMT, manual muscle test; MRA, magnetic resonance arthrography; MRI, magnetic resonance imaging; NCS, nerve conduction velocity study; Neuro, neurological physician specialist; Ortho, orthopaedic surgeon or physician specialist; PCP, primary care physician; PMR, physical medicine and rehabilitation physician specialist; PT, physical therapist; R, right; Rad, radiologist; ROM, range of motion; SportMed, sports medicine physician specialist.

frontal plane perspectives (ONLINE VIDEO). nerve conduction velocity study), prior etabular labral derangement) or periph- treatment (lack of response to ortho- eral neurodynamic (unilateral foraminal Diagnosis paedic-based physical therapy and to stenosis, lumbar plexopathy, lumbar ra- Based on the results of prior diagnostic hip offset osteotomy), and absence of diculopathy) condition was considered testing (essentially normal radiographs, pain, the likelihood of a musculoskeletal to be very low. Given the findings from magnetic resonance imaging, and EMG/ (femoroacetabular impingement, ac- the physical examination, computerized

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42-08 McClinton.indd 690 7/18/2012 3:19:20 PM ficity of the movement dysfunction, (2) Examination Findings of the Second TABLE 2 long history of running with first onset Physical Therapist (PT2) of symptoms during running, (3) incon- sistent orthopaedic examination (muscle Tests Significant Findings performance, coordination, joint mobil- 3-D kinematic/kinetic motion Increased left knee flexion and ankle dorsiflexion at terminal swing through ity, and fractionation testing not consis- analysis midstance phase, followed by increased right hip flexion, knee flexion, and tent with the observed gait pattern), (4) ankle dorsiflexion FIGURE( 1) with elevated right knee extensor moment from negative basic neurological examination, midstance through preswing phase. Increased left hip flexion throughout swing and (5) absence of pain. In addition, dy- phase and initial contact (FIGURE 1). Increased left ankle plantar flexion at namic EMG demonstrated sustained and terminal stance phase in compensation for the vertical depression of the pelvis excessive muscular activation patterns due to findings described above FIGURE( 1). Decreased left step length and common to task-specific dystonia.5,39 The stance phase duration similarities evident in these case studies Dynamic surface EMG Early activation of hamstrings and absence of quadriceps activation during terminal and the patient’s presentation resulted in swing phase on the left (FIGURE 2). Increased activation of left medial ham- a high suspicion of runner’s dystonia and strings, left gastrocnemius, and right vastus lateralis during stance phase, with prompted PT2 to refer the patient to a increased right medial hamstrings during the last 20% of stance (FIGURE 2) physician neurologist who specialized in Lower Extremity Functional 40/80 (80 is normal function) movement-related disorders (Neuro2). Scale One month later, the patient was Modified Oswestry Low Back 0% (0% is no disability) evaluated by Neuro2. Upon the initial Pain Disability Questionnaire examination, 3 diagnoses were con- Lower extremity strength sidered: (1) an autoimmune glutamic (right, left)* acid decarboxylase antibody–associated Hip abnormality (stiff leg syndrome), (2) Flexion 5/5, 4/5 dystonia, and (3) Parkinsonism. The fol- Extension 5/5, 5/5 lowing tests were performed to assist in Abduction 5/5, 4/5 the diagnosis: magnetic resonance imag- Knee ing of the brain, serum ceruloplasmin, Flexion 5/5, 4+/5 glutamic acid decarboxylase antibody Extension 5/5, 5/5 testing, and genetic testing (particularly Ankle to identify presence of the dystonia 1, or Dorsiflexion 5/5, 5/5 DYT1, gene). In addition, a short trial of Plantar flexion 5/5, 5/5 carbidopa-levodopa, typically used for Cranial nerve testing Negative screening for cranial nerves I to XII15 Parkinson’s disease, was prescribed to Fractionation Patient able to demonstrate isolated and segmental control of the thigh, lower determine if the patient would be respon- leg, and foot, including reproduction of normal preswing and stance phase sive to this medication. Even though the movements on the left when performed outside of gait patient demonstrated no other signs or Flexibility/range of motion Sufficient lower extremity flexibility and range of motion to achieve range of motion symptoms of Parkinson’s disease, certain required during gait. No side-to-side differences appreciated forms of dystonia have been responsive to LMN screen Ankle and knee deep tendon reflexes 2+ bilaterally. Normal light-touch sensation Parkinsonian medication (dopa-respon- bilateral lower extremity dermatomes sive dystonia).28 Based on the negative UMN screen Negative Babinski sign bilaterally. Negative Hoffmann sign bilaterally. No ankle clonus findings of the tests listed above and an bilaterally. Normal heel-to-shin coordination bilaterally. Negative Romberg test unsuccessful trial of levodopa, the patient Abbreviations: EMG, electromyography; LMN, lower motor neuron; UMN, upper motor neuron. was diagnosed with primary task-specific *Assessed via the manual muscle test. Patient was able to perform single-leg squat bilaterally without deviation and with symmetry between the 2 lower extremities. dystonia (ie, runner’s dystonia).

Treatment gait analysis, and EMG, a neurological PT3 recommended that the patient’s pre- Once the diagnosis of runner’s dystonia condition of the central nervous system sentation be compared to published case was made, the patient was prescribed was suspected, and PT2 consulted an- studies of individuals with runner’s dys- clonazepam, of which the patient sub- other physical therapist with expertise tonia.19,41 The patient had similar features jectively reported improvement in walk- in gait analysis and motor control (PT3). to these cases, including (1) task speci- ing duration with less perceived need of

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100, and 150 U) to the left hamstring, 50 with which he reported no additional improvement. Eleven months after the 40 last Botox injection, the patient returned to PT2 for further intervention for the 30 first time following confirmation of the

ension, deg primary task-specific dystonia diagnosis. 20 The physical examination test and mea-

xion/Ext sures were repeated and remained simi- 10 lar to those of the first evaluation of the e Hip Fl patient (TABLE 2). The only change was the 0 LEFS score, which increased from 40/80 to 55/80. The patient attributed this im- –10 80 provement to the clonazepam. The patient was questioned about 70 potential movement or sensory tricks

60 that could reduce the dystonic move- ment pattern. Identified tricks included 50 minimal patient-perceived improvement

xion, deg 40 with barefoot sand walking, a unilateral skipping pattern (where the hop only 30

e Knee Fl occurs on the uninvolved side), and

20 manual pressure applied to the involved hip. Additional gait variations, includ- 10 ing walking backward, sidestepping,

0 body-weight-supported treadmill walk- 30 ing, and shortened step length, were at- tempted but did not alter the dystonic 25 gait pattern. At this visit, sensorimotor 20 testing was also performed, based on the

xion, deg category of tests used in a recent clini- 15 cal trial involving individuals with focal 10 hand dystonia6 and as recommended in

xion/Dorsifle 5 the assessment of sensorimotor func- tion.30 These tests were adapted for the e ar Fl 0 foot to allow for application to this case

–5 (TABLE 3).

Ankle Plant Due to a lack of evidence on manage- –10 ment of lower extremity dystonia, the –15 treatment plan for this patient was based 1% 100% Percent of Gait Cycle on the management of task-specific dys- tonia of the upper extremity6 and man- Right, uninvolved Left, involved Normal agement of similar disorders that involve cortical reorganization, such as chronic FIGURE 1. Kinematic impairments are present in the left hip, knee, and ankle primarily during terminal swing through midstance, and compensatory right-side impairments during midstance through preswing (TABLE 2). regional pain syndrome or phantom Positive values represent flexion or dorsiflexion during walking. The gait cycle is represented by initial foot contact limb pain.24,25 The components of the (1%) and the point just before initial foot contact of the subsequent stride (100%). The vertical orange and blue program included physical fitness, brain lines depict toe-off for the left and right sides, respectively. The shaded gray region represents normal kinematic fitness, and learning-based sensorimo- patterns during walking.35 tor training, including graded motor imagery.6 walking aids. Six weeks following the of 3 botulinum toxin (Botox) injections The patient required little guidance on diagnosis, the patient underwent a series 3 months apart in progressive doses (50, physical fitness because he already exer-

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42-08 McClinton.indd 692 7/18/2012 3:19:22 PM cised 3 to 5 times per week, including aer- Right, Uninvolved Left, Involved obic and resistance training. Therefore, 100 100 early treatment focused on the initial s stages of sensorimotor training, including 80 80 60 60 motor imagery. Pictures were taken of the 40 40 patient, with the involved lower extrem- 20 20 Medial Hamstring ity in the gait phases in which the most 0 0 significant deviation occurred (terminal 1% 100% 1% 100% swing and loading response). Based on 24,25 the procedures used by Moseley, the 100 100 patient was instructed to imagine moving 80 80 alis

his limb into these positions during gait r te 60 60 10 times every waking hour. It was also 40 40 20 20 recommended that he consider solutions stus La Va to minimize the dysfunctional move- 0 0 1% 100% 1% 100% ment pattern to include a return to the use of crutches. Due to limitations of the patient’s schedule and the recommended 100 100 80 80 time frame for progression of motor im- 60 60 agery,24,25 the next follow-up occurred 2 ocnemius 40 40 weeks later. 20 20 Gastr At the follow-up 2 weeks later, the 0 0 patient indicated that his work sched- 1% 100% 1% 100% ule made it very difficult to adhere to the motor imagery and that it would not 100 100 be practical to go back to crutches. The 80 80 erior patient indicated that he would be more 60 60 adherent to a program involving more 40 40

ibialis Ant 20 20 movement-related tasks. Therefore, the T patient skipped the initial recommended 0 0 1% 100% 1% 100% phases of imagery-based training6,24,25 and was progressed to additional sen- FIGURE 2. Surface electromyographic analysis revealed the following for the involved (left) side: (1) early and sorimotor training activities, including increased activation of the medial hamstrings during terminal swing and stance phases, (2) delayed and reduced graded movements with feedback based activation of the vastus lateralis during terminal swing and stance phases, (3) cocontraction of the medial on knowledge of performance during hamstrings and vastus lateralis during initial stance phase, (4) increased activation of the tibialis anterior during non–gait-specific tasks. Based on im- swing phase, and (5) early activation of the gastrocnemius during stance phase. The gait cycle is represented by initial foot contact (1%) and the point just before initial foot contact of the subsequent stride (100%). The vertical pairments identified in the examina- orange and blue lines depict toe-off for the left and right sides, respectively. Horizontal bars represent normal tion, the patient was instructed in the muscle-timing patterns during walking.32 The vertical (y) axis represents full wave-rectified EMG signal normalized performance of great-toe tapping and to the maximum activation of that muscle during the gait cycle. Abbreviation: EMG, electromyography. rapid heel-to-toe tapping, with the goal of gradual progression of the performance DISCUSSION ticipation and high-mileage events may of these tasks in a manner similar to that result in the right circumstances for in- of the uninvolved extremity. He was also ue to the reported low preva- creased observation of runner’s dystonia. encouraged to obtain the brain-training lence of runner’s dystonia and any Further investigation is needed to accu- program used in the Byl et al6 investiga- Dother form of primary task-specific rately define the current prevalence of tion or similar commercially available lower extremity dystonia, misdiagnosis as runner’s dystonia. software to fulfill the brain-fitness facet an orthopaedic condition is common.12,41 of the rehabilitative program. The pa- Task-specific dystonias have been as- Clinical Examination Considerations tient was recommended to follow up in sociated with repetitive tasks, including The diagnosis of primary task-specific 2 weeks; however, work and family ob- sport- and instrument-specific activities dystonia is currently based on an idio- ligations prevented his adherence to the that are prone to overuse and overprac- pathic onset of movement dysfunction program and further follow-up. tice.1 Increasing trends in running par- specific to a task in the absence of other

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ner’s dystonia include demonstration of Sensorimotor Tests and Outcomes of Patient sensory or motor tricks. Sensory tricks TABLE 3 Evaluation Postdiagnosis of Runner’s involve the use of touch to ameliorate the Dystonia Affecting the Left Side dysfunctional movement (eg, pressing on the hip while walking) and motor tricks Test Outcome involve voluntary movements (eg, walk- 5 Test Description Right Left ing backward). Although this case did Digital reaction- Number of repetitions fully depressing a spring-loaded 191 159 not clearly demonstrate a dramatic sen- time test6 lever with the hallux in 60 s sory or motor trick, the patient did men- Stereognosis17 Ability of patient to identify 13 common items with 0% incorrect, 7.7% incorrect, tion improvement in gait while walking the foot presented in random order. Percentage of 38.5% 46.2% at the beach and placing pressure on the items identified incorrectly or partially incorrectly is partially partially hip. Sensory and motor tricks are unique reported (ie, percent error) incorrect incorrect features of task-specific dystonia that can Kinesthesia30 Accuracy of response to movement of hallux in exten- 0% 0% aid in the diagnosis of the condition but sion or flexion. Percentage of inaccurate responses is also can be useful as part of treatment. reported (ie, percent error) Interoceptive sensory tricks have been Position sense30 Accuracy of response to position of hallux in exten- 0% 0% demonstrated to temporarily ameliorate sion, flexion, or neutral. Percentage of inaccurate dystonic movements of individuals with responses is reported (ie, percent error) task-specific lower extremity dystonia, 20,36 Vibration30 Ability to detect vibratory versus nonvibratory sensation 0% 0% including 1 case of runner’s dystonia. with tuning fork applied to the tibial tubercle and If dystonia is suspected, the therapist lateral malleolus with ears plugged. Percentage of should inquire about, and test for, sen- inaccurate responses is reported (ie, percent error) sory and motor tricks. Semmes-Weinstein Ability of patient to detect buckling of a 10-g monofila- 0% 0% Sensorimotor examination of the 10-g monofilament ment applied for 1 to 2 s to the plantar surfaces of patient with task-specific dystonia may test the hallux, third metatarsal, and fifth metatarsal.14 reveal altered sensorimotor function, Additional testing of the plantar surface of the as demonstrated through testing of second and fourth metatarsal was performed. graphesthesia, stereognosis, kinesthe- Percentage of inaccurate responses is reported (ie, sia, touch localization, motor accuracy/ percent error) regulation, and spatial discrimination 2-point discrimination Smallest distance (in mm) to detect 2 stimuli applied to 6 mm 7 mm threshold.2,10,22,23,29,33 In this case, the pa- the tip of the hallux using a sliding 2-point discrimi- tient demonstrated impairments in fine nation tool with 1-mm increments. Normal, 6.6 mm30 motor control and stereognosis of the affected lower extremity. Adapted mea- sures from sensorimotor testing in task- neurological or orthopaedic disorders literature reports on runner’s dystonia, specific dystonia of the upper extremity that would explain the presentation.5,10,40 the following features of the physical used to test the lower extremity have not It has been suggested that runner’s dys- therapy examination were consistent been defined in the literature. Further re- tonia is a form of task-specific dystonia, with runner’s dystonia: (1) task speci- search is needed to assess the adaptability with onset during running making this ficity of the movement dysfunction, (2) of sensorimotor tests used in the upper form distinct from other task-specific long history of running with first onset extremity to the lower extremity, in addi- dystonias.41 Currently, the diagnosis of of symptoms during running, (3) incon- tion to the development of tests that can task-specific dystonia is based on exclu- sistent orthopaedic examination (muscle accurately detect lower extremity senso- sion of competing diagnoses, yet tech- performance, coordination, joint mobil- rimotor impairments. nological advancements show promise ity, and fractionation testing not consis- Another consideration of sensorimo- in making a more direct diagnosis of tent with the observed gait pattern), (4) tor testing in task-specific dystonia is that dystonia.38 In the case presented here, negative basic neurological examination, sensorimotor impairments may differ be- inconsistent orthopaedic and basic neu- (5) absence of pain, and (6) sustained and tween the involved and uninvolved limb22 rological examination findings relative excessive muscular activation consistent but also may be demonstrated in both ex- to the gait dysfunction led to suspicion with the altered gait pattern. tremities.10,23 In this case, discrepancies of dystonia as the cause of the patient’s Additional features that can aid the in sensorimotor impairments between gait impairment. When compared to physical therapist in diagnosing run- the involved and uninvolved extremities

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42-08 McClinton.indd 694 7/18/2012 3:19:25 PM were the focus of the sensorimotor learn- Neurophysiological Testing sustained or excessive muscular activa- ing intervention. Comparisons of senso- Further considerations beyond the physi- tion, task-specific motor control,10 and rimotor performance to the uninvolved cal therapy clinical examination to help sensorimotor examination findings) and extremity may not always be valid, con- in making the diagnosis of primary task- paired associative stimulation, transcra- sidering that bilateral impairments have specific dystonia include brain magnetic nial sonography, or magnetoencephalo- been demonstrated in unilateral upper resonance imaging to rule out structural gram results may better detect primary extremity task-specific dystonia.10,23 Ad- lesions or metabolic disorders, genetic task-specific dystonia, yet further work ditional research is needed specific to the testing to identify presence of the DYT1 is needed to assess the sensitivity and lower extremity to improve confidence in gene associated with early-onset gen- specificity of such testing.38 In addition results of sensorimotor testing used for eralized dystonia, and an ineffective to diagnostic utility, further investiga- diagnostic and treatment decisions in therapeutic trial of levodopa to rule out tion of paired associative stimulation, lower extremity task-specific dystonia. dopa-responsive dystonia.40 Currently, transcranial sonography, or magnetoen- Other factors that can be associated tests with known diagnostic standards cephalogram may be valuable to corre- with task-specific dystonia include psy- that can provide further definitive infor- late outcomes of interventions designed chological and traumatic triggers.1,5,18 By mation in altering the diagnostic prob- to modify cortical plasticity observed in definition, primary dystonia includes ability of dystonia are lacking. task-specific dystonia.10 dystonia without a known cause, where- Although primary dystonia is idio- as secondary dystonia includes physi- pathic, there is evidence of abnormal Treatment of Runner’s Dystonia cal or neurological trauma, medicinal neurological manifestations that may The challenges associated with the di- or environmental toxicity, or psycho- provide insight into the etiology of this agnosis of dystonia can have significant genic factors associated with the onset disorder and the potential for develop- implications on the dystonic patient’s of dystonia. In the case presented here, ment of diagnostic tests and treatments treatment plan and outcomes. The rec- a clear link to trauma or environmental for dystonia. Tests such as transcranial ommended treatment plan for dystonia or psychogenic factors cannot be made, magnetic stimulation, temporal dis- is significantly different from the plan but may have some association with the crimination threshold, and magnetoen- for common orthopaedic conditions for patient’s symptoms and should be con- cephalogram reveal abnormal cortical which it may be misdiagnosed. In this sidered in the examination of a patient representations in dystonia.10,38 Paired particular case, the patient’s function suspected of having dystonia. Although associative stimulation and muscle vibra- declined significantly, as indicated by psychosocial inventories were not per- tion techniques reveal abnormal neural the decrease in LEFS score from 51/80 formed, it was evident from discussions plasticity and reduced intracortical inhi- to 40/80 over the 10-month period that with the patient’s family that there was bition in dystonia cases.37,38 Using trans- dystonia was not considered as a diagno- stress related to his work, coupled with a cranial magnetic stimulation, disruption sis. During this time, the patient received busy family schedule. Physical trauma or of the sensory cortex organization and treatment including physical therapy psychogenic factors may trigger dystonia dystonic motor symptoms has been ob- and surgical intervention directed at or simply be a chance co-occurrence.18 served when primates are trained in a re- orthopaedic conditions. Once the diag- Psychogenic characteristics that have petitive motor task for 12 to 25 weeks.7,8 nosis of runner’s dystonia was made, the been associated with dystonia include The sensory cortex disruption appears treatment recommendations, based on perfectionism, social phobias, and other to result in convergence of adjacent ar- a more accurate diagnosis, resulted in specific phobias (acrophobia, claustro- eas of the cortical map that control the improvement of the patient’s condition, phobia, etc).1 Psychological or potential involved limb. Conversely, divergence of reflected by an increase in the LEFS score traumatic findings should be considered the cortical map through training has to 55/80. This level of improvement ex- in conjunction with the physical therapy been observed to occur with the reduc- ceeded the 9-point scale change indica- examination. tion of dystonic symptoms.34 Although tive of the minimal clinically important When clinical examination results neurophysiological tests have demon- difference of this measure.4 suggest a task-specific dystonia, referral strated abnormal neurological findings Cases of runner’s dystonia reported in to a physician specialist in movement- in dystonia, clinical guidelines have yet the literature have been managed with related disorders is needed to confirm to be established to apply these tests in medication used in Parkinson’s disease the diagnosis through additional test- its diagnosis. Given the complexity of the (levodopa, trihexyphenidyl), anticon- ing. Multidisciplinary efforts are im- clinical presentation, the use of a cluster vulsant medication (carbamazepine), portant in making the correct diagnosis of tests and symptoms comprising items neurotoxin injection (Botox), bracing, and providing appropriate treatment from the history or examination (eg, on- and mental imagery based on a sensory recommendations. set with repetitive tasks, absence of pain, trick.19,36,41 Each case demonstrated some

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improvement but continued to demon- writer’s cramp, musician’s dystonia). The absent or minimal pain, (6) sustained or strate impairment and significant limita- ability to achieve improvement or resolu- excessive muscular activation consistent tion of running, despite treatment. tion of task-specific lower extremity dys- with the altered gait pattern, (7) sensory Currently, the most common tonia with less time-intensive training or or motor tricks, and (8) sensorimotor treatment for any type of lower ex- without cessation of the dysfunctional impairments. Diagnosis and manage- tremity dystonia includes Botox and tri- pattern has not been demonstrated, yet ment should include a multidisciplinary hexyphenidyl.21 Only 2 cases were found current recommendations include aver- effort to include physical therapy and a describing nonmedicinal or noninvasive sion of the offending movement pattern physician specialist in movement-re- management of task-specific lower ex- and frequent sensorimotor-based train- lated disorders. Physical therapists can tremity dystonia.3,36 In 1 case, functional ing.6,24,25 In addition, the effect of bypass- provide sensorimotor training in addi- electrical stimulation was shown to im- ing initial imagery phases for the sake of tion to physical and brain-fitness train- prove but not fully resolve the patient’s compliance is not known, although inter- ing that can be facilitated by medicinal gait dysfunction.3 In another case of an pretation of current evidence using sen- and/or injection-based interventions to individual diagnosed with runner’s dysto- sorimotor training can only be applied reduce the dysfunctional movement pat- nia, treatment included the use of mental within the context of the recommended tern. Further research is needed to dem- imagery based on a sensory trick and re- progression, including imagery training. onstrate effectiveness of treatment for duced the dystonic symptoms.36 Longer- Functional electrical stimulation may runner’s dystonia. t term treatment and outcome information be another option in conjunction with of this latter case was not reported, yet sensorimotor and medical management imagery based on a sensory trick may be of dystonia, yet only 1 case has been pre- REFERENCES an effective short-term treatment as a sented using this treatment for lower 1. Altenmüller E, Jabusch HC. Focal dystonia in 3 component of the patient’s overall, lon- extremity dystonia. Further research is musicians: phenomenology, pathophysiology, ger-term management. needed to define the most effective strat- triggering factors, and treatment. 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