Electrical Stimulation for Recovery of Ankle Dorsiflexion in Chronic Stroke Survivors

• Ankle Movement Tracking Error. The subject's task is to try to keep a computer cursor on or as close to a scrolling trace as possible by voluntarily dorsiflexing the ankle. Three to six trials will be administered after a practice trial. [ Time Frame: Pre-treatment, End of treatment, 4-wks & 12-wks Post-treatment. ] [ Designated as safety issue: No ]
• Maximum Voluntary Ankle Dorsiflexion Isometric Moment. Isometric ankle dorsiflexion moment will be measured. Three isometric moment trials will be averaged. [ Time Frame: Pre-treatment, End of treatment, 4-wks & 12-wks Post-treatment. ] [ Designated as safety issue: No ]
• Fugl-Meyer Lower Extremity Motor Assessment. In the lower limb motor impairment component of the Fugl-Meyer Assessment (FMA), the subject is asked to make various isolated and simultaneous movements of the hip, knee, and ankle. [ Time Frame: Pre-treatment, End of treatment, 4-wks & 12-wks Post-treatment. ] [ Designated as safety issue: No ]
• Quantitative Gait Analysis. Gait kinematics and spatio-temporal gait parameters will be assessed using a motion capture and analysis system. [ Time Frame: Pre-treatment, End of treatment, 4-wks & 12-wks Post-treatment. ] [ Designated as safety issue: No ]
• Modified Emory Functional Ambulation Profile (MEFAP). The MEFAP is a measure of functional ambulation, measuring the time to ambulate through 5 common environmental terrains. [ Time Frame: Pre-treatment, End of treatment, 4-wks & 12-wks Post-treatment. ] [ Designated as safety issue: No ]
• Questionnaire. A questionnaire will be administered to assess the participants' impression of the intervention's dose and ease of using the device, as well as of their ability to dorsiflex their ankle and of any effect on their walking. [ Time Frame: Pre-treatment, End of treatment, 4-wks & 12-wks Post-treatment. ] [ Designated as safety issue: No ]

Ankle dorsiflexor weakness (paresis) is one of the most frequently persisting consequences of stroke. The purpose of this exploratory study is to compare two different treatments -- Contralaterally Controlled Neuromuscular Electrical Stimulation (CCNMES) and Cyclic Neuromuscular Electrical Stimulation (cNMES) -- for improved recovery of ankle movement and better walking after stroke.

Ankle dorsiflexor weakness results in inefficient and unstable gait. While routine physical therapy is beneficial, for many individuals it remains limited in its effectiveness, and consequently many stroke survivors have difficulty walking safely or remain non-ambulatory. Ankle-foot-orthoses (AFOs) are often prescribed to provide ankle stability, but because they limit ankle mobility they may actually inhibit recovery of dorsiflexion. Advanced rehabilitation techniques that emphasize active, repetitive, goal-oriented movement of the impaired limb have produced measurable functional improvements, yet a significant degree of lower extremity disability often remains. In addition, some of these emerging therapies are difficult to administer and are applicable only to patients who retain at least some degree of ambulation. Thus, there is a need for alternative treatments.

This is an exploratory study of an innovative neuromuscular electrical stimulation (NMES) treatment for restoring lower extremity motor control following stroke. We will investigate whether stroke survivors with chronic footdrop recover voluntary ankle dorsiflexion after a novel treatment of NMES. Surface electrodes will deliver stimulation to dorsiflex the ankle with an intensity that is proportional to the amount of dorsiflexion of the other unimpaired ankle. Thus, voluntary dorsiflexion of the unaffected ankle produces stimulated dorsiflexion of the affected ankle. We refer to this stimulation paradigm as Contralaterally Controlled Neuromuscular Electrical Stimulation (CCNMES). In contrast to existing peroneal nerve stimulators, CCNMES is not intended to be used to assist ambulation; rather it is intended as solely a motor retraining paradigm that may reduce lower extremity impairment and improve ambulation. The primary objective of the proposed study is to obtain pilot data so that an estimate can be made of the efficacy of CCNMES in reducing lower extremity impairment and improving ambulation.

Twenty-six chronic stroke survivors (>6 months post-stroke) will be randomized to either CCNMES or cyclic NMES, an intervention that provides electrical stimulation of the ankle dorsiflexors, but with preprogrammed timing and intensity. For both groups, the treatment will last 6 weeks followed by a 3-month follow-up period. Assessments of ankle impairment and ambulation will be made at baseline, post-treatment, and 1-month and 3-months post-treatment.

This study is the first randomized controlled trial of CCNMES for restoring ankle dorsiflexion in patients with chronic hemiplegia.

• Stroke
• Hemiparesis
• Lower Extremity Paresis

• Experimental: CCNMES
  Contralaterally Controlled Neuromuscular Electrical Stimulation
  Intervention: Device: Electrical stimulator
• Active Comparator: Cyclic NMES
  Cyclic Neuromuscular Electrical Stimulation
  Intervention: Device: Electrical stimulator

• Nudo RJ, Wise BM, SiFuentes F, Milliken GW. Neural substrates for the effects of rehabilitative training on motor recovery after ischemic infarct. Science. 1996 Jun 21;272(5269):1791-4.
• Luft AR, McCombe-Waller S, Whitall J, Forrester LW, Macko R, Sorkin JD, Schulz JB, Goldberg AP, Hanley DF. Repetitive bilateral arm training and motor cortex activation in chronic stroke: a randomized controlled trial. JAMA. 2004 Oct 20;292(15):1853-61. Erratum in: JAMA. 2004 Nov 24;292(20):2470.
• Robbins SM, Houghton PE, Woodbury MG, Brown JL. The therapeutic effect of functional and transcutaneous electric stimulation on improving gait speed in stroke patients: a meta-analysis. Arch Phys Med Rehabil. 2006 Jun;87(6):853-9.
• Rushton DN. Functional electrical stimulation and rehabilitation--an hypothesis. Med Eng Phys. 2003 Jan;25(1):75-8.
• Khaslavskaia S, Sinkjaer T. Motor cortex excitability following repetitive electrical stimulation of the common peroneal nerve depends on the voluntary drive. Exp Brain Res. 2005 May;162(4):497-502. Epub 2005 Feb 9.
• Knutson JS, Harley MY, Hisel TZ, Chae J. Improving hand function in stroke survivors: a pilot study of contralaterally controlled functional electric stimulation in chronic hemiplegia. Arch Phys Med Rehabil. 2007 Apr;88(4):513-20.
• Knutson JS, Hisel TZ, Harley MY, Chae J. A novel functional electrical stimulation treatment for recovery of hand function in hemiplegia: 12-week pilot study. Neurorehabil Neural Repair. 2009 Jan;23(1):17-25. Epub 2008 Sep 23.
• Sheffler LR, Hennessey MT, Naples GG, Chae J. Peroneal nerve stimulation versus an ankle foot orthosis for correction of footdrop in stroke: impact on functional ambulation. Neurorehabil Neural Repair. 2006 Sep;20(3):355-60.

Inclusion Criteria:

• Age 21 to 80 years
• >6 months from a first clinical non-hemorrhagic or hemorrhagic stroke
• Medically stable
• Unilateral lower extremity hemiparesis
• Ankle dorsiflexor strength of ≤4/5 on the MRC scale, while seated
• Able to ambulate 16 feet (5 meters) continuously with minimal assistance or less, without the use of an AFO.
• AFO is clinically indicated (footdrop during ambulation or inefficient gait patterns)
• NMES of the paretic ankle dorsiflexors produces ankle dorsiflexion to neutral without pain.
• Full voluntary dorsiflexion of the contralateral ankle
• Skin intact on hemiparetic lower extremity
• Able to don the NMES system or caregiver available to assist with device if needed.
• Able to hear and respond to stimulator auditory cues
• Able to follow 3-stage commands
• Able to recall 2 of 3 items after 30 minutes

Exclusion Criteria:

• Brainstem stroke
• Severely impaired cognition and communication
• History of peroneal nerve injury
• History of Parkinson's, SCI, TBI, or multiple sclerosis
• Uncontrolled seizure disorder
• Uncompensated hemi-neglect (extinguishing to double simultaneous stimulation)
• Edema of the affected lower extremity
• Absent sensation of lower leg and foot
• Evidence of deep venous thrombosis or thromboembolism
• History of cardiac arrhythmias with hemodynamic instability
• Cardiac pacemaker or other implanted electronic system
• Botulinum toxin injections to any lower extremity muscle in the last 3 months
• Pregnancy
• Currently receiving Physical Therapy for the lower extremity