The Royal College of Physicians have published their updated National Clinical Guidelines for Stroke for the UK and Ireland. This replaces the 2016 edition and are accredited by NICE, SIGN and the Royal College of Physicians of Ireland.
The new guidelines have improved recommendations for rehabilitation, including a recommended 3 hours of therapy a day within the recovery stage. They also state that people with stroke should be considered to have the potential to benefit from rehabilitation at any point after their stroke. A greater emphasis is put on the need for intensity and repetition to maximise the benefit from therapeutic interventions. In support of this, the role of FES / NMES is recognised and its use is recommended in several areas, including shoulder subluxation pain, muscle weakness, retraining of movement and supporting walking. The exception is the use of NMES for control of spasticity, although it is recommended in conjunction with Botox or where splinting is insufficient.
Listed below are the relevant sections regarding FES / NMES. You can download the whole report for free at https://www.strokeguideline.org/
4.17 Motor impairment
People with stroke who are unable to exercise against gravity independently should be considered for adjuncts to exercise (such as neuromuscular or functional electrical stimulation), to support participation in exercise training. 
Electrical stimulation has been used as an adjunctive treatment for the upper limb for many years. The most common form is therapeutic or cyclical electrical stimulation (also known as neuromuscular electrical stimulation [NMES]) to the wrist and finger extensors, which stimulates the muscles to contract in order to improve weakness and reduce motor impairment. 
4.18 Arm function
People with wrist and finger weakness which limits function after stroke should be considered for functional electrical stimulation applied to the wrist and finger extensors, as an adjunct to conventional therapy. Stimulation protocols should be individualised to the person’s presentation and tolerance, and the person with stroke, their family/carers and clinicians in all settings should be trained in the safe application and use of electrical stimulation devices. 
4.21 Falls and fear of falling
People with stroke and limitations of dorsiflexion or ankle instability causing impaired balance and risk or fear of falling should be considered for referral to orthotics for an ankle-foot orthosis and/or functional electrical stimulation. The person with stroke, their family/carers and clinicians in all settings should be trained in the safe use and application of orthoses and electrical stimulation devices. 
People with stroke with limited ankle/foot stability or limited dorsiflexion (‘foot drop’) that impedes mobility or confidence should be offered an ankle-foot orthosis (using a lightweight, flexible orthosis in the first instance) or functional electrical stimulation to improve walking and balance, including referral to orthotics if required.
- Any orthosis or electrical stimulation device should be evaluated and individually fitted before long-term use.
- The person with stroke, their family/carers and clinicians in all settings should be trained in the safe application and use of orthoses and electrical stimulation devices.
- People using an orthosis after stroke should be educated about the risk of pressure damage from their orthosis, especially if sensory loss is present in addition to weakness. Services should provide timely access for orthotic repairs and adaptations. 
Stroke services should have local protocols and agreements in place to ensure specialist assessment, evaluation and follow-up is available for long-term functional electrical stimulation use. 
4.23.3 Shoulder subluxation and pain
People with inferior shoulder subluxation within 6 months of hemiplegic stroke should be considered for neuromuscular electrical stimulation, unless contraindicated. The stimulation protocol should be individualised to the person’s presentation and tolerance. The person with stroke, their family/carers and clinicians in all settings should be trained in the safe application and use of electrical stimulation devices. 
4.24 Spasticity and contractures
People with spasticity in the upper or lower limbs after stroke should not be treated with electrical stimulation to reduce spasticity. 
People with spasticity in their wrist or fingers who have been treated with botulinum toxin may be considered for electrical stimulation (cyclical/neuromuscular electrical stimulation) after the injection to maintain range of movement and/or to provide regular stretching as an adjunct to splinting or when splinting is not tolerated. 
People with dysphagia after stroke may be considered for neuromuscular electrical stimulation as an adjunct to behavioural rehabilitation where the device is available and it can be delivered by a trained healthcare professional.