Neurological Signs in Muscular Dystrophy

1. Duchenne Muscular Dystrophy (DMD)

• Progressive proximal muscle weakness beginning in early childhood (pelvic girdle first, then shoulder girdle)
• Gowers' sign: uses hands to climb up the thighs when rising from the floor — a hallmark sign of proximal lower-limb weakness
• Waddling gait with wide base of support; lumbar lordosis; toe-walking (equinovarus from calf contractures)
• Pseudohypertrophy of calves — firm, rubbery feel; the muscle is weak despite its bulk
• Muscle fasciculations are absent (distinguishes from spinal muscular atrophy)

• Tendon reflexes are progressively diminished, then lost as muscle fibers disappear; the ankle reflexes are the last to go

• Non-progressive cognitive impairment in a significant proportion; average IQ ~85; ~25% have IQ <70 (range 40–130)
• Cognitive involvement is not progressive — it is a static developmental feature related to dystrophin's role in CNS synaptic function

• Cardiomyopathy with arrhythmias (prominent R waves in right precordial leads, deep Q waves in left); smooth muscle is spared

• EMG: fibrillations, positive sharp waves, short-duration low-amplitude polyphasic motor unit potentials, ± high-frequency discharges (myopathic pattern)
• Nerve conduction velocities are normal (unlike merosinopathy)

— Adams and Victor's Principles of Neurology, 12th Ed., p. 1403

2. Becker Muscular Dystrophy (BMD)

• Similar pattern to DMD but milder and later onset
• Reduced (but not absent) dystrophin
• Cognitive impairment is less common/severe
• Tendon reflexes preserved longer; ambulation often maintained into adulthood

— Adams and Victor's Principles of Neurology, 12th Ed.

3. Myotonic Dystrophy (DM1/DM2)

• Myotonia — inability to relax muscle after contraction (grip myotonia, percussion myotonia)
• Distal weakness and wasting (hands, forearms, anterior tibial muscles) — distinguishes it from other dystrophies which are predominantly proximal
• Ptosis, facial diplegia, temporalis wasting ("hatchet face")
• Dysarthria and dysphagia (pharyngeal and palatal weakness)
• Reduced or absent tendon reflexes

• Cognitive impairment and intellectual disability, particularly in congenital DM1
• Hypersomnia and excessive daytime sleepiness (CNS involvement beyond muscle)
• Apathy, personality changes
• White-matter abnormalities on MRI

• Cardiac conduction defects (AV block, sudden death risk)
• Cataracts, endocrine dysfunction

— Bradley and Daroff's Neurology in Clinical Practice; Adams and Victor's

4. Emery-Dreifuss Muscular Dystrophy (EDMD)

• Scapuloperoneal or humeroperoneal weakness pattern
• Early, prominent contractures of elbow flexors, neck extensors, and posterior calf — often before significant weakness
• Facial muscles occasionally involved
• Cognition is unaffected (important distinguishing feature)
• No pseudohypertrophy
• Severe cardiac conduction defects (sinoatrial and AV block) — risk of sudden cardiac death; pacemaker often required

— Adams and Victor's Principles of Neurology, 12th Ed.

5. Facioscapulohumeral Dystrophy (FSHD)

• Facial weakness (bifacial): inability to close eyes fully, whistle, or smile symmetrically
• Scapular winging, difficulty raising arms above head
• Hearing loss (sensorineural) and retinal vascular abnormalities in some
• Occasional mild cognitive involvement reported in early-onset severe forms
• Tendon reflexes reduced in affected muscle groups
• Generally no CNS involvement

— Adams and Victor's Principles of Neurology, 12th Ed.

6. Congenital Muscular Dystrophies (MDC)

• Severe hypotonia and weakness from birth
• Epilepsy in 12–20%
• White-matter abnormalities on MRI (brain CT/MRI hallmark)
• Slowed nerve conduction velocities (laminin-α2 is also expressed in peripheral nerve)
• Intelligence often normal, but severely physically disabled

• Severe intellectual disability
• Lissencephaly/pachygyria, cerebellar malformations
• Retinal dysplasia
• Hydrocephalus

— Bradley and Daroff's Neurology in Clinical Practice

7. Oculopharyngeal Muscular Dystrophy (OPMD)

• Progressive ptosis (first sign, onset age 40–60)
• Dysphagia from oropharyngeal weakness (reduced pharyngeal constriction, aspiration risk)
• Proximal limb weakness
• Impaired cognitive function has been described
• Postural compensation: raised eyebrows, extended neck due to ptosis

— Bradley and Daroff's Neurology in Clinical Practice

Summary Table