Table 2

Clinical examination of patients with NIID

TotalClinical phenotype
Dementia-dominant typeMovement disorder -dominant typeMuscle weakness-dominant typeParoxysmal symptom-dominant type
Brain MRI
 DWI U-fibre high signal190/212 (89.6%)77/82 (93.9%)51/59 (86.4%)6/12 (50.0%)56/59 (94.9%)
 Severe leukoencephalopathy177/213 (83.1%)75/82 (91.5%)46/57 (80.7%)6/15 (40.0%)50/59 (84.7%)
 Peripheral neurophysiological study101/110 (91.8%)33/38 (86.8%)25/28 (89.3%)18/18 (100.0%)25/26 (96.2%)
 Sensorimotor neuropathy84/110 (76.4%)31/38 (81.6%)21/28 (75.0%)15/18 (83.3%)17/26 (65.4%)
 Pure motor neuropathy16/110 (14.5%)2/38 (5.3%)4/28 (14.3%)3/18 (16.7%)7/26 (26.9%)
 Pure sensory neuropathy1/110 (0.9%)0/38 (0.0%)0/28 (0.0%)0/18 (0.0%)1/26 (3.8%)
 Normal9/110 (8.2%)5/38 (13.2%)3/28 (10.7%)0/18 (0.0%)1/26 (3.8%)
 Nerve conduction study100/110 (90.9%)33/38 (86.8%)25/28 (89.3%)17/18 (94.4%)25/26 (96.2%)
Motor
 MCV slowing98/110 (89.1%)33/38 (86.8%)24/28 (85.7%)17/18 (94.4%)24/26 (92.3%)
 CMAP reduction56/110 (50.9%)21/38 (55.3%)11/28 (39.3%)14/18 (77.8%)10/26 (38.5%)
Sensory
 SCV slowing83/110 (75.5%)31/38 (81.6%)20/28 (71.4%)14/18 (77.8%)18/26 (69.2%)
 SNAP reduction51/110 (45.9%)16/38 (42.1%)12/28 (42.9%)15/18 (83.3%)8/26 (30.8%)
Needle EMG study
 Neurogenic damage48/69 (69.6%)12/20 (60.0%)13/19 (68.4%)17/17 (100.0%)6/13 (46.2%)
 Myogenic damage1/69 (1.4%)0/20 (0.0%)1/19 (5.3%)0/17 (0.0%)0/13 (0.0%)
 Normal20/69 (29.0%)8/20 (40.0%)5/19 (26.3%)0/17 (0.0%)7/13 (53.8%)
Positive skin biopsy118/122 (96.7%)42/44 (95.5%)35/36 (97.2%)10/10 (100%)31/32 (96.7%)
GGC repeat sizes, median (IQR)120 (103.00–143.00)118.5 (103.00–135.00)120.5 (99.50–142.50)155 (108.00–253.00)123 (105.75–141.00)
  • CMAP, compound muscle action potential; DWI, diffusion-weighted imaging; EMG, electromyography; MCV, motor nerve conduction velocity; NIID, neuronal intranuclear inclusion disease; SCV, sensory nerve conduction velocity; SNAP, sensory nerve action potential .