Table 1.

Balance impairment in neurological disorders.

	Disease Definition	Nervous Structures Involved	Pathophysiological Mechanisms	Main Clinical Consequence
Alzheimer’s disease	Neurodegenerative dementia associated with progressive cognitive and functional dysfunction [27]	Cerebral cortex and subcortical structures, prominently involving nucleus accumbens and putamen [28]	Cognitive impairment, abnormal sensorimotor function and vision, peripheral sensory loss, muscle weakness [29,30,31,32]	Hallucinations, inattention, abnormal sensory reweighting
Parkinson’s disease	Neurodegenerative movement disorder associated with progressive motor and cognitive dysfunction [33]	Basal ganglia, locus coeruleus and pedunculopontine nucleus [34]	Impaired scaling of postural responses [35], abnormal central proprioceptive-motor integration [36], reduced kinaesthesia [37], axial rigidity [38], cognitive dysfunction [39]	Postural instability, disrupted trunk-legs coordination, freezing of gait
Multiple sclerosis	Acquired demyelinating disease of the central nervous system [40]	Cortico-spinal tract, cerebellum, proprioceptive pathways, vestibular system, brainstem structures for eye movement control [41]	Abnormal sensorimotor, visual, cerebellar, vestibular and cognitive functions [41], muscle weakness and spasticity [42]	Abnormal coordination and sensory reweighting, reduced attentional resources, strength impairment
Huntington’s disease	Neurodegenerative disease with autosomal dominant pattern of inheritance [43], associated with cognitive and motor impairment, psychiatric disorders and involuntary movements (chorea) [44]	Basal ganglia, prominently interesting caudate and putamen [45]	Involuntary movements, trunk muscles weakness, hip flexor tightness, impairment in visual and vestibular integration, ocular pursuit movements and proprioception [46]	Chorea, abnormal sensory reweighting, increased stride variability
Cerebellar ataxia	Acquired or hereditary, as well as acute or progressive, disorder associated with dysfunction of cerebellum and/or its connections [47]	Cerebellum (primarily vermis and anterior lobe) and/or its connections, including spinocerebellar tracts [47]	Impaired coordination of movements	Axial motor impairment and asynergic movement
Stroke	Acute neurologic syndrome due to the interruption of blood supply to a part of the central nervous system by an ischemic or haemorrhagic vascular injury [48]	Cortico-spinal tract, cerebellum, proprioceptive pathways, vestibular system and brainstem structures [49]	Somatosensory and motor dysfunction [50,51], spasticity [52], visual and perceptual disorders [53,54], including impaired perception of upright body position, cognitive impairment [55]	Hemispatial neglect, strength impairment, abnormal coordination, sensory reweighting
Traumatic brain injury	Acute blunt head traumas or acceleration forces to the head [56]	Vestibular nuclei, cerebellar peduncles, medial lemniscus, dentato-rubro-thalamic and cortico-reticular pathways [57]	Impairment in cognitive and motor functionality [58]	Dizziness, visual-spatial deficits and inattention
Neuropathies	Acute or progressive disorders of the peripheral nervous system, associate with the disruption of nerve action potentials transmission [59]	Peripheral nervous system (nerves)	Sensory and/or motor impairment [59], retinopathy, vestibular and muscle impairment [60], sensory ataxia	Proprioception and strength impairment
Vestibular syndromes	Acute or chronic disorders of the inner-ear balance organs and/or their nervous structures [61] (e.g., Meniere’s disease, benign positional vertigo, bilateral vestibular loss, vestibular neuritis, posterior circulation strokes)	Vestibular system (i.e., inner-ear balance organs, vestibular nerve and central nuclei)	Abnormal spatial orientation and motion perception [62], ataxia, eye movement abnormalities [61]	Dizziness and vertigo