Alzheimer's: recovering executive skills by stimulating the spinal cord

A new clinical trial, carried out by researchers at the Fondazione Santa Lucia IRCCS and the University Federico II of Naples, has shown the benefits of supporting cognitive training in patients withmoderate Alzheimer's diseasewith Transpinal Direct Current Stimulation (TsDCS).

The study involved 16 people with Alzheimer's Disease with moderate-severe symptoms and cognitive difficulties in executive skills. The computerized cognitive treatment was administered in two experimental conditions: one during spinal cord stimulation (tsDCS), and a placebo condition in which stimulation was stopped after a few seconds and the patient continued cognitive training alone. In both conditions, treatment lasted 15 days, with one hour-long session per day.

The results showed greater recovery of executive abilities in patients in whom spinal cord stimulation actually occurred than in the placebo condition. This improvement persisted one month after the end of treatment and was also evidenced by neuropsychological testing in functions that had not been specifically targeted by treatment such as memory and attention.

The result was published in the Journal of Alzheimer's Disease by researchers at the Santa Lucia IRCCS Foundation's Laboratory of Aphasia Research in collaboration with the Laboratory of Memory Neuropsychology.

"The study starts from the theory of Embodied Cognition or 'embodied knowledge' now established in neuroscience. According to this perspective," explains Prof. Paola Marangolo, Head of the Aphasia Research Laboratory at the Santa Lucia IRCCS Foundation and Full Professor of Psychobiology, Physiological Psychology and Cognitive Neuroscience at the Federico II University, "there is a relationship between the cognitive system and the sensorimotor system: language, memory, attention, and executive functions are in part controlled by the motor system, as they are mediated by motor actions.

"My expertise as a neuroscientist," Marangolo says, "matured for years within the Federico II University of Naples, supported by the contribution of doctoral student Francesca Pisano, who belongs to the same University, has allowed us to elaborate a futuristic idea that could become revolutionary and open the way to new frontiers in neurorehabilitation. The spinal cord, in fact, is a structure very rich in nerve fibers that send information to different parts of the cortex: spinal cord stimulation would therefore solve the problem of having to decide a priori which part of the brain should be directly stimulated. Moreover, unlike cortical stimulation, being easy to apply, it would allow the patient to simultaneously perform cognitive exercises without the hindrance of electrodes applied to the head."

"Finally," Marangolo concludes, "given the breadth of lesions that are often found in the brain both in people with neurodegenerative diseases such as Alzheimer's and in stroke victims, spinal cord stimulation could represent a new avenue of access to cognitive recovery. Indeed, transcranial direct current stimulation (tDCS) allows to interfere with neuronal activity by modulating the excitability of the cortex, thus reinforcing ongoing cognitive processing. Moreover, the possibility of extending the application of tDCS to the spinal cord for the recovery of cognitive functions finally allows us to consider the central nervous system as a network that works synergistically through the contribution of its different structures. In the future, we may then consider the spinal cord as a fast track for cognitive recovery. By stimulating the nervous system from the spinal cord, given its rich connections with the cortex, the current would simultaneously reach multiple cortical regions spared by brain damage enhancing recovery."

In 2017, the same research team had shown that in stroke patients, stimulation of the spinal cord resulted in improved speech, with a study published in Frontiers of Neurology.