Helping patients regain the power of speech

Communication is a key piece of the human experience. When that ability is lost or altered by conditions like stroke, primary progressive aphasia, or amyotrophic lateral sclerosis (ALS), it affects every facet of one’s life. Too often, support lies just out of reach.

“Many individuals with communication difficulties struggle to have their voices heard and their needs recognized,” said Leslie Vnenchak, MA, CCC-SLP, a speech-language pathologist at Penn Medicine’s ALS Center and chief of clinical research operations at the Laboratory for Cognition and Neural Stimulation (LCNS).

Communication difficulties are common with neurodegenerative diseases such as Parkinson’s, Huntington’s, and ALS, that affect the muscles involved in speaking. Speech and language interventions are also an important component of therapy for patients with aphasia, a group of neurological language disorders that affect the ability to use or understand spoken or written language. Aphasia is a common complication of stroke.

For many people who have experienced a stroke, aphasia is more challenging than physical impairments, said Roy Hamilton, MD, MS, a professor of Neurology, Psychiatry, and Physical Medicine & Rehabilitation, director of the LCNS, and director of the Penn Brain Science, Translation, Innovation, and Modulation (brainSTIM) Center. “There are lots of ways to accommodate weakness or paralysis, but it’s very hard to accommodate a person who can’t communicate. That need drives our sense of urgency for improving aphasia care,” he said.

Across Penn Medicine, providers use every available tool to help patients communicate, from established, evidence-based speech therapy to new speech-generating devices that clone a patient’s natural speaking voice. Speech pathologists are embedded in the specialized multidisciplinary centers at Pennsylvania Hospital that support patients with Parkinson’s, Huntington’s, and ALS. Penn Medicine researchers are also developing innovative new treatments, such as non-invasive brain stimulation tools to treat aphasia. This year, Vnenchak and Hamilton are launching a new aphasia clinic at Pennsylvania Hospital to help more people regain the power of speech.

Communication problems can vary among different neurodegenerative diseases. Parkinson’s disease patients, for example, often develop soft, mumbled speech. Individuals with Huntington’s disease can develop slurred speech peppered with pauses and sudden bursts of words that make it difficult for others to understand. As ALS progresses, it attacks nerves that deliver messages between the brain and the muscles used to generate speech.

Speech pathologists can help patients develop strategies for communicating—including ways to use their voice as long as possible, and the use of assistive devices as their diseases progress.

Those supports can look quite different from person to person. “The approach to the treatment of communication is very person-specific, and requires a thorough, detailed evaluation,” Vnenchak said.

And high-tech isn’t always better. Small, portable LCD writing tablets are surprisingly helpful for many patients, said Colin Quinn, MD, an associate professor of Clinical Neurology and director of the Penn Comprehensive ALS Center.

Yet there is an ever-expanding array of more advanced options available, depending on patients’ preferences and the stage of their illness. As ALS worsens, people lose the ability to control their limbs. Using eye-gaze devices, they can operate computers or speech-generation devices through eye movements alone. Voice preservation and voice cloning allow those speech-generation devices to “talk” using the patient’s natural voice. To create those systems, patients in the ALS clinic are offered the opportunity to bank their voices, making a series of recordings while their ability to speak remains intact. Another option is voice cloning, which draws on preexisting recordings to generate a computer-generated voice that mimics the patient’s natural voice.

“Communicating through a speech-generating device, using a synthesized version of their own voice, can help individuals preserve their sense of identity—fostering comfort, connection, and joy for both them and their loved ones,” Vnenchak said.

Brain-computer interfaces may be the next step in assisted communication. These experimental systems enable people to control a device such as a computer or robotic limb with their thoughts, via implanted or wearable devices that measure brain signals. While it sounds like science fiction, the technology has advanced significantly in just the last five years, Quinn said.

“We’re getting much closer to brain-computer interfaces becoming available to people,” he added. “I think they are coming, and I think they will be an important part of communication for some people living with ALS.”

For those with aphasia due to stroke or brain injury, however, assistive devices may be a bridge toward the possibility of recovering some lost language. Evidence-based speech therapy interventions can help, but there is room for improvement.

“Between 20 and 40 percent of people who have a stroke are going to have some form of communication deficit afterwards. Although some recovery is typical, the lion’s share of people will not get back to a place where they’re able to functionally communicate in a way that allows them to return to work or pursue many of their instrumental activities of daily living,” Hamilton said.

Given the stakes, and how common stroke is, better aphasia treatments are sorely needed, he added. Yet standard therapies don’t take advantage of everything researchers have learned about brain circuitry—at least, not yet. Hamilton intends to change that through work at the LCNS and the aphasia clinic.

After a stroke, a person with aphasia experiences dramatic changes in the brain. When a neurotypical person performs language-related tasks, the left hemisphere of their brain becomes active. A person with stroke-related aphasia shows activation in both sides of the brain. But it’s not clear whether that difference is the root of their problems, or evidence of the brain’s attempt to compensate for damage to language networks. “We’ve known for a long time that [in people with aphasia], the brain system for representing language changes, but we don’t understand what those changes mean,” Hamilton said.

Neuromodulation devices, which directly stimulate brain circuits, may help answer those questions. Hamilton and his colleagues are exploring the use of transcranial magnetic stimulation (TMS), a non-invasive form of neuromodulation that applies targeted magnetic pulses to the scalp. Using TMS to stimulate brain areas within reorganized language networks, Hamilton and his colleagues have located at least one area that seems to be related to ongoing language difficulties—and that may represent a potential treatment target.

The team is leading multiple clinical trials exploring how neuromodulation could improve aphasia treatment. One study uses transcranial direct current stimulation (tDCS) to treat primary progressive aphasia, a rare neurodegenerative disease that affects areas of the brain related to speech and language. Another combines TMS with standard speech and language therapy in the early weeks after a stroke. “We hope non-invasive brain stimulation can enhance the evidence-based interventions that are already being done in the clinic,” Vnenchak said.

The aphasia clinic will offer patients with aphasia the opportunity to participate in such research, while also streamlining their care. Initially, the team will offer tDCS—a low-risk intervention already considered a viable treatment option by the National Aphasia Association—with plans to add TMS in the future.

The program is a natural fit for Pennsylvania Hospital, with its deep expertise in brain stimulation, Hamilton said. His research team continues to study the language networks affected by aphasia. They’re also developing machine learning models that predict what a given patient’s aphasia will look like and how best to treat it. By targeting the brain directly, their efforts could set a new standard for treating cognitive impairments after a stroke—and in the process, provide new options for millions of people living with aphasia worldwide. “It’s an enormous unmet need,” Hamilton said.