Symptoms and Progression in FTD-ALS

When frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) occur together, the symptoms are not just a simple addition of two diseases. Instead, they create a unique pattern of change that affects how a person moves, speaks, and processes information ^[1][2]. Understanding this progression is key to anticipating the care your loved one will need.

The Shift in Personality and Behavior

While people with “pure” FTD often show impulsive or socially inappropriate behavior (disinhibition), those with the combined FTD-ALS diagnosis are more likely to experience a profound loss of initiative, known as apathy ^[3][4].

Apathy in FTD-ALS often presents as:

• Loss of “Get Up and Go”: The person may sit for hours without starting an activity or conversation, even if they are physically able to do so ^[4].
• Reduced Emotional Warmth: They may seem less responsive to family news or emotional events, which is a result of the disease affecting the brain’s emotional processing centers ^[3].
• Executive Dysfunction: Difficulty with complex tasks, like planning a meal or managing finances, often appears early ^[3].

Language and Communication Challenges

Language impairment is extremely common in FTD-ALS. In some study cohorts, nearly 90% of patients showed language impairments ^[1]. This is often more than just “forgetting words.” It is important to distinguish between aphasia (a language processing issue in the brain) and dysarthria (impaired speech motor control due to muscle weakness).

• Syntactic Comprehension (Aphasia): One of the most distinct signs is difficulty understanding the “logic” of a sentence ^[5]. For example, a patient might struggle to understand “The boy was chased by the dog,” even if they know what “boy,” “dog,” and “chase” mean ^[5].
• Anomia (Aphasia): This is the classic “tip of the tongue” feeling where a person cannot find the name for common objects ^[1].
• Agrammatism (Aphasia): Speech may become “telegraphic,” leaving out small words like “the,” “and,” or “is” ^[2].

Motor Symptoms: The Physical Connection

Because ALS affects the motor neurons (the nerves that control muscles), physical changes will eventually emerge. If your loved one started with FTD symptoms, motor signs may appear later; one study found a median interval of 12 to 24 months, though this interval varies substantially from person to person ^[6].

• Upper Motor Neuron (UMN) Signs: These occur when the brain cannot send clear signals to the spinal cord. Signs include spasticity (muscle stiffness), unusually brisk reflexes, and a general “clumsiness” ^[7][8].
• Lower Motor Neuron (LMN) Signs: These occur when the nerves connecting the spinal cord to the muscles fail. You may see muscle atrophy (wasting away), weakness, and fasciculations—small, involuntary muscle twitches that look like “rippling” under the skin ^[8].

Bulbar Symptoms: Speech and Swallowing

The “bulbar” region refers to the muscles controlled by the brainstem, which are used for speaking, swallowing, and managing saliva.

• Dysarthria: Speech may become slow, slurred, or “labored,” often described as sounding like the person has a “thick tongue” ^[9].
• Dysphagia: Difficulty swallowing can lead to coughing or choking during meals ^[7].
• Sialorrhea: This is the medical term for excessive drooling or difficulty managing saliva, which happens when swallowing becomes less frequent or efficient ^[10].

Tracking the Progression

The progression of FTD-ALS is generally faster than either “pure” FTD or “pure” ALS ^[11]. On average, when the disease begins with motor symptoms, the progression may be quicker than when it begins with cognitive changes, though every person’s journey is different ^[12].

Doctors often use the ECAS (Edinburgh Cognitive and Behavioural ALS Screen) to track these changes. The frequency of testing should be individualized based on symptoms, communication ability, and clinic practice ^[13]. Because the physical symptoms of ALS can make traditional memory tests difficult (for example, if a patient cannot write or speak clearly), the ECAS is specifically designed to be “communication-sensitive,” ensuring that the doctor is measuring the patient’s thinking, not just their physical ability to respond ^[14][15]. Monitoring these changes helps your care team adjust support strategies before a crisis occurs ^[11].

Urgent Warning Signs Checklist:

• Call 911 / Emergency Services Now: Inability to breathe, speak, or cough; cyanosis (turning blue/gray); sudden severe breathlessness; a severe choking episode with ongoing respiratory symptoms.
• Call the Care Team Soon (Same-Day): New wet voice, gradual prolonged meals, increasing coughing during meals, or new swallowing changes.