Maryland Gov. Marvin Mandel, who has been hopitalized for a week, is apparently growing increasingly ill from an illness more serious than originally belived, a court appointed Harvard University neurologist testified today.

This grave assissment of the 56-year-old governor's health was given in U.S. District Court by Dr. Raymond Adams, who examined Mandel at prince George's General Hospital to help determine whether Mandel could stand trial on corruption charges this week as originally scheduled.

His testimony was vague and he would not answer reporters' questions afterwards. But he described the governor as a man who "is obviously getting mor and more ill." He raised, hypothetically, the possibility that Mandel could become completely paralyzed in his right inside and referred to Mandel's illness as "progressive."

Adams said he was "skeptical" of the previous diagnoses that Mandel may have suffered a stroke.

Other doctors who testified during today's hearings on Mandel's motion for a 2 1/2 month postpoenement of his trial, said that if the governor has not suffered a stroke, his symptoms may stem from an as yet undetected brain tumor or from a malignant tumor elsewhere in his body that has led to a secondary brain tumor.

While Adams, the Harvard neurologist who appeared in court this afternoon spoke guardedly, his testimony appeared striking for at least two reasons. First, he was the first court-selected medical specialist to examine Mandel. Second, he was the first to raise bluntly the prospect that the governor may be severely ill and could become paralyzed. Other specialists have appeared to stress the mildness and subtleness of Mandel's symptoms.

"It is my opinion that he is unwell," Adams told Judge Taylor. He suggested that the trial be delayed for two to three months. At one point, Adams graphically described Mandel as suffering from recurrent, severe headaches that cause him to hold his head in his hands.

U.S. Judge Robert L. Taylor did not rule formally today on whether there will be a substantial postponement in the retrial of Mandel and his five codefendants. Instead, he announced that the second neurologist whom he had chosen would examine Mandel Wednesday morning and testify at a hearing later in the day.The second specialist selected by Taylor is Dr. Stanley Appel, a neurology professor at Duk University.

He has already been examined by three doctors who testified at this morning's hearing - Dr. Perry Hookman, his family doctor; Dr. Marvin korengold, a clinical assistant meurology professor at George Washington University and Dr. George B. Udvarhelyi, a neurosurgery professor at Johns Hopkins Medical Center here.

The Mandel trial has already encountered three previous delays, most recently in December after two jury tampering incidents occurred. As a result, a mistrial was declared in th first proceeding.

Both Korengold and Udvarhelyi testified that Weiner's request for a 2 1/2 month delay largely represented an "arbitrary" suggestion for a reasonably recovery period. They said the time Mandel actually needs to recuperate may only become clear after further diagnostic tests and observation of his symptoms have taken place - a point that appeared to rouble the prosecutors.

While Udvarhelyi and Korengold both testifies that Mandel is clearly suffering from some disorder of the left side of his brain they said they could not with certainty identify the cause of the disorder, say when it began, or propose a specific treatment. More elaborate and prolonged testing is required, they said.

Part of the hearing resembled a laymen's course in neurology, as the doctors recounted some simple tests that showed Mandel's symptoms. Because the left side of a person's brain controls the right side of his body, Mandel's symptoms were described as appearing on his right side.

Korengold testified that Mandel could not tap his right foot in a steady rhythm. He repeatedly failed to grab his left thumb with his right hand when his eyes were closed, Korengold said. Mandel also, Korengold testified, frequently could not tell whether a single pointed object or two such objects were touching his right hand.

At today's hearing before the crusty, 77-year-old Tennessee judge in a softly illuminated, modern courtroom here, mine lawyers sat at the defense table, representing all six codefendants in the trial, though only one of them Arnold M. Weiner, Mandel's codefendants - W. Dale Hess and William A. Rodgers - also were present in the courtroom.